From 7dada20c04975f4460abd9b99e77e39bef0b376c Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Sat, 3 Aug 2019 01:59:33 +0200
Subject: [PATCH 01/68] Upgrade to Elixir 1.8

---
 mix.exs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mix.exs b/mix.exs
index dcc1c3d..c73cb6f 100755
--- a/mix.exs
+++ b/mix.exs
@@ -5,7 +5,7 @@ defmodule ExDgraph.MixProject do
     [
       app: :ex_dgraph,
       version: "0.2.0-beta.3",
-      elixir: "~> 1.6",
+      elixir: "~> 1.8",
       start_permanent: Mix.env() == :prod,
       deps: deps(),
       description: description(),

From 64ab24b8c5271626f35b4fb3a3bd76ff37de3cea Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Sat, 3 Aug 2019 02:04:28 +0200
Subject: [PATCH 02/68] Update api.ex

---
 lib/exdgraph/api.ex | 224 ++++++++++++++++++++++++++++----------------
 1 file changed, 141 insertions(+), 83 deletions(-)

diff --git a/lib/exdgraph/api.ex b/lib/exdgraph/api.ex
index 37416e3..2d0d553 100755
--- a/lib/exdgraph/api.ex
+++ b/lib/exdgraph/api.ex
@@ -1,4 +1,6 @@
-defmodule ExDgraph.Api.Request do
+alias ExDgraph.Api
+
+defmodule Api.Request do
   @moduledoc false
   use Protobuf, syntax: :proto3
 
@@ -6,17 +8,21 @@ defmodule ExDgraph.Api.Request do
           query: String.t(),
           vars: %{String.t() => String.t()},
           start_ts: non_neg_integer,
-          lin_read: ExDgraph.Api.LinRead.t()
+          lin_read: Api.LinRead.t() | nil,
+          read_only: boolean,
+          best_effort: boolean
         }
-  defstruct [:query, :vars, :start_ts, :lin_read]
+  defstruct [:query, :vars, :start_ts, :lin_read, :read_only, :best_effort]
 
   field(:query, 1, type: :string)
-  field(:vars, 2, repeated: true, type: ExDgraph.Api.Request.VarsEntry, map: true)
+  field(:vars, 2, repeated: true, type: Api.Request.VarsEntry, map: true)
   field(:start_ts, 13, type: :uint64)
-  field(:lin_read, 14, type: ExDgraph.Api.LinRead)
+  field(:lin_read, 14, type: Api.LinRead)
+  field(:read_only, 15, type: :bool)
+  field(:best_effort, 16, type: :bool)
 end
 
-defmodule ExDgraph.Api.Request.VarsEntry do
+defmodule Api.Request.VarsEntry do
   @moduledoc false
   use Protobuf, map: true, syntax: :proto3
 
@@ -30,41 +36,41 @@ defmodule ExDgraph.Api.Request.VarsEntry do
   field(:value, 2, type: :string)
 end
 
-defmodule ExDgraph.Api.Response do
+defmodule Api.Response do
   @moduledoc false
   use Protobuf, syntax: :proto3
 
   @type t :: %__MODULE__{
-          json: String.t(),
-          schema: [ExDgraph.Api.SchemaNode.t()],
-          txn: ExDgraph.Api.TxnContext.t(),
-          latency: ExDgraph.Api.Latency.t()
+          json: binary,
+          schema: [Api.SchemaNode.t()],
+          txn: Api.TxnContext.t() | nil,
+          latency: Api.Latency.t() | nil
         }
   defstruct [:json, :schema, :txn, :latency]
 
   field(:json, 1, type: :bytes)
-  field(:schema, 2, repeated: true, type: ExDgraph.Api.SchemaNode)
-  field(:txn, 3, type: ExDgraph.Api.TxnContext)
-  field(:latency, 12, type: ExDgraph.Api.Latency)
+  field(:schema, 2, repeated: true, type: Api.SchemaNode, deprecated: true)
+  field(:txn, 3, type: Api.TxnContext)
+  field(:latency, 12, type: Api.Latency)
 end
 
-defmodule ExDgraph.Api.Assigned do
+defmodule Api.Assigned do
   @moduledoc false
   use Protobuf, syntax: :proto3
 
   @type t :: %__MODULE__{
           uids: %{String.t() => String.t()},
-          context: ExDgraph.Api.TxnContext.t(),
-          latency: ExDgraph.Api.Latency.t()
+          context: Api.TxnContext.t() | nil,
+          latency: Api.Latency.t() | nil
         }
   defstruct [:uids, :context, :latency]
 
-  field(:uids, 1, repeated: true, type: ExDgraph.Api.Assigned.UidsEntry, map: true)
-  field(:context, 2, type: ExDgraph.Api.TxnContext)
-  field(:latency, 12, type: ExDgraph.Api.Latency)
+  field(:uids, 1, repeated: true, type: Api.Assigned.UidsEntry, map: true)
+  field(:context, 2, type: Api.TxnContext)
+  field(:latency, 12, type: Api.Latency)
 end
 
-defmodule ExDgraph.Api.Assigned.UidsEntry do
+defmodule Api.Assigned.UidsEntry do
   @moduledoc false
   use Protobuf, map: true, syntax: :proto3
 
@@ -78,17 +84,18 @@ defmodule ExDgraph.Api.Assigned.UidsEntry do
   field(:value, 2, type: :string)
 end
 
-defmodule ExDgraph.Api.Mutation do
+defmodule Api.Mutation do
   @moduledoc false
   use Protobuf, syntax: :proto3
 
   @type t :: %__MODULE__{
-          set_json: String.t(),
-          delete_json: String.t(),
-          set_nquads: String.t(),
-          del_nquads: String.t(),
-          set: [ExDgraph.Api.NQuad.t()],
-          del: [ExDgraph.Api.NQuad.t()],
+          set_json: binary,
+          delete_json: binary,
+          set_nquads: binary,
+          del_nquads: binary,
+          query: String.t(),
+          set: [Api.NQuad.t()],
+          del: [Api.NQuad.t()],
           start_ts: non_neg_integer,
           commit_now: boolean,
           ignore_index_conflict: boolean
@@ -98,6 +105,7 @@ defmodule ExDgraph.Api.Mutation do
     :delete_json,
     :set_nquads,
     :del_nquads,
+    :query,
     :set,
     :del,
     :start_ts,
@@ -109,56 +117,58 @@ defmodule ExDgraph.Api.Mutation do
   field(:delete_json, 2, type: :bytes)
   field(:set_nquads, 3, type: :bytes)
   field(:del_nquads, 4, type: :bytes)
-  field(:set, 10, repeated: true, type: ExDgraph.Api.NQuad)
-  field(:del, 11, repeated: true, type: ExDgraph.Api.NQuad)
+  field(:query, 5, type: :string)
+  field(:set, 10, repeated: true, type: Api.NQuad)
+  field(:del, 11, repeated: true, type: Api.NQuad)
   field(:start_ts, 13, type: :uint64)
   field(:commit_now, 14, type: :bool)
   field(:ignore_index_conflict, 15, type: :bool)
 end
 
-defmodule ExDgraph.Api.AssignedIds do
-  @moduledoc false
-  use Protobuf, syntax: :proto3
-
-  @type t :: %__MODULE__{
-          startId: non_neg_integer,
-          endId: non_neg_integer
-        }
-  defstruct [:startId, :endId]
-
-  field(:startId, 1, type: :uint64)
-  field(:endId, 2, type: :uint64)
-end
-
-defmodule ExDgraph.Api.Operation do
+defmodule Api.Operation do
   @moduledoc false
   use Protobuf, syntax: :proto3
 
   @type t :: %__MODULE__{
           schema: String.t(),
           drop_attr: String.t(),
-          drop_all: boolean
+          drop_all: boolean,
+          drop_op: atom | integer,
+          drop_value: String.t()
         }
-  defstruct [:schema, :drop_attr, :drop_all]
+  defstruct [:schema, :drop_attr, :drop_all, :drop_op, :drop_value]
 
   field(:schema, 1, type: :string)
   field(:drop_attr, 2, type: :string)
   field(:drop_all, 3, type: :bool)
+  field(:drop_op, 4, type: Api.Operation.DropOp, enum: true)
+  field(:drop_value, 5, type: :string)
 end
 
-defmodule ExDgraph.Api.Payload do
+defmodule Api.Operation.DropOp do
+  @moduledoc false
+  use Protobuf, enum: true, syntax: :proto3
+
+  field(:NONE, 0)
+  field(:ALL, 1)
+  field(:DATA, 2)
+  field(:ATTR, 3)
+  field(:TYPE, 4)
+end
+
+defmodule Api.Payload do
   @moduledoc false
   use Protobuf, syntax: :proto3
 
   @type t :: %__MODULE__{
-          Data: String.t()
+          Data: binary
         }
   defstruct [:Data]
 
   field(:Data, 1, type: :bytes)
 end
 
-defmodule ExDgraph.Api.TxnContext do
+defmodule Api.TxnContext do
   @moduledoc false
   use Protobuf, syntax: :proto3
 
@@ -167,25 +177,28 @@ defmodule ExDgraph.Api.TxnContext do
           commit_ts: non_neg_integer,
           aborted: boolean,
           keys: [String.t()],
-          lin_read: ExDgraph.Api.LinRead.t()
+          preds: [String.t()],
+          lin_read: Api.LinRead.t() | nil
         }
-  defstruct [:start_ts, :commit_ts, :aborted, :keys, :lin_read]
+  defstruct [:start_ts, :commit_ts, :aborted, :keys, :preds, :lin_read]
 
   field(:start_ts, 1, type: :uint64)
   field(:commit_ts, 2, type: :uint64)
   field(:aborted, 3, type: :bool)
   field(:keys, 4, repeated: true, type: :string)
-  field(:lin_read, 13, type: ExDgraph.Api.LinRead)
+  field(:preds, 5, repeated: true, type: :string)
+  field(:lin_read, 13, type: Api.LinRead)
 end
 
-defmodule ExDgraph.Api.Check do
+defmodule Api.Check do
   @moduledoc false
   use Protobuf, syntax: :proto3
 
+  @type t :: %__MODULE__{}
   defstruct []
 end
 
-defmodule ExDgraph.Api.Version do
+defmodule Api.Version do
   @moduledoc false
   use Protobuf, syntax: :proto3
 
@@ -197,19 +210,21 @@ defmodule ExDgraph.Api.Version do
   field(:tag, 1, type: :string)
 end
 
-defmodule ExDgraph.Api.LinRead do
+defmodule Api.LinRead do
   @moduledoc false
   use Protobuf, syntax: :proto3
 
   @type t :: %__MODULE__{
-          ids: %{non_neg_integer => non_neg_integer}
+          ids: %{non_neg_integer => non_neg_integer},
+          sequencing: atom | integer
         }
-  defstruct [:ids]
+  defstruct [:ids, :sequencing]
 
-  field(:ids, 1, repeated: true, type: ExDgraph.Api.LinRead.IdsEntry, map: true)
+  field(:ids, 1, repeated: true, type: Api.LinRead.IdsEntry, map: true)
+  field(:sequencing, 2, type: Api.LinRead.Sequencing, enum: true)
 end
 
-defmodule ExDgraph.Api.LinRead.IdsEntry do
+defmodule Api.LinRead.IdsEntry do
   @moduledoc false
   use Protobuf, map: true, syntax: :proto3
 
@@ -223,7 +238,15 @@ defmodule ExDgraph.Api.LinRead.IdsEntry do
   field(:value, 2, type: :uint64)
 end
 
-defmodule ExDgraph.Api.Latency do
+defmodule Api.LinRead.Sequencing do
+  @moduledoc false
+  use Protobuf, enum: true, syntax: :proto3
+
+  field(:CLIENT_SIDE, 0)
+  field(:SERVER_SIDE, 1)
+end
+
+defmodule Api.Latency do
   @moduledoc false
   use Protobuf, syntax: :proto3
 
@@ -239,7 +262,7 @@ defmodule ExDgraph.Api.Latency do
   field(:encoding_ns, 3, type: :uint64)
 end
 
-defmodule ExDgraph.Api.NQuad do
+defmodule Api.NQuad do
   @moduledoc false
   use Protobuf, syntax: :proto3
 
@@ -247,23 +270,23 @@ defmodule ExDgraph.Api.NQuad do
           subject: String.t(),
           predicate: String.t(),
           object_id: String.t(),
-          object_value: ExDgraph.Api.Value.t(),
+          object_value: Api.Value.t() | nil,
           label: String.t(),
           lang: String.t(),
-          facets: [ExDgraph.Api.Facet.t()]
+          facets: [Api.Facet.t()]
         }
   defstruct [:subject, :predicate, :object_id, :object_value, :label, :lang, :facets]
 
   field(:subject, 1, type: :string)
   field(:predicate, 2, type: :string)
   field(:object_id, 3, type: :string)
-  field(:object_value, 4, type: ExDgraph.Api.Value)
+  field(:object_value, 4, type: Api.Value)
   field(:label, 5, type: :string)
   field(:lang, 6, type: :string)
-  field(:facets, 7, repeated: true, type: ExDgraph.Api.Facet)
+  field(:facets, 7, repeated: true, type: Api.Facet)
 end
 
-defmodule ExDgraph.Api.Value do
+defmodule Api.Value do
   @moduledoc false
   use Protobuf, syntax: :proto3
 
@@ -286,14 +309,14 @@ defmodule ExDgraph.Api.Value do
   field(:uid_val, 11, type: :uint64, oneof: 0)
 end
 
-defmodule ExDgraph.Api.Facet do
+defmodule Api.Facet do
   @moduledoc false
   use Protobuf, syntax: :proto3
 
   @type t :: %__MODULE__{
           key: String.t(),
-          value: String.t(),
-          val_type: integer,
+          value: binary,
+          val_type: atom | integer,
           tokens: [String.t()],
           alias: String.t()
         }
@@ -301,12 +324,12 @@ defmodule ExDgraph.Api.Facet do
 
   field(:key, 1, type: :string)
   field(:value, 2, type: :bytes)
-  field(:val_type, 3, type: ExDgraph.Api.Facet.ValType, enum: true)
+  field(:val_type, 3, type: Api.Facet.ValType, enum: true)
   field(:tokens, 4, repeated: true, type: :string)
   field(:alias, 5, type: :string)
 end
 
-defmodule ExDgraph.Api.Facet.ValType do
+defmodule Api.Facet.ValType do
   @moduledoc false
   use Protobuf, enum: true, syntax: :proto3
 
@@ -317,7 +340,7 @@ defmodule ExDgraph.Api.Facet.ValType do
   field(:DATETIME, 4)
 end
 
-defmodule ExDgraph.Api.SchemaNode do
+defmodule Api.SchemaNode do
   @moduledoc false
   use Protobuf, syntax: :proto3
 
@@ -328,9 +351,11 @@ defmodule ExDgraph.Api.SchemaNode do
           tokenizer: [String.t()],
           reverse: boolean,
           count: boolean,
-          list: boolean
+          list: boolean,
+          upsert: boolean,
+          lang: boolean
         }
-  defstruct [:predicate, :type, :index, :tokenizer, :reverse, :count, :list]
+  defstruct [:predicate, :type, :index, :tokenizer, :reverse, :count, :list, :upsert, :lang]
 
   field(:predicate, 1, type: :string)
   field(:type, 2, type: :string)
@@ -339,20 +364,53 @@ defmodule ExDgraph.Api.SchemaNode do
   field(:reverse, 5, type: :bool)
   field(:count, 6, type: :bool)
   field(:list, 7, type: :bool)
+  field(:upsert, 8, type: :bool)
+  field(:lang, 9, type: :bool)
+end
+
+defmodule Api.LoginRequest do
+  @moduledoc false
+  use Protobuf, syntax: :proto3
+
+  @type t :: %__MODULE__{
+          userid: String.t(),
+          password: String.t(),
+          refresh_token: String.t()
+        }
+  defstruct [:userid, :password, :refresh_token]
+
+  field(:userid, 1, type: :string)
+  field(:password, 2, type: :string)
+  field(:refresh_token, 3, type: :string)
+end
+
+defmodule Api.Jwt do
+  @moduledoc false
+  use Protobuf, syntax: :proto3
+
+  @type t :: %__MODULE__{
+          access_jwt: String.t(),
+          refresh_jwt: String.t()
+        }
+  defstruct [:access_jwt, :refresh_jwt]
+
+  field(:access_jwt, 1, type: :string)
+  field(:refresh_jwt, 2, type: :string)
 end
 
-defmodule ExDgraph.Api.Dgraph.Service do
+defmodule Api.Dgraph.Service do
   @moduledoc false
   use GRPC.Service, name: "api.Dgraph"
 
-  rpc(:Query, ExDgraph.Api.Request, ExDgraph.Api.Response)
-  rpc(:Mutate, ExDgraph.Api.Mutation, ExDgraph.Api.Assigned)
-  rpc(:Alter, ExDgraph.Api.Operation, ExDgraph.Api.Payload)
-  rpc(:CommitOrAbort, ExDgraph.Api.TxnContext, ExDgraph.Api.TxnContext)
-  rpc(:CheckVersion, ExDgraph.Api.Check, ExDgraph.Api.Version)
+  rpc(:Login, Api.LoginRequest, Api.Response)
+  rpc(:Query, Api.Request, Api.Response)
+  rpc(:Mutate, Api.Mutation, Api.Assigned)
+  rpc(:Alter, Api.Operation, Api.Payload)
+  rpc(:CommitOrAbort, Api.TxnContext, Api.TxnContext)
+  rpc(:CheckVersion, Api.Check, Api.Version)
 end
 
-defmodule ExDgraph.Api.Dgraph.Stub do
+defmodule Api.Dgraph.Stub do
   @moduledoc false
-  use GRPC.Stub, service: ExDgraph.Api.Dgraph.Service
+  use GRPC.Stub, service: Api.Dgraph.Service
 end

From 84ee37d8dc7c63a15d36fe0dcbb3e52db3bcee59 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Sat, 3 Aug 2019 02:05:29 +0200
Subject: [PATCH 03/68] Upgrade to DBConnection 2.

---
 README.md                          |  7 +--
 config/dev.exs                     |  1 -
 config/test.exs                    |  1 -
 lib/exdgraph.ex                    | 32 +++---------
 lib/exdgraph/mutation.ex           | 51 +++++++++----------
 lib/exdgraph/mutation_statement.ex |  4 +-
 lib/exdgraph/operation.ex          | 11 +++--
 lib/exdgraph/protocol.ex           | 78 +++++++++++++++++++-----------
 lib/exdgraph/query.ex              |  8 ++-
 lib/exdgraph/query_statement.ex    |  4 +-
 lib/exdgraph/utils.ex              |  2 -
 mix.exs                            |  3 +-
 mix.lock                           |  2 +-
 test/config_test.exs               |  4 +-
 14 files changed, 105 insertions(+), 103 deletions(-)

diff --git a/README.md b/README.md
index 80d95fc..4a592d4 100755
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 **ExDgraph is functional but I would be careful using it in production. If you want to help, please drop me a message. Any help is greatly appreciated!**
 
-ExDgraph is a gRPC based client for the [Dgraph](https://github.com/dgraph-io/dgraph) database. It uses the [DBConnection](https://hexdocs.pm/db_connection/DBConnection.html) behaviour to support transactions and connection pooling via [Poolboy](https://github.com/devinus/poolboy). Works with Dgraph v1.0.16 (latest).
+ExDgraph is a gRPC based client for the [Dgraph](https://github.com/dgraph-io/dgraph) database. It uses the [DBConnection](https://hexdocs.pm/db_connection/DBConnection.html) behaviour to support transactions and connection pooling. Works with Dgraph v1.0.16 (latest).
 
 > Dgraph is an open source, horizontally scalable and distributed graph database, providing ACID transactions, consistent replication and linearizable reads. [...] Dgraph's goal is to provide Google production level scale and throughput, with low enough latency to be serving real time user queries, over terabytes of structured data. ([Source](https://github.com/dgraph-io/dgraph))
 
@@ -62,8 +62,7 @@ Add the configuration to your respective configuration file:
 config :ex_dgraph, ExDgraph,
   hostname: 'localhost',
   port: 9080,
-  pool_size: 5,
-  max_overflow: 1
+  pool_size: 5
 ```
 
 And finally don't forget to add ExDgraph to the supervisor tree of your app:
@@ -311,7 +310,6 @@ config :ex_dgraph, ExDgraph,
   # default port considered to be: 9080
   hostname: 'localhost',
   pool_size: 5,
-  max_overflow: 1,
   ssl: true,
   cacertfile: '/path/to/MyRootCA.pem'
 ```
@@ -332,7 +330,6 @@ config :ex_dgraph, ExDgraph,
   # default port considered to be: 9080
   hostname: 'localhost',
   pool_size: 5,
-  max_overflow: 1,
   ssl: true,
   cacertfile: '/path/to/MyRootCA.pem',
   certfile: '/path/to/MyClient1.pem',
diff --git a/config/dev.exs b/config/dev.exs
index 0a60d0b..e1e5d07 100755
--- a/config/dev.exs
+++ b/config/dev.exs
@@ -4,7 +4,6 @@ config :ex_dgraph, ExDgraph,
   # default port considered to be: 9080
   hostname: 'localhost',
   pool_size: 5,
-  max_overflow: 1,
   # retry the request, in case of error - in the example below the retry will
   # linearly increase the delay from 150ms following a Fibonacci pattern,
   # cap the delay at 15 seconds (the value defined by the default `:timeout`
diff --git a/config/test.exs b/config/test.exs
index 04a88a5..d591bbb 100755
--- a/config/test.exs
+++ b/config/test.exs
@@ -4,7 +4,6 @@ config :ex_dgraph, ExDgraph,
   # default port considered to be: 9080
   hostname: '0.0.0.0',
   pool_size: 5,
-  max_overflow: 1,
   # retry the request, in case of error - in the example below the retry will
   # linearly increase the delay from 150ms following a Fibonacci pattern,
   # cap the delay at 15 seconds (the value defined by the default `:timeout`
diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index c7cee0e..6e6289d 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -1,6 +1,6 @@
 defmodule ExDgraph do
   @moduledoc """
-  ExDgraph is a gRPC based client for the Dgraph database. It uses the DBConnection behaviour to support transactions and connection pooling via Poolboy. Works with Dgraph v1.0.16 (latest).
+  ExDgraph is a gRPC based client for the Dgraph database. It uses DBConnection to support transactions and connection pooling. Works with Dgraph v1.0.16 (latest).
 
   ## Installation
 
@@ -41,7 +41,6 @@ defmodule ExDgraph do
     hostname: 'localhost',
     port: 9080,
     pool_size: 5,
-    max_overflow: 1,
     keepalive: :infinity
   ```
 
@@ -52,9 +51,7 @@ defmodule ExDgraph do
     hostname: 'localhost',
     port: 9080,
     pool_size: 5,
-    max_overflow: 1
     timeout: 15_000, # This value is used for the DBConnection timeout and the GRPC client deadline
-    pool: DBConnection.Poolboy,
     ssl: false,
     tls_client_auth: false,
     certfile: nil,
@@ -309,7 +306,6 @@ defmodule ExDgraph do
     # default port considered to be: 9080
     hostname: 'localhost',
     pool_size: 5,
-    max_overflow: 1,
     ssl: true,
     cacertfile: '/path/to/MyRootCA.pem'
   ```
@@ -330,7 +326,6 @@ defmodule ExDgraph do
     # default port considered to be: 9080
     hostname: 'localhost',
     pool_size: 5,
-    max_overflow: 1,
     ssl: true,
     cacertfile: '/path/to/MyRootCA.pem',
     certfile: '/path/to/MyClient1.pem',
@@ -366,9 +361,7 @@ defmodule ExDgraph do
     - `:username` - Username;
     - `:password` - User password;
     - `:pool_size` - maximum pool size;
-    - `:max_overflow` - maximum number of workers created if pool is empty
     - `:timeout` - Connect timeout in milliseconds (default: `#{@timeout}`) for  DBConnection and the GRPC client deadline.
-    - `:pool` - The connection pool. Defaults to `DbConnection.Poolboy`.
     - `:ssl` - If to use ssl for the connection (please see configuration example).
       If you set this option, you also have to set `cacertfile` to the correct path.
     - `:tls_client_auth` - If to use TLS client authentication for the connection
@@ -386,8 +379,7 @@ defmodule ExDgraph do
       config :ex_dgraph, ExDgraph,
         hostname: 'localhost',
         port: 9080,
-        pool_size: 5,
-        max_overflow: 1
+        pool_size: 5
 
   ## With SSL
 
@@ -395,7 +387,6 @@ defmodule ExDgraph do
         # default port considered to be: 9080
         hostname: 'localhost',
         pool_size: 5,
-        max_overflow: 1,
         ssl: true,
         cacertfile: '/path/to/MyRootCA.pem'
 
@@ -405,7 +396,6 @@ defmodule ExDgraph do
         # default port considered to be: 9080
         hostname: 'localhost',
         pool_size: 5,
-        max_overflow: 1,
         ssl: true,
         cacertfile: '/path/to/MyRootCA.pem',
         certfile: '/path/to/MyClient1.pem',
@@ -423,11 +413,13 @@ defmodule ExDgraph do
 
   @doc false
   def init(opts) do
-    cnf = Utils.default_config(opts)
+    cnf =
+      Utils.default_config(opts)
+      |> Keyword.put(:name, :ex_dgraph_pool)
 
     children = [
       {ExDgraph.ConfigAgent, cnf},
-      DBConnection.child_spec(ExDgraph.Protocol, pool_config(cnf))
+      DBConnection.child_spec(ExDgraph.Protocol, cnf)
     ]
 
     Supervisor.init(children, strategy: :one_for_one)
@@ -755,16 +747,4 @@ defmodule ExDgraph do
   """
   @spec operation!(conn, String.t()) :: ExDgraph.Response | ExDgraph.Exception
   defdelegate operation!(conn, statement), to: Operation
-
-  ## Helpers
-  ######################
-
-  defp pool_config(cnf) do
-    [
-      name: {:local, pool_name()},
-      pool: Keyword.get(cnf, :pool),
-      pool_size: Keyword.get(cnf, :pool_size),
-      pool_overflow: Keyword.get(cnf, :max_overflow)
-    ]
-  end
 end
diff --git a/lib/exdgraph/mutation.ex b/lib/exdgraph/mutation.ex
index ba93702..add1d62 100644
--- a/lib/exdgraph/mutation.ex
+++ b/lib/exdgraph/mutation.ex
@@ -7,16 +7,19 @@ defmodule ExDgraph.Mutation do
   @doc false
   def mutation(conn, statement) do
     case mutation_commit(conn, statement) do
-      {:error, f} -> {:error, code: f.code, message: f.message}
-      r -> {:ok, r}
+      {:ok, %MutationStatement{}, result} ->
+        {:ok, result}
+
+      {:error, f} ->
+        {:error, code: f.code, message: f.message}
     end
   end
 
   @doc false
   def mutation!(conn, statement) do
     case mutation(conn, statement) do
-      {:ok, r} ->
-        r
+      {:ok, %MutationStatement{}, result} ->
+        {:ok, result}
 
       {:error, code: code, message: message} ->
         raise Exception, code: code, message: message
@@ -29,8 +32,11 @@ defmodule ExDgraph.Mutation do
     json = Poison.encode!(map_with_tmp_uids)
 
     case set_map_commit(conn, json, map_with_tmp_uids) do
-      {:error, f} -> {:error, code: f.code, message: f.message}
-      r -> {:ok, r}
+      {:ok, r} ->
+        {:ok, r}
+
+      {:error, f} ->
+        {:error, code: f.code, message: f.message}
     end
   end
 
@@ -51,8 +57,11 @@ defmodule ExDgraph.Mutation do
     json = Poison.encode!(uids_and_schema_map)
 
     case set_struct_commit(conn, json, uids_and_schema_map) do
-      {:error, f} -> {:error, code: f.code, message: f.message}
-      r -> {:ok, r}
+      {:ok, r} ->
+        {:ok, r}
+
+      {:error, f} ->
+        {:error, code: f.code, message: f.message}
     end
   end
 
@@ -77,8 +86,7 @@ defmodule ExDgraph.Mutation do
       end
     end
 
-    # Response.transform(DBConnection.run(conn, exec, run_opts()))
-    DBConnection.run(conn, exec, run_opts())
+    DBConnection.run(conn, exec)
   end
 
   defp set_map_commit(conn, json, map_with_tmp_uids) do
@@ -86,19 +94,17 @@ defmodule ExDgraph.Mutation do
       q = %MutationStatement{set_json: json}
 
       case DBConnection.execute(conn, q, %{}) do
-        {:ok, resp} ->
-          parsed_response = Transform.transform_mutation(resp)
+        {:ok, %MutationStatement{}, result} ->
           # Now exchange the tmp ids for the ones returned from the db
-          result_with_uids = replace_tmp_uids(map_with_tmp_uids, parsed_response.uids)
-          Map.put(parsed_response, :result, result_with_uids)
+          result_with_uids = replace_tmp_uids(map_with_tmp_uids, result.uids)
+          {:ok, Map.put(result, :result, result_with_uids)}
 
         other ->
           other
       end
     end
 
-    # Response.transform(DBConnection.run(conn, exec, run_opts()))
-    DBConnection.run(conn, exec, run_opts())
+    DBConnection.run(conn, exec)
   end
 
   defp set_struct_commit(conn, json, struct_with_tmp_uids) do
@@ -106,18 +112,17 @@ defmodule ExDgraph.Mutation do
       q = %MutationStatement{set_json: json}
 
       case DBConnection.execute(conn, q, %{}) do
-        {:ok, resp} ->
-          parsed_response = Transform.transform_mutation(resp)
+        {:ok, %MutationStatement{}, result} ->
           # Now exchange the tmp ids for the ones returned from the db
-          result_with_uids = replace_tmp_struct_uids(struct_with_tmp_uids, parsed_response.uids)
-          Map.put(parsed_response, :result, result_with_uids)
+          result_with_uids = replace_tmp_struct_uids(struct_with_tmp_uids, result.uids)
+          {:ok, Map.put(result, :result, result_with_uids)}
 
         other ->
           other
       end
     end
 
-    DBConnection.run(conn, exec, run_opts())
+    DBConnection.run(conn, exec)
   end
 
   defp insert_tmp_uids(map) when is_list(map), do: Enum.map(map, &insert_tmp_uids/1)
@@ -209,8 +214,4 @@ defmodule ExDgraph.Mutation do
 
   defp set_schema(_schema_name, {key, map_value}, result, _is_enforced_schema),
     do: Map.merge(result, %{key => set_tmp_ids_and_schema(map_value)})
-
-  defp run_opts do
-    [pool: ExDgraph.config(:pool)]
-  end
 end
diff --git a/lib/exdgraph/mutation_statement.ex b/lib/exdgraph/mutation_statement.ex
index 07aa115..1ee7235 100644
--- a/lib/exdgraph/mutation_statement.ex
+++ b/lib/exdgraph/mutation_statement.ex
@@ -4,11 +4,13 @@ defmodule ExDgraph.MutationStatement do
 end
 
 defimpl DBConnection.Query, for: ExDgraph.MutationStatement do
+  alias ExDgraph.Transform
+
   def describe(query, _), do: query
 
   def parse(query, _), do: query
 
   def encode(_query, data, _), do: data
 
-  def decode(_, result, _), do: result
+  def decode(_query, result, _opts), do: Transform.transform_mutation(result)
 end
diff --git a/lib/exdgraph/operation.ex b/lib/exdgraph/operation.ex
index f03ce54..a69d0f7 100644
--- a/lib/exdgraph/operation.ex
+++ b/lib/exdgraph/operation.ex
@@ -10,8 +10,8 @@ defmodule ExDgraph.Operation do
       {:error, f} ->
         {:error, code: f.code, message: f.message}
 
