Errors executing jobs with background job manager gem called Que

Question

I'm writing an Rails 4.2.0 application where I need to deliver emails. I've been advised Que gem for managing background jobs. I've done everything as in installation and usage is listed here.

Also I've specified in application.rb these lines:

    # For https://github.com/chanks/que
    config.active_record.schema_format = :sql
    config.active_job.queue_adapter = :que

My job looks like this send_welcome_message.rb :

class SendWelcomeEmail < Que::Job
  # Default settings for this job. These are optional - without them, jobs
  # will default to priority 100 and run immediately.
  @priority = 10
  @run_at = proc { 1.minute.from_now }

  def run(user_id, options)

    @user = User.find(user_id)
    UserMailer.welcome_email(@user).deliver_now

    # Destroy the job.
    destroy
  end
end

After running the rails s command my console is populated with these messages:

{
   "lib":"que",
   "hostname":"...",
   "pid":13938,
   "thread":69925811873800,
   "event":"job_unavailable"
}

And when I enqueue my job like this in controller

SendWelcomeEmail.enqueue 20, priority: 100

and refresh the page, I get the following errors all the time ( despite I can send messages is sync manner without using que ):

    {
   "lib":"que",
   "hostname":"...",
   "pid":13938,
   "thread":69925811873800,
   "event":"job_errored",
   "error":{
      "class":"ArgumentError",
      "message":"wrong number of arguments (1 for 2)"
   },
   "job":{
      "queue":"",
      "priority":100,
      "run_at":"2015-06-22T01:59:45.187+03:00",
      "job_id":11,
      "job_class":"SendWelcomeEmail",
      "args":[
         20
      ],
      "error_count":2
   }
}

And when I open rails console in the second terminal and enter there Que.worker_states (it's written here and should return information about every worker in the system) I get [].

I think that I have no workers spawned. Am I right? And how to fix it?

UPDATE

Found error in que log:

wrong number of arguments (1 for 2)
/home/username/train/project/app/jobs/send_welcome_email.rb:8:in `run'
/home/username/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/que-0.10.0/lib/que/job.rb:15:in `_run'
/home/username/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/que-0.10.0/lib/que/job.rb:99:in `block in work'
/home/username/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/que-0.10.0/lib/que/adapters/active_record.rb:5:in `block in checkout'
/home/username/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/activerecord-4.2.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:292:in `with_connection'
/home/username/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/que-0.10.0/lib/que/adapters/active_record.rb:34:in `checkout_activerecord_adapter'
/home/username/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/que-0.10.0/lib/que/adapters/active_record.rb:5:in `checkout'
/home/username/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/que-0.10.0/lib/que/job.rb:82:in `work'
/home/username/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/que-0.10.0/lib/que/worker.rb:78:in `block in work_loop'
/home/username/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/que-0.10.0/lib/que/worker.rb:73:in `loop'
/home/username/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/que-0.10.0/lib/que/worker.rb:73:in `work_loop'
/home/username/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/que-0.10.0/lib/que/worker.rb:17:in `block in initialize'

Line 8 is:

def run(user_id, options)

SOLUTION

Now its' working. I've deleted the adapter configuration from application.rb and in place of

SendWelcomeEmail.enqueue 20, priority: 100

wrote

@user = User.find(20)
SendWelcomeEmail.enqueue  @user.id, :priority => 100

Now it's works. Funny thing in the second variant the same values are passed to the function. Still error message said that run obtained only 1 argument - 20.

Answer 1

Reading the que gem, it looks like the enqueue method treats priority keyword as a special case: https://github.com/chanks/que/blob/master/lib/que/job.rb#L31

So, your run method is only passed the first argument. The priority keyword gets swallowed by que.

Changing your run method to

  def run(user_id)

should fix your issue.