Status monitoring per job

[pietern]

To provide feedback to a user about his just-queued job, I've added a simple mechanism in my branch at http://github.com/pietern/resque/commits/job_status .

This allows you to set an ivar @monitor in the class you wish to queue. Resque then adds an ID to the payload and sets the job status to "queued". When the job is started, the status changes to "started" and then to either "done" or "failed". Inbetween, the perform method can modify the jobs status via Resque.current_job.status.

Because Resque forks a new child for every jobs, it is possible to use this accessor on the Resque module and not introduce race conditions.

Statuses expire after a configurable delay that currently defaults to 5 minutes, to prevent Redis from running out of memory.

When a new job is created that needs to be monitored, Resque returns the job ID on Resque#enqueue.

To provide easy access to setting the status, there is a mixin called Resque::Mixin::Status. This mixin automatically sets the @monitor ivar.

Upon completion, the job status only gets set to "done" when the performing method has not touched the status.

This means that a custom status like "50/50" stays intact.
class SomeJob
include Resque::Mixin::Status

  def self.perform(*args)
    resque_status "00/50"
    # ...
    resque_status "50/50"
  end
end

Resque.enqueue(SomeJob)

A jobs status can be retrieved by Resque::Job.status(job_id).

[defunkt]

What is the use case for this? The web UI does a pretty good job letting you know what jobs are running, especially in the "working" tab.

[pietern]

This would be nice to have for user feedback. If a user queues a high priority task, that you obviously want to handle asynchronously, you can instantly provide the user with job-progress. I was thinking of something like:

class PagesController < ApplicationController
    def some_action
      @page = Page.find(params[:id])
      session[:job_id] = @page.async(:do_something)
    end

    def job_status
      render :json => { :status => Resque::Job.status(session[:job_id]) }
    end
end

[defunkt]

Seems like you could easily do this in your application though, right? I'm not sure it belongs in Resque.

[skrat]

I believe similar stuff belong to Resque, workers should be able to report whatever status, so anybody can update the web app to display that status

[defunkt]

skrat: Just pass in a memcached / Redis / id and have the job update it.