skylar-anderson / docker-cron-example

Example implementation of cron jobs on Docker/Aptible

aptible/cron-example

Example implementation of cron jobs on Docker/Aptible

Installation and Usage

git clone https://github.com/aptible/docker-cron-example
cd docker-cron-example/
make run

The example will print "aptible/docker-cron-example" once every minute.

Including Within An App On Aptible

To include within an Aptible app, copy the following 5 body lines of the Dockerfile to your own Dockerfile:

RUN apt-get -y install rsyslog
ADD files/etc/crontab /etc/crontab
ADD files/bin/start-cron.sh /usr/bin/start-cron.sh
RUN chmod +x /usr/bin/start-cron.sh
RUN touch /var/log/cron.log

• Installs rsyslog http://www.rsyslog.com/
• Copies crontab from repo/app data to Docker
• Copies start-cron.sh from repo/app data to Docker
• Adjusts permissions
• Creates log file at /var/log/cron.log

Then, copy files to your own repo, editing files/etc/crontab with your own task, and * * * * * with your own desired job schedule.

Crash course on cron(tab) job schedules https://en.wikipedia.org/wiki/Cron#Format. Consider the asterisk (*) like a wild card. Left to rigt the argument positions are:

[Minute Arg] [Hours Arg] [Day of month arg] [Month arg] [Day of week]

To run every 5 minutes:

*/5 * * * *

To run every 5 hours:

0 */5 * * *

Finally, add an entry in your Procfile for the new cron process:

cron: /usr/bin/start-cron.sh

Copyright and License

MIT License, see LICENSE for details.

Copyright (c) 2015 Aptible and contributors.