Hooks

Run any shell command after a successful service start or unsuccessful service exit.

Events

Hook	When
onstart	Service reaches readiness or a one-shot completes successfully
onerr	Service exits unsuccessfully before or after readiness

Configuration

services:
  postgres:
    command: "postgres -D /var/lib/postgres"
    hooks:
      onstart:
        command: "echo 'Postgres started'"
        timeout: "10s"
      onerr:
        command: "/usr/local/bin/report-crash postgres"

Hooks inherit service environment variables.

Execution

• Run via sh -c
• Fire-and-forget (no retries)
• Timeout kills with SIGKILL
• Failures logged but don't affect service

Behavior

Scenario	Hooks
Start and readiness success	onstart
Successful one-shot completion	onstart
Spawn or readiness failure while running	None
Clean exit	None
Manual stop	None
Unsuccessful exit before or after readiness	onerr
Successful automatic restart	onstart

Tips

• Keep commands short
• Use env vars for secrets
• Make repeated actions idempotent