Init.d script to start shell scripts

You could use /etc/rc.local to call your script.  I think this only works if you're starting in a multi-user run level.  Also, this may only be on Debian-based distros.  I think Fedora has something similar (if not the same thing).  I'm not sure about the other flavors.

Attached worker-dashboard-queue.sh below.  The idea is that eventually it will be more than just that one script that will get run, so I figured that for the sake of simplicity and ease of changes I'd keep it more modularized.

The real heavy lifting is done w/ PHP; all that the shell script is doing is running the PHP script over and over, waiting for it to exit each time.

Eventually, I'd like to turn it into an actual daemon process (my understanding is I need to write a little C program?), but in the meantime I thought this might be the easiest solution.  Open to suggestions tho.

#!/bin/sh
# Based on script at http://www.topbit.co.uk/serendipity/archives/22-Doing-the-work-elsewhere-Sidebar-running-the-worker.html
 
PATH=$PATH:/usr/local/apache2/php/bin
export PATH
 
nice php ./dashboard-queue.php
ERR=$?
 
## Possibilities
# 97    - planned pause/restart
# 98    - planned restart
# 99    - planned stop, exit.
# 0     - unplanned restart (as returned by "exit;")
#       - Anything else is also unplanned paused/restart
 
if [ $ERR -eq 97 ]
then
   # a planned pause, then restart
   sleep 1;
   exec $0 $@;
fi
 
if [ $ERR -eq 98 ]
then
   # a planned restart - instantly
   exec $0 $@;
fi
 
if [ $ERR -eq 99 ]
then
   # planned complete exit
   exit 0;
fi
 
# unplanned exit, pause, and restart
sleep 1
 
exec $0 $@

                                              

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So would I just set up a similar wrapper in the init script to check for exit codes, and see if it's 0 (or anything that I don't want it to be) and if so then do the e-mail?

This may be a separate question, but we're monitoring services with Monit - any idea if there's any way to monitor the script to make sure it's always running?

@guardsman - is there a benefit to launching it using rc.local as opposed to init.d?

Sorry KeremE, you posted as I was replying - didn't see it.  That script looks pretty excellent; I'll give it a shot.

Going back to what I just posted about about monitoring with Monit - that /var/lock/subsys/new_init_script - is that a PID file for the script?

No problem.

The trick ehere is you're including RedHAT stye functions by the inclusion of functions.

RETVAL variable is what is checked to print [OK] or [failed]

/var/lock/subsys/new_init_script is a file and it is created to let RedHAT know that the service is running. As you see it was created with touch.

BTW new_init_script represents the name of the service oyu've designate. Please replace all instances with the name you think that fits.

once addes with chkconfig you can use

service new_init_script start and stop

to see what does it output.

Cheers,
K.
 

KeremE, your script seems to be working pretty well, although I had to remove the ;; on line 47...typo?  Also applied Tintin's fix.  There is just one problem I'm having tho.

The entire purpose of these scripts is to watch a queue server (Beanstalk) waiting for a job, then run that job.  So the PHP script that gets exectuted "hangs" if you will until a job is available, and exits after it has finished the job.  So if at the command like I execute "service new_init_script start" it just chills at "Starting new_init_script:".  I'm assuming that's because worker-dashboard-queue.sh doesn't actually exit, it just keeps looping and executing that php script.  So the question is, is there a way to determine that worker-dashboard-queue.sh has run successfully, without exiting it? Or a way to exit it while still looping that PHP script?

I'm gonna bump the points up too since the question's gotten more in depth than I originally thought.

Yeah I'd noticed it also but you were faster then me : )  ther2s  typo at line 47.

I'm lloking int the issue you're mentioned too..

KeremE, any luck?  I think the fact that it's hanging is causing problems with the rest of the boot process; Apache and Webmin need to be manually started.  There may be other things that don't start too, but I haven't noticed.

Nevermind, ended up using the PEAR System_Daemon library to daemonize my PHP scripts directly.  Points to everyone for helping tho.

For reference:

http://kevin.vanzonneveld.net/techblog/article/create_daemons_in_php/
http://pear.php.net/package/System_Daemon