Crontab fails to execute Python script

Question

crontab fails to execute a Python script. The command line I am using to run the Python script is ok.

These are solutions I had tried:

add #!/usr/bin/env python at the top of the main.py
add PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin at the top of crontab
chmod 777 to the main.py file
service cron restart

my crontab is:

PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin

*/1 * * * * python /home/python_prj/main.py

and the log in /var/log/syslog is:

Nov  6 07:08:01 localhost CRON[28146]: (root) CMD (python /home/python_prj/main.py)

and nothing else.

The main.py script calls some methods from other modules under python_prj, does that matter?

Anyone can help me?

have you tried "/usr/bin/env/python /home/python_prj/main.py" in your cron command? — Tjaart
Maybe your script is crashing before it can get anything done for whatever reason: lack of rights, executing in the wrong cwd? — Tjaart
redirect the output from the script to a file command >> /path/to/output.log 2>&1 otherwise check email that cron sends. — jfs
thanks for your reply, i tried to add the output.log, but there is nothing in this file. — yebw

thebjorn thebjorn · Accepted Answer · 2012-11-06T12:07:50

The main.py script calls some methods from other modules under python_prj, does that matter?

Yes, it does. All modules need to be findable at run time. You can accomplish this in several ways, but the most appropriate might be to set the PYTHONPATH variable in your crontab.

You might also want to set the MAILTO variable in crontab so you get emails with any tracebacks.

[update] here is the top of my crontab:

www:~# crontab -l

DJANGO_SETTINGS_MODULE=djangocron.settings
PATH=...
PYTHONPATH=/home/django
MAILTO="[email protected]"
...
# m h  dom mon dow   command
10-50/10 * * * *               /home/django/cleanup_actions.py
...

(running cleanup actions every 10 minutes, except at the top of the hour).

Crontab fails to execute Python script

3 Answers