Add GitLab Terraform state provider support

README.md

@@ -290,6 +290,7 @@ Please see the [relevant unit test cases](https://github.com/helmfile/vals/blob/
     - [Terraform in S3 bucket (tfstates3)](#terraform-in-s3-bucket-tfstates3)
     - [Terraform in AzureRM Blob storage (tfstateazurerm)](#terraform-in-azurerm-blob-storage-tfstateazurerm)
     - [Terraform in Terraform Cloud / Terraform Enterprise (tfstateremote)](#terraform-in-terraform-cloud--terraform-enterprise-tfstateremote)
+    - [Terraform in GitLab (tfstategitlab)](#terraform-in-gitlab-tfstategitlab)
     - [SOPS](#sops)
     - [Keychain](#keychain)
     - [Echo](#echo)
@@ -735,6 +736,36 @@ which is equivalent to the following input for `vals`:
 $ echo 'foo: ref+tfstateremote://app.terraform.io/myorg/myworkspace/output.virtual_network.name' | vals eval -f -
 ```
 
+### Terraform in GitLab (tfstategitlab)
+
+- `ref+tfstategitlab://{gitlab_host}/api/v4/projects/{project_id}/terraform/state/{state_name}/RESOURCE_NAME[?gitlab_user=GITLAB_USER&gitlab_token=GITLAB_TOKEN]`
+
+* `gitlab_user` defaults to value of `GITLAB_USER` envvar.
+* `gitlab_token` defaults to value of `GITLAB_TOKEN` envvar.
+
+Examples:
+
+- `ref+tfstategitlab://gitlab.com/api/v4/projects/123/terraform/state/my-state/aws_vpc.main.id`
+- `ref+tfstategitlab://my-gitlab.com/api/v4/projects/xx/terraform/state/xxx/output.my_output`
+
+It allows to use Terraform state stored in GitLab given GitLab host, project ID and state name. You can try to read state with command:
+
+```
+$ tfstate-lookup -s https://username:password@my-gitlab.com/api/v4/projects/xx/terraform/state/xxx/ output.my_output
+```
+
+which is equivalent to following input for `vals` (with environment variables `GITLAB_USER` and `GITLAB_TOKEN`):
+
+```
+$ echo 'foo: ref+tfstategitlab://my-gitlab.com/api/v4/projects/xx/terraform/state/xxx/output.my_output' | vals eval -f -
+```
+
+Or you can provide credentials via URL parameters:
+
+```
+$ echo 'foo: ref+tfstategitlab://my-gitlab.com/api/v4/projects/xx/terraform/state/xxx/output.my_output?gitlab_user=username&gitlab_token=token' | vals eval -f -
+```
+
 ### SOPS
 
 - The whole content of a SOPS-encrypted file: `ref+sops://base64_data_or_path_to_file?key_type=[filepath|base64]&format=[binary|dotenv|yaml]`

pkg/providers/tfstate/tfstate.go

@@ -3,6 +3,7 @@ package tfstate
 import (
 	"context"
 	"fmt"
+	"net/url"
 	"os"
 	"strings"
 	"sync"
@@ -94,6 +95,31 @@ func (p *provider) ReadTFState(f, k string) (*tfstate.TFState, error) {
 			return nil, fmt.Errorf("reading tfstate for %s: %w", k, err)
 		}
 		return state, nil
+	case "gitlab":
+		stateURL := f
+		if !strings.HasPrefix(stateURL, "http://") && !strings.HasPrefix(stateURL, "https://") {
+			stateURL = "https://" + f
+		}
+
+		user := os.Getenv("GITLAB_USER")
+		token := os.Getenv("GITLAB_TOKEN")
+
+		parsedURL, err := url.Parse(stateURL)
+		if err != nil {
+			return nil, fmt.Errorf("parsing GitLab URL: %w", err)
+		}
+
+		if user != "" && token != "" {
+			parsedURL.User = url.UserPassword(user, token)
+		} else if token != "" {
+			parsedURL.User = url.UserPassword(token, "")
+		}
+
+		state, err := tfstate.ReadURL(context.TODO(), parsedURL.String())
+		if err != nil {
+			return nil, fmt.Errorf("reading tfstate for %s: %w", k, err)
+		}
+		return state, nil
 	default:
 		url := p.backend + "://" + f
 		state, err := tfstate.ReadURL(context.TODO(), url)

pkg/providers/tfstate/tfstate_test.go

@@ -0,0 +1,64 @@
+package tfstate
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/helmfile/vals/pkg/config"
+)
+
+func TestNewGitLabProvider(t *testing.T) {
+	tests := []struct {
+		cfg      map[string]interface{}
+		expected *provider
+		name     string
+		backend  string
+	}{
+		{
+			cfg: map[string]interface{}{},
+			expected: &provider{
+				backend: "gitlab",
+			},
+			name:    "default config",
+			backend: "gitlab",
+		},
+		{
+			cfg: map[string]interface{}{
+				"gitlab_user":  "testuser",
+				"gitlab_token": "testtoken",
+			},
+			expected: &provider{
+				backend: "gitlab",
+			},
+			name:    "with gitlab_user and gitlab_token",
+			backend: "gitlab",
+		},
+		{
+			cfg: map[string]interface{}{},
+			expected: &provider{
+				backend: "s3",
+			},
+			name:    "s3 backend",
+			backend: "s3",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			cfg := config.MapConfig{M: tt.cfg}
+			p := New(cfg, tt.backend)
+
+			assert.Equal(t, tt.expected.backend, p.backend)
+		})
+	}
+}
+
+func TestProvider_GetStringMap(t *testing.T) {
+	cfg := config.MapConfig{M: map[string]interface{}{}}
+	p := New(cfg, "gitlab")
+
+	_, err := p.GetStringMap("test/path")
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), "path fragment is not supported for tfstate provider")
+}

pkg/stringprovider/stringprovider.go

@@ -61,6 +61,8 @@ func New(l *log.Logger, provider api.StaticConfig, awsLogLevel string) (api.Lazy
 		return tfstate.New(provider, "azurerm"), nil
 	case "tfstateremote":
 		return tfstate.New(provider, "remote"), nil
+	case "tfstategitlab":
+		return tfstate.New(provider, "gitlab"), nil
 	case "azurekeyvault":
 		return azurekeyvault.New(provider), nil
 	case "gitlab":

vals.go

@@ -98,6 +98,7 @@ const (
 	ProviderTFStateS3          = "tfstates3"
 	ProviderTFStateAzureRM     = "tfstateazurerm"
 	ProviderTFStateRemote      = "tfstateremote"
+	ProviderTFStateGitLab      = "tfstategitlab"
 	ProviderAzureKeyVault      = "azurekeyvault"
 	ProviderEnvSubst           = "envsubst"
 	ProviderKeychain           = "keychain"
@@ -256,6 +257,9 @@ func (r *Runtime) prepare() (*expansion.ExpandRegexMatch, error) {
 		case ProviderTFStateRemote:
 			p := tfstate.New(conf, "remote")
 			return p, nil
+		case ProviderTFStateGitLab:
+			p := tfstate.New(conf, "gitlab")
+			return p, nil
 		case ProviderAzureKeyVault:
 			p := azurekeyvault.New(conf)
 			return p, nil