Merge branch '299178-follow-up-from-cached-sidebar-issues-count-in-group-sidebar' into 'master'

Cache merge requests count in group sidebar [RUN ALL RSPEC] [RUN AS-IF-FOSS]

See merge request gitlab-org/gitlab!55971

app/helpers/groups_helper.rb

@@ -67,7 +67,7 @@ module GroupsHelper
 
   def group_open_issues_count(group)
     if Feature.enabled?(:cached_sidebar_open_issues_count, group, default_enabled: :yaml)
-      cached_open_group_issues_count(group)
+      cached_issuables_count(group, type: :issues)
     else
       number_with_delimiter(group_issues_count(state: 'opened'))
     end
@@ -80,18 +80,11 @@ module GroupsHelper
       .count
   end
 
-  def cached_open_group_issues_count(group)
-    count_service = Groups::OpenIssuesCountService
-    issues_count = count_service.new(group, current_user).count
-
-    if issues_count > count_service::CACHED_COUNT_THRESHOLD
-      ActiveSupport::NumberHelper
-        .number_to_human(
-          issues_count,
-          units: { thousand: 'k', million: 'm' }, precision: 1, significant: false, format: '%n%u'
-        )
+  def group_open_merge_requests_count(group)
+    if Feature.enabled?(:cached_sidebar_merge_requests_count, group, default_enabled: :yaml)
+      cached_issuables_count(@group, type: :merge_requests)
     else
-      number_with_delimiter(issues_count)
+      number_with_delimiter(group_merge_requests_count(state: 'opened'))
     end
   end
 
@@ -102,6 +95,14 @@ module GroupsHelper
       .count
   end
 
+  def cached_issuables_count(group, type: nil)
+    count_service = issuables_count_service_class(type)
+    return unless count_service.present?
+
+    issuables_count = count_service.new(group, current_user).count
+    format_issuables_count(count_service, issuables_count)
+  end
+
   def group_dependency_proxy_url(group)
     # The namespace path can include uppercase letters, which
     # Docker doesn't allow. The proxy expects it to be downcased.
@@ -306,6 +307,26 @@ module GroupsHelper
   def ancestor_locked_and_has_been_overridden(group)
     s_("GroupSettings|This setting is applied on %{ancestor_group} and has been overridden on this subgroup.").html_safe % { ancestor_group: ancestor_group(group) }
   end
+
+  def issuables_count_service_class(type)
+    if type == :issues
+      Groups::OpenIssuesCountService
+    elsif type == :merge_requests
+      Groups::MergeRequestsCountService
+    end
+  end
+
+  def format_issuables_count(count_service, count)
+    if count > count_service::CACHED_COUNT_THRESHOLD
+      ActiveSupport::NumberHelper
+        .number_to_human(
+          count,
+          units: { thousand: 'k', million: 'm' }, precision: 1, significant: false, format: '%n%u'
+        )
+    else
+      number_with_delimiter(count)
+    end
+  end
 end
 
 GroupsHelper.prepend_if_ee('EE::GroupsHelper')

app/services/groups/count_service.rb

+# frozen_string_literal: true
+
+module Groups
+  class CountService < BaseCountService
+    include Gitlab::Utils::StrongMemoize
+
+    VERSION = 1
+    CACHED_COUNT_THRESHOLD = 1000
+    EXPIRATION_TIME = 24.hours
+
+    attr_reader :group, :user
+
+    def initialize(group, user = nil)
+      @group = group
+      @user = user
+    end
+
+    def count
+      cached_count = Rails.cache.read(cache_key)
+      return cached_count unless cached_count.blank?
+
+      refreshed_count = uncached_count
+      update_cache_for_key(cache_key) { refreshed_count } if refreshed_count > CACHED_COUNT_THRESHOLD
+      refreshed_count
+    end
+
+    def cache_key
+      ['groups', "#{issuable_key}_count_service", VERSION, group.id, cache_key_name]
+    end
+
+    private
+
+    def relation_for_count
+      raise NotImplementedError
+    end
+
+    def cache_options
+      super.merge({ expires_in: EXPIRATION_TIME })
+    end
+
+    def cache_key_name
+      raise NotImplementedError, 'cache_key_name must be implemented and return a String'
+    end
+
+    def issuable_key
+      raise NotImplementedError, 'issuable_key must be implemented and return a String'
+    end
+  end
+end

