Python scripts with Cronwatch
This check expects a Python job every hour. The Python snippet uses only the standard library, so there is nothing to install on the machine that runs the script.
- Create the check with an hourly schedule and 15 minutes of grace.
- Copy the Python snippet and call urlopen after your work finishes.
- Wrap the work in try/except and request the /fail URL in the except block to alert on errors immediately.
- Run the script once and confirm the check turns UP.
What to know
Scripts started by cron, Task Scheduler, a container or a hosting platform tend to fail outside anyone's view: an expired API token, a changed schema or a missing package raises an exception into a log that nobody reads. A ping at the end of the script is the simplest proof that it ran to completion.
Use urllib.request from the standard library with a timeout so the script never hangs on the ping. If requests is already a dependency, requests.get(url, timeout=10) works the same. Put the ping after the work, not before, so it means "finished" rather than "started".
For long-running jobs, ping the /start URL at the beginning as well. Cronwatch then shows how long each run took, which is how you spot a job that is slowly getting slower before it starts overlapping with the next run.
Updated · Cosmovex
Questions
Do I need to install a package?
No. The snippet uses urllib from the Python standard library.
How do I report an exception?
In your except block, request the check URL with /fail appended. The check goes down immediately and you get an alert.
Will a slow network block my script?
Not for long. The snippet sets a 10-second timeout; wrap it in try/except if you never want monitoring to raise.
Does it work on serverless schedules?
Yes. Any scheduler that can make an HTTPS request at the end of a run can ping a check.
The free plan covers everything on this page. Cronwatch Pro ($5/mo, billed monthly) is described on the Cronwatch page.
