Revert "[webui][api] Change SendEventEmails to 1 event per job."

This reverts commit df92a8f.
Reverted because delayed job cannot handle large number of jobs
in the queue. We should first move to an async system which can
scale, and then move to 1 event / job.

src/api/app/jobs/send_event_emails_job.rb

@@ -1,23 +1,25 @@
 class SendEventEmailsJob < ApplicationJob
   queue_as :mailers
 
-  def perform(event_id)
-    event = Event::Base.find(event_id)
-    subscribers = event.subscribers
+  def perform
+    Event::Base.where(mails_sent: false).order(created_at: :asc).limit(1000).each do |event|
+      subscribers = event.subscribers
 
-    if subscribers.empty?
-      event.update_attributes(mails_sent: true)
-      return
-    end
+      if subscribers.empty?
+        event.update_attributes(mails_sent: true)
+        next
+      end
 
-    begin
-      create_rss_notifications(event)
-      EventMailer.event(subscribers, event).deliver_now
-    rescue StandardError => e
-      Airbrake.notify(e, event_id: event.id)
-    ensure
-      event.update_attributes(mails_sent: true)
+      begin
+        create_rss_notifications(event)
+        EventMailer.event(subscribers, event).deliver_now
+      rescue StandardError => e
+        Airbrake.notify(e, event_id: event.id)
+      ensure
+        event.update_attributes(mails_sent: true)
+      end
     end
+    true
   end
 
   private

src/api/app/models/event/base.rb

@@ -8,8 +8,6 @@ class Base < ApplicationRecord
     self.table_name = 'events'
 
     after_create :create_project_log_entry_job, if: -> { (PROJECT_CLASSES | PACKAGE_CLASSES).include?(self.class.name) }
-    after_create :perform_create_jobs
-    after_create :send_event_emails_job
 
     EXPLANATION_FOR_NOTIFICATIONS =  {
       'Event::BuildFail'          => 'Receive notifications of build failures for packages for which you are...',
@@ -153,6 +151,8 @@ def create_project_log_entry_job
       CreateProjectLogEntryJob.perform_later(payload, created_at.to_s, self.class.name)
     end
 
+    after_create :perform_create_jobs
+
     def perform_create_jobs
       self.undone_jobs = 0
       save
@@ -170,10 +170,6 @@ def perform_create_jobs
       save if self.undone_jobs > 0
     end
 
-    def send_event_emails_job
-      SendEventEmailsJob.perform_later(id) if id.present?
-    end
-
     # to be overwritten in subclasses
     def subject
       'Build Service Notification'

src/api/config/clock.rb

@@ -16,6 +16,10 @@ module Clockwork
     WorkerStatus.new.update_workerstatus_cache
   end
 
+  every(30.seconds, 'send notifications') do
+    SendEventEmailsJob.perform_later
+  end
+
   every(49.minutes, 'rescale history') do
     StatusHistoryRescalerJob.perform_later
   end

src/api/spec/jobs/send_event_emails_job_spec.rb

@@ -1,6 +1,8 @@
 require 'rails_helper'
 
 RSpec.describe SendEventEmailsJob, type: :job do
+  include ActiveJob::TestHelper
+
   describe '#perform' do
     before do
       ActionMailer::Base.deliveries = []
@@ -13,18 +15,16 @@
     let!(:project) { create(:project, name: 'comment_project', maintainer: [user, group]) }
 
     let!(:comment_author) { create(:confirmed_user) }
-    let!(:user_maintainer) { create(:group) }
 
-    let(:comment) do
-      create(:comment_project, commentable: project, body: "Hey @#{user.login} how are things?", user: comment_author)
-    end
+    let!(:comment) { create(:comment_project, commentable: project, body: "Hey @#{user.login} how are things?", user: comment_author) }
+    let!(:user_maintainer) { create(:group) }
 
     context 'with no errors being raised' do
       let!(:subscription1) { create(:event_subscription_comment_for_project, receiver_role: 'maintainer', user: user) }
       let!(:subscription2) { create(:event_subscription_comment_for_project, receiver_role: 'maintainer', user: nil, group: group) }
       let!(:subscription3) { create(:event_subscription_comment_for_project, receiver_role: 'commenter', user: comment_author) }
 
-      subject! { comment }
+      subject! { SendEventEmailsJob.new.perform }
 
       it 'sends an email to the subscribers' do
         email = ActionMailer::Base.deliveries.first
@@ -76,7 +76,7 @@
         allow(Airbrake).to receive(:notify)
       end
 
-      subject! { comment }
+      subject! { SendEventEmailsJob.new.perform }
 
       it 'updates the event mails_sent = true' do
         event = Event::CommentForProject.first
@@ -89,7 +89,7 @@
     end
 
     context 'with no subscriptions for the event' do
-      subject! { comment }
+      subject! { SendEventEmailsJob.new.perform }
 
       it 'updates the event mails_sent = true' do
         event = Event::CommentForProject.first