-      r ->
-        {:ok, r}
+      {:ok, %OperationStatement{}, result} ->
+        {:ok, result}
     end
   end
 
@@ -41,8 +41,11 @@ defmodule ExDgraph.Operation do
       }
 
       case DBConnection.execute(conn, operation, %{}) do
-        {:ok, resp} -> resp
-        other -> other
+        {:ok, resp} ->
+          resp
+
+        other ->
+          other
       end
     end
 
diff --git a/lib/exdgraph/protocol.ex b/lib/exdgraph/protocol.ex
index 44a8ed1..906a8f1 100755
--- a/lib/exdgraph/protocol.ex
+++ b/lib/exdgraph/protocol.ex
@@ -13,6 +13,15 @@ defmodule ExDgraph.Protocol do
   alias ExDgraph.Api
   alias ExDgraph.{Error, Exception, MutationStatement, OperationStatement, QueryStatement}
 
+  defstruct [
+    :adapter,
+    :channel,
+    :connected,
+    :txn_context,
+    :transaction_status,
+    txn_aborted?: false
+  ]
+
   @impl true
   def connect(_opts) do
     host = to_charlist(ExDgraph.config(:hostname))
@@ -25,7 +34,8 @@ defmodule ExDgraph.Protocol do
 
     case GRPC.Stub.connect("#{host}:#{port}", opts) do
       {:ok, channel} ->
-        {:ok, channel}
+        state = %__MODULE__{channel: channel}
+        {:ok, state}
 
       {:error, reason} ->
         {:error, %Error{action: :connect, reason: reason}}
@@ -43,27 +53,32 @@ defmodule ExDgraph.Protocol do
   end
 
   @impl true
-  def disconnect(_error, state) do
-    case GRPC.Stub.disconnect(state) do
+  def disconnect(_error, %{channel: channel} = _state) do
+    case GRPC.Stub.disconnect(channel) do
       {:ok, _} -> :ok
       {:error, _reason} -> :ok
     end
   end
 
   @impl true
-  def ping(%{adapter_payload: %{conn_pid: conn_pid}} = channel) do
+  def ping(%{channel: channel} = state) do
+    %{adapter_payload: %{conn_pid: conn_pid}} = channel
     # check if the server is up and wait 5s seconds before disconnect
     stream = :gun.head(conn_pid, "/")
     response = :gun.await(conn_pid, stream, 5_000)
 
     # return based on response
     case response do
-      {:response, :fin, 200, _} -> {:ok, channel}
-      {:error, reason} -> {:disconnect, reason, channel}
+      {:response, :fin, 200, _} -> {:ok, state}
+      {:error, reason} -> {:disconnect, reason, state}
       _ -> :ok
     end
   end
 
+  def handle_status(_, %{transaction_status: status} = state) do
+    {:idle, state}
+  end
+
   @impl true
   def handle_begin(_opts, _state) do
   end
@@ -77,9 +92,9 @@ defmodule ExDgraph.Protocol do
   end
 
   @impl true
-  def handle_execute(query, params, opts, channel) do
+  def handle_execute(query, params, opts, %{channel: channel} = state) do
     # only try to reconnect if the error is about the broken connection
-    with {:disconnect, _, _} <- execute(query, params, opts, channel) do
+    with {:disconnect, _, _} <- execute(query, params, opts, state) do
       [
         delay: delay,
         factor: factor,
@@ -95,7 +110,7 @@ defmodule ExDgraph.Protocol do
       retry with: delay_stream do
         with {:ok, channel} <- connect([]),
              {:ok, channel} <- checkout(channel) do
-          execute(query, params, opts, channel)
+          execute(query, params, opts, state)
         end
       after
         result -> result
@@ -105,7 +120,7 @@ defmodule ExDgraph.Protocol do
     end
   end
 
-  @impl true
+  @doc false
   def handle_info(msg, state) do
     Logger.error(fn ->
       [inspect(__MODULE__), ?\s, inspect(self()), " received unexpected message: " | inspect(msg)]
@@ -114,78 +129,83 @@ defmodule ExDgraph.Protocol do
     {:ok, state}
   end
 
-  defp execute(%QueryStatement{statement: statement}, _params, _, channel) do
+  defp execute(
+         %QueryStatement{statement: statement} = query,
+         _params,
+         _,
+         %{channel: channel} = state
+       ) do
     request = ExDgraph.Api.Request.new(query: statement)
     timeout = ExDgraph.config(:timeout)
 
     case ExDgraph.Api.Dgraph.Stub.query(channel, request, timeout: timeout) do
       {:ok, res} ->
-        {:ok, res, channel}
+        {:ok, query, res, state}
 
       {:error, f} ->
         raise Exception, code: f.status, message: f.message
     end
   rescue
     e ->
-      {:error, e, channel}
+      {:error, e, state}
   end
 
-  defp execute(%MutationStatement{statement: statement, set_json: ""}, _params, _, channel) do
-    request = ExDgraph.Api.Mutation.new(set_nquads: statement, commit_now: true)
-    do_mutate(channel, request)
+  defp execute(%MutationStatement{statement: statement, set_json: ""} = query, _params, _, state) do
+    dgraph_query = ExDgraph.Api.Mutation.new(set_nquads: statement, commit_now: true)
+    do_mutate(state, dgraph_query, query)
   end
 
-  defp execute(%MutationStatement{statement: "", set_json: set_json}, _params, _, channel) do
-    request = ExDgraph.Api.Mutation.new(set_json: set_json, commit_now: true)
-    do_mutate(channel, request)
+  defp execute(%MutationStatement{statement: "", set_json: set_json} = query, _params, _, state) do
+    dgraph_query = ExDgraph.Api.Mutation.new(set_json: set_json, commit_now: true)
+    do_mutate(state, dgraph_query, query)
   end
 
   defp execute(
          %MutationStatement{statement: _statement, set_json: _set_json},
          _params,
          _,
-         channel
+         %{channel: channel} = state
        ) do
     raise Exception, code: 2, message: "Both set_json and statement defined"
   rescue
     e ->
-      {:error, e, channel}
+      {:error, e, state}
   end
 
   defp execute(
-         %OperationStatement{drop_all: drop_all, schema: schema, drop_attr: drop_attr},
+         %OperationStatement{drop_all: drop_all, schema: schema, drop_attr: drop_attr} = query,
          _params,
          _,
-         channel
+         %{channel: channel} = state
        ) do
     operation = Api.Operation.new(drop_all: drop_all, schema: schema, drop_attr: drop_attr)
     timeout = ExDgraph.config(:timeout)
 
     case ExDgraph.Api.Dgraph.Stub.alter(channel, operation, timeout: timeout) do
       {:ok, res} ->
-        {:ok, res, channel}
+        {:ok, query, res, state}
 
       {:error, f} ->
         raise Exception, code: f.status, message: f.message
     end
   rescue
     e ->
-      {:error, e, channel}
+      {:error, e, state}
   end
 
-  defp do_mutate(channel, request) do
+  defp do_mutate(%{channel: channel} = state, dgraph_query, query) do
     timeout = ExDgraph.config(:timeout)
 
-    case ExDgraph.Api.Dgraph.Stub.mutate(channel, request, timeout: timeout) do
+    case ExDgraph.Api.Dgraph.Stub.mutate(channel, dgraph_query, timeout: timeout) do
       {:ok, res} ->
-        {:ok, res, channel}
+        {:ok, query, res, state}
 
       {:error, f} ->
         raise Exception, code: f.status, message: f.message
     end
   rescue
     e ->
-      {:error, e, channel}
+      {:error, e, state}
   end
 
   defp configure_ssl(ssl_opts \\ []) do
diff --git a/lib/exdgraph/query.ex b/lib/exdgraph/query.ex
index 5b00268..545b668 100644
--- a/lib/exdgraph/query.ex
+++ b/lib/exdgraph/query.ex
@@ -7,8 +7,11 @@ defmodule ExDgraph.Query do
   @doc false
   def query(conn, statement) do
     case query_commit(conn, statement) do
-      {:error, f} -> {:error, code: Map.get(f, :code, Map.get(f, :status)), message: f.message}
-      r -> {:ok, r}
+      {:error, f} ->
+        {:error, code: Map.get(f, :code, Map.get(f, :status)), message: f.message}
+
+      {:ok, %QueryStatement{}, result} ->
+        {:ok, result}
     end
   end
 
@@ -32,6 +35,7 @@ defmodule ExDgraph.Query do
         other -> other
       end
     end
+
     DBConnection.run(conn, exec, run_opts())
   end
 
diff --git a/lib/exdgraph/query_statement.ex b/lib/exdgraph/query_statement.ex
index 2b63b21..5af8a32 100644
--- a/lib/exdgraph/query_statement.ex
+++ b/lib/exdgraph/query_statement.ex
@@ -4,11 +4,13 @@ defmodule ExDgraph.QueryStatement do
 end
 
 defimpl DBConnection.Query, for: ExDgraph.QueryStatement do
+  alias ExDgraph.Transform
+
   def describe(query, _), do: query
 
   def parse(query, _), do: query
 
   def encode(_query, data, _), do: data
 
-  def decode(_, result, _), do: result
+  def decode(_query, result, _opts), do: Transform.transform_query(result)
 end
diff --git a/lib/exdgraph/utils.ex b/lib/exdgraph/utils.ex
index 77663e7..d3b8b4d 100755
--- a/lib/exdgraph/utils.ex
+++ b/lib/exdgraph/utils.ex
@@ -92,9 +92,7 @@ defmodule ExDgraph.Utils do
     |> Keyword.put_new(:hostname, System.get_env("DGRAPH_HOST") || 'localhost')
     |> Keyword.put_new(:port, System.get_env("DGRAPH_PORT") || 9080)
     |> Keyword.put_new(:pool_size, 5)
-    |> Keyword.put_new(:max_overflow, 2)
     |> Keyword.put_new(:timeout, 15_000)
-    |> Keyword.put_new(:pool, DBConnection.Poolboy)
     |> Keyword.put_new(:ssl, false)
     |> Keyword.put_new(:tls_client_auth, false)
     |> Keyword.put_new(:certfile, nil)
diff --git a/mix.exs b/mix.exs
index c73cb6f..3b2e589 100755
--- a/mix.exs
+++ b/mix.exs
@@ -45,8 +45,7 @@ defmodule ExDgraph.MixProject do
       {:grpc, "~> 0.3.1"},
       {:protobuf, "~> 0.6.1"},
       {:poison, "~> 3.1"},
-      {:poolboy, "~> 1.5.2"},
-      {:db_connection, "~> 1.1"},
+      {:db_connection, "~> 2.1"},
       {:retry, "~> 0.11.2"},
       {:morphix, "~> 0.6.0"},
       {:ex_doc, "~> 0.19.0", only: :dev, runtime: false},
diff --git a/mix.lock b/mix.lock
index cabd573..3166b36 100755
--- a/mix.lock
+++ b/mix.lock
@@ -6,7 +6,7 @@
   "cowboy": {:hex, :cowboy, "2.5.0", "4ef3ae066ee10fe01ea3272edc8f024347a0d3eb95f6fbb9aed556dacbfc1337", [:rebar3], [{:cowlib, "~> 2.6.0", [hex: :cowlib, repo: "hexpm", optional: false]}, {:ranch, "~> 1.6.2", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm"},
   "cowlib": {:hex, :cowlib, "2.6.0", "8aa629f81a0fc189f261dc98a42243fa842625feea3c7ec56c48f4ccdb55490f", [:rebar3], [], "hexpm"},
   "credo": {:hex, :credo, "1.0.2", "88bc918f215168bf6ce7070610a6173c45c82f32baa08bdfc80bf58df2d103b6", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
-  "db_connection": {:hex, :db_connection, "1.1.3", "89b30ca1ef0a3b469b1c779579590688561d586694a3ce8792985d4d7e575a61", [:mix], [{:connection, "~> 1.0.2", [hex: :connection, repo: "hexpm", optional: false]}, {:poolboy, "~> 1.5", [hex: :poolboy, repo: "hexpm", optional: true]}, {:sbroker, "~> 1.0", [hex: :sbroker, repo: "hexpm", optional: true]}], "hexpm"},
+  "db_connection": {:hex, :db_connection, "2.1.1", "a51e8a2ee54ef2ae6ec41a668c85787ed40cb8944928c191280fe34c15b76ae5", [:mix], [{:connection, "~> 1.0.2", [hex: :connection, repo: "hexpm", optional: false]}], "hexpm"},
   "earmark": {:hex, :earmark, "1.3.4", "52aba89c60529284df5fc18adc4c808b7346e72668bc2fb2b68d7394996c4af8", [:mix], [], "hexpm"},
   "elixir_uuid": {:hex, :elixir_uuid, "1.2.0", "ff26e938f95830b1db152cb6e594d711c10c02c6391236900ddd070a6b01271d", [:mix], [], "hexpm"},
   "ex_doc": {:hex, :ex_doc, "0.19.3", "3c7b0f02851f5fc13b040e8e925051452e41248f685e40250d7e40b07b9f8c10", [:mix], [{:earmark, "~> 1.2", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.10", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm"},
diff --git a/test/config_test.exs b/test/config_test.exs
index 3d27362..f77698e 100755
--- a/test/config_test.exs
+++ b/test/config_test.exs
@@ -5,8 +5,7 @@ defmodule Config.Test do
   @basic_config [
     hostname: 'ole',
     port: 1234,
-    pool_size: 10,
-    max_overflow: 7
+    pool_size: 10
   ]
 
   @ssl_config [
@@ -20,7 +19,6 @@ defmodule Config.Test do
     assert config[:hostname] == 'ole'
     assert config[:port] == 1234
     assert config[:pool_size] == 10
-    assert config[:max_overflow] == 7
     assert config[:ssl] == false
     assert config[:tls_client_auth] == false
     assert config[:enforce_struct_schema] == false

From 629c6abaa896244abde4a8392c89b13c607e9ef0 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Sat, 3 Aug 2019 02:24:13 +0200
Subject: [PATCH 04/68] Update README.md

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 4a592d4..857909b 100755
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 **ExDgraph is functional but I would be careful using it in production. If you want to help, please drop me a message. Any help is greatly appreciated!**
 
-ExDgraph is a gRPC based client for the [Dgraph](https://github.com/dgraph-io/dgraph) database. It uses the [DBConnection](https://hexdocs.pm/db_connection/DBConnection.html) behaviour to support transactions and connection pooling. Works with Dgraph v1.0.16 (latest).
+ExDgraph is a gRPC based client for the [Dgraph](https://github.com/dgraph-io/dgraph) database. It uses [DBConnection](https://hexdocs.pm/db_connection/DBConnection.html) to support transactions and connection pooling. Works with Dgraph v1.0.16 (latest).
 
 > Dgraph is an open source, horizontally scalable and distributed graph database, providing ACID transactions, consistent replication and linearizable reads. [...] Dgraph's goal is to provide Google production level scale and throughput, with low enough latency to be serving real time user queries, over terabytes of structured data. ([Source](https://github.com/dgraph-io/dgraph))
 

From e35f5099ececdb0e7b97cbb14f3831139d932a09 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Wed, 7 Aug 2019 09:35:58 +0200
Subject: [PATCH 05/68] Switch from Poison to Jason.

---
 README.md                 |  2 +-
 lib/exdgraph.ex           |  2 +-
 lib/exdgraph/mutation.ex  |  4 ++--
 lib/exdgraph/transform.ex |  2 +-
 lib/exdgraph/utils.ex     |  2 +-
 mix.exs                   | 14 +++++++-------
 6 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/README.md b/README.md
index 857909b..40a77ea 100755
--- a/README.md
+++ b/README.md
@@ -298,7 +298,7 @@ request = ExDgraph.Api.Request.new(query: query)
 {:ok, msg} = channel |> ExDgraph.Api.Dgraph.Stub.query(request)
 
 # Parse result
-json = Poison.decode!(msg.json)
+json = Jason.decode!(msg.json)
 ```
 
 ## Using SSL
diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index 6e6289d..41fc3aa 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -294,7 +294,7 @@ defmodule ExDgraph do
   {:ok, msg} = channel |> ExDgraph.Api.Dgraph.Stub.query(request)
 
   # Parse result
-  json = Poison.decode!(msg.json)
+  json = Jason.decode!(msg.json)
   ```
 
   ## Using SSL
diff --git a/lib/exdgraph/mutation.ex b/lib/exdgraph/mutation.ex
index add1d62..2676e3c 100644
--- a/lib/exdgraph/mutation.ex
+++ b/lib/exdgraph/mutation.ex
@@ -29,7 +29,7 @@ defmodule ExDgraph.Mutation do
   @doc false
   def set_map(conn, map) do
     map_with_tmp_uids = insert_tmp_uids(map)
-    json = Poison.encode!(map_with_tmp_uids)
+    json = Jason.encode!(map_with_tmp_uids)
 
     case set_map_commit(conn, json, map_with_tmp_uids) do
       {:ok, r} ->
@@ -54,7 +54,7 @@ defmodule ExDgraph.Mutation do
   @doc false
   def set_struct(conn, struct) do
     uids_and_schema_map = set_tmp_ids_and_schema(struct)
-    json = Poison.encode!(uids_and_schema_map)
+    json = Jason.encode!(uids_and_schema_map)
 
     case set_struct_commit(conn, json, uids_and_schema_map) do
       {:ok, r} ->
diff --git a/lib/exdgraph/transform.ex b/lib/exdgraph/transform.ex
index bb98051..59b3e4a 100644
--- a/lib/exdgraph/transform.ex
+++ b/lib/exdgraph/transform.ex
@@ -8,7 +8,7 @@ defmodule ExDgraph.Transform do
   keys into atom keys.
   """
   def transform_query(%ExDgraph.Api.Response{json: json, schema: schema, txn: txn}) do
-    decoded = Poison.decode!(json)
+    decoded = Jason.decode!(json)
 
     transformed =
       case Morphix.atomorphiform(decoded) do
diff --git a/lib/exdgraph/utils.ex b/lib/exdgraph/utils.ex
index d3b8b4d..f3ed7cb 100755
--- a/lib/exdgraph/utils.ex
+++ b/lib/exdgraph/utils.ex
@@ -5,7 +5,7 @@ defmodule ExDgraph.Utils do
 
   def as_rendered(value) do
     case value do
-      x when is_list(x) -> x |> Poison.encode!()
+      x when is_list(x) -> x |> Jason.encode!()
       %Date{} = x -> x |> Date.to_iso8601() |> Kernel.<>("T00:00:00.0+00:00")
       %DateTime{} = x -> x |> DateTime.to_iso8601() |> String.replace("Z", "+00:00")
       x -> x |> to_string
diff --git a/mix.exs b/mix.exs
index 3b2e589..4c202de 100755
--- a/mix.exs
+++ b/mix.exs
@@ -42,17 +42,17 @@ defmodule ExDgraph.MixProject do
   # Run "mix help deps" to learn about dependencies.
   defp deps do
     [
+      {:db_connection, "~> 2.1"},
+      {:elixir_uuid, "~> 1.2"},
       {:grpc, "~> 0.3.1"},
+      {:jason, "~> 1.1"},
+      {:morphix, "~> 0.6.0"},
       {:protobuf, "~> 0.6.1"},
-      {:poison, "~> 3.1"},
-      {:db_connection, "~> 2.1"},
       {:retry, "~> 0.11.2"},
-      {:morphix, "~> 0.6.0"},
-      {:ex_doc, "~> 0.19.0", only: :dev, runtime: false},
-      {:elixir_uuid, "~> 1.2"},
-      {:mix_test_watch, "~> 0.5", only: :dev, runtime: false},
       {:excoveralls, "~> 0.10", only: :test},
-      {:credo, "~> 1.0", only: [:dev, :test], runtime: false}
+      {:credo, "~> 1.0", only: [:dev, :test], runtime: false},
+      {:ex_doc, "~> 0.19.0", only: :dev, runtime: false},
+      {:mix_test_watch, "~> 0.5", only: :dev, runtime: false}
     ]
   end
 

From dfe7b5315dedb2b5c0bcb1c6db00d438f945b043 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Wed, 7 Aug 2019 10:26:21 +0200
Subject: [PATCH 06/68] Start moving connection related functionality to an
 Adapter module.

---
 lib/exdgraph/adapter.ex  | 16 ++++++++++++++++
 lib/exdgraph/protocol.ex | 15 ++++++++++-----
 2 files changed, 26 insertions(+), 5 deletions(-)
 create mode 100644 lib/exdgraph/adapter.ex

diff --git a/lib/exdgraph/adapter.ex b/lib/exdgraph/adapter.ex
new file mode 100644
index 0000000..8f2fff8
--- /dev/null
+++ b/lib/exdgraph/adapter.ex
@@ -0,0 +1,16 @@
+defmodule ExDgraph.Adapter do
+  alias ExDgraph.Api.Dgraph.Stub, as: ApiStub
+  alias ExDgraph.Error
+
+  require Logger
+
+  def connect(host, port, opts \\ []) do
+    case GRPC.Stub.connect("#{host}:#{port}", opts) do
+      {:ok, channel} ->
+        {:ok, channel}
+
+      {:error, reason} ->
+        {:error, %Error{action: :connect, reason: reason}}
+    end
+  end
+end
diff --git a/lib/exdgraph/protocol.ex b/lib/exdgraph/protocol.ex
index 906a8f1..d6a30fc 100755
--- a/lib/exdgraph/protocol.ex
+++ b/lib/exdgraph/protocol.ex
@@ -1,8 +1,6 @@
 defmodule ExDgraph.Protocol do
   @moduledoc """
   Implements callbacks required by DBConnection.
-
-  Each callback receives an open connection as a state.
   """
 
   use DBConnection
@@ -10,8 +8,15 @@ defmodule ExDgraph.Protocol do
 
   require Logger
 
-  alias ExDgraph.Api
-  alias ExDgraph.{Error, Exception, MutationStatement, OperationStatement, QueryStatement}
+  alias ExDgraph.{
+    Adapter,
+    Api,
+    Error,
+    Exception,
+    MutationStatement,
+    OperationStatement,
+    QueryStatement
+  }
 
   defstruct [
     :adapter,
@@ -32,7 +37,7 @@ defmodule ExDgraph.Protocol do
       |> set_ssl_opts()
       |> Keyword.put(:adapter_opts, %{http2_opts: %{keepalive: ExDgraph.config(:keepalive)}})
 
-    case GRPC.Stub.connect("#{host}:#{port}", opts) do
+    case Adapter.connect(host, port, opts) do
       {:ok, channel} ->
         state = %__MODULE__{channel: channel}
         {:ok, state}

From e3361d8349da996e186db42f971a1e001ebc10d8 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Wed, 7 Aug 2019 10:31:49 +0200
Subject: [PATCH 07/68] Require at least Elixir 1.7. and also test against 1.9.

---
 .travis.yml | 6 +++++-
 mix.exs     | 2 +-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index f044c20..6e9db8d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,8 +1,9 @@
 language: elixir
 
 elixir:
-  - 1.6
+  - 1.7
   - 1.8
+  - 1.9
 
 otp_release:
   - 20.0
@@ -11,6 +12,9 @@ matrix:
   include:
     - elixir: 1.8
       otp_release: 21.2
+    - elixir: 1.9
+      otp_release:
+      otp_release: 22.0
 
 cache:
   directories:
diff --git a/mix.exs b/mix.exs
index 4c202de..dbeb5aa 100755
--- a/mix.exs
+++ b/mix.exs
@@ -5,7 +5,7 @@ defmodule ExDgraph.MixProject do
     [
       app: :ex_dgraph,
       version: "0.2.0-beta.3",
-      elixir: "~> 1.8",
+      elixir: "~> 1.7",
       start_permanent: Mix.env() == :prod,
       deps: deps(),
       description: description(),

From d7f3caab7e75a6cbf765df5426a9529a8b1cc20a Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Wed, 7 Aug 2019 16:55:32 +0200
Subject: [PATCH 08/68] Remove adapter.

---
 lib/exdgraph/adapter.ex  | 16 ----------------
 lib/exdgraph/protocol.ex |  3 +--
 2 files changed, 1 insertion(+), 18 deletions(-)
 delete mode 100644 lib/exdgraph/adapter.ex

diff --git a/lib/exdgraph/adapter.ex b/lib/exdgraph/adapter.ex
deleted file mode 100644
index 8f2fff8..0000000
--- a/lib/exdgraph/adapter.ex
+++ /dev/null
@@ -1,16 +0,0 @@
-defmodule ExDgraph.Adapter do
-  alias ExDgraph.Api.Dgraph.Stub, as: ApiStub
-  alias ExDgraph.Error
-
-  require Logger
-
-  def connect(host, port, opts \\ []) do
-    case GRPC.Stub.connect("#{host}:#{port}", opts) do
-      {:ok, channel} ->
-        {:ok, channel}
-
-      {:error, reason} ->
-        {:error, %Error{action: :connect, reason: reason}}
-    end
-  end
-end
diff --git a/lib/exdgraph/protocol.ex b/lib/exdgraph/protocol.ex
index d6a30fc..e8a97be 100755
--- a/lib/exdgraph/protocol.ex
+++ b/lib/exdgraph/protocol.ex
@@ -9,7 +9,6 @@ defmodule ExDgraph.Protocol do
   require Logger
 
   alias ExDgraph.{
-    Adapter,
     Api,
     Error,
     Exception,
@@ -37,7 +36,7 @@ defmodule ExDgraph.Protocol do
       |> set_ssl_opts()
       |> Keyword.put(:adapter_opts, %{http2_opts: %{keepalive: ExDgraph.config(:keepalive)}})
 
-    case Adapter.connect(host, port, opts) do
+    case GRPC.Stub.connect("#{host}:#{port}", opts) do
       {:ok, channel} ->
         state = %__MODULE__{channel: channel}
         {:ok, state}

From 8c70785df34893d0ae73a1dc02318acd449aa61e Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Wed, 7 Aug 2019 17:53:18 +0200
Subject: [PATCH 09/68] Remove Retry since it is handled by DBConnection 2.

---
 Changelog.md               |  2 +
 config/dev.exs             |  8 ----
 config/test.exs            |  8 ----
 lib/exdgraph.ex            |  6 +--
 lib/exdgraph/protocol.ex   | 86 ++++++++++++++++----------------------
 lib/exdgraph/utils.ex      |  3 +-
 mix.exs                    |  2 -
 mix.lock                   |  2 +-
 test/retry_backof_test.exs | 31 --------------
 9 files changed, 41 insertions(+), 107 deletions(-)
 delete mode 100644 test/retry_backof_test.exs

diff --git a/Changelog.md b/Changelog.md
index 3e0a2de..3969adf 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -6,6 +6,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## [Unreleased]
 
+- Remove retry since DBConnection 2 implements a retry mechanism.
+
 ## [0.2.0-beta.3] - 2019-07-31
 
 - Test against Dgraph `v1.0.16`
diff --git a/config/dev.exs b/config/dev.exs
index e1e5d07..a9cf331 100755
--- a/config/dev.exs
+++ b/config/dev.exs
@@ -4,12 +4,4 @@ config :ex_dgraph, ExDgraph,
   # default port considered to be: 9080
   hostname: 'localhost',
   pool_size: 5,
-  # retry the request, in case of error - in the example below the retry will
-  # linearly increase the delay from 150ms following a Fibonacci pattern,
-  # cap the delay at 15 seconds (the value defined by the default `:timeout`
-  # parameter) and giving up after 3 attempts
-  retry_linear_backoff: [delay: 150, factor: 2, tries: 3],
   enforce_struct_schema: false
-
-# the `retry_linear_backoff` values above are also the default driver values,
-# re-defined here mostly as a reminder
diff --git a/config/test.exs b/config/test.exs
index d591bbb..9cbb857 100755
--- a/config/test.exs
+++ b/config/test.exs
@@ -4,12 +4,4 @@ config :ex_dgraph, ExDgraph,
   # default port considered to be: 9080
   hostname: '0.0.0.0',
   pool_size: 5,
-  # retry the request, in case of error - in the example below the retry will
-  # linearly increase the delay from 150ms following a Fibonacci pattern,
-  # cap the delay at 15 seconds (the value defined by the default `:timeout`
-  # parameter) and giving up after 3 attempts
-  retry_linear_backoff: [delay: 150, factor: 2, tries: 3],
   enforce_struct_schema: true
-
-# the `retry_linear_backoff` values above are also the default driver values,
-# re-defined here mostly as a reminder
diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index 41fc3aa..619e69d 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -343,7 +343,7 @@ defmodule ExDgraph do
 
   use Supervisor
 
-  @pool_name :ex_dgraph_pool
+  @pool_name :ex_dgraph
   @timeout 15_000
 
   alias ExDgraph.Api.{Mutation, Operation}
@@ -413,9 +413,7 @@ defmodule ExDgraph do
 
   @doc false
   def init(opts) do
-    cnf =
-      Utils.default_config(opts)
-      |> Keyword.put(:name, :ex_dgraph_pool)
+    cnf = Utils.default_config(opts)
 
     children = [
       {ExDgraph.ConfigAgent, cnf},
diff --git a/lib/exdgraph/protocol.ex b/lib/exdgraph/protocol.ex
index e8a97be..4e168c3 100755
--- a/lib/exdgraph/protocol.ex
+++ b/lib/exdgraph/protocol.ex
@@ -4,7 +4,6 @@ defmodule ExDgraph.Protocol do
   """
 
   use DBConnection
-  use Retry
 
   require Logger
 
@@ -18,7 +17,6 @@ defmodule ExDgraph.Protocol do
   }
 
   defstruct [
-    :adapter,
     :channel,
     :connected,
     :txn_context,
@@ -95,35 +93,6 @@ defmodule ExDgraph.Protocol do
   def handle_commit(_opts, _state) do
   end
 
-  @impl true
-  def handle_execute(query, params, opts, %{channel: channel} = state) do
-    # only try to reconnect if the error is about the broken connection
-    with {:disconnect, _, _} <- execute(query, params, opts, state) do
-      [
-        delay: delay,
-        factor: factor,
-        tries: tries
-      ] = ExDgraph.config(:retry_linear_backoff)
-
-      delay_stream =
-        delay
-        |> linear_backoff(factor)
-        |> cap(ExDgraph.config(:timeout))
-        |> Stream.take(tries)
-
-      retry with: delay_stream do
-        with {:ok, channel} <- connect([]),
-             {:ok, channel} <- checkout(channel) do
-          execute(query, params, opts, state)
-        end
-      after
-        result -> result
-      else
-        error -> error
-      end
-    end
-  end
-
   @doc false
   def handle_info(msg, state) do
     Logger.error(fn ->
@@ -133,12 +102,13 @@ defmodule ExDgraph.Protocol do
     {:ok, state}
   end
 
