How can I run a rake task from a delayed_job

Question

I'd like to run a rake task (apn:notifications:deliver from the apn_on_rails gem) from a delayed_job. In other words, I'd like enqueue a delayed job which will call the apn:notifications:deliver rake task.

I found this code http://pastie.org/157390 from http://geminstallthat.wordpress.com/2008/02/25/run-rake-tasks-with-delayedjob-dj/.

I added this code as DelayedRake.rb to my lib directory:

require 'rake'
require 'fileutils'

class DelayedRake
  def initialize(task, options = {})
     @task     = task
     @options  = options
 end

  ##
  # Called by Delayed::Job.
  def perform
    FileUtils.cd RAILS_ROOT

    @rake = Rake::Application.new
    Rake.application = @rake
    ### Load all the Rake Tasks.
     Dir[ "./lib/tasks/**/*.rake" ].each { |ext| load ext }
     @options.stringify_keys!.each do |key, value|
      ENV[key] = value  
     end
    begin
       @rake[@task].invoke
    rescue => e
       RAILS_DEFAULT_LOGGER.error "[ERROR]: task \"#{@task}\" failed.  #{e}"
    end
 end
end

Everything runs fine until the delayed_job runs and it complains:

[ERROR]: task "apn:notifications:deliver" failed. Don't know how to build task 'apn:notifications:deliver'

How do I let it know about apn_on_rails? I'd tried require 'apn_on_rails_tasks' at the top of DelayedRake which didn't do anything. I also tried changing the directory of rake tasks to ./lib/tasks/*.rake

I'm somewhat new to Ruby/Rails. This is running on 2.3.5 on heroku.

Answer 1

Why don't do just a system call ?

system "rake apn:notifications:deliver"

Answer 2

I believe it's easier if you call it as a separate process. See 5 ways to run commands from Ruby.

def perform
  `rake -f #{Rails.root.join("Rakefile")} #{@task}`
end

If you want to capture any errors, you should capture STDERR as shown in the article.