Question

I have a ‘long’ python script that takes roughly 45[min] to run. I use another (a ‘scheduler’ script) python script to run this long script. When I run the ‘scheduler’ script using the terminal, everything works perfectly (meaning, the ‘long’ script runs without any issues).

I had some struggles, but eventually succeeded adding the ‘scheduler’ script to run through cron every minute. so it now ‘runs’ other script and works OK.

Here is the problem: whenever a script (that is being ‘run’ by the ‘scheduler’) has a line that says:

print "hello"

or any ‘print’ statement, the cron job runs, but terminates after 20-30 seconds. When I remove any ‘print’ statements, cron runs the jobs normally and does not terminate.

I’d like to fix this situation, and have the scripts continue to run even if they have some ‘print’ statements in them. any hints how to do it?

P.S. from within the ‘scheduler’, I use

subprocess.Popen([sys.executable, command])

to ‘run’ all other python scripts.

Answer 1

I have a hunch that it’s due to the way cron handles stdout. How are you redirecting output?

From http://aplawrence.com/BDD/bbcronbasics.html:

OUTPUT

Normally the output of any program is
sent to STDOUT (standard out) and
usually winds up on someone’s display
screen. For jobs started by cron,
STDOUT will be directed to the local
mail subsystem, which means any output
generated by a cron job will be mailed
to the user owning the job. If this
is not desirable you should take steps
to redirect your cron job’s output to
a file. It is also suggested you
redirect STDERR (standard error) to a
file so as to be able to analyze any
anomalies in your cron job’s
execution.