Rework how recent push events are retrieved

app/helpers/projects_helper.rb

@@ -137,15 +137,7 @@ module ProjectsHelper
   end
 
   def last_push_event
-    return unless current_user
-    return current_user.recent_push unless @project
-
-    project_ids = [@project.id]
-    if fork = current_user.fork_of(@project)
-      project_ids << fork.id
-    end
-
-    current_user.recent_push(project_ids)
+    current_user&.recent_push(@project)
   end
 
   def project_feature_access_select(field)

app/models/event.rb

@@ -49,7 +49,7 @@ class Event < ActiveRecord::Base
   belongs_to :author, class_name: "User"
   belongs_to :project
   belongs_to :target, polymorphic: true # rubocop:disable Cop/PolymorphicAssociations
-  has_one :push_event_payload, foreign_key: :event_id
+  has_one :push_event_payload
 
   # Callbacks
   after_create :reset_project_activity

app/models/push_event.rb

@@ -30,6 +30,44 @@ class PushEvent < Event
   delegate :commit_count, to: :push_event_payload
   alias_method :commits_count, :commit_count
 
+  # Returns events of pushes that either pushed to an existing ref or created a
+  # new one.
+  def self.created_or_pushed
+    actions = [
+      PushEventPayload.actions[:pushed],
+      PushEventPayload.actions[:created]
+    ]
+
+    joins(:push_event_payload)
+      .where(push_event_payloads: { action: actions })
+  end
+
+  # Returns events of pushes to a branch.
+  def self.branch_events
+    ref_type = PushEventPayload.ref_types[:branch]
+
+    joins(:push_event_payload)
+      .where(push_event_payloads: { ref_type: ref_type })
+  end
+
+  # Returns PushEvent instances for which no merge requests have been created.
+  def self.without_existing_merge_requests
+    existing_mrs = MergeRequest.except(:order)
+      .select(1)
+      .where('merge_requests.source_project_id = events.project_id')
+      .where('merge_requests.source_branch = push_event_payloads.ref')
+
+    # For reasons unknown the use of #eager_load will result in the
+    # "push_event_payload" association not being set. Because of this we're
+    # using "joins" here, which does mean an additional query needs to be
+    # executed in order to retrieve the "push_event_association" when the
+    # returned PushEvent is used.
+    joins(:push_event_payload)
+      .where('NOT EXISTS (?)', existing_mrs)
+      .created_or_pushed
+      .branch_events
+  end
+
   def self.sti_name
     PUSHED
   end

app/models/user.rb

@@ -651,20 +651,13 @@ class User < ActiveRecord::Base
     @personal_projects_count ||= personal_projects.count
   end
 
-  def recent_push(project_ids = nil)
-    # Get push events not earlier than 2 hours ago
-    events = recent_events.code_push.where("created_at > ?", Time.now - 2.hours)
-    events = events.where(project_id: project_ids) if project_ids
+  def recent_push(project = nil)
+    service = Users::LastPushEventService.new(self)
 
-    # Use the latest event that has not been pushed or merged recently
-    events.includes(:project).recent.find do |event|
-      next unless event.project.repository.branch_exists?(event.branch_name)
-
-      merge_requests = MergeRequest.where("created_at >= ?", event.created_at)
-        .where(source_project_id: event.project.id,
-               source_branch: event.branch_name)
-
-      merge_requests.empty?
+    if project
+      service.last_event_for_project(project)
+    else
+      service.last_event_for_user
     end
   end
 

app/services/event_create_service.rb

@@ -74,12 +74,19 @@ class EventCreateService
     # We're using an explicit transaction here so that any errors that may occur
     # when creating push payload data will result in the event creation being
     # rolled back as well.
-    Event.transaction do
-      event = create_event(project, current_user, Event::PUSHED)
+    event = Event.transaction do
+      new_event = create_event(project, current_user, Event::PUSHED)
 
-      PushEventPayloadService.new(event, push_data).execute
+      PushEventPayloadService
+        .new(new_event, push_data)
+        .execute
+
+      new_event
     end
 
