Cron python script not executing

Question

I have read a few posts on this but I could not find help in them.

I have a python script that sends mail using smtplib. It works when invoked from the command line.

I have #!/usr/bin/python as the first row and can run it both using /home/pi/ipsender.py and python /home/pi/ipsender.py.

My crontab is */1 * * * * /home/pi/ipsender.py but I have also tried */1 * * * * python /home/pi/ipsender.py and */1 * * * * /usr/bin/python /home/pi/ipsender.py.

Doing which python I get /usr/bin/pyhton and running python from the command line I can import and use smtplib just fine.

In /var/log/syslog I get:

Nov 27 22:57:01 raspberrypi /USR/SBIN/CRON[3764]: (pi) CMD (python /home/pi/ipsender.py)
Nov 27 22:57:01 raspberrypi /USR/SBIN/CRON[3763]: (CRON) info (No MTA installed, discarding output)

And I'm guessing the No MTA... is just about Cron not sending emails about what it's doing, or isn't it?

How do I run this script.

[Edit]

The permission of the script is

-rwxr-xr-x 1 pi   pi       551 Nov 27 22:37 ipsender.py

[Edit2] Using the tip from D Read I'm getting the following log

starting
Traceback (most recent call last):
  File "/home/pi/ipsender.py", line 7, in <module>
    ifconfig_output = sp.check_output(["ifconfig", "wwan0"])
  File "/usr/lib/python2.7/subprocess.py", line 537, in check_output
    process = Popen(stdout=PIPE, *popenargs, **kwargs)
  File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1249, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

Suggesting to me that there is something with the path. Although in /etc/crontab I have PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin and which ifconfig gives /sbin/ifconfig. So that should not be a problem right?

If you try "sudo su", and then run the script manually, does it work? — martincho, Nov 27 '12 at 22:49
Are you running in crontab from the same user as you tried in shell? Ensure that rights and environment are the same in both cases. — unixmin, Nov 27 '12 at 23:59

score 6 · Accepted Answer · answered Nov 27 '12 at 22:50

6

There are lots of gotchas with crons... In the absence of the MTA, see the output an easier way - try piping it to a file:

*/1 * * * * /home/pi/ipsender.py > /home/pi/ipsender.log 2>&1

Start your python file off with a print 'starting' to see if the python file starts to execute ok.

answered Nov 27 '12 at 22:50

D Read

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Well, I can see the script failing [Edit2] but I can't figure out why. – evading Nov 27 '12 at 23:10
Your script is run from the `pi` user's crontab which runs in a different shell to `/etc/crontab`. I think if you put the `PATH=` line in the same crontab as your script it might work. Alternatively try specifying an absolute path to `ifconfig` in your script. – D Read Nov 27 '12 at 23:37

score 1 · Answer 2 · answered Nov 27 '12 at 22:50

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Try to save the STDOUT and STDERR of the script:

*/1 * * * * /home/pi/ipsender.py &> /tmp/ipsender.log

answered Nov 27 '12 at 22:50

László Andrási

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Cron python script not executing

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