Simple cron in Go.

Use with one or more *.yml files, formatted like so:

cron:
- description: some minutely task
  command: echo minutely; date
  lock: yes

- description: some hourly task
  command: echo hourly; date
  minute: 0
  lock: yes

- description: some daily task
  command: echo daily; date
  hour: 1
  minute: 0

- description: some weekly task
  command: echo weekly; date
  weekday: 0
  hour: 2
  minute: 0

- description: some monthly task
  command: echo monthly; date
  day: 5
  hour: 3
  minute: 0

- description: some hourly task with specific working directory
  command: echo task; pwd; date
  pwd: /tmp
  minute: 0

- description: some minutely task with a 30s timeout
  command: possibly-long-running-command
  timeout: 30  # seconds

Each job will run when the server's wall clock hits the exact specified time. Omitted time constraints mean no constraint.

Weekdays start with 0 (Sunday). 7 is NOT aliased to Sunday.

Command is interpreted with /bin/sh via -c.

pwd specifies command's working directory. It is optional; defaults to gron's own cwd.

Each task runs independently of the others that may have started at the same time - there is no blocking. Failures are simply logged - there is no retry or backoff.

If lock is set to yes (default is no), a simple locking mechanism is used. While an instance of the task is still running, the task will not be re-run. So an hourly task, that runs for 90 minutes, will run 12 times per day.

If you specify timeout, the task will be leashed to run for up to that many seconds, and will get a SIGKILL if it does not complete within these bounds.

All of these features are safe to be combined together.

Pass -d to get more debug spam with nicer formatting.

For things like manipulating the command's environment, dropping privileges, chrooting, etc. refer to the excellent utilities such as env(1), gosu, chpst(1), and so on.

You can (optionally) report failing jobs using Sentry. The DSN can be specified by settings the SENTRY_DSN environment variable, or by adding a snippet to one of the config files (which takes precedence):

report:
  SENTRY_DSN: "https://1234:[email protected]/9"
cron:
- description: some job ...