app/services/groups/merge_requests_count_service.rb

+# frozen_string_literal: true
+
+module Groups
+  # Service class for counting and caching the number of open merge requests of a group.
+  class MergeRequestsCountService < Groups::CountService
+    private
+
+    def cache_key_name
+      'open_merge_requests_count'
+    end
+
+    def relation_for_count
+      MergeRequestsFinder
+      .new(user, group_id: group.id, state: 'opened', non_archived: true, include_subgroups: true)
+      .execute
+    end
+
+    def issuable_key
+      'open_merge_requests'
+    end
+  end
+end

app/services/groups/open_issues_count_service.rb

@@ -2,47 +2,12 @@
 
 module Groups
   # Service class for counting and caching the number of open issues of a group.
-  class OpenIssuesCountService < BaseCountService
-    include Gitlab::Utils::StrongMemoize
-
-    VERSION = 1
+  class OpenIssuesCountService < Groups::CountService
     PUBLIC_COUNT_KEY = 'group_public_open_issues_count'
     TOTAL_COUNT_KEY = 'group_total_open_issues_count'
-    CACHED_COUNT_THRESHOLD = 1000
-    EXPIRATION_TIME = 24.hours
-
-    attr_reader :group, :user
-
-    def initialize(group, user = nil)
-      @group = group
-      @user = user
-    end
-
-    # Reads count value from cache and return it if present.
-    # If empty or expired, #uncached_count will calculate the issues count for the group and
-    # compare it with the threshold. If it is greater, it will be written to the cache and returned.
-    # If below, it will be returned without being cached.
-    # This results in only caching large counts and calculating the rest with every call to maintain
-    # accuracy.
-    def count
-      cached_count = Rails.cache.read(cache_key)
-      return cached_count unless cached_count.blank?
-
-      refreshed_count = uncached_count
-      update_cache_for_key(cache_key) { refreshed_count } if refreshed_count > CACHED_COUNT_THRESHOLD
-      refreshed_count
-    end
-
-    def cache_key(key = nil)
-      ['groups', 'open_issues_count_service', VERSION, group.id, cache_key_name]
-    end
 
     private
 
-    def cache_options
-      super.merge({ expires_in: EXPIRATION_TIME })
-    end
-
     def cache_key_name
       public_only? ? PUBLIC_COUNT_KEY : TOTAL_COUNT_KEY
     end
@@ -60,5 +25,9 @@ module Groups
     def relation_for_count
       IssuesFinder.new(user, group_id: group.id, state: 'opened', non_archived: true, include_subgroups: true, public_only: public_only?).execute
     end
+
+    def issuable_key
+      'open_issues'
+    end
   end
 end

app/views/groups/merge_requests.html.haml

@@ -2,7 +2,7 @@
 
 - page_title _("Merge Requests")
 
-- if group_merge_requests_count(state: 'all') == 0
+- if @merge_requests&.size == 0
   = render 'shared/empty_states/merge_requests', project_select_button: true
 - else
   .top-area

app/views/layouts/nav/sidebar/_group.html.haml

 - issues_count = group_open_issues_count(@group)
-- merge_requests_count = group_merge_requests_count(state: 'opened')
+- merge_requests_count = group_open_merge_requests_count(@group)
 - aside_title = @group.subgroup? ? _('Subgroup navigation') : _('Group navigation')
 - overview_title = @group.subgroup? ? _('Subgroup overview') : _('Group overview')
 
@@ -92,13 +92,13 @@
               = sprite_icon('git-merge')
             %span.nav-item-name
               = _('Merge Requests')
-            %span.badge.badge-pill.count= number_with_delimiter(merge_requests_count)
+            %span.badge.badge-pill.count= merge_requests_count
           %ul.sidebar-sub-level-items.is-fly-out-only
             = nav_link(path: 'groups#merge_requests', html_options: { class: "fly-out-top-item" } ) do
               = link_to merge_requests_group_path(@group) do
                 %strong.fly-out-top-item-name
                   = _('Merge Requests')
-                %span.badge.badge-pill.count.merge_counter.js-merge-counter.fly-out-badge= number_with_delimiter(merge_requests_count)
+                %span.badge.badge-pill.count.merge_counter.js-merge-counter.fly-out-badge= merge_requests_count
 
       = render_if_exists "layouts/nav/ee/security_link" # EE-specific
 

changelogs/unreleased/299178-follow-up-from-cached-sidebar-issues-count-in-group-sidebar.yml

