Cache license data in a process-memory cache

Instead of loading the current license once per request, we now cache
the license data for a minute in the process cache.

Relates to https://gitlab.com/gitlab-org/gitlab/-/issues/292900

changelogs/unreleased/sh-cache-license-data.yml

+---
+title: Cache license data in a process-memory cache
+merge_request: 50318
+author:
+type: performance

ee/app/models/license.rb

@@ -242,6 +242,8 @@ class License < ApplicationRecord
   scope :recent, -> { reorder(id: :desc) }
   scope :last_hundred, -> { recent.limit(100) }
 
+  CACHE_KEY = :current_license
+
   class << self
     def features_for_plan(plan)
       FEATURES_BY_PLAN.fetch(plan, [])
@@ -260,11 +262,12 @@ class License < ApplicationRecord
     end
 
     def current
-      if RequestStore.active?
-        RequestStore.fetch(:current_license) { load_license }
-      else
-        load_license
-      end
+      cache.fetch(CACHE_KEY, as: License, expires_in: 1.minute) { load_license }
+    end
+
+    def cache
+      Gitlab::SafeRequestStore[:license_cache] ||=
+        Gitlab::JsonCache.new(namespace: :ee, backend: ::Gitlab::ProcessMemoryCache.cache_backend)
     end
 
     def all_plans
@@ -274,7 +277,7 @@ class License < ApplicationRecord
     delegate :block_changes?, :feature_available?, to: :current, allow_nil: true
 
     def reset_current
-      RequestStore.delete(:current_license)
+      cache.expire(CACHE_KEY)
     end
 
     def load_license

ee/spec/models/license_spec.rb

@@ -415,7 +415,7 @@ RSpec.describe License do
       end
     end
 
-    describe '.current' do
+    describe '.current', :request_store, :use_clean_rails_memory_store_caching do
       context 'when licenses table does not exist' do
         it 'returns nil' do
           allow(described_class).to receive(:table_exists?).and_return(false)
@@ -442,12 +442,28 @@ RSpec.describe License do
       end
 
       context 'when the license is valid' do
+        let!(:current_license) { create_list(:license, 2).last }
+
         it 'returns the license' do
-          current_license = create_list(:license, 2).last
           create(:license, data: create(:gitlab_license, starts_at: Date.current + 1.month).export)
 
           expect(described_class.current).to eq(current_license)
         end
+
+        it 'caches the license' do
+          described_class.reset_current
+
+          expect(described_class).to receive(:load_license).once.and_call_original
+
+          2.times do
+            expect(described_class.current).to eq(current_license)
+          end
+
+          travel_to(61.seconds.from_now) do
+            expect(described_class).to receive(:load_license).once.and_call_original
+            expect(described_class.current).to eq(current_license)
+          end
+        end
       end
     end
 

ee/spec/requests/api/graphql/project/cluster_agents_spec.rb

@@ -69,6 +69,8 @@ RSpec.describe 'Project.cluster_agents' do
     end
 
     it 'does not suffer from N+1 performance issues' do
+      post_graphql(query, current_user: current_user)
+
       expect do
         post_graphql(query, current_user: current_user)
       end.to issue_same_number_of_queries_as { post_graphql(query, current_user: current_user, variables: [first.with(1)]) }

spec/models/application_setting_spec.rb

@@ -850,12 +850,13 @@ RSpec.describe ApplicationSetting do
     end
   end
 
-  describe '#instance_review_permitted?', :request_store do
+  describe '#instance_review_permitted?', :request_store, :use_clean_rails_memory_store_caching do
     subject { setting.instance_review_permitted? }
 
     before do
-      RequestStore.store[:current_license] = nil
-      expect(Rails.cache).to receive(:fetch).and_return(
+      allow(License).to receive(:current).and_return(nil) if Gitlab.ee?
+      allow(Rails.cache).to receive(:fetch).and_call_original
+      expect(Rails.cache).to receive(:fetch).with('limited_users_count', anything).and_return(
         ::ApplicationSetting::INSTANCE_REVIEW_MIN_USERS + users_over_minimum
       )
     end