feat: implement mutex for SlackSendJob (#7783)

app/jobs/mutex_application_job.rb

@@ -0,0 +1,35 @@
+# MutexApplicationJob serves as a base class for jobs that require distributed locking mechanisms.
+# It abstracts the locking logic using Redis and ensures that a block of code can be executed with
+# mutual exclusion.
+#
+# The primary mechanism provided is the `with_lock` method, which accepts a key format and associated
+# arguments. This method attempts to acquire a lock using the generated key, and if successful, it
+# executes the provided block of code. If the lock cannot be acquired, it raises a LockAcquisitionError.
+#
+# To use this class, inherit from MutexApplicationJob and make use of the `with_lock` method in the
+# `perform` method of the derived job class.
+#
+# Also see, retry mechanism here: https://edgeapi.rubyonrails.org/classes/ActiveJob/Exceptions/ClassMethods.html#method-i-retry_on
+#
+class MutexApplicationJob < ApplicationJob
+  class LockAcquisitionError < StandardError; end
+
+  def with_lock(key_format, *args)
+    lock_key = format(key_format, *args)
+    lock_manager = Redis::LockManager.new
+
+    if lock_manager.locked?(lock_key)
+      Rails.logger.warn "[#{self.class.name}] Failed to acquire lock on attempt #{executions}: #{lock_key}"
+      raise LockAcquisitionError, "Failed to acquire lock for key: #{lock_key}"
+    end
+
+    begin
+      lock_manager.lock(lock_key)
+      Rails.logger.info "[#{self.class.name}] Acquired lock for: #{lock_key} on attempt #{executions}"
+      yield
+    ensure
+      # Ensure that the lock is released even if there's an error in processing
+      lock_manager.unlock(lock_key)
+    end
+  end
+end

app/jobs/send_on_slack_job.rb

@@ -1,7 +1,10 @@
-class SendOnSlackJob < ApplicationJob
+class SendOnSlackJob < MutexApplicationJob
   queue_as :medium
+  retry_on LockAcquisitionError, wait: 1.second, attempts: 6
 
   def perform(message, hook)
-    Integrations::Slack::SendOnSlackService.new(message: message, hook: hook).perform
+    with_lock(::Redis::Alfred::SLACK_MESSAGE_MUTEX, sender_id: message.sender_id, reference_id: hook.reference_id) do
+      Integrations::Slack::SendOnSlackService.new(message: message, hook: hook).perform
+    end
   end
 end

app/jobs/webhooks/facebook_events_job.rb

@@ -1,28 +1,16 @@
-class Webhooks::FacebookEventsJob < ApplicationJob
-  class LockAcquisitionError < StandardError; end
-
+class Webhooks::FacebookEventsJob < MutexApplicationJob
   queue_as :default
-  # https://edgeapi.rubyonrails.org/classes/ActiveJob/Exceptions/ClassMethods.html#method-i-retry_on
   retry_on LockAcquisitionError, wait: 1.second, attempts: 6
 
   def perform(message)
     response = ::Integrations::Facebook::MessageParser.new(message)
 
-    lock_key = format(::Redis::Alfred::FACEBOOK_MESSAGE_MUTEX, sender_id: response.sender_id, recipient_id: response.recipient_id)
-    lock_manager = Redis::LockManager.new
-
-    if lock_manager.locked?(lock_key)
-      Rails.logger.error "[Facebook::MessageCreator] Failed to acquire lock on attempt #{executions}: #{lock_key}"
-      raise LockAcquisitionError, "Failed to acquire lock for key: #{lock_key}"
-    end
-
-    begin
-      lock_manager.lock(lock_key)
-      Rails.logger.info "[Facebook::MessageCreator] Acquired lock for: #{lock_key}"
-      ::Integrations::Facebook::MessageCreator.new(response).perform
-    ensure
-      # Ensure that the lock is released even if there's an error in processing
-      lock_manager.unlock(lock_key)
+    with_lock(::Redis::Alfred::FACEBOOK_MESSAGE_MUTEX, sender_id: response.sender_id, recipient_id: response.recipient_id) do
+      process_message(response)
     end
   end
+
+  def process_message(response)
+    ::Integrations::Facebook::MessageCreator.new(response).perform
+  end
 end