Rake task to configure registry vendor/version/features

Adds a rake task to ping the container registry and
populate the associated application settings
Co-authored-by: João Pereira <jpereira@gitlab.com>

lib/tasks/gitlab/container_registry.rake

+namespace :gitlab do
+  namespace :container_registry do
+    desc "GitLab | Container Registry | Configure"
+    task configure: :gitlab_environment do
+      registry_config = Gitlab.config.registry
+
+      unless registry_config.enabled && registry_config.api_url.presence
+        raise 'Registry is not enabled or registry api url is not present.'
+      end
+
+      warn_user_is_not_gitlab
+
+      url = registry_config.api_url
+      client = ContainerRegistry::Client.new(url)
+      info = client.registry_info
+
+      Gitlab::CurrentSettings.update!(
+        container_registry_vendor: info[:vendor] || '',
+        container_registry_version: info[:version] || '',
+        container_registry_features: info[:features] || []
+      )
+    end
+  end
+end

spec/tasks/gitlab/container_registry_rake_spec.rb

+# frozen_string_literal: true
+
+require 'rake_helper'
+
+describe 'gitlab:container_registry namespace rake tasks' do
+  let_it_be(:application_settings) { Gitlab::CurrentSettings }
+
+  before :all do
+    Rake.application.rake_require 'tasks/gitlab/container_registry'
+  end
+
+  describe 'configure' do
+    before do
+      stub_container_registry_config(enabled: true, api_url: 'http://registry.gitlab')
+    end
+
+    shared_examples 'invalid config' do
+      it 'does not update the application settings' do
+        expect { run_rake_task('gitlab:container_registry:configure') }
+          .to raise_error(/Registry is not enabled or registry api url is not present./)
+      end
+    end
+
+    context 'when container registry is disabled' do
+      before do
+        stub_container_registry_config(enabled: false)
+      end
+
+      it_behaves_like 'invalid config'
+    end
+
+    context 'when container registry api_url is blank' do
+      before do
+        stub_container_registry_config(api_url: '')
+      end
+
+      it_behaves_like 'invalid config'
+    end
+
+    context 'when unabled to detect the container registry type' do
+      it 'fails and raises an error message' do
+        stub_registry_info({})
+
+        run_rake_task('gitlab:container_registry:configure')
+
+        application_settings.reload
+        expect(application_settings.container_registry_vendor).to be_blank
+        expect(application_settings.container_registry_version).to be_blank
+        expect(application_settings.container_registry_features).to eq([])
+      end
+    end
+
+    context 'when able to detect the container registry type' do
+      context 'when using the GitLab container registry' do
+        it 'updates application settings accordingly' do
+          stub_registry_info(vendor: 'gitlab', version: '2.9.1-gitlab', features: %w[a,b,c])
+
+          run_rake_task('gitlab:container_registry:configure')
+
+          application_settings.reload
+          expect(application_settings.container_registry_vendor).to eq('gitlab')
+          expect(application_settings.container_registry_version).to eq('2.9.1-gitlab')
+          expect(application_settings.container_registry_features).to eq(%w[a,b,c])
+        end
+      end
+
+      context 'when using a third-party container registry' do
+        it 'updates application settings accordingly' do
+          stub_registry_info(vendor: 'other', version: nil, features: nil)
+
+          run_rake_task('gitlab:container_registry:configure')
+
+          application_settings.reload
+          expect(application_settings.container_registry_vendor).to eq('other')
+          expect(application_settings.container_registry_version).to be_blank
+          expect(application_settings.container_registry_features).to eq([])
+        end
+      end
+    end
+  end
+
+  def stub_registry_info(output)
+    allow_next_instance_of(ContainerRegistry::Client) do |client|
+      allow(client).to receive(:registry_info).and_return(output)
+    end
+  end
+end