-  defp execute(
-         %QueryStatement{statement: statement} = query,
-         _params,
-         _,
-         %{channel: channel} = state
-       ) do
+  @impl true
+  def handle_execute(
+        %QueryStatement{statement: statement} = query,
+        _params,
+        _,
+        %{channel: channel} = state
+      ) do
     request = ExDgraph.Api.Request.new(query: statement)
     timeout = ExDgraph.config(:timeout)
 
@@ -154,34 +124,48 @@ defmodule ExDgraph.Protocol do
       {:error, e, state}
   end
 
-  defp execute(%MutationStatement{statement: statement, set_json: ""} = query, _params, _, state) do
+  @impl true
+  def handle_execute(
+        %MutationStatement{statement: statement, set_json: ""} = query,
+        _params,
+        _,
+        state
+      ) do
     dgraph_query = ExDgraph.Api.Mutation.new(set_nquads: statement, commit_now: true)
     do_mutate(state, dgraph_query, query)
   end
 
-  defp execute(%MutationStatement{statement: "", set_json: set_json} = query, _params, _, state) do
+  @impl true
+  def handle_execute(
+        %MutationStatement{statement: "", set_json: set_json} = query,
+        _params,
+        _,
+        state
+      ) do
     dgraph_query = ExDgraph.Api.Mutation.new(set_json: set_json, commit_now: true)
     do_mutate(state, dgraph_query, query)
   end
 
-  defp execute(
-         %MutationStatement{statement: _statement, set_json: _set_json},
-         _params,
-         _,
-         %{channel: channel} = state
-       ) do
+  @impl true
+  def handle_execute(
+        %MutationStatement{statement: _statement, set_json: _set_json},
+        _params,
+        _,
+        %{channel: channel} = state
+      ) do
     raise Exception, code: 2, message: "Both set_json and statement defined"
   rescue
     e ->
       {:error, e, state}
   end
 
-  defp execute(
-         %OperationStatement{drop_all: drop_all, schema: schema, drop_attr: drop_attr} = query,
-         _params,
-         _,
-         %{channel: channel} = state
-       ) do
+  @impl true
+  def handle_execute(
+        %OperationStatement{drop_all: drop_all, schema: schema, drop_attr: drop_attr} = query,
+        _params,
+        _,
+        %{channel: channel} = state
+      ) do
     operation = Api.Operation.new(drop_all: drop_all, schema: schema, drop_attr: drop_attr)
     timeout = ExDgraph.config(:timeout)
 
diff --git a/lib/exdgraph/utils.ex b/lib/exdgraph/utils.ex
index f3ed7cb..2e7e8f0 100755
--- a/lib/exdgraph/utils.ex
+++ b/lib/exdgraph/utils.ex
@@ -91,14 +91,13 @@ defmodule ExDgraph.Utils do
     config
     |> Keyword.put_new(:hostname, System.get_env("DGRAPH_HOST") || 'localhost')
     |> Keyword.put_new(:port, System.get_env("DGRAPH_PORT") || 9080)
-    |> Keyword.put_new(:pool_size, 5)
+    |> Keyword.put_new(:name, :ex_dgraph)
     |> Keyword.put_new(:timeout, 15_000)
     |> Keyword.put_new(:ssl, false)
     |> Keyword.put_new(:tls_client_auth, false)
     |> Keyword.put_new(:certfile, nil)
     |> Keyword.put_new(:keyfile, nil)
     |> Keyword.put_new(:cacertfile, nil)
-    |> Keyword.put_new(:retry_linear_backoff, delay: 150, factor: 2, tries: 3)
     |> Keyword.put_new(:enforce_struct_schema, false)
     |> Keyword.put_new(:keepalive, :infinity)
     |> Enum.reject(fn {_k, v} -> is_nil(v) end)
diff --git a/mix.exs b/mix.exs
index dbeb5aa..3302a48 100755
--- a/mix.exs
+++ b/mix.exs
@@ -33,7 +33,6 @@ defmodule ExDgraph.MixProject do
       applications: [
         :logger,
         :db_connection,
-        :retry,
         :grpc
       ]
     ]
@@ -48,7 +47,6 @@ defmodule ExDgraph.MixProject do
       {:jason, "~> 1.1"},
       {:morphix, "~> 0.6.0"},
       {:protobuf, "~> 0.6.1"},
-      {:retry, "~> 0.11.2"},
       {:excoveralls, "~> 0.10", only: :test},
       {:credo, "~> 1.0", only: [:dev, :test], runtime: false},
       {:ex_doc, "~> 0.19.0", only: :dev, runtime: false},
diff --git a/mix.lock b/mix.lock
index 3166b36..e5f1d12 100755
--- a/mix.lock
+++ b/mix.lock
@@ -33,7 +33,7 @@
   "poolboy": {:hex, :poolboy, "1.5.2", "392b007a1693a64540cead79830443abf5762f5d30cf50bc95cb2c1aaafa006b", [:rebar3], [], "hexpm"},
   "protobuf": {:hex, :protobuf, "0.6.1", "3ae3ca63d12d1a8c5b10c2e5fbc5145dccbff842ccd541109b74b20b631cea3b", [:mix], [], "hexpm"},
   "ranch": {:hex, :ranch, "1.6.2", "6db93c78f411ee033dbb18ba8234c5574883acb9a75af0fb90a9b82ea46afa00", [:rebar3], [], "hexpm"},
-  "retry": {:hex, :retry, "0.11.2", "29f9ab8e7d78878307f4653adc286d8a8baa6b66b6bcb67925c07a1386ef7867", [:mix], [], "hexpm"},
+  "retry": {:hex, :retry, "0.13.0", "bb9b2713f70f39337837852337ad280c77662574f4fb852a8386c269f3d734c4", [:mix], [], "hexpm"},
   "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.4", "f0eafff810d2041e93f915ef59899c923f4568f4585904d010387ed74988e77b", [:make, :mix, :rebar3], [], "hexpm"},
   "unicode_util_compat": {:hex, :unicode_util_compat, "0.4.1", "d869e4c68901dd9531385bb0c8c40444ebf624e60b6962d95952775cac5e90cd", [:rebar3], [], "hexpm"},
   "uuid": {:hex, :uuid, "1.1.8", "e22fc04499de0de3ed1116b770c7737779f226ceefa0badb3592e64d5cfb4eb9", [:mix], [], "hexpm"},
diff --git a/test/retry_backof_test.exs b/test/retry_backof_test.exs
deleted file mode 100644
index 7f34ddd..0000000
--- a/test/retry_backof_test.exs
+++ /dev/null
@@ -1,31 +0,0 @@
-defmodule Retry.Backoff.Test do
-  use ExUnit.Case, async: true
-  import Stream
-
-  use Retry
-
-  setup_all do
-    {:ok, [conn: ExDgraph.conn()]}
-  end
-
-  test "retry retries execution for specified attempts using an invalid GraphQL+ query",
-       context do
-    conn = context[:conn]
-
-    {elapsed, _} =
-      :timer.tc(fn ->
-        {:error, [code: 2, message: message]} =
-          retry with: 500 |> linear_backoff(1) |> take(5) do
-            ExDgraph.query(conn, "INVALID")
-          after
-            result -> result
-          else
-            error -> error
-          end
-
-        assert message =~ "while lexing INVALID: Invalid operation type: INVALID"
-      end)
-
-    assert elapsed / 1000 >= 2500
-  end
-end

From 5486b5da903e3d8095e00931479fb7bf620f1f39 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Wed, 7 Aug 2019 17:53:27 +0200
Subject: [PATCH 10/68] Add DBConnection config options.

---
 lib/exdgraph/utils.ex | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/lib/exdgraph/utils.ex b/lib/exdgraph/utils.ex
index 2e7e8f0..8f8839a 100755
--- a/lib/exdgraph/utils.ex
+++ b/lib/exdgraph/utils.ex
@@ -100,6 +100,15 @@ defmodule ExDgraph.Utils do
     |> Keyword.put_new(:cacertfile, nil)
     |> Keyword.put_new(:enforce_struct_schema, false)
     |> Keyword.put_new(:keepalive, :infinity)
+    # DBConnection config options
+    |> Keyword.put_new(:name, 1_000)
+    |> Keyword.put_new(:backoff_min, 1_000)
+    |> Keyword.put_new(:backoff_max, 30_000)
+    |> Keyword.put_new(:backoff_type, :rand_exp)
+    |> Keyword.put_new(:pool_size, 5)
+    |> Keyword.put_new(:idle_interval, 5_000)
+    |> Keyword.put_new(:max_restarts, 3)
+    |> Keyword.put_new(:max_seconds, 5)
     |> Enum.reject(fn {_k, v} -> is_nil(v) end)
   end
 end

From b578931df2c65e9a800a89cf86b7ed8cccb6ab85 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Tue, 3 Sep 2019 00:15:58 +0200
Subject: [PATCH 11/68] Delete config_test.exs

---
 test/config_test.exs | 45 --------------------------------------------
 1 file changed, 45 deletions(-)
 delete mode 100755 test/config_test.exs

diff --git a/test/config_test.exs b/test/config_test.exs
deleted file mode 100755
index f77698e..0000000
--- a/test/config_test.exs
+++ /dev/null
@@ -1,45 +0,0 @@
-defmodule Config.Test do
-  use ExUnit.Case, async: true
-  alias ExDgraph.Utils
-
-  @basic_config [
-    hostname: 'ole',
-    port: 1234,
-    pool_size: 10
-  ]
-
-  @ssl_config [
-    ssl: true,
-    cacertfile: "MyRootCA.pem"
-  ]
-
-  test "standard ExDgraph configuration parameters" do
-    config = Utils.default_config(@basic_config)
-
-    assert config[:hostname] == 'ole'
-    assert config[:port] == 1234
-    assert config[:pool_size] == 10
-    assert config[:ssl] == false
-    assert config[:tls_client_auth] == false
-    assert config[:enforce_struct_schema] == false
-    assert config[:keepalive] == :infinity
-  end
-
-  test "standard ExDgraph default configuration" do
-    config = Utils.default_config([])
-
-    assert config[:hostname] == 'localhost'
-    assert config[:port] == 9080
-    assert config[:ssl] == false
-    assert config[:tls_client_auth] == false
-    assert config[:enforce_struct_schema] == false
-    assert config[:keepalive] == :infinity
-  end
-
-  test "ssl config from parameters" do
-    config = Utils.default_config(@ssl_config)
-
-    assert config[:ssl] == true
-    assert config[:cacertfile] == "MyRootCA.pem"
-  end
-end

From f50db88f249b0d9d9c7d941693c1682e3430845b Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Tue, 3 Sep 2019 00:16:14 +0200
Subject: [PATCH 12/68] Update test_helper.exs

---
 test/test_helper.exs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/test_helper.exs b/test/test_helper.exs
index 8fec030..5573444 100755
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@@ -80,4 +80,4 @@ if Process.whereis(ExDgraph.pool_name()) == nil do
   {:ok, _pid} = ExDgraph.start_link(Application.get_env(:ex_dgraph, ExDgraph))
 end
 
-Process.flag(:trap_exit, true)
+ExUnit.configure(exclude: [tls_tests: true])

From ded0ea3d6cad59639346872c055475b263de3d7b Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Tue, 3 Sep 2019 00:16:39 +0200
Subject: [PATCH 13/68] Always use latest version of ex_doc.

---
 mix.exs | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/mix.exs b/mix.exs
index 3302a48..9f768c5 100755
--- a/mix.exs
+++ b/mix.exs
@@ -30,11 +30,7 @@ defmodule ExDgraph.MixProject do
   # Run "mix help compile.app" to learn about applications.
   def application do
     [
-      applications: [
-        :logger,
-        :db_connection,
-        :grpc
-      ]
+      applications: [:logger, :db_connection, :grpc]
     ]
   end
 
@@ -49,7 +45,7 @@ defmodule ExDgraph.MixProject do
       {:protobuf, "~> 0.6.1"},
       {:excoveralls, "~> 0.10", only: :test},
       {:credo, "~> 1.0", only: [:dev, :test], runtime: false},
-      {:ex_doc, "~> 0.19.0", only: :dev, runtime: false},
+      {:ex_doc, "> 0.0.0", only: :dev, runtime: false},
       {:mix_test_watch, "~> 0.5", only: :dev, runtime: false}
     ]
   end

From dfa07dfaae4b62557ce41b61e7414f81c4fe6de7 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Tue, 3 Sep 2019 00:17:58 +0200
Subject: [PATCH 14/68] Remove ConfigAgent.

Gonna keep the options in the state of the genserver.
---
 lib/exdgraph.ex              | 16 ----------------
 lib/exdgraph/config_agent.ex | 17 -----------------
 2 files changed, 33 deletions(-)
 delete mode 100755 lib/exdgraph/config_agent.ex

diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index 619e69d..0ab77b3 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -347,7 +347,6 @@ defmodule ExDgraph do
   @timeout 15_000
 
   alias ExDgraph.Api.{Mutation, Operation}
-  alias ExDgraph.{ConfigAgent, Operation, Mutation, Query, Utils}
 
   @type conn :: DBConnection.conn()
   # @type transaction :: DBConnection.t()
@@ -428,21 +427,6 @@ defmodule ExDgraph do
   """
   def conn, do: pool_name()
 
-  @doc """
-  Returns an environment specific ExDgraph configuration.
-  """
-  def config, do: ConfigAgent.get_config()
-
-  @doc false
-  def config(key), do: Keyword.get(config(), key)
-
-  @doc false
-  def config(key, default) do
-    Keyword.get(config(), key, default)
-  rescue
-    _ -> default
-  end
-
   @doc false
   def pool_name, do: @pool_name
 
diff --git a/lib/exdgraph/config_agent.ex b/lib/exdgraph/config_agent.ex
deleted file mode 100755
index 7a7251c..0000000
--- a/lib/exdgraph/config_agent.ex
+++ /dev/null
@@ -1,17 +0,0 @@
-defmodule ExDgraph.ConfigAgent do
-  @moduledoc """
-  Just hold the user config and offer some utility for accessing it
-  """
-
-  use Agent
-
-  @doc false
-  def start_link(opts) do
-    Agent.start_link(fn -> %{opts: opts} end, name: __MODULE__)
-  end
-
-  @doc false
-  def get_config do
-    Agent.get(__MODULE__, fn state -> state[:opts] end)
-  end
-end

From 0d9a65aa949f53e7ebf681730f1198ced97db7cf Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Tue, 3 Sep 2019 00:18:15 +0200
Subject: [PATCH 15/68] Upgrade Dgraph to 1.0.17.

---
 docker-compose.yml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/docker-compose.yml b/docker-compose.yml
index 6925c19..943bc6a 100755
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -1,7 +1,7 @@
 version: "3.2"
 services:
   zero:
-    image: dgraph/dgraph:v1.0.16
+    image: dgraph/dgraph:v1.0.17
     volumes:
       - type: bind
         source: ./dgraph_data
@@ -14,7 +14,7 @@ services:
     restart: on-failure
     command: dgraph zero --my=zero:5080
   server:
-    image: dgraph/dgraph:v1.0.16
+    image: dgraph/dgraph:v1.0.17
     volumes:
       - type: bind
         source: ./dgraph_data
@@ -27,7 +27,7 @@ services:
     restart: on-failure
     command: dgraph alpha --my=server:7080 --lru_mb=2048 --zero=zero:5080
   ratel:
-    image: dgraph/dgraph:v1.0.16
+    image: dgraph/dgraph:v1.0.17
     volumes:
       - type: bind
         source: ./dgraph_data

From 7c729753a84d567d1e62e080baa9adf24297d507 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Tue, 3 Sep 2019 00:18:49 +0200
Subject: [PATCH 16/68] Set show_sensitive_data_on_connection_error to true
 when testing.

---
 config/test.exs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/config/test.exs b/config/test.exs
index 9cbb857..221c2d9 100755
--- a/config/test.exs
+++ b/config/test.exs
@@ -4,4 +4,5 @@ config :ex_dgraph, ExDgraph,
   # default port considered to be: 9080
   hostname: '0.0.0.0',
   pool_size: 5,
-  enforce_struct_schema: true
+  enforce_struct_schema: true,
+  show_sensitive_data_on_connection_error: true

From 0118f4585075a9b9b27f8768330c2f6d761ea990 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Tue, 3 Sep 2019 00:19:00 +0200
Subject: [PATCH 17/68] Add tls folder to gitignore.

---
 .gitignore | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/.gitignore b/.gitignore
index 5de6e1b..cec5681 100644
--- a/.gitignore
+++ b/.gitignore
@@ -30,3 +30,6 @@ exdgraph-*.tar
 
 # Data directory when running Dgraph from docker-compose for test purposes
 /dgraph_data
+
+# TLS folder with certificates for testing
+/tls/*

From aca5eeb02c31a780bb49a95e51ee5baa02c93a86 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Tue, 3 Sep 2019 00:19:16 +0200
Subject: [PATCH 18/68] Add docker compose file for testing with tls.

---
 docker-compose-tls.yml | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 docker-compose-tls.yml

diff --git a/docker-compose-tls.yml b/docker-compose-tls.yml
new file mode 100644
index 0000000..c61e2a0
--- /dev/null
+++ b/docker-compose-tls.yml
@@ -0,0 +1,42 @@
+version: "3.2"
+services:
+  zero:
+    image: dgraph/dgraph:v1.0.17
+    volumes:
+      - type: bind
+        source: ./dgraph_data
+        target: /dgraph
+        volume:
+          nocopy: true
+    ports:
+      - 5080:5080
+      - 6080:6080
+    restart: on-failure
+    command: dgraph zero --my=zero:5080
+  server:
+    image: dgraph/dgraph:v1.0.17
+    volumes:
+      - type: bind
+        source: ./dgraph_data
+        target: /dgraph
+        volume:
+          nocopy: true
+    ports:
+      - 8080:8080
+      - 9080:9080
+    restart: on-failure
+    command: dgraph alpha --my=server:7080 --lru_mb=2048 --zero=zero:5080 --tls_dir tls
+  ratel:
+    image: dgraph/dgraph:v1.0.17
+    volumes:
+      - type: bind
+        source: ./dgraph_data
+        target: /dgraph
+        volume:
+          nocopy: true
+    ports:
+      - 8000:8000
+    command: dgraph-ratel
+
+volumes:
+  dgraph:

From 95eb584d6a854056b1e7951a33486ff40aaae80c Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Wed, 4 Sep 2019 23:33:39 +0200
Subject: [PATCH 19/68] Remove QueryStatement.

---
 lib/exdgraph/query.ex           | 30 ++++++++++++++++++++----------
 lib/exdgraph/query_statement.ex | 16 ----------------
 2 files changed, 20 insertions(+), 26 deletions(-)
 delete mode 100644 lib/exdgraph/query_statement.ex

diff --git a/lib/exdgraph/query.ex b/lib/exdgraph/query.ex
index 545b668..29ad8da 100644
--- a/lib/exdgraph/query.ex
+++ b/lib/exdgraph/query.ex
@@ -2,7 +2,9 @@ defmodule ExDgraph.Query do
   @moduledoc """
   Provides the functions for the callbacks from the DBConnection behaviour.
   """
-  alias ExDgraph.{Exception, QueryStatement, Transform}
+  alias ExDgraph.{Exception, Query, Transform}
+
+  defstruct statement: ""
 
   @doc false
   def query(conn, statement) do
@@ -10,7 +12,7 @@ defmodule ExDgraph.Query do
       {:error, f} ->
         {:error, code: Map.get(f, :code, Map.get(f, :status)), message: f.message}
 
-      {:ok, %QueryStatement{}, result} ->
+      {:ok, %Query{}, result} ->
         {:ok, result}
     end
   end
@@ -27,19 +29,27 @@ defmodule ExDgraph.Query do
   end
 
   defp query_commit(conn, statement) do
-    exec = fn conn ->
-      q = %QueryStatement{statement: statement}
+    q = %Query{statement: statement}
 
-      case DBConnection.execute(conn, q, %{}) do
-        {:ok, resp} -> Transform.transform_query(resp)
-        other -> other
-      end
+    case DBConnection.execute(conn, q, %{}) do
+      {:ok, resp} -> Transform.transform_query(resp)
+      other -> other
     end
-
-    DBConnection.run(conn, exec, run_opts())
   end
 
   defp run_opts do
     [pool: ExDgraph.config(:pool), timeout: ExDgraph.config(:timeout)]
   end
 end
+
+defimpl DBConnection.Query, for: ExDgraph.Query do
+  alias ExDgraph.Transform
+
+  def describe(query, _), do: query
+
+  def parse(query, _), do: query
+
+  def encode(_query, data, _), do: data
+
+  def decode(_query, result, _opts), do: Transform.transform_query(result)
+end
diff --git a/lib/exdgraph/query_statement.ex b/lib/exdgraph/query_statement.ex
deleted file mode 100644
index 5af8a32..0000000
--- a/lib/exdgraph/query_statement.ex
+++ /dev/null
@@ -1,16 +0,0 @@
-defmodule ExDgraph.QueryStatement do
-  @moduledoc false
-  defstruct statement: ""
-end
-
-defimpl DBConnection.Query, for: ExDgraph.QueryStatement do
-  alias ExDgraph.Transform
-
-  def describe(query, _), do: query
-
-  def parse(query, _), do: query
-
-  def encode(_query, data, _), do: data
-
-  def decode(_query, result, _opts), do: Transform.transform_query(result)
-end

From cefd906996e0971c11c05b09bd3409dd9a44bd98 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Thu, 5 Sep 2019 23:11:49 +0200
Subject: [PATCH 20/68] Add key :code to Error.

---
 lib/exdgraph/error.ex | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/exdgraph/error.ex b/lib/exdgraph/error.ex
index 2665ac9..40dff47 100755
--- a/lib/exdgraph/error.ex
+++ b/lib/exdgraph/error.ex
@@ -2,7 +2,7 @@ defmodule ExDgraph.Error do
   @moduledoc """
   Dgraph or connection error are wrapped in ExDgraph.Error.
   """
-  defexception [:reason, :action]
+  defexception [:reason, :action, :code]
 
   @type t :: %ExDgraph.Error{}
 

From 31ee6b729828f9de64a816d4006da6787a8ba063 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Thu, 5 Sep 2019 23:14:26 +0200
Subject: [PATCH 21/68] Rewrite protocol, keep opts in state and change how ssl
 configuration is set.

---
 lib/exdgraph/protocol.ex | 150 ++++++++++++++++++++++++++++++---------
 1 file changed, 117 insertions(+), 33 deletions(-)

diff --git a/lib/exdgraph/protocol.ex b/lib/exdgraph/protocol.ex
index 4e168c3..14543cd 100755
--- a/lib/exdgraph/protocol.ex
+++ b/lib/exdgraph/protocol.ex
@@ -16,7 +16,10 @@ defmodule ExDgraph.Protocol do
     QueryStatement
   }
 
+  alias GRPC.Stub
+
   defstruct [
+    :opts,
     :channel,
     :connected,
     :txn_context,
@@ -25,19 +28,23 @@ defmodule ExDgraph.Protocol do
   ]
 
   @impl true
-  def connect(_opts) do
-    host = to_charlist(ExDgraph.config(:hostname))
-    port = ExDgraph.config(:port)
+  def connect(opts) do
+    opts = default_opts(opts)
+
+    host = to_charlist(opts[:hostname])
+    port = normalize_port(opts[:port])
 
-    opts =
-      []
-      |> set_ssl_opts()
-      |> Keyword.put(:adapter_opts, %{http2_opts: %{keepalive: ExDgraph.config(:keepalive)}})
+    # TODO: with statement?
+    case gen_stub_options(opts) do
+      {:ok, stub_opts} ->
+        case Stub.connect("#{host}:#{port}", stub_opts) do
+          {:ok, channel} ->
+            state = %__MODULE__{opts: opts, channel: channel}
+            {:ok, state}
 
-    case GRPC.Stub.connect("#{host}:#{port}", opts) do
-      {:ok, channel} ->
-        state = %__MODULE__{channel: channel}
-        {:ok, state}
+          {:error, reason} ->
+            {:error, %Error{action: :connect, reason: reason}}
+        end
 
       {:error, reason} ->
         {:error, %Error{action: :connect, reason: reason}}
@@ -102,17 +109,22 @@ defmodule ExDgraph.Protocol do
     {:ok, state}
   end
 
+  @impl true
+  def handle_prepare(query, _opts, %{txn_context: txn_context} = state) do
+    {:ok, %{query | txn_context: txn_context}, state}
+  end
+
   @impl true
   def handle_execute(
         %QueryStatement{statement: statement} = query,
         _params,
         _,
         %{channel: channel} = state
+        %{channel: channel, opts: opts} = state
       ) do
     request = ExDgraph.Api.Request.new(query: statement)
-    timeout = ExDgraph.config(:timeout)
 
-    case ExDgraph.Api.Dgraph.Stub.query(channel, request, timeout: timeout) do
+    case ExDgraph.Api.Dgraph.Stub.query(channel, request, timeout: opts[:timeout]) do
       {:ok, res} ->
         {:ok, query, res, state}
 
@@ -165,11 +177,11 @@ defmodule ExDgraph.Protocol do
         _params,
         _,
         %{channel: channel} = state
+        %{channel: channel, opts: opts} = state
       ) do
     operation = Api.Operation.new(drop_all: drop_all, schema: schema, drop_attr: drop_attr)
-    timeout = ExDgraph.config(:timeout)
 
-    case ExDgraph.Api.Dgraph.Stub.alter(channel, operation, timeout: timeout) do
+    case ExDgraph.Api.Dgraph.Stub.alter(channel, operation, timeout: opts[:timeout]) do
       {:ok, res} ->
         {:ok, query, res, state}
 
@@ -181,10 +193,8 @@ defmodule ExDgraph.Protocol do
       {:error, e, state}
   end
 
-  defp do_mutate(%{channel: channel} = state, dgraph_query, query) do
-    timeout = ExDgraph.config(:timeout)
-
-    case ExDgraph.Api.Dgraph.Stub.mutate(channel, dgraph_query, timeout: timeout) do
+  defp do_mutate(%{channel: channel, opts: opts} = state, dgraph_query, query) do
+    case ExDgraph.Api.Dgraph.Stub.mutate(channel, dgraph_query, timeout: opts[:timeout]) do
       {:ok, res} ->
         {:ok, query, res, state}
 
@@ -196,31 +206,101 @@ defmodule ExDgraph.Protocol do
       {:error, e, state}
   end
 
-  defp configure_ssl(ssl_opts \\ []) do
-    case ExDgraph.config(:ssl) do
+  @spec default_opts(Keyword.t()) :: Keyword.t()
+  defp default_opts(opts \\ []) do
+    opts
+    |> Keyword.put_new(:hostname, System.get_env("DGRAPH_HOST") || 'localhost')
+    |> Keyword.put_new(:port, System.get_env("DGRAPH_PORT") || 9080)
+    |> Keyword.put_new(:name, :ex_dgraph)
+    |> Keyword.put_new(:timeout, 15_000)
+    |> Keyword.put_new(:ssl, false)
+    |> Keyword.put_new(:tls_client_auth, false)
+    |> Keyword.put_new(:certfile, nil)
+    |> Keyword.put_new(:keyfile, nil)
+    |> Keyword.put_new(:cacertfile, nil)
+    |> Keyword.put_new(:enforce_struct_schema, false)
+    |> Keyword.put_new(:keepalive, :infinity)
+    # DBConnection config options
+    |> Keyword.put_new(:backoff_min, 1_000)
+    |> Keyword.put_new(:backoff_max, 30_000)
+    |> Keyword.put_new(:backoff_type, :rand_exp)
+    |> Keyword.put_new(:pool_size, 5)
+    |> Keyword.put_new(:idle_interval, 5_000)
+    |> Keyword.put_new(:max_restarts, 3)
+    |> Keyword.put_new(:max_seconds, 5)
+    |> Keyword.update!(:port, &normalize_port/1)
+    |> Enum.reject(fn {_k, v} -> is_nil(v) end)
+  end
+
+  def gen_stub_options(opts) do
+    adapter_opts = %{http2_opts: %{keepalive: opts[:keepalive]}}
+    stub_opts = [adapter_opts: adapter_opts]
+
+    case gen_ssl_config(opts) do
+      {:ok, nil} ->
+        {:ok, stub_opts}
+
+      {:ok, ssl_config} ->
+        {:ok, Keyword.put(stub_opts, :cred, GRPC.Credential.new(ssl: ssl_config))}
+
+      {:error, error} ->
+        {:error, error}
+    end
+  end
+
+  def gen_ssl_config(opts) do
+    if opts[:ssl] do
+      case opts[:cacertfile] do
+        nil ->
+          {:error, {:not_provided, :cacertfile}}
+
+        cacertfile ->
+          with {:ok, tls_config} <- check_tls(opts) do
+            ssl_config = [{:cacertfile, cacertfile} | tls_config]
+            ssl_config = for {key, value} <- ssl_config, do: {key, to_charlist(value)}
+            {:ok, ssl_config}
+          end
+      end
+    else
+      {:ok, nil}
+    end
+  end
+
+  defp check_tls(opts) do
+    case {opts[:certfile], opts[:keyfile]} do
+      {nil, nil} -> {:ok, []}
+      {_, nil} -> {:error, %Error{action: :connect, reason: {:not_provided, :keyfile}}}
+      {nil, _} -> {:error, %Error{action: :connect, reason: {:not_provided, :certfile}}}
+      {certfile, keyfile} -> {:ok, [certfile: certfile, keyfile: keyfile]}
+    end
+  end
+
+  defp configure_ssl(opts) do
+    case opts[:ssl] do
       true ->
-        add_ssl_file(ssl_opts, :cacertfile)
+        add_ssl_file(opts, :cacertfile)
 
       false ->
-        ssl_opts
+        opts
     end
   end
 
-  defp configure_tls_auth(ssl_opts \\ []) do
-    case ExDgraph.config(:tls_client_auth) do
+  defp configure_tls_auth(opts) do
+    case opts[:tls_client_auth] do
       true ->
-        ssl_opts
+        opts
         |> add_ssl_file(:certfile)
         |> add_ssl_file(:keyfile)
         |> add_ssl_file(:certfile)
 
       false ->
-        ssl_opts
+        opts
     end
   end
 
-  defp add_ssl_file(ssl_opts \\ [], type) do
-    Keyword.put(ssl_opts, type, validate_tls_file(type, ExDgraph.config(type)))
+  defp add_ssl_file(opts, type) do
+    path = Keyword.fetch!(opts, type)
+    Keyword.put(opts, type, validate_tls_file(type, path))
   end
 
   defp validate_tls_file(type, path) do
@@ -231,14 +311,15 @@ defmodule ExDgraph.Protocol do
       false ->
         raise Exception,
           code: 2,
-          message: "SSL configuration error. File #{type} '#{ExDgraph.config(type)}' not found"
+          message: "SSL configuration error. File #{type} '#{path}' not found"
     end
   end
 
-  defp set_ssl_opts(opts \\ []) do
-    if ExDgraph.config(:ssl) || ExDgraph.config(:tls_client_auth) do
+  defp set_ssl_opts(opts) do
+    if opts[:ssl] || opts[:tls_client_auth] do
       ssl_opts =
-        configure_ssl()
+        opts
+        |> configure_ssl()
         |> configure_tls_auth()
 
       Keyword.put(opts, :cred, GRPC.Credential.new(ssl: ssl_opts))
@@ -246,4 +327,7 @@ defmodule ExDgraph.Protocol do
       opts
     end
   end
+
+  defp normalize_port(port) when is_binary(port), do: String.to_integer(port)
+  defp normalize_port(port) when is_integer(port), do: port
 end

From 64174887ec9b690315dcdd42b22c112a4aef517e Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Thu, 5 Sep 2019 23:15:33 +0200
Subject: [PATCH 22/68] Move Error to structs file.

