Running A Python Cron Job on Cloud Foundry

This repository demonstrates scheduling a Python script on Cloud Foundry using a traditional crontab within a Docker image.

Traditional cron daemons need to run as root and have opinionated defaults for logging and error notifications. This makes them unsuitable for running in a containerized environment like Docker. And Docker is sometimes preferable to Cloud Foundry buildpacks. So, instead of a system cron daemon, we're using supercronic to run the cron tab.

How it works

This application uses supercronic on the crontab file, all within a Docker container. The crontab file specifies a single cron job, which is to execute main.py every 10 seconds. You could add additional jobs by adding new lines to crontab that specify a schedule and command.

Since some Python tasks are a bit more complicated than printing datetime.datetime.now(), this example also demos installation of a few debian dependencies and just one python requirement.

The image based on this Dockerfile can be found on DockerHub, so you can push the app to cloud.gov with

cf push cf-cron-python --docker-image csmcallister/cf-cron-python

Then, after it builds, use cf logs cf-cron-python --recent to see the print messages.