+    Users::LastPushEventService.new(current_user)
+      .cache_last_push_event(event)
+
     Users::ActivityService.new(current_user, 'push').execute
   end
 

app/services/users/last_push_event_service.rb

+module Users
+  # Service class for caching and retrieving the last push event of a user.
+  class LastPushEventService
+    EXPIRATION = 2.hours
+
+    def initialize(user)
+      @user = user
+    end
+
+    # Caches the given push event for the current user in the Rails cache.
+    #
+    # event - An instance of PushEvent to cache.
+    def cache_last_push_event(event)
+      keys = [
+        project_cache_key(event.project),
+        user_cache_key
+      ]
+
+      if event.project.forked?
+        keys << project_cache_key(event.project.forked_from_project)
+      end
+
+      keys.each { |key| set_key(key, event.id) }
+    end
+
+    # Returns the last PushEvent for the current user.
+    #
+    # This method will return nil if no event was found.
+    def last_event_for_user
+      find_cached_event(user_cache_key)
+    end
+
+    # Returns the last PushEvent for the current user and the given project.
+    #
+    # project - An instance of Project for which to retrieve the PushEvent.
+    #
+    # This method will return nil if no event was found.
+    def last_event_for_project(project)
+      find_cached_event(project_cache_key(project))
+    end
+
+    def find_cached_event(cache_key)
+      event_id = get_key(cache_key)
+
+      return unless event_id
+
+      unless (event = find_event_in_database(event_id))
+        # We don't want to keep querying the same data over and over when a
+        # merge request has been created, thus we remove the key if no event
+        # (meaning an MR was created) is returned.
+        Rails.cache.delete(cache_key)
+      end
+
+      event
+    end
+
+    private
+
+    def find_event_in_database(id)
+      PushEvent
+        .without_existing_merge_requests
+        .find_by(id: id)
+    end
+
+    def user_cache_key
+      "last-push-event/#{@user.id}"
+    end
+
+    def project_cache_key(project)
+      "last-push-event/#{@user.id}/#{project.id}"
+    end
+
+    def get_key(key)
+      Rails.cache.read(key, raw: true)
+    end
+
+    def set_key(key, value)
+      # We're using raw values here since this takes up less space and we don't
+      # store complex objects.
+      Rails.cache.write(key, value, raw: true, expires_in: EXPIRATION)
+    end
+  end
+end

changelogs/unreleased/user-recent-push.yml

+---
+title: Rework how recent push events are retrieved
+merge_request:
+author:
+type: other

spec/features/dashboard/projects_spec.rb

@@ -83,12 +83,14 @@ feature 'Dashboard Projects' do
     end
   end
 
-  context 'last push widget' do
+  context 'last push widget', :use_clean_rails_memory_store_caching do
     before do
       event = create(:push_event, project: project, author: user)
 
       create(:push_event_payload, event: event, ref: 'feature', action: :created)
 
+      Users::LastPushEventService.new(user).cache_last_push_event(event)
+
       visit dashboard_projects_path
     end
 

spec/helpers/projects_helper_spec.rb

@@ -313,23 +313,10 @@ describe ProjectsHelper do
 
     it 'returns recent push on the current project' do
       event = double(:event)
-      expect(user).to receive(:recent_push).with([project.id]).and_return(event)
+      expect(user).to receive(:recent_push).with(project).and_return(event)
 
       expect(helper.last_push_event).to eq(event)
     end
-
-    context 'when current user has a fork of the current project' do
-      let(:fork) { double(:fork, id: 2) }
-
-      it 'returns recent push considering fork events' do
-        expect(user).to receive(:fork_of).with(project).and_return(fork)
-
-        event_on_fork = double(:event)
-        expect(user).to receive(:recent_push).with([project.id, fork.id]).and_return(event_on_fork)
-
-        expect(helper.last_push_event).to eq(event_on_fork)
-      end
-    end
   end
 