---
 lib/exdgraph/{error.ex => structs.ex} | 1 +
 1 file changed, 1 insertion(+)
 rename lib/exdgraph/{error.ex => structs.ex} (99%)
 mode change 100755 => 100644

diff --git a/lib/exdgraph/error.ex b/lib/exdgraph/structs.ex
old mode 100755
new mode 100644
similarity index 99%
rename from lib/exdgraph/error.ex
rename to lib/exdgraph/structs.ex
index 40dff47..28c453d
--- a/lib/exdgraph/error.ex
+++ b/lib/exdgraph/structs.ex
@@ -11,3 +11,4 @@ defmodule ExDgraph.Error do
     "#{action} failed with #{inspect(reason)}"
   end
 end
+

From f82d89ed2f5c0e2695929302a442a64a6dfaad37 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Thu, 5 Sep 2019 23:15:41 +0200
Subject: [PATCH 23/68] Add Result struct.

---
 lib/exdgraph/structs.ex | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lib/exdgraph/structs.ex b/lib/exdgraph/structs.ex
index 28c453d..fe2540f 100644
--- a/lib/exdgraph/structs.ex
+++ b/lib/exdgraph/structs.ex
@@ -12,3 +12,10 @@ defmodule ExDgraph.Error do
   end
 end
 
+defmodule ExDgraph.Result do
+  @moduledoc """
+  Results from a query are wrapped in ExDgraph.Result
+  """
+
+  defstruct [:data, :schema, :txn]
+end

From 3a5c58f88dfc69decfdf19eccf4d6c2a008b2a97 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Thu, 5 Sep 2019 23:16:31 +0200
Subject: [PATCH 24/68] Rewrite Query.

---
 lib/exdgraph/query.ex     | 68 +++++++++++++++++----------------------
 lib/exdgraph/transform.ex | 20 ------------
 2 files changed, 30 insertions(+), 58 deletions(-)

diff --git a/lib/exdgraph/query.ex b/lib/exdgraph/query.ex
index 29ad8da..e599a65 100644
--- a/lib/exdgraph/query.ex
+++ b/lib/exdgraph/query.ex
@@ -2,54 +2,46 @@ defmodule ExDgraph.Query do
   @moduledoc """
   Provides the functions for the callbacks from the DBConnection behaviour.
   """
-  alias ExDgraph.{Exception, Query, Transform}
+  alias ExDgraph.{Exception, Error, Query, Transform}
 
-  defstruct statement: ""
-
-  @doc false
-  def query(conn, statement) do
-    case query_commit(conn, statement) do
-      {:error, f} ->
-        {:error, code: Map.get(f, :code, Map.get(f, :status)), message: f.message}
+  defstruct [:statement, :parameters, :txn_context]
+end
 
-      {:ok, %Query{}, result} ->
-        {:ok, result}
-    end
-  end
+defimpl DBConnection.Query, for: ExDgraph.Query do
+  @moduledoc """
+  Implementation of `DBConnection.Query` protocol.
+  """
 
-  @doc false
-  def query!(conn, statement) do
-    case query(conn, statement) do
-      {:ok, r} ->
-        r
+  alias ExDgraph.{Result, Utils}
 
-      {:error, code: code, message: message} ->
-        raise Exception, code: code, message: message
-    end
-  end
+  def describe(query, _), do: query
 
-  defp query_commit(conn, statement) do
-    q = %Query{statement: statement}
+  @doc """
+  Parse a query.
 
-    case DBConnection.execute(conn, q, %{}) do
-      {:ok, resp} -> Transform.transform_query(resp)
-      other -> other
-    end
-  end
+  This function is called to parse a query term before it is prepared.
+  """
+  def parse(%{statement: nil} = query), do: %{query | statement: ""}
 
-  defp run_opts do
-    [pool: ExDgraph.config(:pool), timeout: ExDgraph.config(:timeout)]
+  def parse(%{statement: statement} = query, _) do
+    %{query | statement: IO.iodata_to_binary(statement)}
   end
-end
-
-defimpl DBConnection.Query, for: ExDgraph.Query do
-  alias ExDgraph.Transform
 
-  def describe(query, _), do: query
+  def encode(_query, data, _), do: data
 
-  def parse(query, _), do: query
+  def decode(_query, %ExDgraph.Api.Response{json: json, schema: schema, txn: txn} = result, _opts) do
+    decoded = Jason.decode!(json)
 
-  def encode(_query, data, _), do: data
+    transformed =
+      case Morphix.atomorphiform(decoded) do
+        {:ok, parsed} -> parsed
+        _ -> json
+      end
 
-  def decode(_query, result, _opts), do: Transform.transform_query(result)
+    %Result{
+      data: transformed,
+      schema: schema,
+      txn: txn
+    }
+  end
 end
diff --git a/lib/exdgraph/transform.ex b/lib/exdgraph/transform.ex
index 59b3e4a..350f7f8 100644
--- a/lib/exdgraph/transform.ex
+++ b/lib/exdgraph/transform.ex
@@ -3,26 +3,6 @@ defmodule ExDgraph.Transform do
   Transform a raw response from Dgraph. For example decode the json part.
   """
 
-  @doc """
-  Takes a response from Dgraph, parses the `json` with `Poison` and transforms all string
-  keys into atom keys.
-  """
-  def transform_query(%ExDgraph.Api.Response{json: json, schema: schema, txn: txn}) do
-    decoded = Jason.decode!(json)
-
-    transformed =
-      case Morphix.atomorphiform(decoded) do
-        {:ok, parsed} -> parsed
-        _ -> json
-      end
-
-    %{
-      result: transformed,
-      schema: schema,
-      txn: txn
-    }
-  end
-
   @doc """
   Takes a response from Dgraph and returns a map.
   """

From f92a2a707eecc620106730b26e9c6f50a1278c18 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Thu, 5 Sep 2019 23:16:49 +0200
Subject: [PATCH 25/68] Update test setup.

---
 test/test_helper.exs | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/test/test_helper.exs b/test/test_helper.exs
index 5573444..ef0e2e9 100755
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@@ -60,8 +60,7 @@ defmodule ExDgraph.TestHelper do
      _:st1 <running_time> "132" .
   """
 
-  def import_starwars_sample() do
-    conn = ExDgraph.conn()
+  def import_starwars_sample(conn) do
     ExDgraph.operation(conn, %{schema: @starwars_schema})
     {:ok, _} = ExDgraph.mutation(conn, @starwars_creation_mutation)
   end
@@ -77,7 +76,7 @@ defmodule ExDgraph.TestHelper do
 end
 
 if Process.whereis(ExDgraph.pool_name()) == nil do
-  {:ok, _pid} = ExDgraph.start_link(Application.get_env(:ex_dgraph, ExDgraph))
+  {:ok, _conn} = ExDgraph.start_link(Application.get_env(:ex_dgraph, ExDgraph))
 end
 
 ExUnit.configure(exclude: [tls_tests: true])

From 16bd729da2aeba51a65b916ceb6acd3e6aab408b Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Thu, 5 Sep 2019 23:17:01 +0200
Subject: [PATCH 26/68] Use new test setup in query test.

---
 test/query_test.exs | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/test/query_test.exs b/test/query_test.exs
index a4c2054..3709d2d 100644
--- a/test/query_test.exs
+++ b/test/query_test.exs
@@ -18,14 +18,9 @@ defmodule ExDgraph.QueryTest do
   """
 
   setup_all do
-    conn = ExDgraph.conn()
-    drop_all()
-    import_starwars_sample()
-
-    on_exit(fn ->
-      # close channel ?
-      :ok
-    end)
+    {:ok, conn} = ExDgraph.start_link()
+    ExDgraph.operation(conn, %{drop_all: true})
+    import_starwars_sample(conn)
 
     [conn: conn]
   end

From e98fe137a9288c6b9b961c57a17f7b6118c08f88 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Thu, 5 Sep 2019 23:17:32 +0200
Subject: [PATCH 27/68] Remove default_config from Utils.

---
 lib/exdgraph/utils.ex | 27 ---------------------------
 1 file changed, 27 deletions(-)

diff --git a/lib/exdgraph/utils.ex b/lib/exdgraph/utils.ex
index 8f8839a..ec6a26a 100755
--- a/lib/exdgraph/utils.ex
+++ b/lib/exdgraph/utils.ex
@@ -83,33 +83,6 @@ defmodule ExDgraph.Utils do
     end
   end
 
-  @doc """
-  Fills in the given `opts` with default options.
-  """
-  @spec default_config(Keyword.t()) :: Keyword.t()
-  def default_config(config \\ Application.get_env(:ex_dgraph, ExDgraph)) do
-    config
-    |> Keyword.put_new(:hostname, System.get_env("DGRAPH_HOST") || 'localhost')
-    |> Keyword.put_new(:port, System.get_env("DGRAPH_PORT") || 9080)
-    |> Keyword.put_new(:name, :ex_dgraph)
-    |> Keyword.put_new(:timeout, 15_000)
-    |> Keyword.put_new(:ssl, false)
-    |> Keyword.put_new(:tls_client_auth, false)
-    |> Keyword.put_new(:certfile, nil)
-    |> Keyword.put_new(:keyfile, nil)
-    |> Keyword.put_new(:cacertfile, nil)
-    |> Keyword.put_new(:enforce_struct_schema, false)
-    |> Keyword.put_new(:keepalive, :infinity)
-    # DBConnection config options
-    |> Keyword.put_new(:name, 1_000)
-    |> Keyword.put_new(:backoff_min, 1_000)
-    |> Keyword.put_new(:backoff_max, 30_000)
-    |> Keyword.put_new(:backoff_type, :rand_exp)
-    |> Keyword.put_new(:pool_size, 5)
-    |> Keyword.put_new(:idle_interval, 5_000)
-    |> Keyword.put_new(:max_restarts, 3)
-    |> Keyword.put_new(:max_seconds, 5)
-    |> Enum.reject(fn {_k, v} -> is_nil(v) end)
   end
 end
 

From 229787c87ccaae14278ea5c9cd0af36d009c9c3f Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Thu, 5 Sep 2019 23:21:28 +0200
Subject: [PATCH 28/68] Remove dependency morphix.

---
 lib/exdgraph/query.ex | 13 +++++--------
 lib/exdgraph/utils.ex | 14 ++++++++++++++
 mix.exs               |  1 -
 3 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/lib/exdgraph/query.ex b/lib/exdgraph/query.ex
index e599a65..57f6830 100644
--- a/lib/exdgraph/query.ex
+++ b/lib/exdgraph/query.ex
@@ -30,16 +30,13 @@ defimpl DBConnection.Query, for: ExDgraph.Query do
   def encode(_query, data, _), do: data
 
   def decode(_query, %ExDgraph.Api.Response{json: json, schema: schema, txn: txn} = result, _opts) do
-    decoded = Jason.decode!(json)
-
-    transformed =
-      case Morphix.atomorphiform(decoded) do
-        {:ok, parsed} -> parsed
-        _ -> json
-      end
+    data =
+      json
+      |> Jason.decode!()
+      |> Utils.atomify_map_keys()
 
     %Result{
-      data: transformed,
+      data: data,
       schema: schema,
       txn: txn
     }
diff --git a/lib/exdgraph/utils.ex b/lib/exdgraph/utils.ex
index ec6a26a..be8f5e0 100755
--- a/lib/exdgraph/utils.ex
+++ b/lib/exdgraph/utils.ex
@@ -83,7 +83,21 @@ defmodule ExDgraph.Utils do
     end
   end
 
+  def atomify_map_keys(map) when is_map(map) do
+    Enum.reduce(map, %{}, fn
+      {key, value}, acc when is_atom(key) ->
+        Map.put(acc, key, atomify_map_keys(value))
+
+      {key, value}, acc when is_binary(key) ->
+        Map.put(acc, String.to_existing_atom(key), atomify_map_keys(value))
+    end)
+  end
+
+  def atomify_map_keys(list) when is_list(list) do
+    for el <- list, do: atomify_map_keys(el)
   end
+
+  def atomify_map_keys(map), do: map
 end
 
 # Partly Copyright (c) 2017 Jason Goldberger
diff --git a/mix.exs b/mix.exs
index 9f768c5..2dc18fa 100755
--- a/mix.exs
+++ b/mix.exs
@@ -41,7 +41,6 @@ defmodule ExDgraph.MixProject do
       {:elixir_uuid, "~> 1.2"},
       {:grpc, "~> 0.3.1"},
       {:jason, "~> 1.1"},
-      {:morphix, "~> 0.6.0"},
       {:protobuf, "~> 0.6.1"},
       {:excoveralls, "~> 0.10", only: :test},
       {:credo, "~> 1.0", only: [:dev, :test], runtime: false},

From d01398dca9ca2ee4798c564db26b8c29d374104a Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Thu, 5 Sep 2019 23:21:32 +0200
Subject: [PATCH 29/68] Update mix.lock

---
 mix.lock | 34 ++++++++++++----------------------
 1 file changed, 12 insertions(+), 22 deletions(-)
 mode change 100755 => 100644 mix.lock

diff --git a/mix.lock b/mix.lock
old mode 100755
new mode 100644
index e5f1d12..a78c22f
--- a/mix.lock
+++ b/mix.lock
@@ -1,40 +1,30 @@
 %{
   "bunt": {:hex, :bunt, "0.2.0", "951c6e801e8b1d2cbe58ebbd3e616a869061ddadcc4863d0a2182541acae9a38", [:mix], [], "hexpm"},
-  "certifi": {:hex, :certifi, "2.4.2", "75424ff0f3baaccfd34b1214184b6ef616d89e420b258bb0a5ea7d7bc628f7f0", [:rebar3], [{:parse_trans, "~>3.3", [hex: :parse_trans, repo: "hexpm", optional: false]}], "hexpm"},
-  "chatterbox": {:git, "https://github.com/tony612/chatterbox.git", "7fe9b6d89903c59359e4406842cb68ecfa1e9b5c", [branch: "my-fix"]},
+  "certifi": {:hex, :certifi, "2.5.1", "867ce347f7c7d78563450a18a6a28a8090331e77fa02380b4a21962a65d36ee5", [:rebar3], [{:parse_trans, "~>3.3", [hex: :parse_trans, repo: "hexpm", optional: false]}], "hexpm"},
   "connection": {:hex, :connection, "1.0.4", "a1cae72211f0eef17705aaededacac3eb30e6625b04a6117c1b2db6ace7d5976", [:mix], [], "hexpm"},
   "cowboy": {:hex, :cowboy, "2.5.0", "4ef3ae066ee10fe01ea3272edc8f024347a0d3eb95f6fbb9aed556dacbfc1337", [:rebar3], [{:cowlib, "~> 2.6.0", [hex: :cowlib, repo: "hexpm", optional: false]}, {:ranch, "~> 1.6.2", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm"},
   "cowlib": {:hex, :cowlib, "2.6.0", "8aa629f81a0fc189f261dc98a42243fa842625feea3c7ec56c48f4ccdb55490f", [:rebar3], [], "hexpm"},
-  "credo": {:hex, :credo, "1.0.2", "88bc918f215168bf6ce7070610a6173c45c82f32baa08bdfc80bf58df2d103b6", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
+  "credo": {:hex, :credo, "1.1.4", "c2f3b73c895d81d859cec7fcee7ffdb972c595fd8e85ab6f8c2adbf01cf7c29c", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
   "db_connection": {:hex, :db_connection, "2.1.1", "a51e8a2ee54ef2ae6ec41a668c85787ed40cb8944928c191280fe34c15b76ae5", [:mix], [{:connection, "~> 1.0.2", [hex: :connection, repo: "hexpm", optional: false]}], "hexpm"},
-  "earmark": {:hex, :earmark, "1.3.4", "52aba89c60529284df5fc18adc4c808b7346e72668bc2fb2b68d7394996c4af8", [:mix], [], "hexpm"},
+  "earmark": {:hex, :earmark, "1.4.0", "397e750b879df18198afc66505ca87ecf6a96645545585899f6185178433cc09", [:mix], [], "hexpm"},
   "elixir_uuid": {:hex, :elixir_uuid, "1.2.0", "ff26e938f95830b1db152cb6e594d711c10c02c6391236900ddd070a6b01271d", [:mix], [], "hexpm"},
-  "ex_doc": {:hex, :ex_doc, "0.19.3", "3c7b0f02851f5fc13b040e8e925051452e41248f685e40250d7e40b07b9f8c10", [:mix], [{:earmark, "~> 1.2", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.10", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm"},
-  "excoveralls": {:hex, :excoveralls, "0.10.5", "7c912c4ec0715a6013647d835c87cde8154855b9b84e256bc7a63858d5f284e3", [:mix], [{:hackney, "~> 1.13", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
-  "exjsx": {:hex, :exjsx, "4.0.0", "60548841e0212df401e38e63c0078ec57b33e7ea49b032c796ccad8cde794b5c", [:mix], [{:jsx, "~> 2.8.0", [hex: :jsx, repo: "hexpm", optional: false]}], "hexpm"},
-  "file_system": {:hex, :file_system, "0.2.6", "fd4dc3af89b9ab1dc8ccbcc214a0e60c41f34be251d9307920748a14bf41f1d3", [:mix], [], "hexpm"},
-  "fs": {:hex, :fs, "0.9.2", "ed17036c26c3f70ac49781ed9220a50c36775c6ca2cf8182d123b6566e49ec59", [:rebar], [], "hexpm"},
+  "ex_doc": {:hex, :ex_doc, "0.21.2", "caca5bc28ed7b3bdc0b662f8afe2bee1eedb5c3cf7b322feeeb7c6ebbde089d6", [:mix], [{:earmark, "~> 1.3.3 or ~> 1.4", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm"},
+  "excoveralls": {:hex, :excoveralls, "0.11.2", "0c6f2c8db7683b0caa9d490fb8125709c54580b4255ffa7ad35f3264b075a643", [:mix], [{:hackney, "~> 1.0", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
+  "file_system": {:hex, :file_system, "0.2.7", "e6f7f155970975789f26e77b8b8d8ab084c59844d8ecfaf58cbda31c494d14aa", [:mix], [], "hexpm"},
   "grpc": {:hex, :grpc, "0.3.1", "bba240631f1a262db865d9bc620b3e3abc0acfab27a922ad47727d057a734ab3", [:mix], [{:cowboy, "~> 2.5", [hex: :cowboy, repo: "hexpm", optional: false]}, {:gun, "~> 1.2", [hex: :gun, repo: "hexpm", optional: false]}, {:protobuf, "~> 0.5", [hex: :protobuf, repo: "hexpm", optional: false]}], "hexpm"},
   "gun": {:hex, :gun, "1.3.0", "18e5d269649c987af95aec309f68a27ffc3930531dd227a6eaa0884d6684286e", [:rebar3], [{:cowlib, "~> 2.6.0", [hex: :cowlib, repo: "hexpm", optional: false]}], "hexpm"},
-  "hackney": {:hex, :hackney, "1.15.0", "287a5d2304d516f63e56c469511c42b016423bcb167e61b611f6bad47e3ca60e", [:rebar3], [{:certifi, "2.4.2", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "6.0.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "1.0.1", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "1.0.2", [hex: :mimerl, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.4", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm"},
-  "hpack": {:git, "https://github.com/joedevivo/hpack.git", "6b58b6231e9b6ab83096715120578976f72f4f7c", [tag: "0.2.3"]},
+  "hackney": {:hex, :hackney, "1.15.1", "9f8f471c844b8ce395f7b6d8398139e26ddca9ebc171a8b91342ee15a19963f4", [:rebar3], [{:certifi, "2.5.1", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "6.0.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "1.0.1", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "~>1.1", [hex: :mimerl, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.4", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm"},
   "idna": {:hex, :idna, "6.0.0", "689c46cbcdf3524c44d5f3dde8001f364cd7608a99556d8fbd8239a5798d4c10", [:rebar3], [{:unicode_util_compat, "0.4.1", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm"},
   "jason": {:hex, :jason, "1.1.2", "b03dedea67a99223a2eaf9f1264ce37154564de899fd3d8b9a21b1a6fd64afe7", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm"},
-  "jsx": {:hex, :jsx, "2.8.3", "a05252d381885240744d955fbe3cf810504eb2567164824e19303ea59eef62cf", [:mix, :rebar3], [], "hexpm"},
-  "makeup": {:hex, :makeup, "0.5.5", "9e08dfc45280c5684d771ad58159f718a7b5788596099bdfb0284597d368a882", [:mix], [{:nimble_parsec, "~> 0.4", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm"},
-  "makeup_elixir": {:hex, :makeup_elixir, "0.10.0", "0f09c2ddf352887a956d84f8f7e702111122ca32fbbc84c2f0569b8b65cbf7fa", [:mix], [{:makeup, "~> 0.5.5", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm"},
+  "makeup": {:hex, :makeup, "1.0.0", "671df94cf5a594b739ce03b0d0316aa64312cee2574b6a44becb83cd90fb05dc", [:mix], [{:nimble_parsec, "~> 0.5.0", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm"},
+  "makeup_elixir": {:hex, :makeup_elixir, "0.14.0", "cf8b7c66ad1cff4c14679698d532f0b5d45a3968ffbcbfd590339cb57742f1ae", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm"},
   "metrics": {:hex, :metrics, "1.0.1", "25f094dea2cda98213cecc3aeff09e940299d950904393b2a29d191c346a8486", [:rebar3], [], "hexpm"},
-  "mimerl": {:hex, :mimerl, "1.0.2", "993f9b0e084083405ed8252b99460c4f0563e41729ab42d9074fd5e52439be88", [:rebar3], [], "hexpm"},
+  "mimerl": {:hex, :mimerl, "1.2.0", "67e2d3f571088d5cfd3e550c383094b47159f3eee8ffa08e64106cdf5e981be3", [:rebar3], [], "hexpm"},
   "mix_test_watch": {:hex, :mix_test_watch, "0.9.0", "c72132a6071261893518fa08e121e911c9358713f62794a90c95db59042af375", [:mix], [{:file_system, "~> 0.2.1 or ~> 0.3", [hex: :file_system, repo: "hexpm", optional: false]}], "hexpm"},
-  "morphix": {:hex, :morphix, "0.6.0", "78902c71672a5de64759fb5847f9bed708eb82bc0eb017f1e5cd95f93f1a167b", [:mix], [], "hexpm"},
-  "nimble_parsec": {:hex, :nimble_parsec, "0.4.0", "ee261bb53214943679422be70f1658fff573c5d0b0a1ecd0f18738944f818efe", [:mix], [], "hexpm"},
+  "nimble_parsec": {:hex, :nimble_parsec, "0.5.1", "c90796ecee0289dbb5ad16d3ad06f957b0cd1199769641c961cfe0b97db190e0", [:mix], [], "hexpm"},
   "parse_trans": {:hex, :parse_trans, "3.3.0", "09765507a3c7590a784615cfd421d101aec25098d50b89d7aa1d66646bc571c1", [:rebar3], [], "hexpm"},
-  "poison": {:hex, :poison, "3.1.0", "d9eb636610e096f86f25d9a46f35a9facac35609a7591b3be3326e99a0484665", [:mix], [], "hexpm"},
-  "poolboy": {:hex, :poolboy, "1.5.2", "392b007a1693a64540cead79830443abf5762f5d30cf50bc95cb2c1aaafa006b", [:rebar3], [], "hexpm"},
-  "protobuf": {:hex, :protobuf, "0.6.1", "3ae3ca63d12d1a8c5b10c2e5fbc5145dccbff842ccd541109b74b20b631cea3b", [:mix], [], "hexpm"},
+  "protobuf": {:hex, :protobuf, "0.6.3", "742e9034c20532534ca96d7a7ee1251e0f2327dcf8ea6de0dd3eb3e054b236a7", [:mix], [], "hexpm"},
   "ranch": {:hex, :ranch, "1.6.2", "6db93c78f411ee033dbb18ba8234c5574883acb9a75af0fb90a9b82ea46afa00", [:rebar3], [], "hexpm"},
-  "retry": {:hex, :retry, "0.13.0", "bb9b2713f70f39337837852337ad280c77662574f4fb852a8386c269f3d734c4", [:mix], [], "hexpm"},
   "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.4", "f0eafff810d2041e93f915ef59899c923f4568f4585904d010387ed74988e77b", [:make, :mix, :rebar3], [], "hexpm"},
   "unicode_util_compat": {:hex, :unicode_util_compat, "0.4.1", "d869e4c68901dd9531385bb0c8c40444ebf624e60b6962d95952775cac5e90cd", [:rebar3], [], "hexpm"},
-  "uuid": {:hex, :uuid, "1.1.8", "e22fc04499de0de3ed1116b770c7737779f226ceefa0badb3592e64d5cfb4eb9", [:mix], [], "hexpm"},
 }

From c943253a17732bdea53671cfde50322184455b66 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Thu, 5 Sep 2019 23:25:01 +0200
Subject: [PATCH 30/68] Test connection errors.

---
 test/exdgraph_test.exs | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/test/exdgraph_test.exs b/test/exdgraph_test.exs
index fb49e26..a2fec2e 100755
--- a/test/exdgraph_test.exs
+++ b/test/exdgraph_test.exs
@@ -1,3 +1,22 @@
 defmodule ExDgraphTest do
   use ExUnit.Case
+  import ExUnit.CaptureLog
+
+  test "connection_errors" do
+    Process.flag(:trap_exit, true)
+    opts = [backoff_type: :stop, max_restarts: 0, timeout: 500]
+
+    assert capture_log(fn ->
+             {:ok, pid} = ExDgraph.start_link([hostname: "non_existing"] ++ opts)
+             assert_receive {:EXIT, ^pid, :killed}, 10000
+           end) =~
+             "** (ExDgraph.Error) connect failed with \"Error when opening connection: :timeout\""
+
+    assert capture_log(fn ->
+             {:ok, pid} = ExDgraph.start_link([port: 700] ++ opts)
+
+             assert_receive {:EXIT, ^pid, :killed}, 10000
+           end) =~
+             "** (ExDgraph.Error) connect failed with \"Error when opening connection: :timeout\""
+  end
 end

From 104a6b12f9aa54dd2709292e58c05ab01f7e44c3 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Thu, 5 Sep 2019 23:26:10 +0200
Subject: [PATCH 31/68] Add ProtocolTest and test ssl errors.

---
 test/protocol_test.exs | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 test/protocol_test.exs

diff --git a/test/protocol_test.exs b/test/protocol_test.exs
new file mode 100644
index 0000000..1aa1a18
--- /dev/null
+++ b/test/protocol_test.exs
@@ -0,0 +1,19 @@
+defmodule ExDgraph.ProtocolTest do
+  use ExUnit.Case, async: true
+  alias ExDgraph.Error
+
+  test "ssl_connection_errors" do
+    opts = [
+      backoff_type: :stop,
+      ssl: true
+    ]
+
+    Process.flag(:trap_exit, true)
+
+    assert {:error,
+            %Error{
+              action: :connect,
+              reason: {:not_provided, :cacertfile}
+            }} = ExDgraph.Protocol.connect(opts)
+  end
+end

From 2ab83f8463039877e18cfe06ba3e16c17b8e9b2c Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Thu, 5 Sep 2019 23:26:53 +0200
Subject: [PATCH 32/68] Rewrite start_link in ExDgraph.

---
 lib/exdgraph.ex | 30 +++++++++++++-----------------
 1 file changed, 13 insertions(+), 17 deletions(-)

diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index 0ab77b3..7dbc5ac 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -343,14 +343,20 @@ defmodule ExDgraph do
 
   use Supervisor
 
-  @pool_name :ex_dgraph
-  @timeout 15_000
-
   alias ExDgraph.Api.{Mutation, Operation}
+  alias ExDgraph.{Operation, Mutation, Protocol, Query, Utils}
 
   @type conn :: DBConnection.conn()
   # @type transaction :: DBConnection.t()
 
+  @pool_name :ex_dgraph
+
+  # Inherited from DBConnection
+
+  @idle_timeout 5000
+  @pool_timeout 5000
+  @timeout 15000
+
   @doc """
   Start the connection process and connect to Dgraph
 
@@ -361,6 +367,8 @@ defmodule ExDgraph do
     - `:password` - User password;
     - `:pool_size` - maximum pool size;
     - `:timeout` - Connect timeout in milliseconds (default: `#{@timeout}`) for  DBConnection and the GRPC client deadline.
+    - `:idle_timeout` - Idle timeout to ping database to maintain a connection
+      (default: `#{@idle_timeout}`)
     - `:ssl` - If to use ssl for the connection (please see configuration example).
       If you set this option, you also have to set `cacertfile` to the correct path.
     - `:tls_client_auth` - If to use TLS client authentication for the connection
@@ -406,20 +414,8 @@ defmodule ExDgraph do
       {:ok, pid} = ExDgraph.start_link(opts)
   """
   @spec start_link(Keyword.t()) :: Supervisor.on_start()
-  def start_link(opts) do
-    Supervisor.start_link(__MODULE__, opts, name: __MODULE__)
-  end
-
-  @doc false
-  def init(opts) do
-    cnf = Utils.default_config(opts)
-
-    children = [
-      {ExDgraph.ConfigAgent, cnf},
-      DBConnection.child_spec(ExDgraph.Protocol, cnf)
-    ]
-
-    Supervisor.init(children, strategy: :one_for_one)
+  def start_link(opts \\ []) do
+    DBConnection.start_link(Protocol, opts)
   end
 
   @doc """

From a8eadfd4f60b516d7c9eff524b5c76220e195fa5 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Thu, 5 Sep 2019 23:27:10 +0200
Subject: [PATCH 33/68] Move query to ExDgraph.

---
 lib/exdgraph.ex | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index 7dbc5ac..7d1acd2 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -489,15 +489,29 @@ defmodule ExDgraph do
       {:error, [code: 2, message: "while lexing invalid_statement: Invalid operation type: invalid_statement"]}
 
   """
-  @spec query(conn, String.t()) :: {:ok, ExDgraph.Response} | {:error, ExDgraph.Error}
-  defdelegate query(conn, statement), to: Query
+  @spec query(conn, iodata, map, Keyword.t()) :: {:ok, map} | {:error, Dgraph.Error.t() | term}
+  def query(conn, statement, parameters \\ %{}, opts \\ []) do
+    query = %Query{statement: statement}
+
+    with {:ok, %Query{} = query, result} <-
+           DBConnection.prepare_execute(conn, query, parameters, opts),
+         do: {:ok, query, result}
+  end
 
   @doc """
   The same as `query/2` but raises a ExDgraph.Exception if it fails.
   Returns the server response otherwise.
   """
   @spec query!(conn, String.t()) :: ExDgraph.Response | ExDgraph.Exception
-  defdelegate query!(conn, statement), to: Query
+  def query!(conn, statement) do
+    case query(conn, statement) do
+      {:ok, r} ->
+        r
+
+      {:error, code: code, message: message} ->
+        raise Exception, code: code, message: message
+    end
+  end
 
   ## Mutation
   ######################

From 1079d47e3c639c250b0a8491a7b6663aab0fe51b Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Thu, 5 Sep 2019 23:44:48 +0200
Subject: [PATCH 34/68] Use to_atom instead of to_existing_atom.

