Timer

A Timer spawns a Process on a schedule that is defined using cron syntax.

Definition

A Timer is defined in convox.yml.

    services:
      worker:
        build: ./worker
    timers:
      cleanup:
        command: bin/cleanup
        schedule: "0 3 * * *"
        service: worker

Attributes

Name Required Description
command yes The command to execute once the Process starts
schedule yes A cron formatted schedule for spawning the Process. All times are UTC
service yes The name of the Service that will be used to spawn the Process
concurrency no It specifies how to treat concurrent executions of a job that is created by this cron job. The default value for this field is Allow if is not defined. Check this doc for more info.

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 (0 - 6) OR SUN,MON,TUE,WED,THU,FRI,SAT
|  |  |  |  |
*  *  *  *  *

Please notice that the smallest unit of time here is minute.

Using a Template Service

Timers can run against any Service, even one that is scaled to zero. You can use this to create a template Service for your Timers.

    services:
      web:
        build: .
        command: bin/web
        port: 5000
      jobs:
        build: ./jobs
        scale:
          count: 0
    timers:
      cleanup:
        command: bin/cleanup
        schedule: "*/2 * * * *"
        service: jobs
        concurrency: forbid

On this App the jobs Service is scaled to zero and not running any durable Processes.

The cleanup Timer will spawn a Process of the jobs Service to run bin/cleanup once every two minutes.