Support API requests in Performance Bar

This adds Peek support for Grape API endpoints

changelogs/unreleased/33909-peek-api-requests.yml

+---
+title: Support adding of API requests to the performance bar
+merge_request: 39057
+author:
+type: added

config/initializers/peek.rb

@@ -14,3 +14,9 @@ Peek.into Peek::Views::Rugged
 Peek.into Peek::Views::BulletDetailed if defined?(Bullet)
 
 Peek.into Peek::Views::Tracing if Labkit::Tracing.tracing_url_enabled?
+
+ActiveSupport::Notifications.subscribe('endpoint_run.grape') do |_name, _start, _finish, _id, payload|
+  if request_id = payload[:env]['action_dispatch.request_id']
+    Peek.adapter.save(request_id)
+  end
+end

lib/api/api.rb

@@ -56,6 +56,10 @@ module API
       )
     end
 
+    before do
+      set_peek_enabled_for_current_request
+    end
+
     # The locale is set to the current user's locale when `current_user` is loaded
     after { Gitlab::I18n.use_default_locale }
 
@@ -116,6 +120,7 @@ module API
     # Ensure the namespace is right, otherwise we might load Grape::API::Helpers
     helpers ::API::Helpers
     helpers ::API::Helpers::CommonHelpers
+    helpers ::API::Helpers::PerformanceBarHelpers
 
     namespace do
       after do

lib/api/api_guard.rb

@@ -7,6 +7,7 @@ require 'rack/oauth2'
 module API
   module APIGuard
     extend ActiveSupport::Concern
+    include Gitlab::Utils::StrongMemoize
 
     included do |base|
       # OAuth2 Resource Server Authentication
@@ -64,10 +65,12 @@ module API
       end
 
       def find_user_from_sources
-        deploy_token_from_request ||
-          find_user_from_bearer_token ||
-          find_user_from_job_token ||
-          find_user_from_warden
+        strong_memoize(:find_user_from_sources) do
+          deploy_token_from_request ||
+            find_user_from_bearer_token ||
+            find_user_from_job_token ||
+            find_user_from_warden
+        end
       end
 
       private

lib/api/helpers/performance_bar_helpers.rb

+# frozen_string_literal: true
+
+module API
+  module Helpers
+    module PerformanceBarHelpers
+      def set_peek_enabled_for_current_request
+        Gitlab::SafeRequestStore.fetch(:peek_enabled) { perf_bar_cookie_enabled? && perf_bar_enabled_for_user? }
+      end
+
+      def perf_bar_cookie_enabled?
+        cookies[:perf_bar_enabled] == 'true'
+      end
+
+      def perf_bar_enabled_for_user?
+        # We cannot use `current_user` here because that method raises an exception when the user
+        # is unauthorized and some API endpoints require that `current_user` is not called.
+        Gitlab::PerformanceBar.enabled_for_user?(find_user_from_sources)
+      end
+    end
+  end
+end

spec/requests/api/performance_bar_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'Performance Bar for API requests', :request_store, :clean_gitlab_redis_cache do
+  context 'with user that has access to the performance bar' do
+    let_it_be(:admin) { create(:admin) }
+
+    context 'when cookie is set to true' do
+      before do
+        cookies[:perf_bar_enabled] = 'true'
+      end
+
+      it 'stores performance data' do
+        get api("/users/#{admin.id}", admin)
+
+        expect(Peek.adapter.get(headers['X-Request-Id'])).not_to be_empty
+      end
+    end
+
+    context 'when cookie is missing' do
+      it 'does not store performance data' do
+        get api("/users/#{admin.id}", admin)
+
+        expect(Peek.adapter.get(headers['X-Request-Id'])).to be_nil
+      end
+    end
+  end
+
+  context 'with user that does not have access to the performance bar' do
+    let(:user) { create(:user) }
+
+    it 'does not store performance data' do
+      cookies[:perf_bar_enabled] = 'true'
+
+      get api("/users/#{user.id}", user)
+
+      expect(Peek.adapter.get(headers['X-Request-Id'])).to be_nil
+    end
+  end
+end