+---
+title: Cache open merge requests count in group sidebar
+merge_request: 55971
+author:
+type: performance

config/feature_flags/development/cached_sidebar_merge_requests_count.yml

+---
+name: cached_sidebar_merge_requests_count
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/55971
+rollout_issue_url:
+milestone: '13.11'
+type: development
+group: group::product planning
+default_enabled: true

doc/user/project/merge_requests/reviewing_and_managing_merge_requests.md

@@ -28,6 +28,39 @@ You can [search and filter the results](../../search/index.md#filtering-issue-an
 
 ![Group Issues list view](img/group_merge_requests_list_view.png)
 
+## Cached merge request count
+
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/299542) in GitLab 13.11.
+> - It's [deployed behind a feature flag](../../feature_flags.md), enabled by default.
+> - It's enabled on GitLab.com.
+> - It's recommended for production use.
+> - For GitLab self-managed instances, GitLab administrators can opt to [disable it](#enable-or-disable-cached-merge-request-count).
+
+WARNING:
+This feature might not be available to you. Check the **version history** note above for details.
+
+In a group, the sidebar displays the total count of open merge requests and this value is cached if higher
+than 1000. The cached value is rounded to thousands (or millions) and updated every 24 hours.
+
+### Enable or disable cached merge request count **(FREE SELF)**
+
+Cached merge request count in the left sidebar is under development but ready for production use. It is
+deployed behind a feature flag that is **enabled by default**.
+[GitLab administrators with access to the GitLab Rails console](../../../administration/feature_flags.md)
+can disable it.
+
+To disable it:
+
+```ruby
+Feature.disable(:cached_sidebar_merge_requests_count)
+```
+
+To enable it:
+
+```ruby
+Feature.enable(:cached_sidebar_merge_requests_count)
+```
+
 ## Semi-linear history merge requests
 
 A merge commit is created for every merge, but the branch is only merged if

spec/helpers/groups_helper_spec.rb

@@ -481,13 +481,21 @@ RSpec.describe GroupsHelper do
     end
   end
 
-  describe '#cached_open_group_issues_count' do
+  describe '#cached_issuables_count' do
     let_it_be(:current_user) { create(:user) }
     let_it_be(:group) { create(:group, name: 'group') }
-    let_it_be(:count_service) { Groups::OpenIssuesCountService }
+
+    subject { helper.cached_issuables_count(group, type: type) }
 
     before do
       allow(helper).to receive(:current_user) { current_user }
+      allow(count_service).to receive(:new).and_call_original
+    end
+
+    shared_examples 'caching issuables count' do
+      it 'calls the correct service class' do
+        subject
+        expect(count_service).to have_received(:new).with(group, current_user)
       end
 
       it 'returns all digits for count value under 1000' do
@@ -495,7 +503,7 @@ RSpec.describe GroupsHelper do
           allow(service).to receive(:count).and_return(999)
         end
 
-      expect(helper.cached_open_group_issues_count(group)).to eq('999')
+        expect(subject).to eq('999')
       end
 
       it 'returns truncated digits for count value over 1000' do
@@ -503,7 +511,7 @@ RSpec.describe GroupsHelper do
           allow(service).to receive(:count).and_return(2300)
         end
 
-      expect(helper.cached_open_group_issues_count(group)).to eq('2.3k')
+        expect(subject).to eq('2.3k')
       end
 
       it 'returns truncated digits for count value over 10000' do
@@ -511,7 +519,7 @@ RSpec.describe GroupsHelper do
           allow(service).to receive(:count).and_return(12560)
         end
 
-      expect(helper.cached_open_group_issues_count(group)).to eq('12.6k')
+        expect(subject).to eq('12.6k')
       end
 
       it 'returns truncated digits for count value over 100000' do
@@ -519,7 +527,22 @@ RSpec.describe GroupsHelper do
           allow(service).to receive(:count).and_return(112560)
         end
 
-      expect(helper.cached_open_group_issues_count(group)).to eq('112.6k')
+        expect(subject).to eq('112.6k')
+      end
+    end
+
+    context 'with issue type' do
+      let(:type) { :issues }
+      let(:count_service) { Groups::OpenIssuesCountService }
+
+      it_behaves_like 'caching issuables count'
+    end
+
+    context 'with merge request type' do
+      let(:type) { :merge_requests }
+      let(:count_service) { Groups::MergeRequestsCountService }
+
+      it_behaves_like 'caching issuables count'
     end
   end
 end