---
 lib/exdgraph/utils.ex | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/exdgraph/utils.ex b/lib/exdgraph/utils.ex
index be8f5e0..2385e6b 100755
--- a/lib/exdgraph/utils.ex
+++ b/lib/exdgraph/utils.ex
@@ -89,7 +89,7 @@ defmodule ExDgraph.Utils do
         Map.put(acc, key, atomify_map_keys(value))
 
       {key, value}, acc when is_binary(key) ->
-        Map.put(acc, String.to_existing_atom(key), atomify_map_keys(value))
+        Map.put(acc, String.to_atom(key), atomify_map_keys(value))
     end)
   end
 

From 0fb4a649e53f772942cf3399d1407c7407d4d9ec Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 00:04:46 +0200
Subject: [PATCH 35/68] Remove QueryStatement from Protocol.

---
 lib/exdgraph/protocol.ex | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/lib/exdgraph/protocol.ex b/lib/exdgraph/protocol.ex
index 14543cd..d1a0bc7 100755
--- a/lib/exdgraph/protocol.ex
+++ b/lib/exdgraph/protocol.ex
@@ -13,7 +13,7 @@ defmodule ExDgraph.Protocol do
     Exception,
     MutationStatement,
     OperationStatement,
-    QueryStatement
+    Query
   }
 
   alias GRPC.Stub
@@ -116,10 +116,9 @@ defmodule ExDgraph.Protocol do
 
   @impl true
   def handle_execute(
-        %QueryStatement{statement: statement} = query,
-        _params,
-        _,
-        %{channel: channel} = state
+        %Query{statement: statement} = query,
+        _request,
+        _opts,
         %{channel: channel, opts: opts} = state
       ) do
     request = ExDgraph.Api.Request.new(query: statement)

From 5c48429adc29f17a5488e66f2523cc1480dbd5fe Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 00:05:22 +0200
Subject: [PATCH 36/68] Return ExDgraph.Error and state from handle_prepare.

---
 lib/exdgraph/protocol.ex | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/lib/exdgraph/protocol.ex b/lib/exdgraph/protocol.ex
index d1a0bc7..1a88345 100755
--- a/lib/exdgraph/protocol.ex
+++ b/lib/exdgraph/protocol.ex
@@ -127,12 +127,9 @@ defmodule ExDgraph.Protocol do
       {:ok, res} ->
         {:ok, query, res, state}
 
-      {:error, f} ->
-        raise Exception, code: f.status, message: f.message
+      {:error, error} ->
+        {:error, %Error{action: :query, code: error.status, reason: error.message}, state}
     end
-  rescue
-    e ->
-      {:error, e, state}
   end
 
   @impl true

From d684da8c6145ba7cd930c3c8fb7f0597c23ad95c Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 00:39:13 +0200
Subject: [PATCH 37/68] Properly raise for query!/2.

---
 lib/exdgraph.ex | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index 7d1acd2..3030bed 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -505,11 +505,11 @@ defmodule ExDgraph do
   @spec query!(conn, String.t()) :: ExDgraph.Response | ExDgraph.Exception
   def query!(conn, statement) do
     case query(conn, statement) do
-      {:ok, r} ->
-        r
+      {:ok, query, result} ->
+        result
 
-      {:error, code: code, message: message} ->
-        raise Exception, code: code, message: message
+      {:error, error} ->
+        raise error
     end
   end
 

From 649cc3df5d9f54b9735fb12e0484ae137b113fc8 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 00:39:29 +0200
Subject: [PATCH 38/68] Fix query tests.

---
 test/exdgraph_test.exs | 91 ++++++++++++++++++++++++++++++++++++------
 test/query_test.exs    | 58 ---------------------------
 2 files changed, 78 insertions(+), 71 deletions(-)
 delete mode 100644 test/query_test.exs

diff --git a/test/exdgraph_test.exs b/test/exdgraph_test.exs
index a2fec2e..9390338 100755
--- a/test/exdgraph_test.exs
+++ b/test/exdgraph_test.exs
@@ -1,22 +1,87 @@
 defmodule ExDgraphTest do
   use ExUnit.Case
+  import ExDgraph.TestHelper
   import ExUnit.CaptureLog
 
-  test "connection_errors" do
-    Process.flag(:trap_exit, true)
-    opts = [backoff_type: :stop, max_restarts: 0, timeout: 500]
+  alias ExDgraph.{Error, Query, Result}
 
-    assert capture_log(fn ->
-             {:ok, pid} = ExDgraph.start_link([hostname: "non_existing"] ++ opts)
-             assert_receive {:EXIT, ^pid, :killed}, 10000
-           end) =~
-             "** (ExDgraph.Error) connect failed with \"Error when opening connection: :timeout\""
+  setup_all do
+    {:ok, conn} = ExDgraph.start_link()
+    ExDgraph.operation(conn, %{drop_all: true})
+    import_starwars_sample(conn)
 
-    assert capture_log(fn ->
-             {:ok, pid} = ExDgraph.start_link([port: 700] ++ opts)
+    [conn: conn]
+  end
+
+  describe "connection" do
+    test "connection_errors" do
+      Process.flag(:trap_exit, true)
+      opts = [backoff_type: :stop, max_restarts: 0, timeout: 500]
+
+      assert capture_log(fn ->
+               {:ok, pid} = ExDgraph.start_link([hostname: "non_existing"] ++ opts)
+               assert_receive {:EXIT, ^pid, :killed}, 10000
+             end) =~
+               "** (ExDgraph.Error) connect failed with \"Error when opening connection: :timeout\""
+
+      assert capture_log(fn ->
+               {:ok, pid} = ExDgraph.start_link([port: 700] ++ opts)
+
+               assert_receive {:EXIT, ^pid, :killed}, 10000
+             end) =~
+               "** (ExDgraph.Error) connect failed with \"Error when opening connection: :timeout\""
+    end
+  end
+
+  describe "Query" do
+    @sample_query """
+      {
+          starwars(func: anyofterms(name, "VI"))
+          {
+            uid
+            name
+            release_date
+            starring
+            {
+              name
+            }
+          }
+      }
+    """
+
+    test "query/2 with correct query returns {:ok, %Query{}, %Result{}}", %{conn: conn} do
+      {status, %Query{} = _query, %Result{} = result} = ExDgraph.query(conn, @sample_query)
+      assert status == :ok
+      data = result.data
+      starwars = List.first(data.starwars)
+      assert starwars.name == "Star Wars: Episode VI - Return of the Jedi"
+      assert starwars.release_date == "1983-05-25"
+      assert length(starwars.starring) == 3
+    end
+
+    test "query/2 with wrong query returns {:error, %Error{}}", %{conn: conn} do
+      {status, %Error{} = error} = ExDgraph.query(conn, "wrong")
+      assert status == :error
+
+      assert %Error{} = error
+      assert error.code == 2
+      assert error.action == :query
+      assert error.reason =~ "Invalid operation type: wrong"
+    end
+
+    test "query!/2 with correct query returns query_msg", %{conn: conn} do
+      %Result{} = result = ExDgraph.query!(conn, @sample_query)
+      data = result.data
+      starwars = List.first(data.starwars)
+      assert starwars.name == "Star Wars: Episode VI - Return of the Jedi"
+      assert starwars.release_date == "1983-05-25"
+      assert length(starwars.starring) == 3
+    end
 
-             assert_receive {:EXIT, ^pid, :killed}, 10000
-           end) =~
-             "** (ExDgraph.Error) connect failed with \"Error when opening connection: :timeout\""
+    test "query!/2 raises ExDgraph.Exception", %{conn: conn} do
+      assert_raise ExDgraph.Error, fn ->
+        ExDgraph.query!(conn, "wrong")
+      end
+    end
   end
 end
diff --git a/test/query_test.exs b/test/query_test.exs
deleted file mode 100644
index 3709d2d..0000000
--- a/test/query_test.exs
+++ /dev/null
@@ -1,58 +0,0 @@
-defmodule ExDgraph.QueryTest do
-  use ExUnit.Case, async: true
-  import ExDgraph.TestHelper
-
-  @sample_query """
-    {
-        starwars(func: anyofterms(name, "VI"))
-        {
-          uid
-          name
-          release_date
-          starring
-          {
-            name
-          }
-        }
-    }
-  """
-
-  setup_all do
-    {:ok, conn} = ExDgraph.start_link()
-    ExDgraph.operation(conn, %{drop_all: true})
-    import_starwars_sample(conn)
-
-    [conn: conn]
-  end
-
-  test "query/2 with correct query returns {:ok, query_msg}", %{conn: conn} do
-    {status, query_msg} = ExDgraph.Query.query(conn, @sample_query)
-    assert status == :ok
-    res = query_msg.result
-    starwars = res[:starwars]
-    one = List.first(starwars)
-    assert "Star Wars: Episode VI - Return of the Jedi" == one[:name]
-    assert "1983-05-25" == one[:release_date]
-  end
-
-  test "query/2 with wrong query returns {:error, error}", %{conn: conn} do
-    {status, error} = ExDgraph.Query.query(conn, "wrong")
-    assert status == :error
-    assert error == [code: 2, message: "while lexing wrong: Invalid operation type: wrong"]
-  end
-
-  test "query!/2 with correct query returns query_msg", %{conn: conn} do
-    query_msg = ExDgraph.Query.query!(conn, @sample_query)
-    res = query_msg.result
-    starwars = res[:starwars]
-    one = List.first(starwars)
-    assert "Star Wars: Episode VI - Return of the Jedi" == one[:name]
-    assert "1983-05-25" == one[:release_date]
-  end
-
-  test "query!/2 raises ExDgraph.Exception", %{conn: conn} do
-    assert_raise ExDgraph.Exception, fn ->
-      ExDgraph.Query.query!(conn, "wrong")
-    end
-  end
-end

From fab9427ba6a7a019c7150f6a04d61c47ffc75047 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 00:44:45 +0200
Subject: [PATCH 39/68] Test start/2

---
 test/application_test.exs | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/test/application_test.exs b/test/application_test.exs
index 7a0c9c8..161e6e8 100644
--- a/test/application_test.exs
+++ b/test/application_test.exs
@@ -1,13 +1,10 @@
 defmodule ApplicationTest do
   use ExUnit.Case
 
-  test "Make sure the application is running" do
-    res = Application.ensure_started(:ex_dgraph)
-    assert res == :ok
-    cnf = ExDgraph.Utils.default_config()
-    {state, {message, _}} = ExDgraph.Application.start(%{}, cnf)
-    assert state == :error
-    assert message == :already_started
+  test "start/2 starts the application" do
+    {status, pid} = ExDgraph.Application.start(nil, [])
+    assert status == :ok
+    assert Process.alive?(pid)
   end
 
   test "stop/1 returns :ok" do

From 846ba4933f56e7963ab7d6be644a7a204c31445f Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 00:58:05 +0200
Subject: [PATCH 40/68] Add tests for ExDgraph.start_link/1.

---
 test/exdgraph_test.exs | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/test/exdgraph_test.exs b/test/exdgraph_test.exs
index 9390338..29e4e3e 100755
--- a/test/exdgraph_test.exs
+++ b/test/exdgraph_test.exs
@@ -13,6 +13,23 @@ defmodule ExDgraphTest do
     [conn: conn]
   end
 
+  describe "start_link/1" do
+    test "it starts the client" do
+      {status, pid} = ExDgraph.start_link()
+      assert status == :ok
+      assert Process.alive?(pid)
+    end
+
+    test "it starts the process in the DBConnection.ConnectionPool" do
+      {status, pid} = ExDgraph.start_link()
+      assert status == :ok
+      assert Process.alive?(pid)
+      process_as_map = Process.info(pid) |> Enum.into(%{})
+      {ancestor, :init, _} = process_as_map.dictionary[:"$initial_call"]
+      assert ancestor == DBConnection.ConnectionPool
+    end
+  end
+
   describe "connection" do
     test "connection_errors" do
       Process.flag(:trap_exit, true)

From 31c6a4d6d501b785b6df55c6d0822625112b5355 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 00:58:44 +0200
Subject: [PATCH 41/68] Cleanup.

---
 lib/exdgraph/protocol.ex | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/lib/exdgraph/protocol.ex b/lib/exdgraph/protocol.ex
index 1a88345..d918645 100755
--- a/lib/exdgraph/protocol.ex
+++ b/lib/exdgraph/protocol.ex
@@ -146,8 +146,8 @@ defmodule ExDgraph.Protocol do
   @impl true
   def handle_execute(
         %MutationStatement{statement: "", set_json: set_json} = query,
-        _params,
-        _,
+        _request,
+        _opts,
         state
       ) do
     dgraph_query = ExDgraph.Api.Mutation.new(set_json: set_json, commit_now: true)
@@ -172,7 +172,6 @@ defmodule ExDgraph.Protocol do
         %OperationStatement{drop_all: drop_all, schema: schema, drop_attr: drop_attr} = query,
         _params,
         _,
-        %{channel: channel} = state
         %{channel: channel, opts: opts} = state
       ) do
     operation = Api.Operation.new(drop_all: drop_all, schema: schema, drop_attr: drop_attr)

From 3032561090127342a73a76abb5b6ad99d7191365 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 01:14:00 +0200
Subject: [PATCH 42/68] Add typespecs.

---
 lib/exdgraph/structs.ex | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/lib/exdgraph/structs.ex b/lib/exdgraph/structs.ex
index fe2540f..f53e0ef 100644
--- a/lib/exdgraph/structs.ex
+++ b/lib/exdgraph/structs.ex
@@ -4,7 +4,11 @@ defmodule ExDgraph.Error do
   """
   defexception [:reason, :action, :code]
 
-  @type t :: %ExDgraph.Error{}
+  @type t :: %ExDgraph.Error{
+          reason: String.t(),
+          action: atom(),
+          code: non_neg_integer
+        }
 
   @impl true
   def message(%{action: action, reason: reason}) do
@@ -17,5 +21,11 @@ defmodule ExDgraph.Result do
   Results from a query are wrapped in ExDgraph.Result
   """
 
+  @type t :: %__MODULE__{
+          data: %{optional(any) => any},
+          schema: [any()],
+          txn: %ExDgraph.Api.TxnContext{}
+        }
+
   defstruct [:data, :schema, :txn]
 end

From 88354e34fc208c72140b799f03b9962a5590f034 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 01:15:19 +0200
Subject: [PATCH 43/68] Fix warnings.

---
 lib/exdgraph/query.ex | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/exdgraph/query.ex b/lib/exdgraph/query.ex
index 57f6830..8d9d0e7 100644
--- a/lib/exdgraph/query.ex
+++ b/lib/exdgraph/query.ex
@@ -2,7 +2,6 @@ defmodule ExDgraph.Query do
   @moduledoc """
   Provides the functions for the callbacks from the DBConnection behaviour.
   """
-  alias ExDgraph.{Exception, Error, Query, Transform}
 
   defstruct [:statement, :parameters, :txn_context]
 end
@@ -29,7 +28,11 @@ defimpl DBConnection.Query, for: ExDgraph.Query do
 
   def encode(_query, data, _), do: data
 
-  def decode(_query, %ExDgraph.Api.Response{json: json, schema: schema, txn: txn} = result, _opts) do
+  def decode(
+        _query,
+        %ExDgraph.Api.Response{json: json, schema: schema, txn: txn} = _result,
+        _opts
+      ) do
     data =
       json
       |> Jason.decode!()

From 976057d8c269ca5959f958899ad44f1ba40c5b63 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 13:26:19 +0200
Subject: [PATCH 44/68] Update docs and specs.

---
 lib/exdgraph.ex        | 18 +++++++++---------
 test/exdgraph_test.exs |  4 ++--
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index 3030bed..0449b95 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -489,7 +489,7 @@ defmodule ExDgraph do
       {:error, [code: 2, message: "while lexing invalid_statement: Invalid operation type: invalid_statement"]}
 
   """
-  @spec query(conn, iodata, map, Keyword.t()) :: {:ok, map} | {:error, Dgraph.Error.t() | term}
+  @spec query(conn, iodata, map, Keyword.t()) :: {:ok, map} | {:error, ExDgraph.Error.t() | term}
   def query(conn, statement, parameters \\ %{}, opts \\ []) do
     query = %Query{statement: statement}
 
@@ -499,10 +499,10 @@ defmodule ExDgraph do
   end
 
   @doc """
-  The same as `query/2` but raises a ExDgraph.Exception if it fails.
+  The same as `query/3` but raises a ExDgraph.Exception if it fails.
   Returns the server response otherwise.
   """
-  @spec query!(conn, String.t()) :: ExDgraph.Response | ExDgraph.Exception
+  @spec query!(conn, String.t()) :: ExDgraph.Result | ExDgraph.Error
   def query!(conn, statement) do
     case query(conn, statement) do
       {:ok, query, result} ->
@@ -591,14 +591,14 @@ defmodule ExDgraph do
       }
 
   """
-  @spec mutation(conn, String.t()) :: {:ok, ExDgraph.Response} | {:error, ExDgraph.Error}
+  @spec mutation(conn, String.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
   defdelegate mutation(conn, statement), to: Mutation
 
   @doc """
   The same as `mutation/2` but raises an `ExDgraph.Exception` if it fails.
   Returns the server response otherwise.
   """
-  @spec mutation!(conn, String.t()) :: ExDgraph.Response | ExDgraph.Exception
+  @spec mutation!(conn, String.t()) :: ExDgraph.Result | ExDgraph.Exception
   defdelegate mutation!(conn, statement), to: Mutation
 
   @doc """
@@ -638,14 +638,14 @@ defmodule ExDgraph do
         }
       }
   """
-  @spec set_map(conn, Map.t()) :: {:ok, ExDgraph.Response} | {:error, ExDgraph.Error}
+  @spec set_map(conn, Map.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
   defdelegate set_map(conn, map), to: Mutation
 
   @doc """
   The same as `set_map/2` but raises an `ExDgraph.Exception` if it fails.
   Returns the server response otherwise.
   """
-  @spec set_map!(conn, Map.t()) :: {:ok, ExDgraph.Response} | {:error, ExDgraph.Error}
+  @spec set_map!(conn, Map.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
   defdelegate set_map!(conn, map), to: Mutation
 
   @doc """
@@ -691,14 +691,14 @@ defmodule ExDgraph do
         }
       }
   """
-  @spec set_struct(conn, Map.t()) :: {:ok, ExDgraph.Response} | {:error, ExDgraph.Error}
+  @spec set_struct(conn, Map.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
   defdelegate set_struct(conn, map), to: Mutation
 
   @doc """
   The same as `set_struct/2` but raises an `ExDgraph.Exception` if it fails.
   Returns the server response otherwise.
   """
-  @spec set_struct!(conn, Map.t()) :: {:ok, ExDgraph.Response} | {:error, ExDgraph.Error}
+  @spec set_struct!(conn, Map.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
   defdelegate set_struct!(conn, map), to: Mutation
 
   ## Operation
diff --git a/test/exdgraph_test.exs b/test/exdgraph_test.exs
index 29e4e3e..3ed4701 100755
--- a/test/exdgraph_test.exs
+++ b/test/exdgraph_test.exs
@@ -66,7 +66,7 @@ defmodule ExDgraphTest do
       }
     """
 
-    test "query/2 with correct query returns {:ok, %Query{}, %Result{}}", %{conn: conn} do
+    test "query/3 with correct query returns {:ok, %Query{}, %Result{}}", %{conn: conn} do
       {status, %Query{} = _query, %Result{} = result} = ExDgraph.query(conn, @sample_query)
       assert status == :ok
       data = result.data
@@ -76,7 +76,7 @@ defmodule ExDgraphTest do
       assert length(starwars.starring) == 3
     end
 
-    test "query/2 with wrong query returns {:error, %Error{}}", %{conn: conn} do
+    test "query/3 with wrong query returns {:error, %Error{}}", %{conn: conn} do
       {status, %Error{} = error} = ExDgraph.query(conn, "wrong")
       assert status == :error
 

From d635df58818774f35988e2b7ffe4e2a19555c871 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 13:26:28 +0200
Subject: [PATCH 45/68] Add Payload struct.

---
 lib/exdgraph/structs.ex | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/lib/exdgraph/structs.ex b/lib/exdgraph/structs.ex
index f53e0ef..e034cce 100644
--- a/lib/exdgraph/structs.ex
+++ b/lib/exdgraph/structs.ex
@@ -29,3 +29,15 @@ defmodule ExDgraph.Result do
 
   defstruct [:data, :schema, :txn]
 end
+
+defmodule ExDgraph.Payload do
+  @moduledoc """
+  Results from alter are wrapped in ExDgraph.Payload
+  """
+
+  @type t :: %__MODULE__{
+          data: %{optional(any) => any}
+        }
+
+  defstruct [:data]
+end

From 30b8dfe3047c1a747164a3d554a2c2990e174176 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 13:27:06 +0200
Subject: [PATCH 46/68] Use correct types and explicit parameter names in
 callbacks.

---
 lib/exdgraph/query.ex | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/lib/exdgraph/query.ex b/lib/exdgraph/query.ex
index 8d9d0e7..83a1e48 100644
--- a/lib/exdgraph/query.ex
+++ b/lib/exdgraph/query.ex
@@ -11,22 +11,22 @@ defimpl DBConnection.Query, for: ExDgraph.Query do
   Implementation of `DBConnection.Query` protocol.
   """
 
-  alias ExDgraph.{Result, Utils}
+  alias ExDgraph.{Query, Result, Utils}
 
-  def describe(query, _), do: query
+  def describe(query, _opts), do: query
 
   @doc """
   Parse a query.
 
   This function is called to parse a query term before it is prepared.
   """
-  def parse(%{statement: nil} = query), do: %{query | statement: ""}
+  def parse(%{statement: nil} = query, _opts), do: %Query{query | statement: ""}
 
-  def parse(%{statement: statement} = query, _) do
-    %{query | statement: IO.iodata_to_binary(statement)}
+  def parse(%{statement: statement} = query, _opts) do
+    %Query{query | statement: IO.iodata_to_binary(statement)}
   end
 
-  def encode(_query, data, _), do: data
+  def encode(_query, data, _opts), do: data
 
   def decode(
         _query,

From 72f76bf027785d0094ab1c7babdc69d34eb673e8 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 13:28:06 +0200
Subject: [PATCH 47/68] Rewrite Operation and add alter/3 function.

---
 lib/exdgraph.ex           | 38 ++++++++++++++++++++--
 lib/exdgraph/operation.ex | 68 +++++++++++++--------------------------
 lib/exdgraph/protocol.ex  | 13 +++-----
 3 files changed, 64 insertions(+), 55 deletions(-)

diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index 0449b95..910b35a 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -730,8 +730,42 @@ defmodule ExDgraph do
       %{:ok, %ExDgraph.Api.Payload{Data: ""}}
 
   """
-  @spec operation(conn, String.t()) :: {:ok, ExDgraph.Response} | {:error, ExDgraph.Error}
-  defdelegate operation(conn, statement), to: Operation
+  # @spec operation(conn, String.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
+  # defdelegate operation(conn, statement), to: Operation
+  @spec alter(conn, iodata | map, Keyword.t()) :: {:ok, map} | {:error, ExDgraph.Error.t() | term}
+  def alter(conn, query, opts \\ [])
+
+  def alter(conn, query, opts) when is_binary(query) do
+    operation = %Operation{schema: query}
+
+    with {:ok, %Operation{} = operation, result} <-
+           DBConnection.prepare_execute(conn, operation, %{}, opts),
+         do: {:ok, query, result}
+  end
+
+  @spec alter(conn, iodata | map, Keyword.t()) :: {:ok, map} | {:error, ExDgraph.Error.t() | term}
+  def alter(conn, query, opts) when is_map(query) do
+    operation = struct(Operation, query)
+
+    with {:ok, %Operation{} = operation, result} <-
+           DBConnection.prepare_execute(conn, operation, %{}, opts),
+         do: {:ok, query, result}
+  end
+
+  @doc """
+  The same as `alter/3` but raises a ExDgraph.Exception if it fails.
+  Returns the server response otherwise.
+  """
+  @spec alter!(conn, String.t()) :: ExDgraph.Payload | ExDgraph.Error
+  def alter!(conn, query) do
+    case alter(conn, query) do
+      {:ok, query, payload} ->
+        payload
+
+      {:error, error} ->
+        raise error
+    end
+  end
 
   @doc """
   The same as `operation/2` but raises an `ExDgraph.Exception` if it fails.
diff --git a/lib/exdgraph/operation.ex b/lib/exdgraph/operation.ex
index a69d0f7..00db327 100644
--- a/lib/exdgraph/operation.ex
+++ b/lib/exdgraph/operation.ex
@@ -2,58 +2,36 @@ defmodule ExDgraph.Operation do
   @moduledoc """
   Provides the functions for the callbacks from the DBConnection behaviour.
   """
-  alias ExDgraph.{Exception, OperationStatement}
+  alias ExDgraph.Error
 
-  @doc false
-  def operation(conn, operation) do
-    case operation_commit(conn, operation) do
-      {:error, f} ->
-        {:error, code: f.code, message: f.message}
+  defstruct drop_all: false, drop_attr: "", schema: "", txn_context: nil
+end
 
-      {:ok, %OperationStatement{}, result} ->
-        {:ok, result}
-    end
-  end
+defimpl DBConnection.Query, for: ExDgraph.Operation do
+  alias ExDgraph.{Operation, Payload}
 
-  @doc false
-  def operation!(conn, operation) do
-    case operation(conn, operation) do
-      {:ok, r} ->
-        r
+  def describe(query, _opts), do: query
 
-      {:error, code: code, message: message} ->
-        raise Exception, code: code, message: message
-    end
+  def parse(%{drop_attr: drop_attr, schema: schema, drop_all: _} = query, _opts) do
+    %Operation{
+      query
+      | drop_attr: IO.iodata_to_binary(drop_attr),
+        schema: IO.iodata_to_binary(schema)
+    }
   end
 
-  defp operation_commit(conn, operation) do
-    operation_processed =
-      operation
-      |> Map.put_new(:drop_all, false)
-      |> Map.put_new(:drop_attr, "")
-      |> Map.put_new(:schema, "")
-
-    exec = fn conn ->
-      operation = %OperationStatement{
-        drop_all: operation_processed.drop_all,
-        drop_attr: operation_processed.drop_attr,
-        schema: operation_processed.schema
-      }
-
-      case DBConnection.execute(conn, operation, %{}) do
-        {:ok, resp} ->
-          resp
-
-        other ->
-          other
-      end
-    end
-
-    # Response.transform(DBConnection.run(conn, exec, run_opts()))
-    DBConnection.run(conn, exec, run_opts())
+  def encode(query, _, _) do
+    %{drop_all: drop_all, schema: schema, drop_attr: drop_attr} = query
+    %Operation{drop_all: drop_all, schema: schema, drop_attr: drop_attr}
   end
 
-  defp run_opts do
-    [pool: ExDgraph.config(:pool)]
+  def decode(
+        _query,
+        %ExDgraph.Api.Payload{Data: data} = _result,
+        _opts
+      ) do
+    %Payload{
+      data: data
+    }
   end
 end
diff --git a/lib/exdgraph/protocol.ex b/lib/exdgraph/protocol.ex
index d918645..8c341c0 100755
--- a/lib/exdgraph/protocol.ex
+++ b/lib/exdgraph/protocol.ex
@@ -12,7 +12,7 @@ defmodule ExDgraph.Protocol do
     Error,
     Exception,
     MutationStatement,
-    OperationStatement,
+    Operation,
     Query
   }
 
@@ -169,9 +169,9 @@ defmodule ExDgraph.Protocol do
 
   @impl true
   def handle_execute(
-        %OperationStatement{drop_all: drop_all, schema: schema, drop_attr: drop_attr} = query,
+        %Operation{drop_all: drop_all, schema: schema, drop_attr: drop_attr} = query,
         _params,
-        _,
+        _opts,
         %{channel: channel, opts: opts} = state
       ) do
     operation = Api.Operation.new(drop_all: drop_all, schema: schema, drop_attr: drop_attr)
@@ -180,12 +180,9 @@ defmodule ExDgraph.Protocol do
       {:ok, res} ->
         {:ok, query, res, state}
 
-      {:error, f} ->
-        raise Exception, code: f.status, message: f.message
+      {:error, error} ->
+        {:error, %Error{action: :alter, code: error.status, reason: error.message}, state}
     end
-  rescue
-    e ->
-      {:error, e, state}
   end
 
   defp do_mutate(%{channel: channel, opts: opts} = state, dgraph_query, query) do

From 3242d830381c185fe1222f19639c8524c1190835 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 13:29:28 +0200
Subject: [PATCH 48/68] Cleanup.

---
 lib/exdgraph.ex | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index 910b35a..bd101f1 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -730,8 +730,6 @@ defmodule ExDgraph do
       %{:ok, %ExDgraph.Api.Payload{Data: ""}}
 
   """
-  # @spec operation(conn, String.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
-  # defdelegate operation(conn, statement), to: Operation
   @spec alter(conn, iodata | map, Keyword.t()) :: {:ok, map} | {:error, ExDgraph.Error.t() | term}
   def alter(conn, query, opts \\ [])
 
@@ -766,11 +764,4 @@ defmodule ExDgraph do
         raise error
     end
   end
-
-  @doc """
-  The same as `operation/2` but raises an `ExDgraph.Exception` if it fails.
-  Returns the server response otherwise.
-  """
-  @spec operation!(conn, String.t()) :: ExDgraph.Response | ExDgraph.Exception
-  defdelegate operation!(conn, statement), to: Operation
 end

From 6efdf07f12b6c3b153458d9fc8dd3ae0f01e4ba6 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 17:33:29 +0200
Subject: [PATCH 49/68] Cleanup and add typespecs.

