Add GraphQL query for single Terraform State

Add terraformState query to GraphQL
Updated associated docs

app/finders/terraform/states_finder.rb

+# frozen_string_literal: true
+
+module Terraform
+  class StatesFinder
+    def initialize(project, current_user, params: {})
+      @project = project
+      @current_user = current_user
+      @params = params
+    end
+
+    def execute
+      return ::Terraform::State.none unless can_read_terraform_states?
+
+      states = project.terraform_states
+      states = states.with_name(params[:name]) if params[:name].present?
+
+      states.ordered_by_name
+    end
+
+    private
+
+    attr_reader :project, :current_user, :params
+
+    def can_read_terraform_states?
+      current_user.can?(:read_terraform_state, project)
+    end
+  end
+end

app/graphql/resolvers/terraform/states_resolver.rb

@@ -3,20 +3,20 @@
 module Resolvers
   module Terraform
     class StatesResolver < BaseResolver
-      type Types::Terraform::StateType, null: true
+      type Types::Terraform::StateType.connection_type, null: true
 
       alias_method :project, :object
 
-      def resolve(**args)
-        return ::Terraform::State.none unless can_read_terraform_states?
-
-        project.terraform_states.ordered_by_name
+      when_single do
+        argument :name, GraphQL::STRING_TYPE,
+            required: true,
+            description: 'Name of the Terraform state.'
       end
 
-      private
-
-      def can_read_terraform_states?
-        current_user.can?(:read_terraform_state, project)
+      def resolve(**args)
+        ::Terraform::StatesFinder
+          .new(project, current_user, params: args)
+          .execute
       end
     end
   end

app/graphql/types/project_type.rb

@@ -305,10 +305,16 @@ module Types
               description: 'Title of the label'
           end
 
+    field :terraform_state,
+          Types::Terraform::StateType,
+          null: true,
+          description: 'Find a single Terraform state by name.',
+          resolver: Resolvers::Terraform::StatesResolver.single
+
     field :terraform_states,
           Types::Terraform::StateType.connection_type,
           null: true,
-          description: 'Terraform states associated with the project',
+          description: 'Terraform states associated with the project.',
           resolver: Resolvers::Terraform::StatesResolver
 
     field :pipeline_analytics, Types::Ci::AnalyticsType, null: true,

app/models/terraform/state.rb

@@ -22,6 +22,7 @@ module Terraform
 
     scope :versioning_not_enabled, -> { where(versioning_enabled: false) }
     scope :ordered_by_name, -> { order(:name) }
+    scope :with_name, -> (name) { where(name: name) }
 
     validates :project_id, presence: true
     validates :uuid, presence: true, uniqueness: true, length: { is: UUID_LENGTH },

changelogs/unreleased/291140-query-single-state.yml

+---
+title: Add GraphQL query for single Terraform state
+merge_request: 51145
+author:
+type: added

doc/api/graphql/reference/gitlab_schema.graphql

@@ -19280,7 +19280,17 @@ type Project {
   tagList: String
 
   """
-  Terraform states associated with the project
+  Find a single Terraform state by name.
+  """
+  terraformState(
+    """
+    Name of the Terraform state.
+    """
+    name: String!
+  ): TerraformState
+
+  """
+  Terraform states associated with the project.
   """
   terraformStates(
     """

doc/api/graphql/reference/gitlab_schema.json

@@ -55993,9 +55993,36 @@
               "isDeprecated": false,
               "deprecationReason": null
             },
+            {
+              "name": "terraformState",
+              "description": "Find a single Terraform state by name.",
+              "args": [
+                {
+                  "name": "name",
+                  "description": "Name of the Terraform state.",
+                  "type": {
+                    "kind": "NON_NULL",
+                    "name": null,
+                    "ofType": {
+                      "kind": "SCALAR",
+                      "name": "String",
+                      "ofType": null
+                    }
+                  },
+                  "defaultValue": null
+                }
+              ],
+              "type": {
+                "kind": "OBJECT",
+                "name": "TerraformState",
+                "ofType": null
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
             {
               "name": "terraformStates",
-              "description": "Terraform states associated with the project",
+              "description": "Terraform states associated with the project.",
               "args": [
                 {
                   "name": "after",

doc/api/graphql/reference/index.md

@@ -2778,7 +2778,8 @@ Autogenerated return type of PipelineRetry.
 | `statistics` | ProjectStatistics | Statistics of the project |
 | `suggestionCommitMessage` | String | The commit message used to apply merge request suggestions |
 | `tagList` | String | List of project topics (not Git tags) |
-| `terraformStates` | TerraformStateConnection | Terraform states associated with the project |
+| `terraformState` | TerraformState | Find a single Terraform state by name. |
+| `terraformStates` | TerraformStateConnection | Terraform states associated with the project. |
 | `userPermissions` | ProjectPermissions! | Permissions for the current user on the resource |
 | `visibility` | String | Visibility of the project |
 | `vulnerabilities` | VulnerabilityConnection | Vulnerabilities reported on the project |