   describe "#project_feature_access_select" do

spec/models/push_event_spec.rb

@@ -11,6 +11,94 @@ describe PushEvent do
     event
   end
 
+  describe '.created_or_pushed' do
+    let(:event1) { create(:push_event) }
+    let(:event2) { create(:push_event) }
+    let(:event3) { create(:push_event) }
+
+    before do
+      create(:push_event_payload, event: event1, action: :pushed)
+      create(:push_event_payload, event: event2, action: :created)
+      create(:push_event_payload, event: event3, action: :removed)
+    end
+
+    let(:relation) { described_class.created_or_pushed }
+
+    it 'includes events for pushing to existing refs' do
+      expect(relation).to include(event1)
+    end
+
+    it 'includes events for creating new refs' do
+      expect(relation).to include(event2)
+    end
+
+    it 'does not include events for removing refs' do
+      expect(relation).not_to include(event3)
+    end
+  end
+
+  describe '.branch_events' do
+    let(:event1) { create(:push_event) }
+    let(:event2) { create(:push_event) }
+
+    before do
+      create(:push_event_payload, event: event1, ref_type: :branch)
+      create(:push_event_payload, event: event2, ref_type: :tag)
+    end
+
+    let(:relation) { described_class.branch_events }
+
+    it 'includes events for branches' do
+      expect(relation).to include(event1)
+    end
+
+    it 'does not include events for tags' do
+      expect(relation).not_to include(event2)
+    end
+  end
+
+  describe '.without_existing_merge_requests' do
+    let(:project) { create(:project, :repository) }
+    let(:event1) { create(:push_event, project: project) }
+    let(:event2) { create(:push_event, project: project) }
+    let(:event3) { create(:push_event, project: project) }
+    let(:event4) { create(:push_event, project: project) }
+
+    before do
+      create(:push_event_payload, event: event1, ref: 'foo', action: :created)
+      create(:push_event_payload, event: event2, ref: 'bar', action: :created)
+      create(:push_event_payload, event: event3, ref: 'baz', action: :removed)
+      create(:push_event_payload, event: event4, ref: 'baz', ref_type: :tag)
+
+      project.repository.create_branch('bar', 'master')
+
+      create(
+        :merge_request,
+        source_project: project,
+        target_project: project,
+        source_branch: 'bar'
+      )
+    end
+
+    let(:relation) { described_class.without_existing_merge_requests }
+
+    it 'includes events that do not have a corresponding merge request' do
+      expect(relation).to include(event1)
+    end
+
+    it 'does not include events that have a corresponding merge request' do
+      expect(relation).not_to include(event2)
+    end
+
+    it 'does not include events for removed refs' do
+      expect(relation).not_to include(event3)
+    end
+
+    it 'does not include events for pushing to tags' do
+      expect(relation).not_to include(event4)
+    end
+  end
+
   describe '.sti_name' do
     it 'returns Event::PUSHED' do
       expect(described_class.sti_name).to eq(Event::PUSHED)

spec/models/user_spec.rb

@@ -1349,56 +1349,24 @@ describe User do
   end
 
   describe "#recent_push" do
-    subject { create(:user) }
-    let!(:project1) { create(:project, :repository) }
-    let!(:project2) { create(:project, :repository, forked_from_project: project1) }
-
-    let!(:push_event) do
-      event = create(:push_event, project: project2, author: subject)
-
-      create(:push_event_payload,
-             event: event,
-             commit_to: '1cf19a015df3523caf0a1f9d40c98a267d6a2fc2',
-             commit_count: 0,
-             ref: 'master')
-
-      event
-    end
-
-    before do
-      project1.team << [subject, :master]
-      project2.team << [subject, :master]
-    end
-
-    it "includes push event" do
-      expect(subject.recent_push).to eq(push_event)
-    end
-
-    it "excludes push event if branch has been deleted" do
-      allow_any_instance_of(Repository).to receive(:branch_exists?).with('master').and_return(false)
-
-      expect(subject.recent_push).to eq(nil)
-    end
+    let(:user) { build(:user) }
+    let(:project) { build(:project) }
+    let(:event) { build(:push_event) }
 
-    it "excludes push event if MR is opened for it" do
-      create(:merge_request, source_project: project2, target_project: project1, source_branch: project2.default_branch, target_branch: 'fix', author: subject)
+    it 'returns the last push event for the user' do
+      expect_any_instance_of(Users::LastPushEventService)
+        .to receive(:last_event_for_user)
+        .and_return(event)
 
-      expect(subject.recent_push).to eq(nil)
+      expect(user.recent_push).to eq(event)
     end
 
-    it "includes push events on any of the provided projects" do
-      expect(subject.recent_push(project1)).to eq(nil)
-      expect(subject.recent_push(project2)).to eq(push_event)
-
-      push_event1 = create(:push_event, project: project1, author: subject)
-
-      create(:push_event_payload,
-             event: push_event1,
-             commit_to: '1cf19a015df3523caf0a1f9d40c98a267d6a2fc2',
-             commit_count: 0,
-             ref: 'master')
+    it 'returns the last push event for a project when one is given' do
+      expect_any_instance_of(Users::LastPushEventService)
+        .to receive(:last_event_for_project)
+        .and_return(event)
 
