Python program not running from cron

spiri · 03-06-2006, 05:38 PM

Hi,
I made a small program in python to send mail (without the need of mail server in the running machine)
it work fine if started from the command line but executed from a bash script in a cron schedule it
doesn't run (send the mail) but the bash script runs ok.

I made a lot of tests.

Any help will be very grateful.

Thanks.

timmeke · 03-07-2006, 01:39 AM

In many cases, when a program runs fine at your regular command line and doesn't work when used in a cron schedule, the problem is the setting of the environment variables.
Cron uses it's own, limited settings of environment variables. If your Python program requires any, please make sure that you set them up properly. The easiest way for you to do this is to include some exports in
the bash script that runs the Python program.

Maybe the man pages for python show you what environment settings you'll need. Or simply post the contents of your environment settings (output of command

Code:

env

at command line).

spiri · 03-07-2006, 10:38 AM

Here it goes my env output:

Quote:

TERM=xterm
SHELL=/bin/bash
SSH_CLIENT=192.168.0.5 3078 22
SSH_TTY=/dev/pts/0
USER=root
LS_COLORS=no= (ommited)
MAIL=/var/mail/root
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/bin/X11
PWD=/home2/tmp
LANG=en_US
PS1=\h:\w\$
SHLVL=1
HOME=/root
LANGUAGE=en_PT:en_US:en_GB:en
LS_OPTIONS=--color=auto
LOGNAME=root
SSH_CONNECTION=192.168.0.5 3078 192.168.0.1 22
_=/usr/bin/env
OLDPWD=/

Thanks for your replay.

timmeke · 03-08-2006, 02:11 AM

And what are your PhP e-mail settings (probably in a file called php.ini) and commands?

Are you sure that crontab finds and runs your program? ie do you see a PhP error message? Or a shell error message (like "file not found")?

Please post your crontab settings as well.

From your "env" output, I don't see much abnormal. The only suspects for me, are $PATH and $PWD so far.

spiri · 03-08-2006, 09:21 AM

Hi,
I'am not using PhP!
this bash script calls the python program,
it makes a file with the df output

Code:

#!/bin/bash
rm diskfree.txt -f
echo `date` > /var/log/diskfree.txt
df -h >> /var/log/diskfree.txt
python anexo_shell.py /var/log/diskfree.txt

this is the python code
it sends the diskfree.txt by mail.

anexo means attachment

Code:

import smtplib
import sys
from email.MIMEMultipart import MIMEMultipart
from email.MIMEBase import MIMEBase
from email.MIMEText import MIMEText
from email.Utils import COMMASPACE, formatdate
from email import Encoders
import os

def sendMail(to, subject, text, files=[],server="mail.mypythontest.com"):
    assert type(to)==list
    assert type(files)==list
    fro = "<xeo@mypythontest.com>"

    msg = MIMEMultipart()
    msg['From'] = fro
    msg['To'] = COMMASPACE.join(to)
    msg['Date'] = formatdate(localtime=True)
    msg['Subject'] = subject

    msg.attach( MIMEText(text) )

    for file in files:
        part = MIMEBase('application', "octet-stream")
        part.set_payload( open(file,"rb").read() )
        Encoders.encode_base64(part)
        part.add_header('Content-Disposition', 'attachment; filename="%s"'
                       % os.path.basename(file))
        msg.attach(part)

    smtp = smtplib.SMTP(server)
    smtp.sendmail(fro, to, msg.as_string() )
    smtp.close()


sendMail(
        ["xeo@mypithontest.com"],
        "Registo de backups","Mensagem automatica.",
        [sys.argv[1]]
    )

If I run the script it works as expected, by if it as to be run by cron
the script create the file output but don't send the mail.

Thanks a lot for the help.

timmeke · 03-08-2006, 09:59 AM

Sorry, I mistook your thread for another one. Of course you're not working with PhP but with Python.

There may be an easier way to send the mails you want (ie using /bin/mail or the "nail" program you can download for free). But let's try to make the Python program work first.

Do you get any error messages? Cron usually sends them by mail to the user who submitted the cron job, unless you configured it otherwise. But you may be able to redirect standard output of the cron job into a file so that you can read it afterwards.

Furthermore, does Python know where to find it's libraries (for the import-statements)?

You can also try putting the full path to the Python interpreter in your Bash script, rather than just putting "python". When running a program using cron, it doesn't use your normal $PATH settings, so it may be unable to find your python executable.

dive · 03-08-2006, 10:16 AM

Quote:

Originally Posted by spiri

Code:

#!/bin/bash
rm diskfree.txt -f
echo `date` > /var/log/diskfree.txt
df -h >> /var/log/diskfree.txt
python anexo_shell.py /var/log/diskfree.txt

You probably need to put full path to diskfree.txt, python and anexo_shell.py
Cron is notorious for not knowing $PATH

timmeke · 03-09-2006, 02:02 AM

Quote:

Originally Posted by dive

Cron is notorious for not knowing $PATH

Indeed it is and for obvious and clearly documented reasons.
This is mentioned explicitly in the man pages of cron and/or crontab.