Running python file from inside a bash script through cron

Question

I have created a bash script which first activates a python virtual environment, and then runs a python file. When I execute the bash script manually, the python file runs as intended. Bash script code:

sample.sh

#!/usr/bin/env bash

source ./project/bin/activate
python3 /home/abc/project/server/sample.py

However, when I try to run this bash script using cron, the python file does not execute. cron:

16 12 * * * /home/abc/sample.sh > /home/abc/bulkcat.log 2>&1

When this cron triggers at the specified time, the python file inside my bash script does not run and the log file is empty.

What seems to be wrong with my code?

try giving full path to python. ex: /usr/bin/python3 /home/abc/project/server/sample.py — Rakesh
– Rakesh, Commented Mar 15, 2018 at 7:01
@Rakesh Giving the full Python path gave me this error: SyntaxError: unknown decode error — Manas Chaturvedi
– Manas Chaturvedi, Commented Mar 15, 2018 at 7:36

sebastian · Accepted Answer · 2018-03-15 07:02:39Z

1

It might well be the relative path you're using in the source command. Cron will run your script from a different directory, so

source ./project/bin/activate

will likely not be a valid path. Try

source /home/abc/project/bin/activate

... guessed path based on the full path in your python3 ... line.

answered Mar 15, 2018 at 7:02

sebastian

9,71628 silver badges56 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Manas Chaturvedi Over a year ago

I tried giving the absolute path for activating my virtual environment, but this didn't seem to solve my issue.

ElmoVanKielmo · Accepted Answer · 2018-03-15 10:10:50Z

Cron writes logs and you can find the error which occured when it tried to execute the task - an answer to this question mentions usual locations where to look for these logs.

Most common issues are:

cron is using sh and not bash ignoring shebang in your script - you can try configuring your cron job like 6 12 * * * /bin/bash /home/abc/sample.sh > /home/abc/bulkcat.log 2>&1
the script not having permission to be executable set - this can be fixed by running chmod 700 /home/abc/sample.sh or chmod 755 /home/abc/sample.sh - the latter should be used only if you want to allow other users to read and execute your script
as mentioned already in another answer, always use absolute paths in cron job as cron might execute your script from other directory than you expect - I'm also using wrapper bash script in such scenarios - I give absolute path to the script in cron job and the first thing the bash script does is cd /desired/work/directory

Collectives™ on Stack Overflow

Running python file from inside a bash script through cron

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related