#171 Delayed Job (revised)

Lower priority numbers have higher priority. It is in documentation

By default all jobs are scheduled with priority = 0, which is top priority. You can change this by setting Delayed::Worker.default_priority to something else. Lower numbers have higher priority.

Anyway great tutorial ! Thanks

You must've been lucky with using delay as a Class method. I wonder what your stack is (ruby version/gem version/bundler version/rails version).

Gives a NoMethodError on Class when executing the job. The target class doesnt serialize/deserialize properly it seems. Seems like there are 3 open tickets relating to this on Github.

While I like how the #delay method looks in the code, automatically serializing/deserializing objects, it does feel somewhat dirty. I recall it being fairly slow when working with large objects, and in most cases I think providing a hash of options along with the model's id would be faster. But, please do correct me if I'm wrong about that. I think that the less data you store in the database, faster the retrieval and serialization/deserialization will be when just using Struct classes, but it does mean you need to write a bit more code for everything you want to queue up. And, if you're going to do that then you might want to consider using Resque instead. I've used both a few times, and they both have their pros and cons. Note: I haven't tried out the new Delayed Job 3 that was recently released.

Can i configure different delay time between jobs calls for different queues?

Hi Ryan,
i see that there are some hooks you can define using delayed job.
i want to do some task after the job is done and, as the docs suggest i add the method

def after(job)
  # do something
end

in my class but it never been called.
What is the right way to use the hooks or maybe there is some other way to define callbacks instead?

I know that sending the actual emails/newsletters is not the focus of this episode, but I would like to see how Ryan would setup sending newsletters like this. I haven't been able to find a good example of sending group emails in Rails.

Hi Ryan. Instead of using daemons gem when running 'sciprt/jobs'. Could you just use foreman and have it 'run bundle exec rake jobs:work'?

I use foreman in development and in production too so this would be useful to know.

DelayedJob doesn't seem to work with JRuby unfortunately, at least not on windows -- as best I can tell. It will queue jobs, but starting a background job fails.

I'm using delayed_job (Rails 3.1) on Heroku. It seems to stall a lot, and can be tricky to start workers. I'm constantly paranoid that delayed_job may have fallen asleep and jobs are piling up in the queue (this happens pretty often, actually). Anyone know of any good resources for getting delayed_job to work reliably on Heroku? I installed the 'daemons' gem, but I generally just run "heroku rake jobs: work" to get things going again.

I'm sure I'm just doing it wrong, but I can't find too much out there to help me get everything set up to run efficiently.

Suggestions?

Changed from Bj(no longer supported in Rail3) to Delayed_job but seems not to handle rails runner.

lib/report_job.rb
class ReportJob < Struct.new(:prawn_script_name , :account_id )
def perform
bundle exec rails runner "#{Rails.root}/jobs/#{prawn_script_name}.rb #{account_id}"
end

Error in last_error field.
{undefined method `runner' for #ReportJob:0xc28f080

OUCH! .... will try Resque.

One very good explanation why my approach does not work.

http://stackoverflow.com/questions/10930300/delayed-job-and-prawn-scripts

load "#{Rails.root}/jobs/#{prawn_script_name}.rb" DOES WORK.

BUT

I need to pass arguments e.g account_id to the Prawn scripts to scope the data for the pdfs.

runner allows ARG[]s to be passed but "load" does not!

Delayed_job has the arguments in its table but how do I make these accessible to the Prawn scripts?

This is my next hurdle to overcome.

Hi Ryan,

Awesome info. Two questions:

1. Wouldn't it be better to call the delay method from within the Newsletter model (or use handle_asynchronously)? That way the background functionality can be encapsulated into the Newsletter model and away from the controller. Better if we need to change it later...?

2. It seems to me that the big difference between serializing the object and just saving the ID is the state of the object. If you serialize it, then you are capturing the state when the delay method is called. If you just save the ID, then it will use the state of the object when the Newsletter is delivered.
   I imagine that one or the other would be desirable, depending on the details of the application.

Using delayed_job gem with my rails 3 app on development working great but when I tried to use it on production using capistrano it gives me these error

script/delayed_job: Permission denied

I am using their method and I followed your method

https://github.com/collectiveidea/delayed_job/wiki/Rails-3-and-Capistrano

So far we've been starting Delayed Job by running rake jobs:work but in production we should use the delayed_job script provided in the script folder.

The reason why is explained here https://github.com/collectiveidea/delayed_job/issues/659.

Hy all, i have installed delayed_job gem,
I have an rails app qith mongoid, and the gem save correctly the queue in mongodb (db.delayed_backend_mongoid_jobs), but not exectue the queue command, why?

Hi all,

What might have been obvious to some but was not to me was the necessity to pay on Heroku a worker (35$) to have the queue taken care of if I'm not mistaken.

https://devcenter.heroku.com/articles/delayed-job

Best

Nicolas