Question

How to limit a script or program execution time using bash or sh

Asked by: flob9

Hello,

I have some scripts running on a debian server, called by various cronjobs, wich call php scripts.

Sometimes the php scripts are stucked for some hours, and I need to avoid it.

I already use the trap mechanism to avoid overlapping of the scripts, but in the cases of previous cron beeing stucked, nothing is working anymore.

I attach the code of the bash script. Cannot give you the php scripts, wich is very huge and access mysql database, lucene/solr engine, and files.

The ideal solution could be to stop the execution of the inner script/program if the time exceed the delay param.
I know I could kill the previous cron if i find the lockfile, but this seems bad practice.

Any help appreciated.

#!/bin/bash
 
#param delay in minutes, can be 15,30,60,120,240 ... determines the duration and id of the script
# cron 15 can overlap cron 30, but not another cron 15
DELAY=$1
 
 
LOCKFILE=/tmp/cronfeed_${DELAY}.lock
 
[ -f $LOCKFILE ] && exit 0
 
trap "{ rm -f $LOCKFILE ; exit 255; }" EXIT SIGINT SIGTERM
 
touch $LOCKFILE
 
pushd /path/to/the/scripts > /dev/null
 
thescript 2>&1 >> /var/log/cronf${DELAY}.log
 
popd > /dev/null
 
exit 0

                                  
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Asked On
2009-08-10 at 15:46:12ID24641643
Tags

linux bash cron script debian

Topics

Linux Programming

,

Debian Linux

,

Bourne-Again Shell (bash)

Participating Experts
1
Points
500
Comments
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Answers

 

by: TintinPosted on 2009-08-10 at 16:50:37ID: 25065171

Why do you use pushd/popd?  I can't see any purpose for them in your script.

Anyway, if you want a timer, you can do something like:

#!/bin/bash
 
#param delay in minutes, can be 15,30,60,120,240 ... determines the duration and id of the script
# cron 15 can overlap cron 30, but not another cron 15
DELAY=$1
 
let timer="$DELAY * 60" 
 
LOCKFILE=/tmp/cronfeed_${DELAY}.lock
 
[ -f $LOCKFILE ] && exit 0
 
trap "{ rm -f $LOCKFILE ; exit 255; }" EXIT SIGINT SIGTERM
 
touch $LOCKFILE
 
cd /path/to/the/scripts 
 
thescript 2>&1 >> /var/log/cronf${DELAY}.log &
pid=$!
sleep $timer
 
ps -p $pid >/dev/null && kill $pid
rm -f $LOCKFILE
 
 
 
 
                                              
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by: flob9Posted on 2009-08-10 at 23:34:06ID: 25066580

I used pushd/popd when running it outside the cron, but, you're right, it is useless now.

I'll try the timer trick, this seems promising.

Thanks

 

by: flob9Posted on 2009-08-11 at 01:07:15ID: 31613972

Thanks, it works

 

by: flob9Posted on 2009-08-11 at 03:15:59ID: 25067470

Hmmm, I closed the question too fast. I have an issue when the script ends too fast, the timer keep waiting for nothing ...

I'll reopen a question :)

20120131-EE-VQP-002

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