How to monitor Fly.io scheduled work jobs
A Machine can fail to start or run in a different region than expected. Heartbeats reveal missing completions.
Report success and failure
Create a check and set PING_URL to its private URL. Replace the example command with your actual task. These examples preserve command failure and do not let a failed reporting request turn a successful job into a failure.
#!/bin/sh
# PING_URL is the private URL copied from your check.
: "${PING_URL:?Set PING_URL first}"
rid="$(date +%s)-$$"
report() { curl -fsS -m 10 --retry 3 "$PING_URL/$1?rid=$rid" >/dev/null 2>&1 || :; }
trap 'code=$?; report "$code"; exit "$code"' EXIT
report start
sleep 1
/app/backup.sh
Connect it to Fly.io scheduled work
In your job Machine image, make the one-shot entrypoint the wrapper.
ENTRYPOINT ["/bin/sh", "/opt/monitored-job.sh"]These are integration fragments for an existing project, not a full application. Set the URL in the job’s environment, keep credentials private and ensure the runtime has the dependencies shown.
Things to watch
The shell examples wait one second between start and work to respect the per-check rate guard. For very short tasks, completion-only pings avoid that delay. A killed process may never send a failure ping; the completion deadline catches the missing run instead.
Test the setup
- Run a successful task and confirm the check turns up.
- Force a nonzero exit or exception and verify the check turns down.
- Stop the scheduler after one success and wait for the expected run plus grace.
Set the schedule to your task’s completion cadence, allowing for runtime and queue delay. Use the cron helper to review your calendar schedule.
Questions about Fly.io scheduled work
Where should the heartbeat run?
Which grace period should I use?
Does this test the result of my work?
Platform reference: official Fly.io scheduled work documentation. Adapt fragments to your installed version.