Using Sidekiq for Active Job and getting ActiveJob::DeserializationError

Question

I'm trying to use Sidekiq to run the below job.

The job performs fine when not queued (perform_now) but fails when called as (perform_later), which uses Sidekiq.

AddEmployeesToRoomJob.perform_now room  ## works fine
AddEmployeesToRoomJob.perform_later room  ## breaks in Sidekiq

Error:

AddEmployeesToRoomJob JID-da24b13f405b1ece1212bbd5 INFO: fail: 0.003     sec
2016-08-20T14:57:16.645Z 19456 TID-owmym5fbk WARN:     {"class":"ActiveJob::QueueAdapters::SidekiqAdapter::JobWrapper","wrapped"    :"AddEmployeesToRoomJob","queue":"default","args":    [{"job_class":"AddEmployeesToRoomJob","job_id":"0ba5bd30-e281-49a7-a93f-    6e50445183ac","queue_name":"default","priority":null,"arguments":    [{"_aj_globalid":"gid://dragonfly/Room/1"}],"locale":"en"}],"retry":true,    "jid":"da24b13f405b1ece1212bbd5","created_at":1471704675.739077,"enqueued    _at":1471705036.6406531,"error_message":"Error while trying to     deserialize arguments: Couldn't find Room with     'id'=1","error_class":"ActiveJob::DeserializationError","failed_at":14717    04675.946183,"retry_count":4,"retried_at":1471705036.644416}
2016-08-20T14:57:16.645Z 19456 TID-owmym5fbk WARN:     ActiveJob::DeserializationError: Error while trying to deserialize     arguments: Couldn't find Room with 'id'=1
2016-08-20T14:57:16.645Z 19456 TID-owmym5fbk WARN:     /Users/tamlyn/.rvm/gems/ruby-2.2.3/gems/activerecord-    5.0.0.1/lib/active_record/relation/finder_methods.rb:357:in     `raise_record_not_found_exception!'

My Job class AddEmployeesToRoomJob < ApplicationJob queue_as :default

  def perform(room)
    employees = Employee.all
    if employees.length > 0
      employees.each do |employee|
        UserRoom.create(user: employee, room: room)
      end
    end
  end
end

My Thoughts I don't understand why it can't find the room which I'm passing into the perform method. It's as though it somehow loses that variable in the queueifying / JSONifying of the job?

The Sidekiq docs say

"Unfortunately this means that if the [Room] record is deleted after the job is enqueued but before the perform method is called, exception handling is different."

They suggest a workaround but I don't see how that would help me:

rescue_from ActiveJob::DeserializationError do |exception|
    # handle a deleted user record
end

Thanks in advance for any help!

Answer 1

I don't think it is a good idea to pass the Room object into a Sidekiq worker. I've always passed the primary key for a database object and then re-queried. Try this.

AddEmployeesToRoomJob.perform_later room.id

def perform(room_id)
  room = Room.find(room_id)
  employees = Employee.all
    if employees.length > 0
      employees.each do |employee|
        UserRoom.create(user: employee, room: room)
      end
    end
  end
end

Answer 2

Stumbled upon this myself and found the method discard_on very useful. Mostly it is very unnecessary to do jobs on deleted or never created records.

Example:

class ApplicationJob < ActiveJob::Base
  discard_on ActiveJob::DeserializationError do |job, error|
    Rails.logger.error("Skipping job because of ActiveJob::DeserializationError (#{error.message})")
  end
end