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