Adds KAS properties to GraphQL

app/graphql/types/metadata/kas_type.rb

+# frozen_string_literal: true
+
+module Types
+  module Metadata
+    class KasType < ::Types::BaseObject
+      graphql_name 'Kas'
+
+      authorize :read_instance_metadata
+
+      field :enabled, GraphQL::BOOLEAN_TYPE, null: false,
+            description: 'Indicates whether the Kubernetes Agent Server is enabled.'
+      field :version, GraphQL::STRING_TYPE, null: true,
+            description: 'KAS version.'
+      field :external_url, GraphQL::STRING_TYPE, null: true,
+            description: 'The URL used by the Agents to communicate with KAS.'
+    end
+  end
+end

app/graphql/types/metadata_type.rb

@@ -10,5 +10,7 @@ module Types
           description: 'Version.'
     field :revision, GraphQL::STRING_TYPE, null: false,
           description: 'Revision.'
+    field :kas, ::Types::Metadata::KasType, null: false,
+          description: 'Metadata about KAS.'
   end
 end

app/models/instance_metadata.rb

 # frozen_string_literal: true
 
 class InstanceMetadata
-  attr_reader :version, :revision
+  attr_reader :version, :revision, :kas
 
   def initialize(version: Gitlab::VERSION, revision: Gitlab.revision)
     @version = version
     @revision = revision
+    @kas = ::InstanceMetadata::Kas.new
   end
 end

app/models/instance_metadata/kas.rb

+# frozen_string_literal: true
+
+class InstanceMetadata::Kas
+  attr_reader :enabled, :version, :external_url
+
+  def initialize
+    @enabled = Gitlab::Kas.enabled?
+    @version = Gitlab::Kas.version if @enabled
+    @external_url = Gitlab::Kas.external_url if @enabled
+  end
+
+  def self.declarative_policy_class
+    "InstanceMetadataPolicy"
+  end
+end

changelogs/unreleased/feature-adds-kas-metadata-to-graphql.yml

+---
+title: Expose KAS metadata through GraphQL - enabled, version and externalUrl
+merge_request: 59696
+author:
+type: added

doc/api/graphql/reference/index.md

@@ -9500,6 +9500,16 @@ four standard [pagination arguments](#connection-pagination-arguments):
 | <a id="jobpermissionsreadjobartifacts"></a>`readJobArtifacts` | [`Boolean!`](#boolean) | Indicates the user can perform `read_job_artifacts` on this resource. |
 | <a id="jobpermissionsupdatebuild"></a>`updateBuild` | [`Boolean!`](#boolean) | Indicates the user can perform `update_build` on this resource. |
 
+### `Kas`
+
+#### Fields
+
+| Name | Type | Description |
+| ---- | ---- | ----------- |
+| <a id="kasenabled"></a>`enabled` | [`Boolean!`](#boolean) | Indicates whether the Kubernetes Agent Server is enabled. |
+| <a id="kasexternalurl"></a>`externalUrl` | [`String`](#string) | The URL used by the Agents to communicate with KAS. |
+| <a id="kasversion"></a>`version` | [`String`](#string) | KAS version. |
+
 ### `Label`
 
 #### Fields
@@ -10083,6 +10093,7 @@ four standard [pagination arguments](#connection-pagination-arguments):
 
 | Name | Type | Description |
 | ---- | ---- | ----------- |
+| <a id="metadatakas"></a>`kas` | [`Kas!`](#kas) | Metadata about KAS. |
 | <a id="metadatarevision"></a>`revision` | [`String!`](#string) | Revision. |
 | <a id="metadataversion"></a>`version` | [`String!`](#string) | Version. |
 

lib/gitlab/kas.rb

@@ -3,6 +3,7 @@
 module Gitlab
   module Kas
     INTERNAL_API_REQUEST_HEADER = 'Gitlab-Kas-Api-Request'
+    VERSION_FILE = 'GITLAB_KAS_VERSION'
     JWT_ISSUER = 'gitlab-kas'
 
     include JwtAuthenticatable
@@ -29,6 +30,27 @@ module Gitlab
 
         Feature.enabled?(:kubernetes_agent_on_gitlab_com, project, default_enabled: :yaml)
       end
+
+      # Return GitLab KAS version
+      #
+      # @return [String] version
+      def version
+        @_version ||= Rails.root.join(VERSION_FILE).read.chomp
+      end
+
+      # Return GitLab KAS external_url
+      #
+      # @return [String] external_url
+      def external_url
+        Gitlab.config.gitlab_kas.external_url
+      end
+
+      # Return whether GitLab KAS is enabled
+      #
+      # @return [Boolean] external_url
+      def enabled?
+        !!Gitlab.config['gitlab_kas']&.fetch('enabled', false)
+      end
     end
   end
 end

spec/graphql/resolvers/metadata_resolver_spec.rb

@@ -7,7 +7,10 @@ RSpec.describe Resolvers::MetadataResolver do
 
   describe '#resolve' do
     it 'returns version and revision' do
-      expect(resolve(described_class)).to have_attributes(version: Gitlab::VERSION, revision: Gitlab.revision)
+      expect(resolve(described_class)).to have_attributes(
+        version: Gitlab::VERSION,
+        revision: Gitlab.revision,
+        kas: kind_of(InstanceMetadata::Kas))
     end
   end
 end

