Broadcast issue updates to an ActionCable channel

This allows us to update the issue sidebar in real-time

app/channels/application_cable/channel.rb

+# frozen_string_literal: true
+
+module ApplicationCable
+  class Channel < ActionCable::Channel::Base
+  end
+end

app/channels/application_cable/connection.rb

+# frozen_string_literal: true
+
+module ApplicationCable
+  class Connection < ActionCable::Connection::Base
+    identified_by :current_user
+
+    def connect
+      self.current_user = find_user_from_session_store
+    end
+
+    private
+
+    def find_user_from_session_store
+      session = ActiveSession.sessions_from_ids([session_id]).first
+      Warden::SessionSerializer.new('rack.session' => session).fetch(:user)
+    end
+
+    def session_id
+      Rack::Session::SessionId.new(cookies[Gitlab::Application.config.session_options[:key]])
+    end
+  end
+end

app/channels/issues_channel.rb

+# frozen_string_literal: true
+
+class IssuesChannel < ApplicationCable::Channel
+  def subscribed
+    project = Project.find_by_full_path(params[:project_path])
+    return reject unless project
+
+    issue = project.issues.find_by_iid(params[:iid])
+    return reject unless issue && Ability.allowed?(current_user, :read_issue, issue)
+
+    stream_for issue
+  end
+end

app/models/active_session.rb

@@ -124,7 +124,7 @@ class ActiveSession
     end
   end
 
-  # Lists the ActiveSession objects for the given session IDs.
+  # Lists the session Hash objects for the given session IDs.
   #
   # session_ids - An array of Rack::Session::SessionId objects
   #
@@ -143,7 +143,7 @@ class ActiveSession
     end
   end
 
-  # Deserializes an ActiveSession object from Redis.
+  # Deserializes a session Hash object from Redis.
   #
   # raw_session - Raw bytes from Redis
   #

app/services/issues/update_service.rb

@@ -21,6 +21,10 @@ module Issues
       spam_check(issue, current_user) unless skip_spam_check
     end
 
+    def after_update(issue)
+      IssuesChannel.broadcast_to(issue, event: 'updated') if Feature.enabled?(:broadcast_issue_updates, issue.project)
+    end
+
     def handle_changes(issue, options)
       old_associations = options.fetch(:old_associations, {})
       old_labels = old_associations.fetch(:labels, [])

config/cable.yml.example

+# This file is used for configuring ActionCable in our CI environment
+# When using GDK or Omnibus, cable.yml is generated from a different template
+development:
+  adapter: redis
+  url: redis://localhost:6379
+  channel_prefix: gitlab_development
+test:
+  adapter: redis
+  url: redis://localhost:6379
+  channel_prefix: gitlab_test
+production:
+  adapter: redis
+  url: unix:/var/run/redis/redis.sock
+  channel_prefix: gitlab_production

lib/quality/test_level.rb

@@ -14,6 +14,7 @@ module Quality
       ],
       unit: %w[
         bin
+        channels
         config
         db
         dependencies

scripts/prepare_build.sh

@@ -33,6 +33,9 @@ if [ -f config/database_geo.yml ]; then
   sed -i 's/username: git/username: postgres/g' config/database_geo.yml
 fi
 
+cp config/cable.yml.example config/cable.yml
+sed -i 's|url:.*$|url: redis://redis:6379|g' config/cable.yml
+
 cp config/resque.yml.example config/resque.yml
 sed -i 's|url:.*$|url: redis://redis:6379|g' config/resque.yml
 

spec/channels/application_cable/connection_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe ApplicationCable::Connection, :clean_gitlab_redis_shared_state do
+  let(:session_id) { Rack::Session::SessionId.new('6919a6f1bb119dd7396fadc38fd18d0d') }
+
+  before do
+    Gitlab::Redis::SharedState.with do |redis|
+      redis.set("session:gitlab:#{session_id.private_id}", Marshal.dump(session_hash))
+    end
+
+    cookies[Gitlab::Application.config.session_options[:key]] = session_id.public_id
+  end
+
+  context 'when user is logged in' do
+    let(:user) { create(:user) }
+    let(:session_hash) { { 'warden.user.user.key' => [[user.id], user.encrypted_password[0, 29]] } }
+
+    it 'sets current_user' do
+      connect
+
+      expect(connection.current_user).to eq(user)
+    end
+
+    context 'with a stale password' do
+      let(:partial_password_hash) { build(:user, password: 'some_old_password').encrypted_password[0, 29] }
+      let(:session_hash) { { 'warden.user.user.key' => [[user.id], partial_password_hash] } }
+
+      it 'sets current_user to nil' do
+        connect
+
+        expect(connection.current_user).to be_nil
+      end
+    end
+  end
+
+  context 'when user is not logged in' do
+    let(:session_hash) { {} }
+
+    it 'sets current_user to nil' do
+      connect
+
+      expect(connection.current_user).to be_nil
+    end
+  end
+end

