Convox | Scheduled Tasks

Convox can set up cron-like recurring tasks on any of your application processes. This can be useful for background work like data dumps, batch jobs, or even queueing other background jobs for a worker.

Configuring tasks

Scheduled tasks are configured in docker-compose.yml using labels in the convox.cron namespace. The label format is:

convox.cron.<task name>=<cron expression> <command>

task name is a unique name for each task that you choose. Task names may not be reused within the same application process and may only contain alphanumeric characters and dashes.
cron expression describes the schedule on which the task will be invoked. See "Cron expression format" below for more info.
command is the command to be run in this process. Before configuring the task you can test that your command works by running convox run <process name> <command>.

Example: to run the command bin/myjob every hour on the web process, you would configure the label like this:

web:
  labels:
    - convox.cron.myjob=0 * * * ? bin/myjob

Cron expression format

Cron expressions use the following format. All times are UTC.

.----------------- minute (0 - 59)
|  .-------------- hour (0 - 23)
|  |  .----------- day-of-month (1 - 31)
|  |  |  .-------- month (1 - 12) OR JAN,FEB,MAR,APR ...
|  |  |  |  .----- day-of-week (1 - 7) OR SUN,MON,TUE,WED,THU,FRI,SAT
|  |  |  |  |
*  *  *  *  *

Some example expressions:

See the Scheduled Events AWS documentation for more details.

Run options and persistence

The service a scheduled task is associated with does not necessarily need running containers all the time. The service can be scaled down to -1 or 0, and the scheduled task will "wake it up," causing a container to be created for the scheduled to task to run in, and exiting when it finishes.