Explanation about Delayed_Jobs

Question

Looking for an explanation into the delayed_job gem.

I understand it schedules and keeps a list of tasks that need to be done, and that those tasks can be created via the active_job interface.

What I don't understand is what starts the taskrunner or whatever it is that starts going through the list of jobs in the delayed_job table. Am I able to use the whenever gem to do this and call it as a chron job? Or should I be using the daemons gem? If so, what is the difference between daemons gem and whenever ?

I am just a bit confused in all of this.

Lastly, I use heroku for staging, and a vpn managed via capistrano. How would that play into this?

Thank you.

Answer 1

There is a delayed_job script for that It needs to be run as a separate process.

script/delayed_job can be used to manage a background process which will start working off jobs.

To do so, add gem "daemons" to your Gemfile and make sure you've run rails generate delayed_job.

https://github.com/collectiveidea/delayed_job#running-jobs

For heroku, see docs

You need to update the Procfile with:

worker: rake jobs:work