-      expect(subject.recent_push([project1, project2])).to eq(push_event1) # Newest
+      expect(user.recent_push(project)).to eq(event)
     end
   end
 

spec/services/event_create_service_spec.rb

@@ -149,6 +149,14 @@ describe EventCreateService do
         .to change { user_activity(user) }
     end
 
+    it 'caches the last push event for the user' do
+      expect_any_instance_of(Users::LastPushEventService)
+        .to receive(:cache_last_push_event)
+        .with(an_instance_of(PushEvent))
+
+      service.push(project, user, push_data)
+    end
+
     it 'does not create any event data when an error is raised' do
       payload_service = double(:service)
 

spec/services/users/last_push_event_service_spec.rb

+require 'spec_helper'
+
+describe Users::LastPushEventService do
+  let(:user) { build(:user, id: 1) }
+  let(:project) { build(:project, id: 2) }
+  let(:event) { build(:push_event, id: 3, author: user, project: project) }
+  let(:service) { described_class.new(user) }
+
+  describe '#cache_last_push_event' do
+    it "caches the event for the event's project and current user" do
+      expect(service).to receive(:set_key)
+        .ordered
+        .with('last-push-event/1/2', 3)
+
+      expect(service).to receive(:set_key)
+        .ordered
+        .with('last-push-event/1', 3)
+
+      service.cache_last_push_event(event)
+    end
+
+    it 'caches the event for the origin project when pushing to a fork' do
+      source = build(:project, id: 5)
+
+      allow(project).to receive(:forked?).and_return(true)
+      allow(project).to receive(:forked_from_project).and_return(source)
+
+      expect(service).to receive(:set_key)
+        .ordered
+        .with('last-push-event/1/2', 3)
+
+      expect(service).to receive(:set_key)
+        .ordered
+        .with('last-push-event/1', 3)
+
+      expect(service).to receive(:set_key)
+        .ordered
+        .with('last-push-event/1/5', 3)
+
+      service.cache_last_push_event(event)
+    end
+  end
+
+  describe '#last_event_for_user' do
+    it 'returns the last push event for the current user' do
+      expect(service).to receive(:find_cached_event)
+        .with('last-push-event/1')
+        .and_return(event)
+
+      expect(service.last_event_for_user).to eq(event)
+    end
+
+    it 'returns nil when no push event could be found' do
+      expect(service).to receive(:find_cached_event)
+        .with('last-push-event/1')
+        .and_return(nil)
+
+      expect(service.last_event_for_user).to be_nil
+    end
+  end
+
+  describe '#last_event_for_project' do
+    it 'returns the last push event for the given project' do
+      expect(service).to receive(:find_cached_event)
+        .with('last-push-event/1/2')
+        .and_return(event)
+
+      expect(service.last_event_for_project(project)).to eq(event)
+    end
+
+    it 'returns nil when no push event could be found' do
+      expect(service).to receive(:find_cached_event)
+        .with('last-push-event/1/2')
+        .and_return(nil)
+
+      expect(service.last_event_for_project(project)).to be_nil
+    end
+  end
+
+  describe '#find_cached_event', :use_clean_rails_memory_store_caching do
+    context 'with a non-existing cache key' do
+      it 'returns nil' do
+        expect(service.find_cached_event('bla')).to be_nil
+      end
+    end
+
+    context 'with an existing cache key' do
+      before do
+        service.cache_last_push_event(event)
+      end
+
+      it 'returns a PushEvent when no merge requests exist for the event' do
+        allow(service).to receive(:find_event_in_database)
+          .with(event.id)
+          .and_return(event)
+
+        expect(service.find_cached_event('last-push-event/1')).to eq(event)
+      end
+
+      it 'removes the cache key when no event could be found and returns nil' do
+        allow(PushEvent).to receive(:without_existing_merge_requests)
+          .and_return(PushEvent.none)
+
+        expect(Rails.cache).to receive(:delete)
+          .with('last-push-event/1')
+          .and_call_original
+
+        expect(service.find_cached_event('last-push-event/1')).to be_nil
+      end
+    end
+  end
+end