Merge pull request #360 from ansonK/email-send-refactor

Refactor the jobs that send email.

Author: alanth

Gemfile.lock

@@ -334,6 +334,3 @@ DEPENDENCIES
   webmock
   whenever
   will_paginate
-
-BUNDLED WITH
-   1.10.4

app/jobs/concerns/email_all_petition_signatories.rb

@@ -0,0 +1,89 @@
+module EmailAllPetitionSignatories
+  extend ActiveSupport::Concern
+
+  #
+  # Concern to add shared functionality to ActiveJob classes that are responsible
+  # for enqueuing send email jobs
+  #
+
+  included do
+    queue_as :default
+
+    def self.run_later_tonight(petition)
+      requested_at = Time.current
+
+      petition.set_email_requested_at_for(new.timestamp_name, to: requested_at)
+
+      set(wait_until: later_tonight).
+        perform_later(petition, requested_at.getutc.iso8601(6))
+    end
+
+    def self.later_tonight
+      1.day.from_now.at_midnight + rand(240).minutes + rand(60).seconds
+    end
+    private_class_method :later_tonight
+
+  end
+
+
+
+  def perform(petition, requested_at_string)
+    @petition = petition
+    @requested_at = requested_at_string.in_time_zone
+    do_work!
+  end
+
+  def timestamp_name
+    raise NotImplementedError.new "Including classes must implement #timestamp_name method"
+  end
+
+  private
+
+  attr_reader :petition, :requested_at
+
+  def do_work!
+    return if petition_has_been_updated?
+
+    logger.info("Starting #{self.class.name} for petition '#{petition.action}' with email requested at: #{petition_timestamp}")
+    enqueue_send_email_jobs
+    logger.info("Finished #{self.class.name} for petition '#{petition.action}'")
+
+  end
+
+  #
+  # Batches the signataries to send emails to in groups of 1000
+  # and enqueues a job to do the actual sending
+  #
+  def enqueue_send_email_jobs
+    signatures_to_email.find_each do |signature|
+      email_delivery_job_class.perform_later(
+        signature:                    signature,
+        timestamp_name:               timestamp_name,
+        petition:                     petition,
+        requested_at_as_string:       requested_at.getutc.iso8601(6)
+      )
+    end
+  end
+
+  # admins can ask to send the email multiple times and each time they
+  # ask we enqueues a new job to send out emails with a new timestamp
+  # we want to execute only the latest job enqueued
+  def petition_has_been_updated?
+    (petition_timestamp - requested_at).abs > 1
+  end
+
+  def petition_timestamp
+    petition.get_email_requested_at_for(timestamp_name)
+  end
+
+  def signatures_to_email
+    petition.signatures_to_email_for(timestamp_name)
+  end
+
+  # The job class that handles the actual email sending for this job type
+  def email_delivery_job_class
+    raise NotImplementedError.new "Including classes must implement #email_delivery_job_class method"
+  end
+end
+
+

app/jobs/concerns/email_delivery.rb

@@ -0,0 +1,83 @@
+module EmailDelivery
+  extend ActiveSupport::Concern
+
+  #
+  # Send a single email to a recipient informing them about a petition that they have signed
+  # Implemented as a custom job rather than using action mailers #deliver_later so we can do
+  # extra checking before sending the email
+  #
+
+  included do
+    queue_as :default
+  end
+
+  def perform(signature:, timestamp_name:, petition:,
+    requested_at_as_string:, mailer: PetitionMailer.name, logger: nil)
+
+    @mailer = mailer.constantize
+    @signature = signature
+    @petition = petition
+    @requested_at = requested_at_as_string.in_time_zone
+    @timestamp_name = timestamp_name
+    @logger = logger
+
+    if can_send_email?
+      send_email
+      record_email_sent
+    end
+  end
+
+  private
+
+  attr_reader :mailer, :signature, :timestamp_name, :petition, :requested_at
+
+  def can_send_email?
+    petition_has_not_been_updated? && email_not_previously_sent?
+  end
+
+  def send_email
+    create_email.deliver_now
+
+    rescue Errno::ECONNREFUSED, Errno::ETIMEDOUT, Net::SMTPError, Timeout::Error => e
+      # log that the send failed
+      logger.info("#{e.class.name} while sending email for #{self.class.name} to: #{signature.email} for #{signature.petition.action}")
+
+      #
+      # TODO: check the error and if it is a n AWS SES rate error:
+      # 454 Throttling failure: Maximum sending rate exceeded
+      # 454 Throttling failure: Daily message quota exceeded
+      #
+      # Then reschedule the send for a day later rather than keep failing
+      #
+
+      # reraise to rerun the job later via the job retry mechanism
+      raise e
+  end
+
+  def create_email
+    raise NotImplementedError.new "Including classes must implement #create_email method"
+  end
+
+  def record_email_sent
+    signature.set_email_sent_at_for timestamp_name, to: petition_timestamp
+  end
+
+  def petition_timestamp
+    petition.get_email_requested_at_for(timestamp_name)
+  end
+
+  # We do not want to send the email if the petition has been updated
+  # As email sending is enqueued straight after a petition has been updated
+  def petition_has_not_been_updated?
+    (petition_timestamp - requested_at).abs < 1
+  end
+
+  #
+  # Have we already sent an email for this petition version?
+  # If we have then the timestamp for the signature will match the timestamp for the petition
+  #
+  def email_not_previously_sent?
+    # check that the signature is still in the list of signatures
+    petition.signatures_to_email_for(timestamp_name).where(id: signature.id).exists?
+  end
+end

