Implement GraphQL Mutation to modify runner details

app/graphql/mutations/ci/runner/update.rb

+# frozen_string_literal: true
+
+module Mutations
+  module Ci
+    module Runner
+      class Update < BaseMutation
+        graphql_name 'RunnerUpdate'
+
+        authorize :update_runner
+
+        RunnerID = ::Types::GlobalIDType[::Ci::Runner]
+
+        argument :id, RunnerID,
+                 required: true,
+                 description: 'ID of the runner to update.'
+
+        argument :description, GraphQL::STRING_TYPE,
+                 required: false,
+              description: 'Description of the runner.'
+
+        argument :maximum_timeout, GraphQL::INT_TYPE,
+              required: false,
+              description: 'Maximum timeout (in seconds) for jobs processed by the runner.'
+
+        argument :access_level, ::Types::Ci::RunnerAccessLevelEnum,
+                 required: false,
+              description: 'Access level of the runner.'
+
+        argument :active, GraphQL::BOOLEAN_TYPE,
+              required: false,
+              description: 'Indicates the runner is allowed to receive jobs.'
+
+        argument :locked, GraphQL::BOOLEAN_TYPE, required: false,
+              description: 'Indicates the runner is locked.'
+
+        argument :run_untagged, GraphQL::BOOLEAN_TYPE,
+                 required: false,
+              description: 'Indicates the runner is able to run untagged jobs.'
+
+        argument :tag_list, [GraphQL::STRING_TYPE], required: false,
+              description: 'Tags associated with the runner.'
+
+        field :runner,
+              Types::Ci::RunnerType,
+              null: true,
+              description: 'The runner after mutation.'
+
+        def resolve(id:, **runner_attrs)
+          runner = authorized_find!(id)
+
+          unless ::Ci::UpdateRunnerService.new(runner).update(runner_attrs)
+            return { runner: nil, errors: runner.errors.full_messages }
+          end
+
+          { runner: runner, errors: [] }
+        end
+
+        def find_object(id)
+          # TODO: remove this line when the compatibility layer is removed
+          # See: https://gitlab.com/gitlab-org/gitlab/-/issues/257883
+          id = RunnerID.coerce_isolated_input(id)
+
+          GitlabSchema.find_by_gid(id)
+        end
+      end
+    end
+  end
+end

app/graphql/types/mutation_type.rb

@@ -99,6 +99,7 @@ module Types
     mount_mutation Mutations::Ci::CiCdSettingsUpdate
     mount_mutation Mutations::Ci::Job::Play
     mount_mutation Mutations::Ci::Job::Retry
+    mount_mutation Mutations::Ci::Runner::Update, feature_flag: :runner_graphql_query
     mount_mutation Mutations::Namespace::PackageSettings::Update
     mount_mutation Mutations::UserCallouts::Create
   end

doc/api/graphql/reference/index.md

@@ -3568,6 +3568,34 @@ Input type: `RunDASTScanInput`
 | <a id="mutationrundastscanerrors"></a>`errors` | [`[String!]!`](#string) | Errors encountered during execution of the mutation. |
 | <a id="mutationrundastscanpipelineurl"></a>`pipelineUrl` | [`String`](#string) | URL of the pipeline that was created. |
 