spec/graphql/types/metadata/kas_type_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe GitlabSchema.types['Kas'] do
+  specify { expect(described_class.graphql_name).to eq('Kas') }
+  specify { expect(described_class).to require_graphql_authorizations(:read_instance_metadata) }
+end

spec/lib/gitlab/kas_spec.rb

@@ -33,6 +33,46 @@ RSpec.describe Gitlab::Kas do
     end
   end
 
+  describe '.enabled?' do
+    before do
+      allow(Gitlab).to receive(:config).and_return(gitlab_config)
+    end
+
+    subject { described_class.enabled? }
+
+    context 'gitlab_config is not enabled' do
+      let(:gitlab_config) { { 'gitlab_kas' => { 'enabled' => false } } }
+
+      it { is_expected.to be_falsey }
+    end
+
+    context 'gitlab_config is enabled' do
+      let(:gitlab_config) { { 'gitlab_kas' => { 'enabled' => true } } }
+
+      it { is_expected.to be_truthy }
+    end
+
+    context 'enabled is unset' do
+      let(:gitlab_config) { { 'gitlab_kas' => {} } }
+
+      it { is_expected.to be_falsey }
+    end
+  end
+
+  describe '.external_url' do
+    it 'returns gitlab_kas external_url config' do
+      expect(described_class.external_url).to eq(Gitlab.config.gitlab_kas.external_url)
+    end
+  end
+
+  describe '.version' do
+    it 'returns gitlab_kas version config' do
+      version_file = Rails.root.join(described_class::VERSION_FILE)
+
+      expect(described_class.version).to eq(version_file.read.chomp)
+    end
+  end
+
   describe '.ensure_secret!' do
     context 'secret file exists' do
       before do

spec/models/instance_metadata/kas_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe ::InstanceMetadata::Kas do
+  it 'has InstanceMetadataPolicy as declarative policy' do
+    expect(described_class.declarative_policy_class).to eq("InstanceMetadataPolicy")
+  end
+
+  context 'when KAS is enabled' do
+    it 'has the correct properties' do
+      allow(Gitlab::Kas).to receive(:enabled?).and_return(true)
+
+      expect(subject).to have_attributes(
+        enabled: Gitlab::Kas.enabled?,
+        version: Gitlab::Kas.version,
+        external_url: Gitlab::Kas.external_url
+      )
+    end
+  end
+
+  context 'when KAS is disabled' do
+    it 'has the correct properties' do
+      allow(Gitlab::Kas).to receive(:enabled?).and_return(false)
+
+      expect(subject).to have_attributes(
+        enabled: Gitlab::Kas.enabled?,
+        version: nil,
+        external_url: nil
+      )
+    end
+  end
+end

spec/models/instance_metadata_spec.rb

@@ -6,7 +6,8 @@ RSpec.describe InstanceMetadata do
   it 'has the correct properties' do
     expect(subject).to have_attributes(
       version: Gitlab::VERSION,
-      revision: Gitlab.revision
+      revision: Gitlab.revision,
+      kas: kind_of(::InstanceMetadata::Kas)
     )
   end
 end

spec/requests/api/graphql/metadata_query_spec.rb

@@ -8,16 +8,48 @@ RSpec.describe 'getting project information' do
   let(:query) { graphql_query_for('metadata', {}, all_graphql_fields_for('Metadata')) }
 
   context 'logged in' do
-    it 'returns version and revision' do
-      post_graphql(query, current_user: create(:user))
-
-      expect(graphql_errors).to be_nil
-      expect(graphql_data).to eq(
+    let(:expected_data) do
+      {
         'metadata' => {
           'version' => Gitlab::VERSION,
-          'revision' => Gitlab.revision
+          'revision' => Gitlab.revision,
+          'kas' => {
+            'enabled' => Gitlab::Kas.enabled?,
+            'version' => expected_kas_version,
+            'externalUrl' => expected_kas_external_url
+          }
         }
-      )
+      }
+    end
+
+    context 'kas is enabled' do
+      let(:expected_kas_version) { Gitlab::Kas.version }
+      let(:expected_kas_external_url) { Gitlab::Kas.external_url }
+
+      before do
+        allow(Gitlab::Kas).to receive(:enabled?).and_return(true)
+        post_graphql(query, current_user: create(:user))
+      end
+
+      it 'returns version, revision, kas_enabled, kas_version, kas_external_url' do
+        expect(graphql_errors).to be_nil
+        expect(graphql_data).to eq(expected_data)
+      end
+    end
+
+    context 'kas is disabled' do
+      let(:expected_kas_version) { nil }
+      let(:expected_kas_external_url) { nil }
+
+      before do
+        allow(Gitlab::Kas).to receive(:enabled?).and_return(false)
+        post_graphql(query, current_user: create(:user))
+      end
+
+      it 'returns version and revision' do
+        expect(graphql_errors).to be_nil
+        expect(graphql_data).to eq(expected_data)
+      end
     end
   end