From 3891d02d8b3c4db054514595a8f57b3b9dfe8c28 Mon Sep 17 00:00:00 2001
From: Mate Lakat <mlakat@suse.com>
Date: Wed, 19 Jul 2017 13:41:50 +0200
Subject: [PATCH 1/2] postgresql - reload: refactor

Move out logic from the template to the cookbook, so it can be re-used
later.
---
 chef/cookbooks/postgresql/recipes/server.rb   | 20 +++++++++++++++++++
 .../templates/default/postgresql.conf.erb     | 16 ++-------------
 2 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/chef/cookbooks/postgresql/recipes/server.rb b/chef/cookbooks/postgresql/recipes/server.rb
index 947acc4a78..9c496c0744 100644
--- a/chef/cookbooks/postgresql/recipes/server.rb
+++ b/chef/cookbooks/postgresql/recipes/server.rb
@@ -98,11 +98,31 @@
 
 change_notify = node["postgresql"]["server"]["config_change_notify"]
 
+raw_configuration = node["postgresql"]["config"]
+postgresql_configuration = {}
+raw_configuration.each do |key, value|
+  next if value.nil?
+  formatted_value = case value
+  when String
+    "'#{value}'"
+  when TrueClass
+    "on"
+  when FalseClass
+    "off"
+  else
+    value
+  end
+  postgresql_configuration[key] = formatted_value
+end
+
 template "#{node['postgresql']['dir']}/postgresql.conf" do
   source "postgresql.conf.erb"
   owner "postgres"
   group "postgres"
   mode 0600
+  variables(
+    config: postgresql_configuration.sort,
+  )
   notifies change_notify, "service[postgresql]", :immediately
 end
 
diff --git a/chef/cookbooks/postgresql/templates/default/postgresql.conf.erb b/chef/cookbooks/postgresql/templates/default/postgresql.conf.erb
index d2facc2a3d..6dd85d53cb 100644
--- a/chef/cookbooks/postgresql/templates/default/postgresql.conf.erb
+++ b/chef/cookbooks/postgresql/templates/default/postgresql.conf.erb
@@ -3,18 +3,6 @@
 # Please refer to the PostgreSQL documentation for details on
 # configuration settings.
 
-<% node['postgresql']['config'].sort.each do |key, value| %>
-<% next if value.nil? -%>
-<%= key %> = <%=
-  case value
-  when String
-    "'#{value}'"
-  when TrueClass
-    'on'
-  when FalseClass
-    'off'
-  else
-    value
-  end
-%>
+<% @config.each do |key, value| %>
+<%= key %> = <%= value %>
 <% end %>

From e6b408f05dc9cbbc199519704f2b254b9576da98 Mon Sep 17 00:00:00 2001
From: Mate Lakat <mlakat@suse.com>
Date: Wed, 19 Jul 2017 13:43:51 +0200
Subject: [PATCH 2/2] postgresql - reload: Graceful reload of configuration

This change splits the postgresql configuration file into two pieces.
One should contain the options that require a server restart (the main
postgresql.conf file) and that is sourcing the other file
(postgresql_reloadable.conf) which is the home for reloadable
parameters. This way we can use chef's notification mechanism to either
reload or restart the server.

Please consult postgresql's manual for reloadable configuration options.
If you want to be able to gracefuly reload a specific parameter, amend
that to `reloadable_parameters`
---
 chef/cookbooks/postgresql/recipes/server.rb   | 38 ++++++++++++++++++-
 .../templates/default/postgresql.conf.erb     |  2 +
 .../default/postgresql_reloadable.conf.erb    |  3 ++
 3 files changed, 42 insertions(+), 1 deletion(-)
 create mode 100644 chef/cookbooks/postgresql/templates/default/postgresql_reloadable.conf.erb

diff --git a/chef/cookbooks/postgresql/recipes/server.rb b/chef/cookbooks/postgresql/recipes/server.rb
index 9c496c0744..c3de5fb295 100644
--- a/chef/cookbooks/postgresql/recipes/server.rb
+++ b/chef/cookbooks/postgresql/recipes/server.rb
@@ -115,17 +115,40 @@
   postgresql_configuration[key] = formatted_value
 end
 
+reloadable_parameters = [
+  "log_line_prefix"
+]
+
+config_needs_restart = postgresql_configuration.reject do |key, value|
+  reloadable_parameters.include? key
+end
+
+config_needs_reload = postgresql_configuration.select do |key, value|
+  reloadable_parameters.include? key
+end
+
 template "#{node['postgresql']['dir']}/postgresql.conf" do
   source "postgresql.conf.erb"
   owner "postgres"
   group "postgres"
   mode 0600
   variables(
-    config: postgresql_configuration.sort,
+    config: config_needs_restart.sort
   )
   notifies change_notify, "service[postgresql]", :immediately
 end
 
+template "#{node['postgresql']['dir']}/postgresql_reloadable.conf" do
+  source "postgresql_reloadable.conf.erb"
+  owner "postgres"
+  group "postgres"
+  mode "0600"
+  variables(
+    config: config_needs_reload.sort
+  )
+  notifies :run, "bash[reload-postgresql-configuration]", :immediately
+end
+
 template "#{node['postgresql']['dir']}/pg_hba.conf" do
   source "pg_hba.conf.erb"
   owner "postgres"
@@ -184,3 +207,16 @@
   only_if only_if_command if ha_enabled
   action :run
 end
+
+# Reload the configuration file
+# We use the SQL interface for that. This way it will work
+# in clustered mode as well, no matter which node runs it
+# first
+bash "reload-postgresql-configuration" do
+  user "postgres"
+  code <<-EOH
+    echo "SELECT pg_reload_conf();" | psql
+  EOH
+  action :nothing
+end
+
diff --git a/chef/cookbooks/postgresql/templates/default/postgresql.conf.erb b/chef/cookbooks/postgresql/templates/default/postgresql.conf.erb
index 6dd85d53cb..f90fcc6f6e 100644
--- a/chef/cookbooks/postgresql/templates/default/postgresql.conf.erb
+++ b/chef/cookbooks/postgresql/templates/default/postgresql.conf.erb
@@ -3,6 +3,8 @@
 # Please refer to the PostgreSQL documentation for details on
 # configuration settings.
 
+include 'postgresql_reloadable.conf'
+
 <% @config.each do |key, value| %>
 <%= key %> = <%= value %>
 <% end %>
diff --git a/chef/cookbooks/postgresql/templates/default/postgresql_reloadable.conf.erb b/chef/cookbooks/postgresql/templates/default/postgresql_reloadable.conf.erb
new file mode 100644
index 0000000000..4eafb7a28c
--- /dev/null
+++ b/chef/cookbooks/postgresql/templates/default/postgresql_reloadable.conf.erb
@@ -0,0 +1,3 @@
+<% @config.each do |key, value| %>
+<%= key %> = <%= value %>
+<% end %>