+### `Mutation.runnerUpdate`
+
+Available only when feature flag `runner_graphql_query` is enabled.
+
+Input type: `RunnerUpdateInput`
+
+#### Arguments
+
+| Name | Type | Description |
+| ---- | ---- | ----------- |
+| <a id="mutationrunnerupdateaccesslevel"></a>`accessLevel` | [`CiRunnerAccessLevel`](#cirunneraccesslevel) | Access level of the runner. |
+| <a id="mutationrunnerupdateactive"></a>`active` | [`Boolean`](#boolean) | Indicates the runner is allowed to receive jobs. |
+| <a id="mutationrunnerupdateclientmutationid"></a>`clientMutationId` | [`String`](#string) | A unique identifier for the client performing the mutation. |
+| <a id="mutationrunnerupdatedescription"></a>`description` | [`String`](#string) | Description of the runner. |
+| <a id="mutationrunnerupdateid"></a>`id` | [`CiRunnerID!`](#cirunnerid) | ID of the runner to update. |
+| <a id="mutationrunnerupdatelocked"></a>`locked` | [`Boolean`](#boolean) | Indicates the runner is locked. |
+| <a id="mutationrunnerupdatemaximumtimeout"></a>`maximumTimeout` | [`Int`](#int) | Maximum timeout (in seconds) for jobs processed by the runner. |
+| <a id="mutationrunnerupdaterununtagged"></a>`runUntagged` | [`Boolean`](#boolean) | Indicates the runner is able to run untagged jobs. |
+| <a id="mutationrunnerupdatetaglist"></a>`tagList` | [`[String!]`](#string) | Tags associated with the runner. |
+
+#### Fields
+
+| Name | Type | Description |
+| ---- | ---- | ----------- |
+| <a id="mutationrunnerupdateclientmutationid"></a>`clientMutationId` | [`String`](#string) | A unique identifier for the client performing the mutation. |
+| <a id="mutationrunnerupdateerrors"></a>`errors` | [`[String!]!`](#string) | Errors encountered during execution of the mutation. |
+| <a id="mutationrunnerupdaterunner"></a>`runner` | [`CiRunner`](#cirunner) | The runner after mutation. |
+
 ### `Mutation.terraformStateDelete`
 
 Input type: `TerraformStateDeleteInput`

spec/graphql/mutations/ci/runner/update_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Mutations::Ci::Runner::Update do
+  include GraphqlHelpers
+
+  let_it_be(:user) { create(:user) }
+  let_it_be(:runner) { create(:ci_runner, active: true, locked: false, run_untagged: true) }
+
+  let(:current_ctx) { { current_user: user } }
+  let(:mutated_runner) { subject[:runner] }
+
+  let(:mutation_params) do
+    {
+      id: runner.to_global_id,
+      description: 'updated description'
+    }
+  end
+
+  specify { expect(described_class).to require_graphql_authorizations(:update_runner) }
+
+  describe '#resolve' do
+    subject do
+      sync(resolve(described_class, args: mutation_params, ctx: current_ctx))
+    end
+
+    context 'when the user cannot admin the runner' do
+      it 'raises an error' do
+        expect { subject }.to raise_error(Gitlab::Graphql::Errors::ResourceNotAvailable)
+      end
+    end
+
+    context 'with invalid params' do
+      it 'raises an error' do
+        mutation_params[:id] = "invalid-id"
+
+        expect { subject }.to raise_error(::GraphQL::CoercionError)
+      end
+    end
+
+    context 'when required arguments are missing' do
+      let(:mutation_params) { {} }
+
+      it 'raises an error' do
+        expect { subject }.to raise_error(ArgumentError, "missing keyword: :id")
+      end
+    end
+
+    context 'when user can update runner', :enable_admin_mode do
+      let(:admin_user) { create(:user, :admin) }
+      let(:current_ctx) { { current_user: admin_user } }
+
+      let(:mutation_params) do
+        {
+          id: runner.to_global_id,
+          description: 'updated description',
+          maximum_timeout: 900,
+          access_level: 'ref_protected',
+          active: false,
+          locked: true,
+          run_untagged: false,
+          tag_list: %w(tag1 tag2)
+        }
+      end
+
+      context 'with valid arguments' do
+        it 'updates runner with correct values' do
+          expected_attributes = {
+            description: 'updated description',
+            maximum_timeout: 900,
+            access_level: 'ref_protected',
+            active: false,
+            locked: true,
+            run_untagged: false,
+            tag_list: %w(tag1 tag2)
+          }
+
+          subject
+
+          expect(subject[:errors]).to be_empty
+          expect(subject[:runner]).to be_an_instance_of(Ci::Runner)
+          expect(subject[:runner]).to have_attributes(expected_attributes)
+          expect(runner.reload).to have_attributes(expected_attributes)
+        end
+      end
+
+      context 'with out-of-range maximum_timeout and missing tag_list' do
+        it 'returns a descriptive error' do
+          mutation_params[:maximum_timeout] = 100
+          mutation_params.delete(:tag_list)
+
+          expect(subject[:errors]).to contain_exactly(
+            'Maximum timeout needs to be at least 10 minutes',
+            'Tags list can not be empty when runner is not allowed to pick untagged jobs'
+          )
+        end
+      end
+    end
+  end
+end