app/jobs/deliver_debate_outcome_email_job.rb

@@ -0,0 +1,8 @@
+class DeliverDebateOutcomeEmailJob < ActiveJob::Base
+  include EmailDelivery
+
+  def create_email
+    mailer.notify_signer_of_debate_outcome signature.petition, signature
+  end
+
+end

app/jobs/deliver_debate_scheduled_email_job.rb

@@ -0,0 +1,8 @@
+class DeliverDebateScheduledEmailJob < ActiveJob::Base
+  include EmailDelivery
+
+  def create_email
+    mailer.notify_signer_of_debate_scheduled signature.petition, signature
+  end
+
+end

app/jobs/deliver_threshold_response_email_job.rb

@@ -0,0 +1,8 @@
+class DeliverThresholdResponseEmailJob < ActiveJob::Base
+  include EmailDelivery
+
+  def create_email
+    mailer.notify_signer_of_threshold_response signature.petition, signature
+  end
+
+end

app/jobs/email_debate_outcomes_job.rb

@@ -1,19 +1,11 @@
-class EmailDebateOutcomesJob < EmailPetitionSignatories::Job
-  def self.run_later_tonight(petition)
-    petition.set_email_requested_at_for('debate_outcome', to: Time.current)
-    super(petition, petition.get_email_requested_at_for('debate_outcome'))
-  end
+class EmailDebateOutcomesJob < ActiveJob::Base
+  include EmailAllPetitionSignatories
 
-  def perform(petition, requested_at_string, mailer = PetitionMailer.name, logger = nil)
-    @mailer = mailer.constantize
-    worker(petition, requested_at_string, logger).do_work!
+  def email_delivery_job_class
+    DeliverDebateOutcomeEmailJob
   end
 
   def timestamp_name
     'debate_outcome'
   end
-
-  def create_email(petition, signature)
-    @mailer.notify_signer_of_debate_outcome(petition, signature)
-  end
 end

app/jobs/email_debate_scheduled_job.rb

@@ -1,19 +1,11 @@
-class EmailDebateScheduledJob < EmailPetitionSignatories::Job
-  def self.run_later_tonight(petition)
-    petition.set_email_requested_at_for('debate_scheduled', to: Time.current)
-    super(petition, petition.get_email_requested_at_for('debate_scheduled'))
-  end
+class EmailDebateScheduledJob < ActiveJob::Base
+  include EmailAllPetitionSignatories
 
-  def perform(petition, requested_at_string, mailer = PetitionMailer.name, threshold_logger = nil)
-    @mailer = mailer.constantize
-    worker(petition, requested_at_string, threshold_logger).do_work!
+  def email_delivery_job_class
+    DeliverDebateScheduledEmailJob
   end
 
   def timestamp_name
     'debate_scheduled'
   end
-
-  def create_email(petition, signature)
-    @mailer.notify_signer_of_debate_scheduled(petition, signature)
-  end
 end

app/jobs/email_petition_signatories.rb

@@ -1,19 +1,11 @@
-class EmailThresholdResponseJob < EmailPetitionSignatories::Job
-  def self.run_later_tonight(petition, requested_at = Time.current)
-    petition.set_email_requested_at_for('government_response', to: requested_at)
-    super(petition, petition.get_email_requested_at_for('government_response'))
-  end
+class EmailThresholdResponseJob < ActiveJob::Base
+  include EmailAllPetitionSignatories
 
-  def perform(petition, requested_at_string, mailer = PetitionMailer.name, logger = nil)
-    @mailer = mailer.constantize
-    worker(petition, requested_at_string, logger).do_work!
+  def email_delivery_job_class
+    DeliverThresholdResponseEmailJob
   end
 
   def timestamp_name
     'government_response'
   end
-
-  def create_email(petition, signature)
-    @mailer.notify_signer_of_threshold_response(petition, signature)
-  end
 end