---
 lib/exdgraph.ex           | 17 +++++++------
 lib/exdgraph/operation.ex | 50 ++++++++++++++++++++++++++-------------
 lib/exdgraph/query.ex     | 41 +++++++++++++++++++++-----------
 lib/exdgraph/structs.ex   |  3 ++-
 4 files changed, 71 insertions(+), 40 deletions(-)

diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index bd101f1..575d60e 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -344,7 +344,7 @@ defmodule ExDgraph do
   use Supervisor
 
   alias ExDgraph.Api.{Mutation, Operation}
-  alias ExDgraph.{Operation, Mutation, Protocol, Query, Utils}
+  alias ExDgraph.{Operation, Mutation, Protocol, Query}
 
   @type conn :: DBConnection.conn()
   # @type transaction :: DBConnection.t()
@@ -354,7 +354,6 @@ defmodule ExDgraph do
   # Inherited from DBConnection
 
   @idle_timeout 5000
-  @pool_timeout 5000
   @timeout 15000
 
   @doc """
@@ -505,7 +504,7 @@ defmodule ExDgraph do
   @spec query!(conn, String.t()) :: ExDgraph.Result | ExDgraph.Error
   def query!(conn, statement) do
     case query(conn, statement) do
-      {:ok, query, result} ->
+      {:ok, _query, result} ->
         result
 
       {:error, error} ->
@@ -736,7 +735,7 @@ defmodule ExDgraph do
   def alter(conn, query, opts) when is_binary(query) do
     operation = %Operation{schema: query}
 
-    with {:ok, %Operation{} = operation, result} <-
+    with {:ok, %Operation{} = _operation, result} <-
            DBConnection.prepare_execute(conn, operation, %{}, opts),
          do: {:ok, query, result}
   end
@@ -745,7 +744,7 @@ defmodule ExDgraph do
   def alter(conn, query, opts) when is_map(query) do
     operation = struct(Operation, query)
 
-    with {:ok, %Operation{} = operation, result} <-
+    with {:ok, %Operation{} = _operation, result} <-
            DBConnection.prepare_execute(conn, operation, %{}, opts),
          do: {:ok, query, result}
   end
@@ -754,10 +753,10 @@ defmodule ExDgraph do
   The same as `alter/3` but raises a ExDgraph.Exception if it fails.
   Returns the server response otherwise.
   """
-  @spec alter!(conn, String.t()) :: ExDgraph.Payload | ExDgraph.Error
-  def alter!(conn, query) do
-    case alter(conn, query) do
-      {:ok, query, payload} ->
+  @spec alter!(conn, String.t(), Keyword.t()) :: ExDgraph.Payload | ExDgraph.Error
+  def alter!(conn, query, opts \\ []) do
+    case alter(conn, query, opts) do
+      {:ok, _query, payload} ->
         payload
 
       {:error, error} ->
diff --git a/lib/exdgraph/operation.ex b/lib/exdgraph/operation.ex
index 00db327..92322c2 100644
--- a/lib/exdgraph/operation.ex
+++ b/lib/exdgraph/operation.ex
@@ -1,8 +1,14 @@
 defmodule ExDgraph.Operation do
   @moduledoc """
-  Provides the functions for the callbacks from the DBConnection behaviour.
+  Wrapper for operations sent to DBConnection.
   """
-  alias ExDgraph.Error
+
+  @type t :: %ExDgraph.Operation{
+          drop_all: true | false | nil,
+          drop_attr: String.t(),
+          schema: String.t(),
+          txn_context: any()
+        }
 
   defstruct drop_all: false, drop_attr: "", schema: "", txn_context: nil
 end
@@ -10,28 +16,40 @@ end
 defimpl DBConnection.Query, for: ExDgraph.Operation do
   alias ExDgraph.{Operation, Payload}
 
-  def describe(query, _opts), do: query
-
-  def parse(%{drop_attr: drop_attr, schema: schema, drop_all: _} = query, _opts) do
-    %Operation{
-      query
-      | drop_attr: IO.iodata_to_binary(drop_attr),
-        schema: IO.iodata_to_binary(schema)
+  @doc """
+  This function is called to decode a result after it is returned by a connection callback module.
+  """
+  def decode(
+        _query,
+        %ExDgraph.Api.Payload{Data: data} = _result,
+        _opts
+      ) do
+    %Payload{
+      data: data
     }
   end
 
+  @doc """
+  This function is called to describe a query after it is prepared using a connection callback module.
+  """
+  def describe(query, _opts), do: query
+
+  @doc """
+  This function is called to encode a query before it is executed using a connection callback module.
+  """
   def encode(query, _, _) do
     %{drop_all: drop_all, schema: schema, drop_attr: drop_attr} = query
     %Operation{drop_all: drop_all, schema: schema, drop_attr: drop_attr}
   end
 
-  def decode(
-        _query,
-        %ExDgraph.Api.Payload{Data: data} = _result,
-        _opts
-      ) do
-    %Payload{
-      data: data
+  @doc """
+  This function is called to parse a query term before it is prepared using a connection callback module.
+  """
+  def parse(%{drop_attr: drop_attr, schema: schema, drop_all: _} = query, _opts) do
+    %Operation{
+      query
+      | drop_attr: IO.iodata_to_binary(drop_attr),
+        schema: IO.iodata_to_binary(schema)
     }
   end
 end
diff --git a/lib/exdgraph/query.ex b/lib/exdgraph/query.ex
index 83a1e48..5fbefb4 100644
--- a/lib/exdgraph/query.ex
+++ b/lib/exdgraph/query.ex
@@ -1,8 +1,14 @@
 defmodule ExDgraph.Query do
   @moduledoc """
-  Provides the functions for the callbacks from the DBConnection behaviour.
+  Wrapper for queries sent to DBConnection.
   """
 
+  @type t :: %ExDgraph.Query{
+          statement: String.t(),
+          parameters: any(),
+          txn_context: any()
+        }
+
   defstruct [:statement, :parameters, :txn_context]
 end
 
@@ -13,21 +19,9 @@ defimpl DBConnection.Query, for: ExDgraph.Query do
 
   alias ExDgraph.{Query, Result, Utils}
 
-  def describe(query, _opts), do: query
-
   @doc """
-  Parse a query.
-
-  This function is called to parse a query term before it is prepared.
+  This function is called to decode a result after it is returned by a connection callback module.
   """
-  def parse(%{statement: nil} = query, _opts), do: %Query{query | statement: ""}
-
-  def parse(%{statement: statement} = query, _opts) do
-    %Query{query | statement: IO.iodata_to_binary(statement)}
-  end
-
-  def encode(_query, data, _opts), do: data
-
   def decode(
         _query,
         %ExDgraph.Api.Response{json: json, schema: schema, txn: txn} = _result,
@@ -44,4 +38,23 @@ defimpl DBConnection.Query, for: ExDgraph.Query do
       txn: txn
     }
   end
+
+  @doc """
+  This function is called to describe a query after it is prepared using a connection callback module.
+  """
+  def describe(query, _opts), do: query
+
+  @doc """
+  This function is called to encode a query before it is executed using a connection callback module.
+  """
+  def encode(_query, data, _opts), do: data
+
+  @doc """
+  This function is called to parse a query term before it is prepared using a connection callback module.
+  """
+  def parse(%{statement: nil} = query, _opts), do: %Query{query | statement: ""}
+
+  def parse(%{statement: statement} = query, _opts) do
+    %Query{query | statement: IO.iodata_to_binary(statement)}
+  end
 end
diff --git a/lib/exdgraph/structs.ex b/lib/exdgraph/structs.ex
index e034cce..cf29f90 100644
--- a/lib/exdgraph/structs.ex
+++ b/lib/exdgraph/structs.ex
@@ -2,7 +2,6 @@ defmodule ExDgraph.Error do
   @moduledoc """
   Dgraph or connection error are wrapped in ExDgraph.Error.
   """
-  defexception [:reason, :action, :code]
 
   @type t :: %ExDgraph.Error{
           reason: String.t(),
@@ -10,6 +9,8 @@ defmodule ExDgraph.Error do
           code: non_neg_integer
         }
 
+  defexception [:reason, :action, :code]
+
   @impl true
   def message(%{action: action, reason: reason}) do
     "#{action} failed with #{inspect(reason)}"

From 6534f4b2b00a1f916e37d123c1a78617dfae2d2a Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 17:33:38 +0200
Subject: [PATCH 50/68] Upgrade credo.

---
 mix.exs  | 2 +-
 mix.lock | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/mix.exs b/mix.exs
index 2dc18fa..dc3bcdb 100755
--- a/mix.exs
+++ b/mix.exs
@@ -43,7 +43,7 @@ defmodule ExDgraph.MixProject do
       {:jason, "~> 1.1"},
       {:protobuf, "~> 0.6.1"},
       {:excoveralls, "~> 0.10", only: :test},
-      {:credo, "~> 1.0", only: [:dev, :test], runtime: false},
+      {:credo, "~> 1.1.0", only: [:dev, :test], runtime: false},
       {:ex_doc, "> 0.0.0", only: :dev, runtime: false},
       {:mix_test_watch, "~> 0.5", only: :dev, runtime: false}
     ]
diff --git a/mix.lock b/mix.lock
index a78c22f..564bd83 100644
--- a/mix.lock
+++ b/mix.lock
@@ -6,8 +6,10 @@
   "cowlib": {:hex, :cowlib, "2.6.0", "8aa629f81a0fc189f261dc98a42243fa842625feea3c7ec56c48f4ccdb55490f", [:rebar3], [], "hexpm"},
   "credo": {:hex, :credo, "1.1.4", "c2f3b73c895d81d859cec7fcee7ffdb972c595fd8e85ab6f8c2adbf01cf7c29c", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
   "db_connection": {:hex, :db_connection, "2.1.1", "a51e8a2ee54ef2ae6ec41a668c85787ed40cb8944928c191280fe34c15b76ae5", [:mix], [{:connection, "~> 1.0.2", [hex: :connection, repo: "hexpm", optional: false]}], "hexpm"},
+  "dialyxir": {:hex, :dialyxir, "1.0.0-rc.6", "78e97d9c0ff1b5521dd68041193891aebebce52fc3b93463c0a6806874557d7d", [:mix], [{:erlex, "~> 0.2.1", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm"},
   "earmark": {:hex, :earmark, "1.4.0", "397e750b879df18198afc66505ca87ecf6a96645545585899f6185178433cc09", [:mix], [], "hexpm"},
   "elixir_uuid": {:hex, :elixir_uuid, "1.2.0", "ff26e938f95830b1db152cb6e594d711c10c02c6391236900ddd070a6b01271d", [:mix], [], "hexpm"},
+  "erlex": {:hex, :erlex, "0.2.4", "23791959df45fe8f01f388c6f7eb733cc361668cbeedd801bf491c55a029917b", [:mix], [], "hexpm"},
   "ex_doc": {:hex, :ex_doc, "0.21.2", "caca5bc28ed7b3bdc0b662f8afe2bee1eedb5c3cf7b322feeeb7c6ebbde089d6", [:mix], [{:earmark, "~> 1.3.3 or ~> 1.4", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm"},
   "excoveralls": {:hex, :excoveralls, "0.11.2", "0c6f2c8db7683b0caa9d490fb8125709c54580b4255ffa7ad35f3264b075a643", [:mix], [{:hackney, "~> 1.0", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
   "file_system": {:hex, :file_system, "0.2.7", "e6f7f155970975789f26e77b8b8d8ab084c59844d8ecfaf58cbda31c494d14aa", [:mix], [], "hexpm"},

From b1faa11f502c530859dae0465dda97f7dcbd0434 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 17:41:22 +0200
Subject: [PATCH 51/68] Implement missing DBConnection callbacks.

---
 lib/exdgraph/protocol.ex | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/lib/exdgraph/protocol.ex b/lib/exdgraph/protocol.ex
index 8c341c0..399e58f 100755
--- a/lib/exdgraph/protocol.ex
+++ b/lib/exdgraph/protocol.ex
@@ -185,6 +185,26 @@ defmodule ExDgraph.Protocol do
     end
   end
 
+  @impl true
+  def handle_close(_query, _opts, state) do
+    {:ok, nil, state}
+  end
+
+  @impl true
+  def handle_deallocate(_query, _cursor, _opts, state) do
+    {:ok, nil, state}
+  end
+
+  @impl true
+  def handle_declare(query, _params, _opts, state) do
+    {:ok, query, nil, state}
+  end
+
+  @impl true
+  def handle_fetch(_query, _cursor, _opts, state) do
+    {:halt, nil, state}
+  end
+
   defp do_mutate(%{channel: channel, opts: opts} = state, dgraph_query, query) do
     case ExDgraph.Api.Dgraph.Stub.mutate(channel, dgraph_query, timeout: opts[:timeout]) do
       {:ok, res} ->

From e01ad16f2b82cc00a112c5e313a53d00c5fa753a Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 17:54:50 +0200
Subject: [PATCH 52/68] Move query tests to separate file.

---
 test/exdgraph_test.exs | 62 ----------------------------------------
 test/query_test.exs    | 65 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+), 62 deletions(-)
 create mode 100644 test/query_test.exs

diff --git a/test/exdgraph_test.exs b/test/exdgraph_test.exs
index 3ed4701..bcdc1fa 100755
--- a/test/exdgraph_test.exs
+++ b/test/exdgraph_test.exs
@@ -3,16 +3,6 @@ defmodule ExDgraphTest do
   import ExDgraph.TestHelper
   import ExUnit.CaptureLog
 
-  alias ExDgraph.{Error, Query, Result}
-
-  setup_all do
-    {:ok, conn} = ExDgraph.start_link()
-    ExDgraph.operation(conn, %{drop_all: true})
-    import_starwars_sample(conn)
-
-    [conn: conn]
-  end
-
   describe "start_link/1" do
     test "it starts the client" do
       {status, pid} = ExDgraph.start_link()
@@ -49,56 +39,4 @@ defmodule ExDgraphTest do
                "** (ExDgraph.Error) connect failed with \"Error when opening connection: :timeout\""
     end
   end
-
-  describe "Query" do
-    @sample_query """
-      {
-          starwars(func: anyofterms(name, "VI"))
-          {
-            uid
-            name
-            release_date
-            starring
-            {
-              name
-            }
-          }
-      }
-    """
-
-    test "query/3 with correct query returns {:ok, %Query{}, %Result{}}", %{conn: conn} do
-      {status, %Query{} = _query, %Result{} = result} = ExDgraph.query(conn, @sample_query)
-      assert status == :ok
-      data = result.data
-      starwars = List.first(data.starwars)
-      assert starwars.name == "Star Wars: Episode VI - Return of the Jedi"
-      assert starwars.release_date == "1983-05-25"
-      assert length(starwars.starring) == 3
-    end
-
-    test "query/3 with wrong query returns {:error, %Error{}}", %{conn: conn} do
-      {status, %Error{} = error} = ExDgraph.query(conn, "wrong")
-      assert status == :error
-
-      assert %Error{} = error
-      assert error.code == 2
-      assert error.action == :query
-      assert error.reason =~ "Invalid operation type: wrong"
-    end
-
-    test "query!/2 with correct query returns query_msg", %{conn: conn} do
-      %Result{} = result = ExDgraph.query!(conn, @sample_query)
-      data = result.data
-      starwars = List.first(data.starwars)
-      assert starwars.name == "Star Wars: Episode VI - Return of the Jedi"
-      assert starwars.release_date == "1983-05-25"
-      assert length(starwars.starring) == 3
-    end
-
-    test "query!/2 raises ExDgraph.Exception", %{conn: conn} do
-      assert_raise ExDgraph.Error, fn ->
-        ExDgraph.query!(conn, "wrong")
-      end
-    end
-  end
 end
diff --git a/test/query_test.exs b/test/query_test.exs
new file mode 100644
index 0000000..70be5ce
--- /dev/null
+++ b/test/query_test.exs
@@ -0,0 +1,65 @@
+defmodule ExDgraph.QueryTest do
+  @moduledoc false
+
+  use ExUnit.Case
+  import ExDgraph.TestHelper
+  alias ExDgraph.{Error, Query, Result}
+
+  @sample_query """
+    {
+        starwars(func: anyofterms(name, "VI"))
+        {
+          uid
+          name
+          release_date
+          starring
+          {
+            name
+          }
+        }
+    }
+  """
+
+  setup_all do
+    {:ok, conn} = ExDgraph.start_link()
+    ExDgraph.alter(conn, %{drop_all: true})
+    import_starwars_sample(conn)
+
+    [conn: conn]
+  end
+
+  test "query/3 with correct query returns {:ok, %Query{}, %Result{}}", %{conn: conn} do
+    {status, %Query{} = _query, %Result{} = result} = ExDgraph.query(conn, @sample_query)
+    assert status == :ok
+    data = result.data
+    starwars = List.first(data.starwars)
+    assert starwars.name == "Star Wars: Episode VI - Return of the Jedi"
+    assert starwars.release_date == "1983-05-25"
+    assert length(starwars.starring) == 3
+  end
+
+  test "query/3 with wrong query returns {:error, %Error{}}", %{conn: conn} do
+    {status, %Error{} = error} = ExDgraph.query(conn, "wrong")
+    assert status == :error
+
+    assert %Error{} = error
+    assert error.code == 2
+    assert error.action == :query
+    assert error.reason =~ "Invalid operation type: wrong"
+  end
+
+  test "query!/2 with correct query returns query_msg", %{conn: conn} do
+    %Result{} = result = ExDgraph.query!(conn, @sample_query)
+    data = result.data
+    starwars = List.first(data.starwars)
+    assert starwars.name == "Star Wars: Episode VI - Return of the Jedi"
+    assert starwars.release_date == "1983-05-25"
+    assert length(starwars.starring) == 3
+  end
+
+  test "query!/2 raises ExDgraph.Exception", %{conn: conn} do
+    assert_raise ExDgraph.Error, fn ->
+      ExDgraph.query!(conn, "wrong")
+    end
+  end
+end

From 269350e7c1c0abcf327568a24cfb758ca95fbbe5 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 17:55:37 +0200
Subject: [PATCH 53/68] Adapt TestHelper to removal of ExDgraph.operation/2.

---
 test/test_helper.exs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/test_helper.exs b/test/test_helper.exs
index ef0e2e9..041c4f8 100755
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@@ -61,7 +61,7 @@ defmodule ExDgraph.TestHelper do
   """
 
   def import_starwars_sample(conn) do
-    ExDgraph.operation(conn, %{schema: @starwars_schema})
+    ExDgraph.alter(conn, %{schema: @starwars_schema})
     {:ok, _} = ExDgraph.mutation(conn, @starwars_creation_mutation)
   end
 
@@ -71,7 +71,7 @@ defmodule ExDgraph.TestHelper do
 
   def drop_all() do
     conn = ExDgraph.conn()
-    ExDgraph.operation(conn, %{drop_all: true})
+    ExDgraph.alter(conn, %{drop_all: true})
   end
 end
 

From 837cd51e34e0dc2ff070b7d376aa60ec1c9aba2b Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 17:55:47 +0200
Subject: [PATCH 54/68] Fix operation tests.

---
 test/operation_test.exs | 46 ++++++++++++++++++++++-------------------
 1 file changed, 25 insertions(+), 21 deletions(-)

diff --git a/test/operation_test.exs b/test/operation_test.exs
index e5565a1..dec57ba 100644
--- a/test/operation_test.exs
+++ b/test/operation_test.exs
@@ -1,43 +1,47 @@
-defmodule OperationTest do
+defmodule ExDgraph.OperationTest do
   @moduledoc """
   """
   use ExUnit.Case
   require Logger
   import ExDgraph.TestHelper
 
-  setup do
-    conn = ExDgraph.conn()
-    drop_all()
-    import_starwars_sample()
+  alias ExDgraph.{Error, Payload}
 
-    on_exit(fn ->
-      # close channel ?
-      :ok
-    end)
+  setup do
+    {:ok, conn} = ExDgraph.start_link()
+    ExDgraph.alter(conn, %{drop_all: true})
+    import_starwars_sample(conn)
 
     [conn: conn]
   end
 
-  test "operation(%{drop_all: true}) is successful", %{conn: conn} do
-    {status, operation_msg} = ExDgraph.operation(conn, %{drop_all: true})
+  test "alter(%{drop_all: true}) is successful", %{conn: conn} do
+    {status, _operation, payload} = ExDgraph.alter(conn, %{drop_all: true})
     assert status == :ok
-    assert operation_msg == %ExDgraph.Api.Payload{Data: ""}
+    assert payload == %Payload{data: ""}
   end
 
-  test "operation/2 returns {:error, error} for incorrect operation", %{conn: conn} do
-    {status, error} = ExDgraph.operation(conn, %{})
+  test "alter/3 returns the operation", %{conn: conn} do
+    {:ok, operation, _payload} = ExDgraph.alter(conn, %{drop_all: true})
+    assert %{drop_all: true} = operation
+  end
+
+  test "alter/3 returns {:error, error} for incorrect operation", %{conn: conn} do
+    {status, error} = ExDgraph.alter(conn, %{})
     assert status == :error
-    assert error[:code] == 2
+
+    assert %Error{action: :alter, code: 2, reason: "Operation must have at least one field set"} =
+             error
   end
 
-  test "operation!(%{drop_all: true}) is successful", %{conn: conn} do
-    operation_msg = ExDgraph.operation!(conn, %{drop_all: true})
-    assert operation_msg == %ExDgraph.Api.Payload{Data: ""}
+  test "alter!(%{drop_all: true}) is successful", %{conn: conn} do
+    payload = ExDgraph.alter!(conn, %{drop_all: true})
+    assert payload == %Payload{data: ""}
   end
 
-  test "operation!/2 raises ExDgraph.Exception for incorrect operation", %{conn: conn} do
-    assert_raise ExDgraph.Exception, fn ->
-      ExDgraph.operation!(conn, %{})
+  test "alter!/3 raises ExDgraph.Exception for incorrect operation", %{conn: conn} do
+    assert_raise Error, fn ->
+      ExDgraph.alter!(conn, %{})
     end
   end
 end

From bf5068aa86eacc6c7aca658477928d13fd30311b Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 18:11:18 +0200
Subject: [PATCH 55/68] Add additional tests.

---
 test/operation_test.exs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/test/operation_test.exs b/test/operation_test.exs
index dec57ba..b78f450 100644
--- a/test/operation_test.exs
+++ b/test/operation_test.exs
@@ -21,6 +21,18 @@ defmodule ExDgraph.OperationTest do
     assert payload == %Payload{data: ""}
   end
 
+  test "alter(%{drop_attr: attr}) is successful", %{conn: conn} do
+    {status, _operation, payload} = ExDgraph.alter(conn, %{drop_attr: "name"})
+    assert status == :ok
+    assert payload == %Payload{data: ""}
+  end
+
+  test "alter(%{schema: schema}) is successful", %{conn: conn} do
+    {status, _operation, payload} = ExDgraph.alter(conn, %{schema: "name: string @index(term) ."})
+    assert status == :ok
+    assert payload == %Payload{data: ""}
+  end
+
   test "alter/3 returns the operation", %{conn: conn} do
     {:ok, operation, _payload} = ExDgraph.alter(conn, %{drop_all: true})
     assert %{drop_all: true} = operation

From 667cde39f2b13359ba5ef1e5aaaf4d25f540c2f0 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Fri, 6 Sep 2019 18:11:29 +0200
Subject: [PATCH 56/68] Formatting.

---
 lib/exdgraph.ex        | 4 ++--
 test/exdgraph_test.exs | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index 575d60e..3156da0 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -353,8 +353,8 @@ defmodule ExDgraph do
 
   # Inherited from DBConnection
 
-  @idle_timeout 5000
-  @timeout 15000
+  @idle_timeout 5_000
+  @timeout 15_000
 
   @doc """
   Start the connection process and connect to Dgraph
diff --git a/test/exdgraph_test.exs b/test/exdgraph_test.exs
index bcdc1fa..8b0b8a0 100755
--- a/test/exdgraph_test.exs
+++ b/test/exdgraph_test.exs
@@ -27,14 +27,14 @@ defmodule ExDgraphTest do
 
       assert capture_log(fn ->
                {:ok, pid} = ExDgraph.start_link([hostname: "non_existing"] ++ opts)
-               assert_receive {:EXIT, ^pid, :killed}, 10000
+               assert_receive {:EXIT, ^pid, :killed}, 10_000
              end) =~
                "** (ExDgraph.Error) connect failed with \"Error when opening connection: :timeout\""
 
       assert capture_log(fn ->
                {:ok, pid} = ExDgraph.start_link([port: 700] ++ opts)
 
-               assert_receive {:EXIT, ^pid, :killed}, 10000
+               assert_receive {:EXIT, ^pid, :killed}, 10_000
              end) =~
                "** (ExDgraph.Error) connect failed with \"Error when opening connection: :timeout\""
     end

From fac80fa7eb824d34387a8e95d4420c058b6bd640 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Tue, 10 Sep 2019 22:20:16 +0200
Subject: [PATCH 57/68] Rename Result -> QueryResult.

---
 lib/exdgraph.ex         |  4 ++--
 lib/exdgraph/query.ex   |  4 ++--
 lib/exdgraph/structs.ex | 10 ++++++----
 test/query_test.exs     |  6 +++---
 4 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index 3156da0..dbcd5f2 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -343,7 +343,7 @@ defmodule ExDgraph do
 
   use Supervisor
 
-  alias ExDgraph.Api.{Mutation, Operation}
+  # alias ExDgraph.Api
   alias ExDgraph.{Operation, Mutation, Protocol, Query}
 
   @type conn :: DBConnection.conn()
@@ -501,7 +501,7 @@ defmodule ExDgraph do
   The same as `query/3` but raises a ExDgraph.Exception if it fails.
   Returns the server response otherwise.
   """
-  @spec query!(conn, String.t()) :: ExDgraph.Result | ExDgraph.Error
+  @spec query!(conn, String.t()) :: ExDgraph.QueryResult | ExDgraph.Error
   def query!(conn, statement) do
     case query(conn, statement) do
       {:ok, _query, result} ->
diff --git a/lib/exdgraph/query.ex b/lib/exdgraph/query.ex
index 5fbefb4..95ac4e9 100644
--- a/lib/exdgraph/query.ex
+++ b/lib/exdgraph/query.ex
@@ -17,7 +17,7 @@ defimpl DBConnection.Query, for: ExDgraph.Query do
   Implementation of `DBConnection.Query` protocol.
   """
 
-  alias ExDgraph.{Query, Result, Utils}
+  alias ExDgraph.{Api, Query, QueryResult, Utils}
 
   @doc """
   This function is called to decode a result after it is returned by a connection callback module.
@@ -32,7 +32,7 @@ defimpl DBConnection.Query, for: ExDgraph.Query do
       |> Jason.decode!()
       |> Utils.atomify_map_keys()
 
-    %Result{
+    %QueryResult{
       data: data,
       schema: schema,
       txn: txn
diff --git a/lib/exdgraph/structs.ex b/lib/exdgraph/structs.ex
index cf29f90..77a08e7 100644
--- a/lib/exdgraph/structs.ex
+++ b/lib/exdgraph/structs.ex
@@ -17,18 +17,20 @@ defmodule ExDgraph.Error do
   end
 end
 
-defmodule ExDgraph.Result do
+defmodule ExDgraph.QueryResult do
   @moduledoc """
-  Results from a query are wrapped in ExDgraph.Result
+  Results from a query are wrapped in ExDgraph.QueryResult
   """
 
   @type t :: %__MODULE__{
           data: %{optional(any) => any},
           schema: [any()],
-          txn: %ExDgraph.Api.TxnContext{}
+          txn: %ExDgraph.Api.TxnContext{},
+          uids: map() | nil
         }
 
-  defstruct [:data, :schema, :txn]
+  defstruct [:data, :schema, :txn, :uids]
+end
 end
 
 defmodule ExDgraph.Payload do
diff --git a/test/query_test.exs b/test/query_test.exs
index 70be5ce..56480f8 100644
--- a/test/query_test.exs
+++ b/test/query_test.exs
@@ -3,7 +3,7 @@ defmodule ExDgraph.QueryTest do
 
   use ExUnit.Case
   import ExDgraph.TestHelper
-  alias ExDgraph.{Error, Query, Result}
+  alias ExDgraph.{Error, Query, QueryResult}
 
   @sample_query """
     {
@@ -29,7 +29,7 @@ defmodule ExDgraph.QueryTest do
   end
 
   test "query/3 with correct query returns {:ok, %Query{}, %Result{}}", %{conn: conn} do
-    {status, %Query{} = _query, %Result{} = result} = ExDgraph.query(conn, @sample_query)
+    {status, %Query{} = _query, %QueryResult{} = result} = ExDgraph.query(conn, @sample_query)
     assert status == :ok
     data = result.data
     starwars = List.first(data.starwars)
@@ -49,7 +49,7 @@ defmodule ExDgraph.QueryTest do
   end
 
   test "query!/2 with correct query returns query_msg", %{conn: conn} do
-    %Result{} = result = ExDgraph.query!(conn, @sample_query)
+    %QueryResult{} = result = ExDgraph.query!(conn, @sample_query)
     data = result.data
     starwars = List.first(data.starwars)
     assert starwars.name == "Star Wars: Episode VI - Return of the Jedi"

From b846b31b71a42bad0d7be04437366a2703c8c785 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Tue, 10 Sep 2019 22:26:35 +0200
Subject: [PATCH 58/68] Pass in opts to query!/3

---
 lib/exdgraph.ex | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index dbcd5f2..7cd431a 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -498,12 +498,12 @@ defmodule ExDgraph do
   end
 
   @doc """
-  The same as `query/3` but raises a ExDgraph.Exception if it fails.
+  The same as `query/3` but raises a ExDgraph.Error if it fails.
   Returns the server response otherwise.
   """
   @spec query!(conn, String.t()) :: ExDgraph.QueryResult | ExDgraph.Error
-  def query!(conn, statement) do
-    case query(conn, statement) do
+  def query!(conn, statement, opts \\ []) do
+    case query(conn, statement, opts) do
       {:ok, _query, result} ->
         result
 

From f8de15fd181d2ee877ce1de9e267d9f5c70a35b7 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Tue, 10 Sep 2019 22:27:15 +0200
Subject: [PATCH 59/68] Rewrite mutations.

