From: Tim Pease <tim.pease@...>
Date: 2012-01-11T11:44:13+09:00
Subject: Re: Servolux: monitoring outside change?


On Jan 10, 2012, at 1:05 PM, Aldric Giacomoni wrote:

> Hi Tim,
> 
> I started using Servolux on a small internal project and so far I'm really
> pleased with it. What I'm doing is very simple: I have to manage a few
> scripts and start them with the right command-line arguments (does the
> acronym CLA mean anything to anyone? I've never seen it used but it would
> make my life so much easier). I use Servolux::Child objects for that.
> 

I'm glad you are finding Servolux useful!

> Is there a way, internally, to know whether one of the processes handled by
> the Child object has been kill-9'd by, say, an outside human hand? I don't
> really know enough about the popen stuff and process communication to
> figure that out.
> 

The Servolux::Child class provides several methods to determine the status of the child process.

* alive? -- This method returns +true+ if the child process is still alive. So if someone kills the process (kill -9) then this method will return +false+. If this method returns +nil+, the the child process was never started.

There are several methods that map directly to the ruby Process::Status class and can be used to find out exactly how and why the child process exited. All of these methods can be called on your Servolux::Child instance:

* coredump?
* exited?
* signaled?
* stopped?
* success?
* exitstatus
* stopsig
* termsig

You can read the documentation for these methods here => http://ruby-doc.org/core-1.9.3/Process/Status.html
In your case the methods to look at are "signaled?" and "termsig". If "termsig" returns 9, then someone used kill -9 to stop the process.

Hope all this helps!

Blessings,
TwP