spec/channels/issues_channel_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe IssuesChannel do
+  let_it_be(:issue) { create(:issue) }
+
+  it 'rejects when project path is invalid' do
+    subscribe(project_path: 'invalid_project_path', iid: issue.iid)
+
+    expect(subscription).to be_rejected
+  end
+
+  it 'rejects when iid is invalid' do
+    subscribe(project_path: issue.project.full_path, iid: non_existing_record_iid)
+
+    expect(subscription).to be_rejected
+  end
+
+  it 'rejects when the user does not have access' do
+    stub_connection current_user: nil
+
+    subscribe(project_path: issue.project.full_path, iid: issue.iid)
+
+    expect(subscription).to be_rejected
+  end
+
+  it 'subscribes to a stream when the user has access' do
+    stub_connection current_user: issue.author
+
+    subscribe(project_path: issue.project.full_path, iid: issue.iid)
+
+    expect(subscription).to be_confirmed
+    expect(subscription).to have_stream_for(issue)
+  end
+end

spec/lib/quality/test_level_spec.rb

@@ -21,7 +21,7 @@ RSpec.describe Quality::TestLevel do
     context 'when level is unit' do
       it 'returns a pattern' do
         expect(subject.pattern(:unit))
-          .to eq("spec/{bin,config,db,dependencies,factories,finders,frontend,graphql,haml_lint,helpers,initializers,javascripts,lib,models,policies,presenters,rack_servers,replicators,routing,rubocop,serializers,services,sidekiq,support_specs,tasks,uploaders,validators,views,workers,elastic_integration}{,/**/}*_spec.rb")
+          .to eq("spec/{bin,channels,config,db,dependencies,factories,finders,frontend,graphql,haml_lint,helpers,initializers,javascripts,lib,models,policies,presenters,rack_servers,replicators,routing,rubocop,serializers,services,sidekiq,support_specs,tasks,uploaders,validators,views,workers,elastic_integration}{,/**/}*_spec.rb")
       end
     end
 
@@ -89,7 +89,7 @@ RSpec.describe Quality::TestLevel do
     context 'when level is unit' do
       it 'returns a regexp' do
         expect(subject.regexp(:unit))
-          .to eq(%r{spec/(bin|config|db|dependencies|factories|finders|frontend|graphql|haml_lint|helpers|initializers|javascripts|lib|models|policies|presenters|rack_servers|replicators|routing|rubocop|serializers|services|sidekiq|support_specs|tasks|uploaders|validators|views|workers|elastic_integration)})
+          .to eq(%r{spec/(bin|channels|config|db|dependencies|factories|finders|frontend|graphql|haml_lint|helpers|initializers|javascripts|lib|models|policies|presenters|rack_servers|replicators|routing|rubocop|serializers|services|sidekiq|support_specs|tasks|uploaders|validators|views|workers|elastic_integration)})
       end
     end
 

spec/services/issues/update_service_spec.rb

@@ -842,5 +842,33 @@ describe Issues::UpdateService, :mailer do
       let(:open_issuable) { issue }
       let(:closed_issuable) { create(:closed_issue, project: project) }
     end
+
+    context 'real-time updates' do
+      let(:update_params) { { assignee_ids: [user2.id] } }
+
+      context 'when broadcast_issue_updates is enabled' do
+        before do
+          stub_feature_flags(broadcast_issue_updates: true)
+        end
+
+        it 'broadcasts to the issues channel' do
+          expect(IssuesChannel).to receive(:broadcast_to).with(issue, event: 'updated')
+
+          update_issue(update_params)
+        end
+      end
+
+      context 'when broadcast_issue_updates is disabled' do
+        before do
+          stub_feature_flags(broadcast_issue_updates: false)
+        end
+
+        it 'does not broadcast to the issues channel' do
+          expect(IssuesChannel).not_to receive(:broadcast_to)
+
+          update_issue(update_params)
+        end
+      end
+    end
   end
 end