from Hacker News

Show HN: My weekend project – simple cron monitoring

by augustflanagan on 6/19/14, 6:34 PM with 30 comments

• by encoderer on 6/19/14, 6:38 PM

  Hey HN! My friend augustflanagan and I both had a need for some really simple cron monitoring. A way to monitor our critical jobs without configuring Nagios first. We wanted a simple SAAS monitoring solution that we could trust to alert us right away when a job isn't running on schedule. 

  We mentioned this to a couple of friends who said they needed the same simple monitoring. Having people tell you they need something is a great motivator, so we built cronitor in a couple of weekends and are putting it out there. We'd love feedback and suggestions on how to make it better. Thanks!

• by vijayaggarwal on 6/19/14, 7:40 PM

  Writing a fail-safe cron is an incredibly hard job as crons are infamous for failing rather silently. The cron script writer must take a very pessimist approach and handle every possibility of error. Even then, some scenarios are easy to miss. Following are some cases I have come across often:

  1. crash - any runtime error that causes your script to stop execution abruptly.

  2. un-handled, non-crashing error - db connection failure, remote api failure, file not found, etc. The script may continue execution, the results may not be logically correct.

  3. concurrent execution - What if an instance of cron is not over by the time the next instance should start? crontab will simply start the next instance.

  4. internet connection error - even the notification mechanism will fail if it depends on an active internet connection.

  Your service is a very valuable one, and a challenging one too I believe. You can do a lot many things in cron monitoring and reporting.

• by eam on 6/19/14, 6:52 PM

  I really liked the plan names especially the top plan, NSA (Monitor Everything). Got a good laugh out of it. :)

• by gmjosack on 6/19/14, 7:21 PM

  One way I've solved this in the past which is a bit hacky but novel and fun was to set the MAILTO to some e-mail address like cron-error@ and use the local postfix process to map that e-mail to a command via transports. This allows us to inject cron errors into our exception tracking system and alert minimizing the amount of cron storming to our inboxes.

• by tyrionaura on 6/19/14, 7:01 PM

  Good to have the "one is always free" plan, will give it a try.

• by cheeken on 6/20/14, 4:07 AM

  Neat little service! I'd be careful about &&'ing commands together (as in the timing example) should one of the pre-command curl calls fail. It would be a serious kick in the pants if the service to monitor the health of your cron jobs was (indirectly) responsible for preventing them from running.

• by crazyiiiiii on 6/19/14, 8:00 PM

  Any chance of selling a version I can host myself? Or, even better, making it open source? Congrats on shipping tho!

• by yansuck on 6/19/14, 11:00 PM

  I really doubt this is just a weekend project. I am sorry but titles like this has been getting on my nerves.

• by 0x420 on 6/19/14, 6:46 PM

  Looks cool. The "Pick this Plan" buttons at the bottom don't appear to be working, though. I'm not sure if you're aware of that.

• by acron0 on 6/19/14, 6:54 PM

  Awesome idea but the price outweighs the pain factor, for me.

• by spncr2 on 6/19/14, 7:20 PM

  I've gotta hand it to https://deadmanssnitch.com. Free referrals! :)