PERF: Restrict number of skipped email log for `Jobs::UserEmail`.

app/jobs/concerns/skippable.rb

@@ -0,0 +1,28 @@
+module Skippable
+  extend ActiveSupport::Concern
+
+  def create_skipped_email_log(email_type:,
+                               to_address:,
+                               user_id:,
+                               post_id:,
+                               reason_type:)
+
+    attributes = {
+      email_type: email_type,
+      to_address: to_address,
+      user_id: user_id,
+      post_id: post_id,
+      reason_type: reason_type
+    }
+
+    if reason_type == SkippedEmailLog.reason_types[:exceeded_emails_limit]
+      exists = SkippedEmailLog.exists?({
+        created_at: (Time.zone.now.beginning_of_day..Time.zone.now.end_of_day)
+      }.merge!(attributes.except(:post_id)))
+
+      return if exists
+    end
+
+    SkippedEmailLog.create!(attributes)
+  end
+end

app/jobs/regular/notify_mailing_list_subscribers.rb

@@ -3,6 +3,7 @@ require_dependency 'post'
 module Jobs
 
   class NotifyMailingListSubscribers < Jobs::Base
+    include Skippable
 
     sidekiq_options queue: 'low'
 
@@ -80,23 +81,13 @@ module Jobs
     end
 
     def skip(to_address, user_id, post_id, reason_type)
-      attributes = {
+      create_skipped_email_log(
         email_type: 'mailing_list',
         to_address: to_address,
         user_id: user_id,
         post_id: post_id,
         reason_type: reason_type
-      }
-
-      if reason_type == SkippedEmailLog.reason_types[:exceeded_emails_limit]
-        exists = SkippedEmailLog.exists?({
-          created_at: (Time.zone.now.beginning_of_day..Time.zone.now.end_of_day)
-        }.merge!(attributes.except(:post_id)))
-
-        return if exists
-      end
-
-      SkippedEmailLog.create!(attributes)
+      )
     end
   end
 end

app/jobs/regular/user_email.rb

@@ -5,6 +5,7 @@ module Jobs
 
   # Asynchronously send an email to a user
   class UserEmail < Jobs::Base
+    include Skippable
 
     sidekiq_options queue: 'low'
 
@@ -202,7 +203,7 @@ module Jobs
     end
 
     def skip(reason_type)
-      SkippedEmailLog.create!(
+      create_skipped_email_log(
         email_type: @skip_context[:type],
         to_address: @skip_context[:to_address],
         user_id: @skip_context[:user_id],

spec/jobs/notify_mailing_list_subscribers_spec.rb

@@ -136,7 +136,7 @@ describe Jobs::NotifyMailingListSubscribers do
             end
 
             Jobs::NotifyMailingListSubscribers.new.execute(
-              post_id: Fabricate(:post, user: user)
+              post_id: Fabricate(:post, user: user).id
             )
           end.to change { SkippedEmailLog.count }.by(1)
 
@@ -148,13 +148,19 @@ describe Jobs::NotifyMailingListSubscribers do
             reason_type: SkippedEmailLog.reason_types[:exceeded_emails_limit]
           )).to eq(true)
 
-          freeze_time(Time.zone.now + 1.day)
+          freeze_time(Time.zone.now.tomorrow + 1.second)
 
           expect do
+            post = Fabricate(:post, user: user)
+
+            UserNotifications.expects(:mailing_list_notify)
+              .with(mailing_list_user, post)
+              .once
+
             Jobs::NotifyMailingListSubscribers.new.execute(
-              post_id: Fabricate(:post, user: user)
+              post_id: post.id
             )
-          end.to change { SkippedEmailLog.count }.by(1)
+          end.to change { SkippedEmailLog.count }.by(0)
         end
       end
 

spec/jobs/user_email_spec.rb

@@ -245,12 +245,14 @@ describe Jobs::UserEmail do
 
         it "does not send notification if limit is reached" do
           expect do
+            2.times do
               Jobs::UserEmail.new.execute(
                 type: :user_mentioned,
                 user_id: user.id,
                 notification_id: notification.id,
                 post_id: post.id
               )
+            end
           end.to change { SkippedEmailLog.count }.by(1)
 
           expect(SkippedEmailLog.exists?(
@@ -260,6 +262,17 @@ describe Jobs::UserEmail do
             to_address: user.email,
             reason_type: SkippedEmailLog.reason_types[:exceeded_emails_limit]
           )).to eq(true)
+
+          freeze_time(Time.zone.now.tomorrow + 1.second)
+
+          expect do
+            Jobs::UserEmail.new.execute(
+              type: :user_mentioned,
+              user_id: user.id,
+              notification_id: notification.id,
+              post_id: post.id
+            )
+          end.to change { SkippedEmailLog.count }.by(0)
         end
 
         it "sends critical email" do