Backgroundrb devel - Feb 2007 - Starting / stopping background rb when apache starts/stops

Hello -

I would like to figure out a way to have backgroundrb start/stop with the 
same UID that dispatch.fcgi uses, at the same point in time that apache is 
started/stopped. I see a technique that seems plausable in this archive 
message:

http://rubyforge.org/pipermail/backgroundrb-devel/2007-February/000723.html

which addresses the starting aspect, in a lazy fashion. That seems fine, 
particularly given it''s resilience to unexpected terminations of the 
backgroundrb processes.

What I have not seen any discussion of is how to insure that backgroundrb 
is terminated (ideally cleanly) at the point in time that apache (or 
whatever web server you use) is terminated. In other words, I am hoping to 
use "apachectl {start|stop}" to control dispatch.fcgi and
backgroundrb.

Does anyone have any suggestions?

Thanks in advance - Marc

On Fri, 16 Feb 2007, Marc Evans wrote:
> Hello -
>
> I would like to figure out a way to have backgroundrb start/stop with the 
> same UID that dispatch.fcgi uses, at the same point in time that apache is 
> started/stopped. I see a technique that seems plausable in this archive 
> message:
>
> http://rubyforge.org/pipermail/backgroundrb-devel/2007-February/000723.html
>
> which addresses the starting aspect, in a lazy fashion. That seems fine, 
> particularly given it''s resilience to unexpected terminations of
the
> backgroundrb processes.
>
> What I have not seen any discussion of is how to insure that backgroundrb
is
> terminated (ideally cleanly) at the point in time that apache (or whatever 
> web server you use) is terminated. In other words, I am hoping to use 
> "apachectl {start|stop}" to control dispatch.fcgi and
backgroundrb.
>
> Does anyone have any suggestions?
In response to my own message, but in hopes of either being told that I am 
doing idiotic things, or helping others with the same problem, here is the 
solution that I have finally come up with.

My answer was to use the following code within my config/environment.rb 
file:

require ''pathname''
BACKGROUNDRB_STANDALONE = false
BACKGROUNDRB_ROOT = Pathname.new(RAILS_ROOT).realpath.to_s
BACKGROUNDRB_CODE = BACKGROUNDRB_ROOT +
''/vendor/plugins/backgroundrb''
$LOAD_PATH << File.join(BACKGROUNDRB_CODE + ''/lib'')
$LOAD_PATH << File.join(BACKGROUNDRB_CODE +
''/server/lib'')
require ''backgroundrb_server''
Process.fork {
   # Code lifted from script/backgroundrb
   ARGV.clear
   ARGV << ''start''
   exit(0) if File.exists?(BACKGROUNDRB_ROOT +
''/log/backgroundrb.ppid'');
   BackgrounDRb::Server.new.run
}
at_exit {
   ARGV.clear
   ARGV << ''stop''
   exit(0) unless File.exists?(BACKGROUNDRB_ROOT +
''/log/backgroundrb.ppid'');
   BackgrounDRb::Server.new.run
}

For reasons not understood at this time, I am finding that invoking 
script/backgroundrb {start|stop} does not work. Copying chunks of the code 
as shown above, does.

Yes, there are some holes, such as relying on the ppid file and not 
checking if the pid is actually running; such as relying on at_exit to 
perform proper cleanup; such as not cleaning up open file descriptors in 
the forked child prior to calling run.

If you have better suggestions, I would love to hear them.

Thanks in advance - Marc