Custom Notifications

[Dan Cook]

I need to execute a some ruby code on notification.
We have a central health monitoring service on the box and process
health is just one part of the overall reports.
I would like to put the events into a queue on the disk and have our
health monitoring service slurp up any events and send them to another
centralized server.

I assume I can just do this:

w.transition(:up, :start) do |on|
on.condition(:process_exits) do |c|
# custom notification method here....
end
end

Is this correct?

Cheers,
Dan

[Dan Cook]

A little more context on this:
I set up a very simple test where god was using the above condition.

w.transition(:up, :start) do |on|
 on.condition(:process_exits) do |c|

   LOG.info("Hello world.")
 end
end

and the resulting output is:

I [2012-02-19 18:22:08]  INFO: Loading foo.god
I [2012-02-19 18:22:08]  INFO: Syslog enabled.
I [2012-02-19 18:22:08]  INFO: Using pid file directory: /var/run/god
I [2012-02-19 18:22:08]  INFO: Hello world.
I [2012-02-19 18:22:08]  INFO: Started on drbunix:///tmp/god.17165.sock

So the above code only runs once at start time so my original question stands.

How do I register a custom notification hook in god?

Cheers,
Dan

[Shadab Ahmed]

Hi, 

I searched up of google and found this thread. This is how I got my custom code executed on process_exit:

Create a god/contact subclass like this:

require 'god/contact'

class DelayedJobUnlockingNotifier < God::Contact

  def notify(message, time, priority, category, host)

    if pid = (message.match(/process (?<pid>.*) exited/) || {})['pid']

      `bundle exec rake RAILS_ENV=#{RAILS_ENV} PID=#{pid} delayed_job:recover_locked_jobs`

      applog(nil, :info, "delayed_job_unlocking_notifier: ran rake task to unlock locked jobs for PID: #{pid}")

    end

  rescue Object => e

    applog(nil, :info, "delayed_job_unlocking_notifier: failed to unlock locked jobs for PID: #{pid}")

    applog(nil, :debug, e.backtrace.join("\n"))

  end

end

If your godfile on top:

require APPLICATION_ROOT + '/lib/god/contacts/delayed_job_unlocking_notifier'

God.contact(:delayed_job_unlocking_notifier) do |c|

  c.name = 'stuck_jobs_unlocker'

end

and then in the watch block

w.transition(:up, :start) do |on|

    on.condition(:process_exits) do |c|

     c.notify = 'stuck_jobs_unlocker'

    end

  end

Only problem is not that you cannot customize the parameters sent to the notifier so I had to parse out PID from the message sent.