pass the exception to failure hook

[Nowaker]

I use delayed_job to run background tasks in VirtKick, example tasks are creating a new machine, creating a new disk, mounting an ISO, etc. Some I/O related tasks can't be performed when load is high, libvirt is just rejecting the call. Therefore, I set some big max_attempts and reschedule_at in 2 seconds. That's fine.

module Bugsnagable
  def error job, e
    unless Rails.env.test?
      puts e.message
      puts e.backtrace.map { |e| '    ' + e }.join "\n"
    end
    Bugsnag.notify_or_ignore e
  end
end

I catch every unhandled exception with Bugsnag so as to know of every exception. The problem is this reports too much. If the job fails for the first time and succeeds for the second, one exception will be reported anyway. One way would be to check if attempt == max_attempts before reporting to Bugsnag, but I believe the best way is to introduce def failure(job, exception).

I didn't write any specs at this point - tell me if you're OK with def failure job, exception first. :) Please also see my questions directly in the code.

[Nowaker]

time param is never used across the code. All tests still pass when removed. Can we get rid of it?

[albus522]

Technically part of the public API. Leave it.

[coveralls]

Coverage remained the same when pulling d913e92 on Nowaker:feature/exception-in-failure-hook into c85a4fe on collectiveidea:master.

[albus522]

This needs to work with old failure callbacks that only accept 1 argument. This PR would break everyone's current code.

[Nowaker]

@albus522 There haven't been any specs for error hooks, right? Will write and make sure all works OK.

Please also answer my question in the code.

[coveralls]

Coverage remained the same when pulling d1a9cde on Nowaker:feature/exception-in-failure-hook into 6d0a6b2 on collectiveidea:master.

[coveralls]

Coverage increased (+0.02%) when pulling f13e6af on Nowaker:feature/exception-in-failure-hook into 6d0a6b2 on collectiveidea:master.

[coveralls]

Coverage increased (+0.02%) when pulling db016ee on Nowaker:feature/exception-in-failure-hook into 6d0a6b2 on collectiveidea:master.

[Nowaker]

Will submit a new PR when done.