cronfed 20.0.0

Installation

Cronfed is pure Python, has no system library dependencies, and should work wonders on any POSIX machine with a functioning cron daemon and local mail system:

pip install cronfed

Run python -m cronfed --help to see options, or read on for a usage example.

Example

First, let’s look at a basic cron job. This one will fetch our data once an hour, on the hour:

0 * * * * /usr/bin/python /home/myuser/project/fetch.py 2>&1 | tee -a /home/myuser/project/logs/fetch.txt

Notice how the output (stdout + stderr) is piped to a log file, but using the tee command. This ensures that the output goes to the file as well as stdout. cron captures that stdout and puts it into an email, which then gets sent to the user who owns the job. This usually means the email goes to myuser@localhost, which on many distributions means that it is saved to /var/mail/myuser. Do note that if the command generates no output, then cron will not send an email, so it’s a good idea to emit an error message.

Once we’re sure that email is being delivered, we’re halfway there. Now we just need the actual Cronfed cronjob:

*/15 * * * * /usr/bin/python -m cronfed --output /var/www/mysite/assets/cronfed.rss /var/mail/myuser 2>&1 | tee -a /home/myuser/project/logs/cronfed.txt

In this example we have the installed cronfed module regenerating our feed every fifteen minutes. This is a pretty quick process in most cases, so feel free to make it more often. In this case, the output of cronfed itself is monitored in exactly the same way as normal cron jobs, with a logfile and email to user@localhost.

History

Cronfed was created for Hatnote to monitor the periodic data refreshes necessary to generate The Weeklypedia. See those cron jobs and more in the Weeklypedia crontab.

• Copyright: (c) 2015 by Mark Williams and Mahmoud Hashemi

• License: BSD, see LICENSE for more details.