ActiveJob::DeserializationError: Error while trying to deserialize arguments

Question

I am trying to send mail in production but it is throwing Activejob deserailization error.sidekiq is running in background. I have added sidekiq gem. I wrote one method in comment_notification.rb for sending email to the user. Then in controller in create action I have added this

def create
    CommentNotification.send_comment_mail(@current_user).deliver_later(wait: 1.minute)
end


def send_comment_email(current_user)
    mail( to: current_user.email,
    :subject => "commented on post",
    :from => "<[email protected]>")
end

It was working fine in local server but in production I am getting this error

/home/apps/commentpost/shared/bundle/ruby/2.3.0/gems/sidekiq-4.2.3/lib/sidekiq/processor.rb:69:in `run'
/home/apps/commentpost/shared/bundle/ruby/2.3.0/gems/sidekiq-4.2.3/lib/sidekiq/util.rb:17:in `watchdog'
/home/apps/commentpost/shared/bundle/ruby/2.3.0/gems/sidekiq-4.2.3/lib/sidekiq/util.rb:25:in `block in safe_thread'
2016-11-18T06:47:16.162Z 19093 TID-uw66g ActionMailer::DeliveryJob JID-e56b150964abf082e78089d9 INFO: start
2016-11-18T06:47:16.167Z 19093 TID-uw66g ActionMailer::DeliveryJob JID-e56b150964abf082e78089d9 INFO: fail: 0.005 sec
2016-11-18T06:47:16.167Z 19093 TID-uw66g WARN: {"context":"Job raised exception","job":{"class":"ActiveJob::QueueAdapters::SidekiqAdapter::JobWrapper","wrapped":"ActionMailer::DeliveryJob","queue":"mailers","args":[{"job_class":"ActionMailer::DeliveryJob","job_id":"96e06bc6-1380-47b9-9393-9727868b3897","queue_name":"mailers","priority":null,"arguments":["CommentNotification","send_comment_email","deliver_later",{"_aj_globalid":"gid://commentpost/comment/40"},{"_aj_globalid":"gid://commentpost/User/20"}],"locale":"en"}],"retry":true,"jid":"e56b150964abf082e78089d9","created_at":1479450405.8364522,"enqueued_at":1479451636.1602836,"error_message":"Error while trying to deserialize arguments: Couldn't find Comment with 'id'=40","error_class":"ActiveJob::DeserializationError","failed_at":1479450405.8429642,"retry_count":6,"retried_at":1479451636.1668367},"jobstr":"{\"class\":\"ActiveJob::QueueAdapters::SidekiqAdapter::JobWrapper\",\"wrapped\":\"ActionMailer::DeliveryJob\",\"queue\":\"mailers\",\"args\":[{\"job_class\":\"ActionMailer::DeliveryJob\",\"job_id\":\"96e06bc6-1380-47b9-9393-9727868b3897\",\"queue_name\":\"mailers\",\"priority\":null,\"arguments\":[\"CommentNotification\",\"send_comment_email\",\"deliver_later\",{\"_aj_globalid\":\"gid://commentpost/comment/40\"},{\"_aj_globalid\":\"gid://commentpost/User/20\"}],\"locale\":\"en\"}],\"retry\":true,\"jid\":\"e56b150964abf082e78089d9\",\"created_at\":1479450405.8364522,\"enqueued_at\":1479451636.1602836,\"error_message\":\"Error while trying to deserialize arguments: Couldn't find Comment with 'id'=40\",\"error_class\":\"ActiveJob::DeserializationError\",\"failed_at\":1479450405.8429642,\"retry_count\":5,\"retried_at\":1479450981.998904}"}
2016-11-18T06:47:16.167Z 19093 TID-uw66g WARN: ActiveJob::DeserializationError: Error while trying to deserialize arguments: Couldn't find Comment with 'id'=40
2016-11-18T06:47:16.167Z 19093 TID-uw66g WARN: /

Could anyone please help me regarding this doubt? For this I will be thankful.

Answer 1

As I understand correctly the create method in controller creates also the comment and sends the email for the freshly created comment?

Then it would be better to use a callback here.
We had the same issue in our project and we solved it by using something like that:

# in model
after_commit :send_mail, on: :create

private

def send_mail
  CommentNotification.send_comment_mail(campaign.user).deliver_later
end

Then you can be sure that the record really exists in the Database before the mail gets delivered.

The problem here is, that you run a Comment#create and enqueue the mail in the controller. Now it can happen, that Sidekiq runs the task before Rails commits the new comment.
And then you get exactly this error.

Regards,
spa