spec/finders/terraform/states_finder_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Terraform::StatesFinder do
+  describe '#execute' do
+    let_it_be(:project) { create(:project) }
+    let_it_be(:state_1) { create(:terraform_state, project: project) }
+    let_it_be(:state_2) { create(:terraform_state, project: project) }
+
+    let(:user) { project.creator }
+
+    subject { described_class.new(project, user).execute }
+
+    it { is_expected.to contain_exactly(state_1, state_2) }
+
+    context 'user does not have permission' do
+      let(:user) { create(:user) }
+
+      before do
+        project.add_guest(user)
+      end
+
+      it { is_expected.to be_empty }
+    end
+
+    context 'filtering by name' do
+      let(:params) { { name: name_param } }
+
+      subject { described_class.new(project, user, params: params).execute }
+
+      context 'name does not match' do
+        let(:name_param) { 'other-name' }
+
+        it { is_expected.to be_empty }
+      end
+
+      context 'name does match' do
+        let(:name_param) { state_1.name }
+
+        it { is_expected.to contain_exactly(state_1) }
+      end
+    end
+  end
+end

spec/graphql/resolvers/terraform/states_resolver_spec.rb

@@ -5,7 +5,7 @@ require 'spec_helper'
 RSpec.describe Resolvers::Terraform::StatesResolver do
   include GraphqlHelpers
 
-  it { expect(described_class.type).to eq(Types::Terraform::StateType) }
+  it { expect(described_class).to have_nullable_graphql_type(Types::Terraform::StateType.connection_type) }
   it { expect(described_class.null).to be_truthy }
 
   describe '#resolve' do
@@ -31,3 +31,21 @@ RSpec.describe Resolvers::Terraform::StatesResolver do
     end
   end
 end
+
+RSpec.describe Resolvers::Terraform::StatesResolver.single do
+  it { expect(described_class).to be < Resolvers::Terraform::StatesResolver }
+
+  describe 'arguments' do
+    subject { described_class.arguments[argument] }
+
+    describe 'name' do
+      let(:argument) { 'name' }
+
+      it do
+        expect(subject).to be_present
+        expect(subject.type.to_s).to eq('String!')
+        expect(subject.description).to be_present
+      end
+    end
+  end
+end

spec/graphql/types/project_type_spec.rb

@@ -159,6 +159,13 @@ RSpec.describe GitlabSchema.types['Project'] do
     it { is_expected.to have_graphql_type(Types::ContainerExpirationPolicyType) }
   end
 
+  describe 'terraform state field' do
+    subject { described_class.fields['terraformState'] }
+
+    it { is_expected.to have_graphql_type(Types::Terraform::StateType) }
+    it { is_expected.to have_graphql_resolver(Resolvers::Terraform::StatesResolver.single) }
+  end
+
   describe 'terraform states field' do
     subject { described_class.fields['terraformStates'] }
 

spec/models/terraform/state_spec.rb

@@ -25,6 +25,15 @@ RSpec.describe Terraform::State do
 
       it { expect(subject.map(&:name)).to eq(names.sort) }
     end
+
+    describe '.with_name' do
+      let_it_be(:matching_name) { create(:terraform_state, name: 'matching-name') }
+      let_it_be(:other_name) { create(:terraform_state, name: 'other-name') }
+
+      subject { described_class.with_name(matching_name.name) }
+
+      it { is_expected.to contain_exactly(matching_name) }
+    end
   end
 
   describe '#destroy' do

spec/requests/api/graphql/project/terraform/state_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'query a single terraform state' do
+  include GraphqlHelpers
+  include ::API::Helpers::RelatedResourcesHelpers
+
+  let_it_be(:terraform_state) { create(:terraform_state, :with_version, :locked) }
+
+  let(:latest_version) { terraform_state.latest_version }
+  let(:project) { terraform_state.project }
+  let(:current_user) { project.creator }
+  let(:data) { graphql_data.dig('project', 'terraformState') }
+
+  let(:query) do
+    graphql_query_for(
+      :project,
+      { fullPath: project.full_path },
+      query_graphql_field(
+        :terraformState,
+        { name: terraform_state.name },
+        %{
+          id
+          name
+          lockedAt
+          createdAt
+          updatedAt
+
+          latestVersion {
+            id
+            serial
+            createdAt
+            updatedAt
+
+            createdByUser {
+              id
+            }
+
+            job {
+              name
+            }
+          }
+
+          lockedByUser {
+            id
+          }
+        }
+      )
+    )
+  end
+
+  before do
+    post_graphql(query, current_user: current_user)
+  end
+
+  it_behaves_like 'a working graphql query'
+
+  it 'returns terraform state data' do
+    expect(data).to match(a_hash_including({
+      'id'            => global_id_of(terraform_state),
+      'name'          => terraform_state.name,
+      'lockedAt'      => terraform_state.locked_at.iso8601,
+      'createdAt'     => terraform_state.created_at.iso8601,
+      'updatedAt'     => terraform_state.updated_at.iso8601,
+      'lockedByUser'  => { 'id' => global_id_of(terraform_state.locked_by_user) },
+      'latestVersion' => {
+        'id'            => eq(global_id_of(latest_version)),
+        'serial'        => eq(latest_version.version),
+        'createdAt'     => eq(latest_version.created_at.iso8601),
+        'updatedAt'     => eq(latest_version.updated_at.iso8601),
+        'createdByUser' => { 'id' => eq(global_id_of(latest_version.created_by_user)) },
+        'job'           => { 'name' => eq(latest_version.build.name) }
+      }
+    }))
+  end
+
+  context 'unauthorized users' do
+    let(:current_user) { nil }
+
+    it { expect(data).to be_nil }
+  end
+end