---
 lib/exdgraph.ex           |  54 +++++---
 lib/exdgraph/mutation.ex  | 259 ++++++++++++++------------------------
 lib/exdgraph/protocol.ex  |  30 +----
 lib/exdgraph/structs.ex   |  16 +++
 lib/exdgraph/transform.ex |  15 ---
 test/test_helper.exs      |   2 +-
 6 files changed, 154 insertions(+), 222 deletions(-)
 delete mode 100644 lib/exdgraph/transform.ex

diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index 7cd431a..33a65bd 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -516,7 +516,7 @@ defmodule ExDgraph do
   ######################
 
   @doc """
-  Sends the mutation to the server and returns `{:ok, result}` or
+  Sends the mutation to the server and returns `{:ok, query, result}` or
   `{:error, error}` otherwise
 
   ## Examples
@@ -564,8 +564,9 @@ defmodule ExDgraph do
   \"\"\"
   ```
 
-      iex> ExDgraph.mutation(conn, starwars_creation_mutation)
+      iex> ExDgraph.mutate(conn, starwars_creation_mutation)
       %{:ok,
+        query,
         %{
           context: %ExDgraph.Api.TxnContext{
             aborted: false,
@@ -590,15 +591,40 @@ defmodule ExDgraph do
       }
 
   """
-  @spec mutation(conn, String.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
-  defdelegate mutation(conn, statement), to: Mutation
+  @spec mutate(conn, iodata | map() | struct(), Keyword.t()) ::
+          {:ok, map()} | {:ok, ExDgraph.MutationResult} | {:error, ExDgraph.Error.t() | term}
+  def mutate(conn, query, opts \\ [])
+
+  def mutate(conn, query, opts) do
+    mutation = %Mutation{statement: query}
+
+    with {:ok, %Mutation{} = _query, result} <-
+           DBConnection.prepare_execute(conn, mutation, %{}, opts),
+         do: {:ok, query, result}
+  end
+
+  @doc """
+  The same as `mutate/3` but raises a ExDgraph.Error if it fails.
+  Returns the server response otherwise.
+  """
+  @spec mutate(conn, iodata | map() | struct(), Keyword.t()) ::
+          ExDgraph.MutationResult | ExDgraph.Error.t()
+  def mutate!(conn, statement, opts \\ []) do
+    case mutate(conn, statement, opts) do
+      {:ok, _query, result} ->
+        result
+
+      {:error, error} ->
+        raise error
+    end
+  end
 
   @doc """
   The same as `mutation/2` but raises an `ExDgraph.Exception` if it fails.
   Returns the server response otherwise.
   """
-  @spec mutation!(conn, String.t()) :: ExDgraph.Result | ExDgraph.Exception
-  defdelegate mutation!(conn, statement), to: Mutation
+  # @spec mutation!(conn, String.t()) :: ExDgraph.MutationResult | ExDgraph.Exception
+  # defdelegate mutation!(conn, statement), to: Mutation
 
   @doc """
   Allow you to pass a map to insert into the database. The function sends the mutation to the server and returns `{:ok, result}` or `{:error, error}` otherwise. Internally it uses Dgraphs `set_json`.
@@ -637,15 +663,15 @@ defmodule ExDgraph do
         }
       }
   """
-  @spec set_map(conn, Map.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
-  defdelegate set_map(conn, map), to: Mutation
+  # @spec set_map(conn, Map.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
+  # defdelegate set_map(conn, map), to: Mutation
 
   @doc """
   The same as `set_map/2` but raises an `ExDgraph.Exception` if it fails.
   Returns the server response otherwise.
   """
-  @spec set_map!(conn, Map.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
-  defdelegate set_map!(conn, map), to: Mutation
+  # @spec set_map!(conn, Map.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
+  # defdelegate set_map!(conn, map), to: Mutation
 
   @doc """
   This function allow you to convert an struct type into a mutation (json based) type in dgraph.
@@ -690,15 +716,15 @@ defmodule ExDgraph do
         }
       }
   """
-  @spec set_struct(conn, Map.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
-  defdelegate set_struct(conn, map), to: Mutation
+  # @spec set_struct(conn, Map.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
+  # defdelegate set_struct(conn, map), to: Mutation
 
   @doc """
   The same as `set_struct/2` but raises an `ExDgraph.Exception` if it fails.
   Returns the server response otherwise.
   """
-  @spec set_struct!(conn, Map.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
-  defdelegate set_struct!(conn, map), to: Mutation
+  # @spec set_struct!(conn, Map.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
+  # defdelegate set_struct!(conn, map), to: Mutation
 
   ## Operation
   ######################
diff --git a/lib/exdgraph/mutation.ex b/lib/exdgraph/mutation.ex
index 2676e3c..1d86e94 100644
--- a/lib/exdgraph/mutation.ex
+++ b/lib/exdgraph/mutation.ex
@@ -1,167 +1,122 @@
 defmodule ExDgraph.Mutation do
   @moduledoc """
-  Provides the functions for the callbacks from the DBConnection behaviour.
+  Wrapper for mutations sent to DBConnection.
   """
-  alias ExDgraph.{Exception, MutationStatement, Transform}
 
-  @doc false
-  def mutation(conn, statement) do
-    case mutation_commit(conn, statement) do
-      {:ok, %MutationStatement{}, result} ->
-        {:ok, result}
+  alias ExDgraph.{Exception, Transform}
 
-      {:error, f} ->
-        {:error, code: f.code, message: f.message}
-    end
-  end
-
-  @doc false
-  def mutation!(conn, statement) do
-    case mutation(conn, statement) do
-      {:ok, %MutationStatement{}, result} ->
-        {:ok, result}
-
-      {:error, code: code, message: message} ->
-        raise Exception, code: code, message: message
-    end
-  end
-
-  @doc false
-  def set_map(conn, map) do
-    map_with_tmp_uids = insert_tmp_uids(map)
-    json = Jason.encode!(map_with_tmp_uids)
-
-    case set_map_commit(conn, json, map_with_tmp_uids) do
-      {:ok, r} ->
-        {:ok, r}
-
-      {:error, f} ->
-        {:error, code: f.code, message: f.message}
-    end
-  end
-
-  @doc false
-  def set_map!(conn, map) do
-    case set_map(conn, map) do
-      {:ok, r} ->
-        r
-
-      {:error, code: code, message: message} ->
-        raise Exception, code: code, message: message
-    end
-  end
+  @type t :: %ExDgraph.Mutation{
+          statement: String.t() | map() | struct(),
+          set_json: String.t(),
+          txn_context: any(),
+          original_statement: any()
+        }
 
-  @doc false
-  def set_struct(conn, struct) do
-    uids_and_schema_map = set_tmp_ids_and_schema(struct)
-    json = Jason.encode!(uids_and_schema_map)
-
-    case set_struct_commit(conn, json, uids_and_schema_map) do
-      {:ok, r} ->
-        {:ok, r}
+  defstruct statement: nil, set_json: nil, txn_context: nil, original_statement: nil
+end
 
-      {:error, f} ->
-        {:error, code: f.code, message: f.message}
-    end
-  end
+defimpl DBConnection.Query, for: ExDgraph.Mutation do
+  @moduledoc """
+  Implementation of `DBConnection.Query` protocol.
+  """
 
-  @doc false
-  def set_struct!(conn, struct) do
-    case set_struct(conn, struct) do
-      {:ok, r} ->
-        r
+  alias ExDgraph.{Api, Mutation, MutationResult, Transform, Utils}
 
-      {:error, code: code, message: message} ->
-        raise Exception, code: code, message: message
-    end
+  @doc """
+  This function is called to decode a result after it is returned by a connection callback module.
+  """
+  def decode(
+        %Mutation{
+          set_json: set_json,
+          statement: statement,
+          original_statement: original_statement
+        } = query,
+        %Api.Assigned{context: context, latency: latency, uids: uids} = _result,
+        _opts
+      )
+      when is_binary(set_json) and is_nil(statement) do
+    data =
+      set_json
+      |> Jason.decode!()
+      |> Utils.atomify_map_keys()
+      |> replace_tmp_uids(uids)
+      |> merge_result_with_statement(original_statement)
+
+    %MutationResult{
+      data: data,
+      context: context,
+      latency: latency,
+      uids: uids
+    }
   end
 
-  defp mutation_commit(conn, statement) do
-    exec = fn conn ->
-      q = %MutationStatement{statement: statement}
-
-      case DBConnection.execute(conn, q, %{}) do
-        {:ok, resp} -> Transform.transform_mutation(resp)
-        other -> other
-      end
-    end
-
-    DBConnection.run(conn, exec)
+  def decode(
+        %Mutation{
+          set_json: set_json,
+          statement: statement
+        } = query,
+        %Api.Assigned{context: context, latency: latency, uids: uids} = _result,
+        _opts
+      )
+      when is_nil(set_json) and is_binary(statement) do
+    %MutationResult{
+      context: context,
+      latency: latency,
+      uids: uids
+    }
   end
 
-  defp set_map_commit(conn, json, map_with_tmp_uids) do
-    exec = fn conn ->
-      q = %MutationStatement{set_json: json}
-
-      case DBConnection.execute(conn, q, %{}) do
-        {:ok, %MutationStatement{}, result} ->
-          # Now exchange the tmp ids for the ones returned from the db
-          result_with_uids = replace_tmp_uids(map_with_tmp_uids, result.uids)
-          {:ok, Map.put(result, :result, result_with_uids)}
+  @doc """
+  This function is called to describe a query after it is prepared using a connection callback module.
+  """
+  def describe(query, _opts), do: query
 
-        other ->
-          other
-      end
-    end
+  @doc """
+  This function is called to encode a query before it is executed using a connection callback module.
+  """
+  def encode(_query, data, _opts), do: data
 
-    DBConnection.run(conn, exec)
+  @doc """
+  This function is called to parse a query term before it is prepared using a connection callback module.
+  """
+  def parse(%{statement: %{__struct__: struct_name} = statement} = query, _opts) do
+    json =
+      statement
+      |> Map.from_struct()
+      |> insert_tmp_uids()
+      |> Jason.encode!()
+
+    %Mutation{query | statement: nil, set_json: json, original_statement: statement}
   end
 
-  defp set_struct_commit(conn, json, struct_with_tmp_uids) do
-    exec = fn conn ->
-      q = %MutationStatement{set_json: json}
-
-      case DBConnection.execute(conn, q, %{}) do
-        {:ok, %MutationStatement{}, result} ->
-          # Now exchange the tmp ids for the ones returned from the db
-          result_with_uids = replace_tmp_struct_uids(struct_with_tmp_uids, result.uids)
-          {:ok, Map.put(result, :result, result_with_uids)}
-
-        other ->
-          other
-      end
-    end
+  def parse(%{statement: statement} = query, _opts) when is_map(statement) do
+    json =
+      statement
+      |> insert_tmp_uids()
+      |> Jason.encode!()
 
-    DBConnection.run(conn, exec)
+    %Mutation{query | statement: nil, set_json: json, original_statement: statement}
   end
 
-  defp insert_tmp_uids(map) when is_list(map), do: Enum.map(map, &insert_tmp_uids/1)
-
-  defp insert_tmp_uids(map) when is_map(map) do
-    map
-    |> Map.update(:uid, "_:#{UUID.uuid4()}", fn existing_uuid -> existing_uuid end)
-    |> Enum.reduce(%{}, fn {key, map_value}, a ->
-      Map.merge(a, %{key => insert_tmp_uids(map_value)})
-    end)
+  def parse(%{statement: statement} = query, _opts) when is_binary(statement) do
+    %Mutation{query | statement: IO.iodata_to_binary(statement), original_statement: statement}
   end
 
-  defp insert_tmp_uids(value), do: value
-
-  defp set_tmp_ids_and_schema(map) when is_list(map), do: Enum.map(map, &set_tmp_ids_and_schema/1)
-
-  defp set_tmp_ids_and_schema(%x{} = map) do
-    schema = x |> get_schema_name()
+  defp insert_tmp_uids(map, acc \\ 0)
 
-    map
-    |> Map.from_struct()
-    |> Map.update(:uid, "_:#{UUID.uuid4()}", fn
-      nil -> "_:#{UUID.uuid4()}"
-      existing_uuid -> existing_uuid
-    end)
-    |> Enum.reduce(%{}, fn {key, map_value}, a ->
-      set_schema(schema, {key, map_value}, a, ExDgraph.config(:enforce_struct_schema))
-    end)
-  end
+  defp insert_tmp_uids(map, acc) when is_list(map),
+    do: Enum.map(map, &insert_tmp_uids(&1, acc).())
 
-  defp set_tmp_ids_and_schema(map) when is_map(map) do
+  defp insert_tmp_uids(map, acc) when is_map(map) do
     map
-    |> Map.update(:uid, "_:#{UUID.uuid4()}", fn existing_uuid -> existing_uuid end)
+    |> Map.update(:uid, "_:#{acc}", fn existing_uuid -> existing_uuid end)
     |> Enum.reduce(%{}, fn {key, map_value}, a ->
-      Map.merge(a, %{key => set_tmp_ids_and_schema(map_value)})
+      new_acc = acc + 1
+      Map.merge(a, %{key => insert_tmp_uids(map_value, new_acc)})
     end)
   end
 
-  defp set_tmp_ids_and_schema(value), do: value
+  defp insert_tmp_uids(value, acc), do: value
 
   defp replace_tmp_uids(map, uids) when is_list(map),
     do: Enum.map(map, &replace_tmp_uids(&1, uids))
@@ -181,37 +136,9 @@ defmodule ExDgraph.Mutation do
 
   defp replace_tmp_uids(value, _uids), do: value
 
-  defp replace_tmp_struct_uids(map, uids) when is_list(map),
-    do: Enum.map(map, &replace_tmp_struct_uids(&1, uids))
-
-  defp replace_tmp_struct_uids(map, uids) when is_map(map) do
-    map
-    |> Map.update(:uid, map[:uid], fn existing_uuid ->
-      case String.slice(existing_uuid, 0, 2) == "_:" do
-        true -> uids[String.replace_leading(existing_uuid, "_:", "")]
-        false -> existing_uuid
-      end
-    end)
-    |> Enum.reduce(%{}, fn {key, map_value}, a ->
-      # delete the schema prefix
-      key = key |> to_string() |> String.split(".") |> List.last() |> String.to_existing_atom()
-      Map.merge(a, %{key => replace_tmp_struct_uids(map_value, uids)})
-    end)
-  end
-
-  defp replace_tmp_struct_uids(value, _uids), do: value
-
-  defp get_schema_name(schema) do
-    schema |> to_string() |> String.split(".") |> List.last() |> String.downcase()
+  defp merge_result_with_statement(result, %{__struct__: struct_name} = _original_statement) do
+    struct(struct_name, result)
   end
 
-  defp set_schema(_schema_name, {:uid, map_value}, result, _is_enforced_schema),
-    do: Map.merge(result, %{:uid => set_tmp_ids_and_schema(map_value)})
-
-  defp set_schema(schema_name, {key, map_value}, result, is_enforced_schema)
-       when is_enforced_schema == true,
-       do: Map.merge(result, %{"#{schema_name}.#{key}" => set_tmp_ids_and_schema(map_value)})
-
-  defp set_schema(_schema_name, {key, map_value}, result, _is_enforced_schema),
-    do: Map.merge(result, %{key => set_tmp_ids_and_schema(map_value)})
+  defp merge_result_with_statement(result, _original_statement), do: result
 end
diff --git a/lib/exdgraph/protocol.ex b/lib/exdgraph/protocol.ex
index 399e58f..ef142c0 100755
--- a/lib/exdgraph/protocol.ex
+++ b/lib/exdgraph/protocol.ex
@@ -11,7 +11,7 @@ defmodule ExDgraph.Protocol do
     Api,
     Error,
     Exception,
-    MutationStatement,
+    Mutation,
     Operation,
     Query
   }
@@ -134,39 +134,17 @@ defmodule ExDgraph.Protocol do
 
   @impl true
   def handle_execute(
-        %MutationStatement{statement: statement, set_json: ""} = query,
+        %Mutation{statement: statement, set_json: set_json} = query,
         _params,
         _,
         state
       ) do
-    dgraph_query = ExDgraph.Api.Mutation.new(set_nquads: statement, commit_now: true)
-    do_mutate(state, dgraph_query, query)
-  end
+    dgraph_query =
+      ExDgraph.Api.Mutation.new(set_nquads: statement, set_json: set_json, commit_now: true)
 
-  @impl true
-  def handle_execute(
-        %MutationStatement{statement: "", set_json: set_json} = query,
-        _request,
-        _opts,
-        state
-      ) do
-    dgraph_query = ExDgraph.Api.Mutation.new(set_json: set_json, commit_now: true)
     do_mutate(state, dgraph_query, query)
   end
 
-  @impl true
-  def handle_execute(
-        %MutationStatement{statement: _statement, set_json: _set_json},
-        _params,
-        _,
-        %{channel: channel} = state
-      ) do
-    raise Exception, code: 2, message: "Both set_json and statement defined"
-  rescue
-    e ->
-      {:error, e, state}
-  end
-
   @impl true
   def handle_execute(
         %Operation{drop_all: drop_all, schema: schema, drop_attr: drop_attr} = query,
diff --git a/lib/exdgraph/structs.ex b/lib/exdgraph/structs.ex
index 77a08e7..a245eaf 100644
--- a/lib/exdgraph/structs.ex
+++ b/lib/exdgraph/structs.ex
@@ -31,6 +31,22 @@ defmodule ExDgraph.QueryResult do
 
   defstruct [:data, :schema, :txn, :uids]
 end
+
+defmodule ExDgraph.MutationResult do
+  @moduledoc """
+  Results from a mutation are wrapped in ExDgraph.MutationResult
+  """
+
+  alias ExDgraph.Api
+
+  @type t :: %__MODULE__{
+          data: %{optional(any) => any},
+          uids: %{String.t() => String.t()},
+          context: Api.TxnContext.t() | nil,
+          latency: Api.Latency.t() | nil
+        }
+
+  defstruct [:data, :uids, :context, :latency]
 end
 
 defmodule ExDgraph.Payload do
diff --git a/lib/exdgraph/transform.ex b/lib/exdgraph/transform.ex
deleted file mode 100644
index 350f7f8..0000000
--- a/lib/exdgraph/transform.ex
+++ /dev/null
@@ -1,15 +0,0 @@
-defmodule ExDgraph.Transform do
-  @moduledoc """
-  Transform a raw response from Dgraph. For example decode the json part.
-  """
-
-  @doc """
-  Takes a response from Dgraph and returns a map.
-  """
-  def transform_mutation(%ExDgraph.Api.Assigned{context: context, uids: uids}) do
-    %{
-      context: context,
-      uids: uids
-    }
-  end
-end
diff --git a/test/test_helper.exs b/test/test_helper.exs
index 041c4f8..f760f48 100755
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@@ -62,7 +62,7 @@ defmodule ExDgraph.TestHelper do
 
   def import_starwars_sample(conn) do
     ExDgraph.alter(conn, %{schema: @starwars_schema})
-    {:ok, _} = ExDgraph.mutation(conn, @starwars_creation_mutation)
+    {:ok, _, _} = ExDgraph.mutate(conn, @starwars_creation_mutation)
   end
 
   def starwars_creation_mutation() do

From 8ada086c37e1d58238a06ff430fefaeb80e11145 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Tue, 10 Sep 2019 22:27:23 +0200
Subject: [PATCH 60/68] Use proper alias.

---
 lib/exdgraph/operation.ex | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/exdgraph/operation.ex b/lib/exdgraph/operation.ex
index 92322c2..b59829c 100644
--- a/lib/exdgraph/operation.ex
+++ b/lib/exdgraph/operation.ex
@@ -14,14 +14,14 @@ defmodule ExDgraph.Operation do
 end
 
 defimpl DBConnection.Query, for: ExDgraph.Operation do
-  alias ExDgraph.{Operation, Payload}
+  alias ExDgraph.{Api, Operation, Payload}
 
   @doc """
   This function is called to decode a result after it is returned by a connection callback module.
   """
   def decode(
         _query,
-        %ExDgraph.Api.Payload{Data: data} = _result,
+        %Api.Payload{Data: data} = _result,
         _opts
       ) do
     %Payload{

From ff8244f3686b40bb8ef14bea922d4550a9aacfee Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Tue, 10 Sep 2019 22:53:47 +0200
Subject: [PATCH 61/68] Rename txn_context in result structs.

---
 lib/exdgraph/mutation.ex | 4 ++--
 lib/exdgraph/query.ex    | 2 +-
 lib/exdgraph/structs.ex  | 8 ++++----
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/lib/exdgraph/mutation.ex b/lib/exdgraph/mutation.ex
index 1d86e94..f8d65ca 100644
--- a/lib/exdgraph/mutation.ex
+++ b/lib/exdgraph/mutation.ex
@@ -44,7 +44,7 @@ defimpl DBConnection.Query, for: ExDgraph.Mutation do
 
     %MutationResult{
       data: data,
-      context: context,
+      txn_context: context,
       latency: latency,
       uids: uids
     }
@@ -60,7 +60,7 @@ defimpl DBConnection.Query, for: ExDgraph.Mutation do
       )
       when is_nil(set_json) and is_binary(statement) do
     %MutationResult{
-      context: context,
+      txn_context: context,
       latency: latency,
       uids: uids
     }
diff --git a/lib/exdgraph/query.ex b/lib/exdgraph/query.ex
index 95ac4e9..1a871f0 100644
--- a/lib/exdgraph/query.ex
+++ b/lib/exdgraph/query.ex
@@ -35,7 +35,7 @@ defimpl DBConnection.Query, for: ExDgraph.Query do
     %QueryResult{
       data: data,
       schema: schema,
-      txn: txn
+      txn_context: txn
     }
   end
 
diff --git a/lib/exdgraph/structs.ex b/lib/exdgraph/structs.ex
index a245eaf..ebdb06e 100644
--- a/lib/exdgraph/structs.ex
+++ b/lib/exdgraph/structs.ex
@@ -25,11 +25,11 @@ defmodule ExDgraph.QueryResult do
   @type t :: %__MODULE__{
           data: %{optional(any) => any},
           schema: [any()],
-          txn: %ExDgraph.Api.TxnContext{},
+          txn_context: %ExDgraph.Api.TxnContext{},
           uids: map() | nil
         }
 
-  defstruct [:data, :schema, :txn, :uids]
+  defstruct [:data, :schema, :txn_context, :uids]
 end
 
 defmodule ExDgraph.MutationResult do
@@ -42,11 +42,11 @@ defmodule ExDgraph.MutationResult do
   @type t :: %__MODULE__{
           data: %{optional(any) => any},
           uids: %{String.t() => String.t()},
-          context: Api.TxnContext.t() | nil,
+          txn_context: Api.TxnContext.t() | nil,
           latency: Api.Latency.t() | nil
         }
 
-  defstruct [:data, :uids, :context, :latency]
+  defstruct [:data, :uids, :txn_context, :latency]
 end
 
 defmodule ExDgraph.Payload do

From 2711bc7497e758267bdbac8b4b0f6ed13a6ec57b Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Tue, 10 Sep 2019 22:53:52 +0200
Subject: [PATCH 62/68] Cleanup.

---
 lib/exdgraph.ex | 107 ------------------------------------------------
 1 file changed, 107 deletions(-)

diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index 33a65bd..197838d 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -619,113 +619,6 @@ defmodule ExDgraph do
     end
   end
 
-  @doc """
-  The same as `mutation/2` but raises an `ExDgraph.Exception` if it fails.
-  Returns the server response otherwise.
-  """
-  # @spec mutation!(conn, String.t()) :: ExDgraph.MutationResult | ExDgraph.Exception
-  # defdelegate mutation!(conn, statement), to: Mutation
-
-  @doc """
-  Allow you to pass a map to insert into the database. The function sends the mutation to the server and returns `{:ok, result}` or `{:error, error}` otherwise. Internally it uses Dgraphs `set_json`.
-  The `result` is a map of all values you have passed in but with the field `uid` populated from the database.
-
-  ## Examples
-
-  ```elixir
-  map = %{
-     name: "Alice",
-     friends: %{
-       name: "Betty"
-     }
-   }
-   ```
-
-      iex> ExDgraph.set_map(conn, map)
-      %{:ok,
-        %{
-          context: %ExDgraph.Api.TxnContext{
-            aborted: false,
-            commit_ts: 1703,
-            keys: [],
-            lin_read: %ExDgraph.Api.LinRead{ids: %{1 => 1508}},
-            start_ts: 1702
-          },
-          result: %{
-            friends: [%{name: "Betty", uid: "0xd82"}],
-            name: "Alice",
-            uid: "0xd81"
-          },
-          uids: %{
-            "763d617a-af34-4ff9-9863-e072bf85146d" => "0xd82",
-            "e94713a5-54a7-4e36-8ab8-0d3019409892" => "0xd81"
-          }
-        }
-      }
-  """
-  # @spec set_map(conn, Map.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
-  # defdelegate set_map(conn, map), to: Mutation
-
-  @doc """
-  The same as `set_map/2` but raises an `ExDgraph.Exception` if it fails.
-  Returns the server response otherwise.
-  """
-  # @spec set_map!(conn, Map.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
-  # defdelegate set_map!(conn, map), to: Mutation
-
-  @doc """
-  This function allow you to convert an struct type into a mutation (json based) type in dgraph.
-  It also allows you to enforce the schema in database (adding a "class name" info before every predicate, this class name is the single name given to the elixir module struct) by activating the `enforce_struct_schema` in the config files.
-  The function sends the mutation to the server and returns `{:ok, result}` or `{:error, error}` otherwise.
-  Internally it uses Dgraphs `set_json`.
-  The `result` is a map without the "classname" (you can apply the built-in function `struct` to convert the map into the struct you desire) of all values you have passed in but with the field `uid` populated from the database.
-
-  ## Examples
-
-  ```elixir
-  struct_data = %MutationTest.Person{
-    name: "Alice",
-    identifier: "alice_json",
-    dogs: [
-      %MutationTest.Dog{
-        name: "Bello"
-      }
-    ]
-  }
-   ```
-
-      iex> ExDgraph.set_struct(conn, struct_data)
-      %{:ok,
-        %{
-          context: %ExDgraph.Api.TxnContext{
-            aborted: false,
-            commit_ts: 1703,
-            keys: [],
-            lin_read: %ExDgraph.Api.LinRead{ids: %{1 => 1508}},
-            start_ts: 1702
-          },
-          result: %{
-            dogs: [%{name: "Bello", uid: "0xd82"}],
-            name: "Alice",
-            uid: "0xd81"
-          },
-          uids: %{
-            "763d617a-af34-4ff9-9863-e072bf85146d" => "0xd82",
-            "e94713a5-54a7-4e36-8ab8-0d3019409892" => "0xd81"
-          }
-        }
-      }
-  """
-  # @spec set_struct(conn, Map.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
-  # defdelegate set_struct(conn, map), to: Mutation
-
-  @doc """
-  The same as `set_struct/2` but raises an `ExDgraph.Exception` if it fails.
-  Returns the server response otherwise.
-  """
-  # @spec set_struct!(conn, Map.t()) :: {:ok, ExDgraph.Result} | {:error, ExDgraph.Error}
-  # defdelegate set_struct!(conn, map), to: Mutation
-
   ## Operation
   ######################
 

From 5d2d1bf4c2236054397c714a86c70db0f6564543 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Tue, 10 Sep 2019 23:39:02 +0200
Subject: [PATCH 63/68] Implement handle_execute for mutations.

---
 lib/exdgraph/protocol.ex | 25 +++++++++----------------
 1 file changed, 9 insertions(+), 16 deletions(-)

diff --git a/lib/exdgraph/protocol.ex b/lib/exdgraph/protocol.ex
index ef142c0..fc47987 100755
--- a/lib/exdgraph/protocol.ex
+++ b/lib/exdgraph/protocol.ex
@@ -137,12 +137,18 @@ defmodule ExDgraph.Protocol do
         %Mutation{statement: statement, set_json: set_json} = query,
         _params,
         _,
-        state
+        %{channel: channel, opts: opts} = state
       ) do
-    dgraph_query =
+    request =
       ExDgraph.Api.Mutation.new(set_nquads: statement, set_json: set_json, commit_now: true)
 
-    do_mutate(state, dgraph_query, query)
+    case ExDgraph.Api.Dgraph.Stub.mutate(channel, request, timeout: opts[:timeout]) do
+      {:ok, res} ->
+        {:ok, query, res, state}
+
+      {:error, error} ->
+        {:error, %Error{action: :query, code: error.status, reason: error.message}, state}
+    end
   end
 
   @impl true
@@ -183,19 +189,6 @@ defmodule ExDgraph.Protocol do
     {:halt, nil, state}
   end
 
-  defp do_mutate(%{channel: channel, opts: opts} = state, dgraph_query, query) do
-    case ExDgraph.Api.Dgraph.Stub.mutate(channel, dgraph_query, timeout: opts[:timeout]) do
-      {:ok, res} ->
-        {:ok, query, res, state}
-
-      {:error, f} ->
-        raise Exception, code: f.status, message: f.message
-    end
-  rescue
-    e ->
-      {:error, e, state}
-  end
-
   @spec default_opts(Keyword.t()) :: Keyword.t()
   defp default_opts(opts \\ []) do
     opts

From 2cbe97e01539d0c890d68a007bfcc36a17c0c617 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Tue, 10 Sep 2019 23:39:19 +0200
Subject: [PATCH 64/68] Fix mutation tests.

---
 lib/exdgraph/mutation.ex |   2 +-
 test/mutation_test.exs   | 263 ++++++++++++++++-----------------------
 2 files changed, 111 insertions(+), 154 deletions(-)

diff --git a/lib/exdgraph/mutation.ex b/lib/exdgraph/mutation.ex
index f8d65ca..ac30f5a 100644
--- a/lib/exdgraph/mutation.ex
+++ b/lib/exdgraph/mutation.ex
@@ -105,7 +105,7 @@ defimpl DBConnection.Query, for: ExDgraph.Mutation do
   defp insert_tmp_uids(map, acc \\ 0)
 
   defp insert_tmp_uids(map, acc) when is_list(map),
-    do: Enum.map(map, &insert_tmp_uids(&1, acc).())
+    do: Enum.map(map, &insert_tmp_uids(&1, acc))
 
   defp insert_tmp_uids(map, acc) when is_map(map) do
     map
diff --git a/test/mutation_test.exs b/test/mutation_test.exs
index 3c5972a..ba4f777 100644
--- a/test/mutation_test.exs
+++ b/test/mutation_test.exs
@@ -80,166 +80,123 @@ defmodule MutationTest do
   """
 
   setup do
-    conn = ExDgraph.conn()
-    drop_all()
-    import_starwars_sample()
-
-    on_exit(fn ->
-      # close channel ?
-      :ok
-    end)
+    {:ok, conn} = ExDgraph.start_link()
+    ExDgraph.alter(conn, %{drop_all: true})
+    import_starwars_sample(conn)
 
     [conn: conn]
   end
 
-  test "mutation/2 returns {:ok, mutation_msg} for correct mutation", %{conn: conn} do
-    {status, mutation_msg} = ExDgraph.mutation(conn, starwars_creation_mutation())
-    assert status == :ok
-    assert mutation_msg.context.aborted == false
-  end
-
