How to run Django cron in crontab?

Question

I have a Django application which uses django-cron (https://django-cron.readthedocs.io/en/latest/installation.html), and I need to execute python manage.py runcrons every 5 mins in AWS EC2 running on Ubuntu. I tried putting this command in crontab -e but nothing happens, is there something I missed?

*/5 * * * * source /home/user/.bashrc && source /home/user/django-apps/venv/bin/activate && python /home/user/django-apps/project/manage.py runcrons > /home/bongga-admin/cronjob.log

Solution

I'm not familiar with Django, but I'm seeing the next:

1. The default Cron's shell is /bin/sh.

2. The command source is synopsis to . within bash, but not in sh.

3. So sh -c 'source ...' will return an error, but && means if the previous command return true do the next one, apparently your command fails on this first part. You've redirected only the output of the last command to the log file, so probably it remains blank.

4. In addition I do not think you can successfully source .bashrc within sh.

5. Within crontab, the default vale of the envvar $PATH is /usr/bin:/bin. For all commands/scripts, that are located outside of these directories, you should apply the full path; you can export a new value of $PATH, before the job; or even you can use $(which my_command) instead of just my_command.

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According to the above, I suppose, your crontab entry must be something like:

*/5 * * * * bash -c 'source /home/user/.bashrc && source /home/user/django-apps/venv/bin/activate && python /home/user/django-apps/project/manage.py runcrons' > /home/user/cronjob.log 2>&1

• The last part 2>&1 will redirect also the errors to the log file.

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The other way, that I would prefer, is to create a simple script that will execute all these commands:

#!/bin/bash
source /home/user/.bashrc
source /home/user/django-apps/venv/bin/activate
python /home/user/django-apps/project/manage.py runcrons

The script should be executable:

chmod +x /path/to/script.sh

And the crontab will be more simple:

*/5 * * * * /path/to/script.sh > /home/user/cronjob.log 2>&1

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If the Cron job is triggered by the crontab of a specific user, and if you want to make the script more portable you can replace /home/user with the environment variable $HOME (keep in mind you need to use double quotes, when you work with variables in the shell).

Comments

[Jos]

Always provide full path names to your executables (in this case python).

[Vince Gonzales]

I've updated already to: /home/user/django-apps/venv/bin/python, but it's still not running

[Vince Gonzales]

Thank you!! It works now, although I just had to replace 'source' with './' to make it work inside the script. :)

[cwhisperer]

What about the deactivate? When the script is running every 5 minutes, you enter the env each time...