spec/services/groups/merge_requests_count_service_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Groups::MergeRequestsCountService, :use_clean_rails_memory_store_caching do
+  let_it_be(:user) { create(:user) }
+  let_it_be(:group) { create(:group, :public)}
+  let_it_be(:project) { create(:project, :repository, namespace: group) }
+  let_it_be(:merge_request) { create(:merge_request, source_project: project, target_project: project) }
+
+  subject { described_class.new(group, user) }
+
+  describe '#relation_for_count' do
+    before do
+      group.add_reporter(user)
+      allow(MergeRequestsFinder).to receive(:new).and_call_original
+    end
+
+    it 'uses the MergeRequestsFinder to scope merge requests' do
+      expect(MergeRequestsFinder)
+        .to receive(:new)
+        .with(user, group_id: group.id, state: 'opened', non_archived: true, include_subgroups: true)
+
+      subject.count
+    end
+  end
+
+  it_behaves_like 'a counter caching service with threshold'
+end

spec/services/groups/open_issues_count_service_spec.rb

@@ -54,53 +54,7 @@ RSpec.describe Groups::OpenIssuesCountService, :use_clean_rails_memory_store_cac
         end
       end
 
-      context 'with different cache values' do
-        let(:public_count_key) { subject.cache_key(described_class::PUBLIC_COUNT_KEY) }
-        let(:under_threshold) { described_class::CACHED_COUNT_THRESHOLD - 1 }
-        let(:over_threshold) { described_class::CACHED_COUNT_THRESHOLD + 1 }
-
-        context 'when cache is empty' do
-          before do
-            Rails.cache.delete(public_count_key)
-          end
-
-          it 'refreshes cache if value over threshold' do
-            allow(subject).to receive(:uncached_count).and_return(over_threshold)
-
-            expect(subject.count).to eq(over_threshold)
-            expect(Rails.cache.read(public_count_key)).to eq(over_threshold)
-          end
-
-          it 'does not refresh cache if value under threshold' do
-            allow(subject).to receive(:uncached_count).and_return(under_threshold)
-
-            expect(subject.count).to eq(under_threshold)
-            expect(Rails.cache.read(public_count_key)).to be_nil
-          end
-        end
-
-        context 'when cached count is under the threshold value' do
-          before do
-            Rails.cache.write(public_count_key, under_threshold)
-          end
-
-          it 'does not refresh cache' do
-            expect(Rails.cache).not_to receive(:write)
-            expect(subject.count).to eq(under_threshold)
-          end
-        end
-
-        context 'when cached count is over the threshold value' do
-          before do
-            Rails.cache.write(public_count_key, over_threshold)
-          end
-
-          it 'does not refresh cache' do
-            expect(Rails.cache).not_to receive(:write)
-            expect(subject.count).to eq(over_threshold)
-          end
-        end
-      end
+      it_behaves_like 'a counter caching service with threshold'
     end
   end
 end

spec/support/shared_examples/services/groups_count_service_shared_examples.rb

+# frozen_string_literal: true
+
+# The calling spec should use `:use_clean_rails_memory_store_caching`
+# when including this shared example. E.g.:
+#
+#   describe MyCountService, :use_clean_rails_memory_store_caching do
+#     it_behaves_like 'a counter caching service with threshold'
+#   end
+RSpec.shared_examples 'a counter caching service with threshold' do
+  let(:cache_key) { subject.cache_key }
+  let(:under_threshold) { described_class::CACHED_COUNT_THRESHOLD - 1 }
+  let(:over_threshold) { described_class::CACHED_COUNT_THRESHOLD + 1 }
+
+  context 'when cache is empty' do
+    before do
+      Rails.cache.delete(cache_key)
+    end
+
+    it 'refreshes cache if value over threshold' do
+      allow(subject).to receive(:uncached_count).and_return(over_threshold)
+
+      expect(subject.count).to eq(over_threshold)
+      expect(Rails.cache.read(cache_key)).to eq(over_threshold)
+    end
+
+    it 'does not refresh cache if value under threshold' do
+      allow(subject).to receive(:uncached_count).and_return(under_threshold)
+
+      expect(subject.count).to eq(under_threshold)
+      expect(Rails.cache.read(cache_key)).to be_nil
+    end
+  end
+
+  context 'when cached count is under the threshold value' do
+    before do
+      Rails.cache.write(cache_key, under_threshold)
+    end
+
+    it 'does not refresh cache' do
+      expect(Rails.cache).not_to receive(:write)
+      expect(subject.count).to eq(under_threshold)
+    end
+  end
+
+  context 'when cached count is over the threshold value' do
+    before do
+      Rails.cache.write(cache_key, over_threshold)
+    end
+
+    it 'does not refresh cache' do
+      expect(Rails.cache).not_to receive(:write)
+      expect(subject.count).to eq(over_threshold)
+    end
+  end
+end