A Cron Scheduler for Tutum

##Intro

To use you simply need to add a link to each service you wish to schedule and then an environment variable that starts with the capitalized name of the service and which ends in _CRON_SCHEDULE, e.g.:

  environment:
    TEST_CRON_SCHEDULE: '*/5 * * * *'
  links:
    - test

You'll also want to make sure you add the global role on tutum-cron:

  roles:
    - global

Everything you really need to know is in the tutum.yml file, just take a look and you'll get the idea. So just press the button and get going:

##Schedules

Everything you need to know about scheduling can be found in the fcrontab documentation but simply you can use the cron syntax you are familiar with:

* * * * * *
| | | | | | 
| | | | | +-- Year              (range: 1900-3000)
| | | | +---- Day of the Week   (range: 1-7, 1 standing for Monday)
| | | +------ Month of the Year (range: 1-12)
| | +-------- Day of the Month  (range: 1-31)
| +---------- Hour              (range: 0-23)
+------------ Minute            (range: 0-59)

You can of course use an online generator such as http://crontab-generator.org/ to help you along.

##Further Info

This scheduler uses fcron to schedule commands, fcron is great because like anacron it catches up with running services it misses while down. So it's totally okay to change the config and restart the server.

The base container uses work originally taken from https://github.com/just-containers/base-alpine credit to john@jrjrtech.com this provides us with the S6 supervisor which this image uses to run cron, dnsmasq and the main run.sh script.

The real base of this image though is Alpine Linux brought to Docker via Glider Labs.