-  test "mutation/2 returns {:error, error} for incorrect mutation", %{conn: conn} do
-    {status, error} = ExDgraph.mutation(conn, "wrong")
-    assert status == :error
-    assert error[:code] == 2
-  end
-
-  # TODO: Take care of updates via uid
-  test "set_map/2 returns {:ok, mutation_msg} for correct mutation", %{conn: conn} do
-    {status, mutation_msg} = ExDgraph.set_map(conn, @map_insert_mutation)
-    assert status == :ok
-    assert mutation_msg.context.aborted == false
-    query_msg = ExDgraph.Query.query!(conn, @map_insert_check_query)
-    res = query_msg.result
-    people = res[:people]
-    alice = List.first(people)
-    assert alice[:name] == "Alice"
-    betty = List.first(alice[:friends])
-    assert betty[:name] == "Betty"
-  end
-
-  test "set_map!/2 returns mutation_message", %{conn: conn} do
-    mutation_msg = ExDgraph.set_map!(conn, @map_insert_mutation)
-    assert mutation_msg.context.aborted == false
-    query_msg = ExDgraph.Query.query!(conn, @map_insert_check_query)
-    res = query_msg.result
-    people = res[:people]
-    alice = List.first(people)
-    assert alice[:name] == "Alice"
-    betty = List.first(alice[:friends])
-    assert betty[:name] == "Betty"
-  end
-
-  test "set_map/2 returns result with uids", %{conn: conn} do
-    {status, mutation_msg} = ExDgraph.set_map(conn, @map_insert_mutation)
-    assert status == :ok
-    assert is_map(mutation_msg.result)
-    mutation_alice = mutation_msg.result
-    mutation_betty = List.first(mutation_alice[:friends])
-    query_msg = ExDgraph.Query.query!(conn, @map_insert_check_query)
-    query_people = query_msg.result[:people]
-    query_alice = List.first(query_people)
-    query_betty = List.first(query_alice[:friends])
-    assert mutation_alice[:uid] == query_alice[:uid]
-    assert mutation_betty[:uid] == query_betty[:uid]
-  end
-
-  test "set_map!/2 returns result with uids", %{conn: conn} do
-    mutation_msg = ExDgraph.set_map!(conn, @map_insert_mutation)
-    assert is_map(mutation_msg.result)
-    mutation_alice = mutation_msg.result
-    mutation_betty = List.first(mutation_alice[:friends])
-    query_msg = ExDgraph.Query.query!(conn, @map_insert_check_query)
-    query_people = query_msg.result[:people]
-    query_alice = List.first(query_people)
-    query_betty = List.first(query_alice[:friends])
-    assert mutation_alice[:uid] == query_alice[:uid]
-    assert mutation_betty[:uid] == query_betty[:uid]
-  end
-
-  # TODO: Take care of updates via uid
-  test "set_map/2 struct returns {:ok, mutation_msg} for correct mutation", %{conn: conn} do
-    {status, mutation_msg} = ExDgraph.set_struct(conn, @struct_insert_mutation)
-    assert status == :ok
-    assert mutation_msg.context.aborted == false
-    query_msg = ExDgraph.Query.query!(conn, @struct_insert_check_query)
-    res = query_msg.result
-    people = res[:people]
-    alice = List.first(people)
-    assert alice[:name] == "Alice"
-    betty = List.first(alice[:dogs])
-    assert betty[:name] == "Betty"
-    some_map = List.first(alice[:some_map])
-    assert some_map.some == "value"
-    bob = List.first(some_map[:map_owner])
-    assert bob.name == "Bob"
-  end
-
-  test "set_map!/2 struct returns mutation_message", %{conn: conn} do
-    mutation_msg = ExDgraph.set_struct!(conn, @struct_insert_mutation)
-    assert mutation_msg.context.aborted == false
-    query_msg = ExDgraph.Query.query!(conn, @struct_insert_check_query)
-    res = query_msg.result
-    people = res[:people]
-    alice = List.first(people)
-    assert alice[:name] == "Alice"
-    betty = List.first(alice[:dogs])
-    assert betty[:name] == "Betty"
-    some_map = List.first(alice[:some_map])
-    assert some_map.some == "value"
-    bob = List.first(some_map[:map_owner])
-    assert bob.name == "Bob"
-  end
-
-  test "set_map/2 struct returns result with uids", %{conn: conn} do
-    {status, mutation_msg} = ExDgraph.set_struct(conn, @struct_insert_mutation)
-    assert status == :ok
-    assert is_map(mutation_msg.result)
-    mutation_alice = mutation_msg.result
-    mutation_betty = List.first(mutation_alice[:dogs])
-    mutation_some_map = mutation_alice[:some_map]
-    mutation_bob = mutation_some_map[:map_owner]
-    query_msg = ExDgraph.Query.query!(conn, @struct_insert_check_query)
-    query_people = query_msg.result[:people]
-    query_alice = List.first(query_people)
-    query_betty = List.first(query_alice[:dogs])
-    query_some_map = List.first(query_alice[:some_map])
-    query_bob = List.first(query_some_map[:map_owner])
-    assert mutation_alice[:uid] == query_alice[:uid]
-    assert mutation_betty[:uid] == query_betty[:uid]
-    assert mutation_some_map[:uid] == query_some_map[:uid]
-    assert mutation_bob[:uid] == query_bob[:uid]
-  end
+  describe "mutate/3" do
+    test "it returns {:ok, %Mutation{}, %MutationResult{}} for correct mutation", %{
+      conn: conn
+    } do
+      {status, _mutation, result} = ExDgraph.mutate(conn, starwars_creation_mutation())
+      assert status == :ok
+      assert result.txn_context.aborted == false
+    end
+
+    test "it returns {:error, error} for incorrect mutation", %{conn: conn} do
+      {status, error} = ExDgraph.mutate(conn, "wrong")
+      assert status == :error
+      assert error.code == 2
+    end
+
+    test "it writes the data to Dgraph", %{
+      conn: conn
+    } do
+      {status, _mutation, result} = ExDgraph.mutate(conn, @map_insert_mutation)
+      assert status == :ok
+      assert result.txn_context.aborted == false
+      query_msg = ExDgraph.query!(conn, @map_insert_check_query)
+      res = query_msg.data
+      people = res[:people]
+      alice = List.first(people)
+      assert alice[:name] == "Alice"
+      betty = List.first(alice[:friends])
+      assert betty[:name] == "Betty"
+    end
+
+    test "it returns result with uids", %{conn: conn} do
+      {status, _mutation, result} = ExDgraph.mutate(conn, @map_insert_mutation)
+      assert status == :ok
+      assert is_map(result.data)
+      mutation_alice = result.data
+      mutation_betty = List.first(mutation_alice[:friends])
+      query_msg = ExDgraph.query!(conn, @map_insert_check_query)
+      query_people = query_msg.data[:people]
+      query_alice = List.first(query_people)
+      query_betty = List.first(query_alice[:friends])
+      assert mutation_alice[:uid] == query_alice[:uid]
+      assert mutation_betty[:uid] == query_betty[:uid]
+    end
+
+    test "it updates a node if a uid is present and returns the uid again", %{conn: conn} do
+      user = %{name: "bob", occupation: "dev"}
+      {:ok, _mutation, result} = ExDgraph.mutate(conn, user)
+
+      other_mutation = %{
+        uid: result.data.uid,
+        friends: [%{name: "Paul", occupation: "diver"}, %{name: "Lisa", gender: "female"}]
+      }
 
-  test "set_map!/2 struct returns result with uids", %{conn: conn} do
-    mutation_msg = ExDgraph.set_struct!(conn, @struct_insert_mutation)
-    assert is_map(mutation_msg.result)
-    mutation_alice = mutation_msg.result
-    mutation_betty = List.first(mutation_alice[:dogs])
-    mutation_some_map = mutation_alice[:some_map]
-    mutation_bob = mutation_some_map[:map_owner]
-    query_msg = ExDgraph.Query.query!(conn, @struct_insert_check_query)
-    query_people = query_msg.result[:people]
-    query_alice = List.first(query_people)
-    query_betty = List.first(query_alice[:dogs])
-    query_some_map = List.first(query_alice[:some_map])
-    query_bob = List.first(query_some_map[:map_owner])
-    assert mutation_alice[:uid] == query_alice[:uid]
-    assert mutation_betty[:uid] == query_betty[:uid]
-    assert mutation_some_map[:uid] == query_some_map[:uid]
-    assert mutation_bob[:uid] == query_bob[:uid]
+      {:ok, _mutation, result2} = ExDgraph.mutate(conn, other_mutation)
+      assert result.data.uid == result2.data.uid
+    end
   end
 
-  test "set_map/2 updates a node if a uid is present and returns the uid again", %{conn: conn} do
-    user = %{name: "bob", occupation: "dev"}
-    {:ok, res} = ExDgraph.set_map(conn, user)
-
-    other_mutation = %{
-      uid: res.result.uid,
-      friends: [%{name: "Paul", occupation: "diver"}, %{name: "Lisa", gender: "female"}]
-    }
+  describe "mutate!/3" do
+    test "it returns %MutationResult{} for correct mutation", %{
+      conn: conn
+    } do
+      result = ExDgraph.mutate!(conn, starwars_creation_mutation())
+      assert result.txn_context.aborted == false
+    end
+
+    test "it raises ExDgraph.Error for incorrect mutation", %{conn: conn} do
+      assert_raise(ExDgraph.Error, fn ->
+        ExDgraph.mutate!(conn, "wrong")
+      end)
+    end
+
+    test "it writes the data to Dgraph", %{
+      conn: conn
+    } do
+      result = ExDgraph.mutate!(conn, @map_insert_mutation)
+      assert result.txn_context.aborted == false
+      query_msg = ExDgraph.query!(conn, @map_insert_check_query)
+      res = query_msg.data
+      people = res[:people]
+      alice = List.first(people)
+      assert alice[:name] == "Alice"
+      betty = List.first(alice[:friends])
+      assert betty[:name] == "Betty"
+    end
+
+    test "it returns result with uids", %{conn: conn} do
+      result = ExDgraph.mutate!(conn, @map_insert_mutation)
+      assert is_map(result.data)
+      mutation_alice = result.data
+      mutation_betty = List.first(mutation_alice[:friends])
+      query_msg = ExDgraph.query!(conn, @map_insert_check_query)
+      query_people = query_msg.data[:people]
+      query_alice = List.first(query_people)
+      query_betty = List.first(query_alice[:friends])
+      assert mutation_alice[:uid] == query_alice[:uid]
+      assert mutation_betty[:uid] == query_betty[:uid]
+    end
+
+    test "it updates a node if a uid is present and returns the uid again", %{conn: conn} do
+      user = %{name: "bob", occupation: "dev"}
+      result = ExDgraph.mutate!(conn, user)
+
+      other_mutation = %{
+        uid: result.data.uid,
+        friends: [%{name: "Paul", occupation: "diver"}, %{name: "Lisa", gender: "female"}]
+      }
 
-    {:ok, res2} = ExDgraph.set_map(conn, other_mutation)
-    assert res.result.uid == res2.result.uid
+      result2 = ExDgraph.mutate!(conn, other_mutation)
+      assert result.data.uid == result2.data.uid
+    end
   end
 end

From d67809db405672dd61e1785494ab09cbf44bbe09 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Wed, 11 Sep 2019 22:02:52 +0200
Subject: [PATCH 65/68] Cleanup.

---
 lib/exdgraph/mutation.ex           |  4 +---
 lib/exdgraph/mutation_statement.ex | 16 ----------------
 2 files changed, 1 insertion(+), 19 deletions(-)
 delete mode 100644 lib/exdgraph/mutation_statement.ex

diff --git a/lib/exdgraph/mutation.ex b/lib/exdgraph/mutation.ex
index ac30f5a..027a6a9 100644
--- a/lib/exdgraph/mutation.ex
+++ b/lib/exdgraph/mutation.ex
@@ -3,8 +3,6 @@ defmodule ExDgraph.Mutation do
   Wrapper for mutations sent to DBConnection.
   """
 
-  alias ExDgraph.{Exception, Transform}
-
   @type t :: %ExDgraph.Mutation{
           statement: String.t() | map() | struct(),
           set_json: String.t(),
@@ -20,7 +18,7 @@ defimpl DBConnection.Query, for: ExDgraph.Mutation do
   Implementation of `DBConnection.Query` protocol.
   """
 
-  alias ExDgraph.{Api, Mutation, MutationResult, Transform, Utils}
+  alias ExDgraph.{Api, Mutation, MutationResult, Utils}
 
   @doc """
   This function is called to decode a result after it is returned by a connection callback module.
diff --git a/lib/exdgraph/mutation_statement.ex b/lib/exdgraph/mutation_statement.ex
deleted file mode 100644
index 1ee7235..0000000
--- a/lib/exdgraph/mutation_statement.ex
+++ /dev/null
@@ -1,16 +0,0 @@
-defmodule ExDgraph.MutationStatement do
-  @moduledoc false
-  defstruct statement: "", set_json: ""
-end
-
-defimpl DBConnection.Query, for: ExDgraph.MutationStatement do
-  alias ExDgraph.Transform
-
-  def describe(query, _), do: query
-
-  def parse(query, _), do: query
-
-  def encode(_query, data, _), do: data
-
-  def decode(_query, result, _opts), do: Transform.transform_mutation(result)
-end

From 6f86e8d5b18501ecf8446bb6491563d8e76a93fb Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Wed, 11 Sep 2019 22:19:37 +0200
Subject: [PATCH 66/68] Remove elixir_uuid as dependency.

---
 mix.exs  | 1 -
 mix.lock | 3 ---
 2 files changed, 4 deletions(-)

diff --git a/mix.exs b/mix.exs
index dc3bcdb..fbe9a02 100755
--- a/mix.exs
+++ b/mix.exs
@@ -38,7 +38,6 @@ defmodule ExDgraph.MixProject do
   defp deps do
     [
       {:db_connection, "~> 2.1"},
-      {:elixir_uuid, "~> 1.2"},
       {:grpc, "~> 0.3.1"},
       {:jason, "~> 1.1"},
       {:protobuf, "~> 0.6.1"},
diff --git a/mix.lock b/mix.lock
index 564bd83..733ebd7 100644
--- a/mix.lock
+++ b/mix.lock
@@ -6,10 +6,7 @@
   "cowlib": {:hex, :cowlib, "2.6.0", "8aa629f81a0fc189f261dc98a42243fa842625feea3c7ec56c48f4ccdb55490f", [:rebar3], [], "hexpm"},
   "credo": {:hex, :credo, "1.1.4", "c2f3b73c895d81d859cec7fcee7ffdb972c595fd8e85ab6f8c2adbf01cf7c29c", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
   "db_connection": {:hex, :db_connection, "2.1.1", "a51e8a2ee54ef2ae6ec41a668c85787ed40cb8944928c191280fe34c15b76ae5", [:mix], [{:connection, "~> 1.0.2", [hex: :connection, repo: "hexpm", optional: false]}], "hexpm"},
-  "dialyxir": {:hex, :dialyxir, "1.0.0-rc.6", "78e97d9c0ff1b5521dd68041193891aebebce52fc3b93463c0a6806874557d7d", [:mix], [{:erlex, "~> 0.2.1", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm"},
   "earmark": {:hex, :earmark, "1.4.0", "397e750b879df18198afc66505ca87ecf6a96645545585899f6185178433cc09", [:mix], [], "hexpm"},
-  "elixir_uuid": {:hex, :elixir_uuid, "1.2.0", "ff26e938f95830b1db152cb6e594d711c10c02c6391236900ddd070a6b01271d", [:mix], [], "hexpm"},
-  "erlex": {:hex, :erlex, "0.2.4", "23791959df45fe8f01f388c6f7eb733cc361668cbeedd801bf491c55a029917b", [:mix], [], "hexpm"},
   "ex_doc": {:hex, :ex_doc, "0.21.2", "caca5bc28ed7b3bdc0b662f8afe2bee1eedb5c3cf7b322feeeb7c6ebbde089d6", [:mix], [{:earmark, "~> 1.3.3 or ~> 1.4", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm"},
   "excoveralls": {:hex, :excoveralls, "0.11.2", "0c6f2c8db7683b0caa9d490fb8125709c54580b4255ffa7ad35f3264b075a643", [:mix], [{:hackney, "~> 1.0", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
   "file_system": {:hex, :file_system, "0.2.7", "e6f7f155970975789f26e77b8b8d8ab084c59844d8ecfaf58cbda31c494d14aa", [:mix], [], "hexpm"},

From 7f87dcbbcdbc653f89a0a89be8e0da510f8b237c Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Wed, 11 Sep 2019 22:34:31 +0200
Subject: [PATCH 67/68] Cleanup Utils.

---
 lib/exdgraph/expr/uid.ex | 122 ---------------------------------------
 lib/exdgraph/utils.ex    |  85 ++-------------------------
 test/expr/uid_test.exs   |  22 -------
 test/utils_test.exs      |  94 +++++-------------------------
 4 files changed, 20 insertions(+), 303 deletions(-)
 delete mode 100644 lib/exdgraph/expr/uid.ex
 delete mode 100644 test/expr/uid_test.exs

diff --git a/lib/exdgraph/expr/uid.ex b/lib/exdgraph/expr/uid.ex
deleted file mode 100644
index 87fbf5f..0000000
--- a/lib/exdgraph/expr/uid.ex
+++ /dev/null
@@ -1,122 +0,0 @@
-defmodule ExDgraph.Expr.Uid do
-  @moduledoc """
-  Helper functions to deal with uids. Not in use yet. Intended for query builder.
-
-  https://docs.dgraph.io/query-language/#uid
-
-  ## Syntax Examples:
-
-      q(func: uid(<uid>))
-      predicate @filter(uid(<uid1>, ..., <uidn>))
-      predicate @filter(uid(a)) for variable a
-      q(func: uid(a,b)) for variables a and b
-
-  """
-  alias ExDgraph.Expr.Uid
-  alias ExDgraph.Utils
-
-  defstruct [
-    :value,
-    :type
-  ]
-
-  defmacro __using__(_) do
-    quote do
-      def uid(value) do
-        ExDgraph.Expr.Uid.new(value)
-      end
-    end
-  end
-
-  @types [
-    :literal,
-    :expression
-  ]
-
-  @doc false
-  def new(value) when is_binary(value) do
-    new(value, :literal)
-  end
-
-  @doc false
-  def new(value) when is_atom(value) do
-    new(value, :expression)
-  end
-
-  @doc false
-  def new(uids) when is_list(uids) do
-    # lists of uid literals are rendered inside a `uid(<uids_here>)` function (as in @filter)
-    # lists of uid variables are rendered inside a `uid(<uids_here>)` function (as in @filter)
-    # therefore any list is an uid expression
-    new(uids, :expression)
-  end
-
-  @doc false
-  def new(value, type)
-      when (is_atom(value) or is_binary(value) or is_list(value)) and type in @types do
-    %Uid{
-      value: value,
-      type: type
-    }
-  end
-
-  @doc false
-  def as_expression(%Uid{} = u) do
-    %{u | type: :expression}
-  end
-
-  @doc false
-  def as_literal(%Uid{} = u) do
-    %{u | type: :literal}
-  end
-
-  @doc false
-  def as_naked(%Uid{} = u) do
-    %{u | type: :naked}
-  end
-
-  @doc false
-  def render(%Uid{value: value}) when is_atom(value) do
-    render_expression([value])
-  end
-
-  @doc false
-  def render(%Uid{value: value, type: :literal}) when is_binary(value) do
-    {:ok, uid_literal} = Utils.as_literal(value, :uid)
-    uid_literal
-  end
-
-  @doc false
-  def render(%Uid{value: value, type: :naked}) when is_binary(value) do
-    value
-  end
-
-  @doc false
-  def render(%Uid{value: value, type: :expression}) when is_atom(value) or is_binary(value) do
-    render_expression([value])
-  end
-
-  @doc false
-  def render(%Uid{value: value, type: :expression}) when is_list(value) do
-    render_expression(value)
-  end
-
-  @doc false
-  defp render_expression(uids) when is_list(uids) do
-    args =
-      uids
-      |> Enum.map(&to_string/1)
-      |> Enum.join(", ")
-
-    "uid(" <> args <> ")"
-  end
-end
-
-defimpl String.Chars, for: ExDgraph.Expr.Uid do
-  def to_string(uid) do
-    ExDgraph.Expr.Uid.render(uid)
-  end
-end
-
-# Source https://github.com/elbow-jason/dgraph_ex
-# Copyright (c) 2017 Jason Goldberger
diff --git a/lib/exdgraph/utils.ex b/lib/exdgraph/utils.ex
index 2385e6b..b40be29 100755
--- a/lib/exdgraph/utils.ex
+++ b/lib/exdgraph/utils.ex
@@ -1,88 +1,15 @@
 defmodule ExDgraph.Utils do
   @moduledoc "Common utilities"
 
-  alias ExDgraph.Expr.Uid
+  @doc """
+  Turns all keys of a nested map into atoms.
 
-  def as_rendered(value) do
-    case value do
-      x when is_list(x) -> x |> Jason.encode!()
-      %Date{} = x -> x |> Date.to_iso8601() |> Kernel.<>("T00:00:00.0+00:00")
-      %DateTime{} = x -> x |> DateTime.to_iso8601() |> String.replace("Z", "+00:00")
-      x -> x |> to_string
-    end
-  end
-
-  def infer_type(type) do
-    case type do
-      x when is_boolean(x) -> :bool
-      x when is_binary(x) -> :string
-      x when is_integer(x) -> :int
-      x when is_float(x) -> :float
-      x when is_list(x) -> :geo
-      %DateTime{} -> :datetime
-      %Date{} -> :date
-      %Uid{} -> :uid
-    end
-  end
-
-  def as_literal(value, type) do
-    case {type, value} do
-      {:int, v} when is_integer(v) -> {:ok, to_string(v)}
-      {:float, v} when is_float(v) -> {:ok, as_rendered(v)}
-      {:bool, v} when is_boolean(v) -> {:ok, as_rendered(v)}
-      {:string, v} when is_binary(v) -> {:ok, v |> strip_quotes |> wrap_quotes}
-      {:date, %Date{} = v} -> {:ok, as_rendered(v)}
-      {:datetime, %DateTime{} = v} -> {:ok, as_rendered(v)}
-      {:geo, v} when is_list(v) -> check_and_render_geo_numbers(v)
-      {:uid, v} when is_binary(v) -> {:ok, "<" <> v <> ">"}
-      _ -> {:error, {:invalidly_typed_value, value, type}}
-    end
-  end
+  ## Example
 
-  def as_string(value) do
-    value
-    |> as_rendered
-    |> strip_quotes
-    |> wrap_quotes
-  end
-
-  defp check_and_render_geo_numbers(nums) do
-    if nums |> List.flatten() |> Enum.all?(&is_float/1) do
-      {:ok, nums |> as_rendered}
-    else
-      {:error, :invalid_geo_json}
-    end
-  end
-
-  defp wrap_quotes(value) when is_binary(value) do
-    "\"" <> value <> "\""
-  end
-
-  defp strip_quotes(value) when is_binary(value) do
-    value
-    |> String.replace(~r/^"/, "")
-    |> String.replace(~r/"&/, "")
-  end
-
-  def has_function?(module, func, arity) do
-    :erlang.function_exported(module, func, arity)
-  end
-
-  def has_struct?(module) when is_atom(module) do
-    Code.ensure_loaded?(module)
-    has_function?(module, :__struct__, 0)
-  end
-
-  def get_value(params, key, default \\ nil) when is_atom(key) do
-    str_key = to_string(key)
-
-    cond do
-      Map.has_key?(params, key) -> Map.get(params, key)
-      Map.has_key?(params, str_key) -> Map.get(params, str_key)
-      true -> default
-    end
-  end
+      iex> ExDgraph.Utils.atomify_map_keys(%{"name" => "Ole", "dogs" => [%{"name" => "Pluto"}]})
+      %{name: "Ole", dogs: [%{name: "Pluto"}]}
 
+  """
   def atomify_map_keys(map) when is_map(map) do
     Enum.reduce(map, %{}, fn
       {key, value}, acc when is_atom(key) ->
diff --git a/test/expr/uid_test.exs b/test/expr/uid_test.exs
deleted file mode 100644
index 2821e58..0000000
--- a/test/expr/uid_test.exs
+++ /dev/null
@@ -1,22 +0,0 @@
-defmodule ExDgraph.Expr.UidTest do
-  use ExUnit.Case, async: true
-
-  alias ExDgraph.Expr.Uid
-  use ExDgraph.Expr.Uid
-
-  test "uid given a string renders a plain-old uid literal" do
-    assert "0x9" |> uid() |> Uid.render() == "<0x9>"
-  end
-
-  test "uid given an atom renders a uid expression" do
-    assert :some_atom |> uid() |> Uid.render() == "uid(some_atom)"
-  end
-
-  test "uid given a list of strings renders a multi-arg uid expr" do
-    assert ["0x9", "0x10"] |> uid() |> Uid.render() == "uid(0x9, 0x10)"
-  end
-
-  test "uid given a list of atoms renders a multi-arg uid expr" do
-    assert [:a, :b, :c] |> uid() |> Uid.render() == "uid(a, b, c)"
-  end
-end
diff --git a/test/utils_test.exs b/test/utils_test.exs
index 737a84b..89ae27c 100644
--- a/test/utils_test.exs
+++ b/test/utils_test.exs
@@ -1,89 +1,23 @@
 defmodule ExDgraph.Utils.Test do
   use ExUnit.Case, async: true
-  doctest ExDgraph.Utils
 
   alias ExDgraph.Utils
 
-  test "as_rendered/1 float" do
-    assert Utils.as_rendered(3.14) == "3.14"
-  end
-
-  test "as_rendered/1 bool" do
-    assert Utils.as_rendered(true) == "true"
-  end
-
-  test "as_rendered/1 int" do
-    assert Utils.as_rendered(1) == "1"
-  end
-
-  test "as_rendered/1 string" do
-    assert Utils.as_rendered("beef") == "beef"
-  end
-
-  test "as_rendered/1 date" do
-    {:ok, written_on} = Date.new(2017, 8, 5)
-    assert Utils.as_rendered(written_on) == "2017-08-05T00:00:00.0+00:00"
-  end
+  test "atomify_map_keys/1 turns all keys of a nested map into atoms" do
+    map = %{
+      "name" => "Ole",
+      "dogs" => [%{"name" => "Pluto"}],
+      "friend" => %{"name" => "Eleasar"},
+      already_atom: "value"
+    }
 
-  test "as_rendered/1 datetime" do
-    {:ok, written_at, 0} = DateTime.from_iso8601("2017-08-05T22:32:36.000+00:00")
-    assert Utils.as_rendered(written_at) == "2017-08-05T22:32:36.000+00:00"
-  end
-
-  test "as_rendered/1 geo (json)" do
-    assert Utils.as_rendered([-111.925278, 33.501324]) == "[-111.925278,33.501324]"
-  end
-
-  test "as_literal/2 float" do
-    assert Utils.as_literal(3.14, :float) == {:ok, "3.14"}
-  end
-
-  test "as_literal/2 bool" do
-    assert Utils.as_literal(true, :bool) == {:ok, "true"}
-  end
-
-  test "as_literal/2 int" do
-    assert Utils.as_literal(1, :int) == {:ok, "1"}
-  end
+    result = Utils.atomify_map_keys(map)
 
-  test "as_literal/2 string" do
-    assert Utils.as_literal("beef", :string) == {:ok, "\"beef\""}
-  end
-
-  test "as_literal/2 date" do
-    {:ok, written_on} = Date.new(2017, 8, 5)
-    assert Utils.as_literal(written_on, :date) == {:ok, "2017-08-05T00:00:00.0+00:00"}
-  end
-
-  test "as_literal/2 datetime" do
-    {:ok, written_at, 0} = DateTime.from_iso8601("2017-08-05T22:32:36.000+00:00")
-    assert Utils.as_literal(written_at, :datetime) == {:ok, "2017-08-05T22:32:36.000+00:00"}
-  end
-
-  test "as_literal/2 geo (json)" do
-    assert Utils.as_literal([-111.925278, 33.501324], :geo) == {:ok, "[-111.925278,33.501324]"}
-  end
-
-  test "as_literal/2 type error" do
-    assert Utils.as_literal("Eef", :int) == {:error, {:invalidly_typed_value, "Eef", :int}}
-  end
-
-  test "as_literal/2 uid" do
-    assert Utils.as_literal("beef", :uid) == {:ok, "<beef>"}
-  end
-
-  test "has_struct?/1 returns false for non-struct-modules" do
-    assert Utils.has_struct?(Path) == false
-  end
-
-  test "has_struct?/1 returns false for non-struct-atoms" do
-    assert Utils.has_struct?(:ok) == false
-  end
-
-  test "has_struct?/1 returns true for struct-having-modules" do
-    assert Utils.has_struct?(URI) == true
+    assert result == %{
+             name: "Ole",
+             dogs: [%{name: "Pluto"}],
+             friend: %{name: "Eleasar"},
+             already_atom: "value"
+           }
   end
 end
-
-# Copyright (c) 2017 Jason Goldberger
-# Source https://github.com/elbow-jason/dgraph_ex

From bc49c1808681d24b6dd4fba08380e42d4d56edc3 Mon Sep 17 00:00:00 2001
From: Ole Spaarmann <os@ospaarmann.com>
Date: Wed, 11 Sep 2019 22:41:07 +0200
Subject: [PATCH 68/68] Add function query_schema/2 and query_schema!/2

---
 lib/exdgraph.ex     | 86 +++++++++++++++++++++++++++++++++++++++++++++
 test/query_test.exs | 17 ++++++++-
 2 files changed, 102 insertions(+), 1 deletion(-)

diff --git a/lib/exdgraph.ex b/lib/exdgraph.ex
index 197838d..018beeb 100755
--- a/lib/exdgraph.ex
+++ b/lib/exdgraph.ex
@@ -512,6 +512,92 @@ defmodule ExDgraph do
     end
   end
 
+  @doc """
+  Queries the current Dgraph schema and returns `{:ok, result}` or
+  `{:error, error}` if it fails.
+
+  ## Parameters
+
+  - `conn`: The pool name from `ExDgraph.conn()`.
+  - `opts`: Options for DBConnection.
+
+  ## Examples
+
+      iex> ExDgraph.query_schema(conn)
+      %ExDgraph.QueryResult{
+        data: %{
+          schema: [
+            %{list: true, predicate: "_predicate_", type: "string"},
+            %{
+              count: true,
+              index: true,
+              predicate: "name",
+              tokenizer: ["exact", "term"],
+              type: "string"
+            },
+          ]
+        },
+        schema: [
+          %ExDgraph.Api.SchemaNode{
+            count: false,
+            index: false,
+            lang: false,
+            list: true,
+            predicate: "_predicate_",
+            reverse: false,
+            tokenizer: [],
+            type: "string",
+            upsert: false
+          },
+          %ExDgraph.Api.SchemaNode{
+            count: true,
+            index: true,
+            lang: false,
+            list: false,
+            predicate: "name",
+            reverse: false,
+            tokenizer: ["exact", "term"],
+            type: "string",
+            upsert: false
+          },
+        ],
+        txn_context: %ExDgraph.Api.TxnContext{
+          aborted: false,
+          commit_ts: 0,
+          keys: [],
+          lin_read: nil,
+          preds: [],
+          start_ts: 130675
+        },
+        uids: nil
+      }
+
+
+  """
+  @spec query!(conn, Keyword.t()) :: {:ok, ExDgraph.QueryResult} | {:ok, ExDgraph.Error}
+  def query_schema(conn, opts \\ []) do
+    case query(conn, "schema{}", opts) do
+      {:ok, _query, result} ->
+        {:ok, result}
+
+      {:error, error} ->
+        {:error, error}
+    end
+  end
+
+  @doc """
+  Same as `query_schema/2 but raises `ExDgraph.Error` if it fails.
+  """
+  def query_schema!(conn, opts \\ []) do
+    case query_schema(conn, opts) do
+      {:ok, result} ->
+        result
+
+      {:error, error} ->
+        raise error
+    end
+  end
+
   ## Mutation
   ######################
 
diff --git a/test/query_test.exs b/test/query_test.exs
index 56480f8..1f0240c 100644
--- a/test/query_test.exs
+++ b/test/query_test.exs
@@ -57,9 +57,24 @@ defmodule ExDgraph.QueryTest do
     assert length(starwars.starring) == 3
   end
 
-  test "query!/2 raises ExDgraph.Exception", %{conn: conn} do
+  test "query!/2 raises ExDgraph.Error", %{conn: conn} do
     assert_raise ExDgraph.Error, fn ->
       ExDgraph.query!(conn, "wrong")
     end
   end
+
+  test "query_schema/2 returns the current schema", %{conn: conn} do
+    {status, %QueryResult{} = result} = ExDgraph.query_schema(conn)
+    assert status == :ok
+    schema = result.schema
+    data = result.data
+
+    assert Enum.any?(schema, fn %{__struct__: struct, predicate: predicate} ->
+             struct == ExDgraph.Api.SchemaNode and predicate == "name"
+           end)
+
+    assert Enum.any?(data.schema, fn %{predicate: predicate} ->
+             predicate == "name"
+           end)
+  end
 end