Azure WebJob not accepting a valid(?) CRON expression

Question

I used crontab.guru to create a very simple CRON expression with the desired behavior to execute every day at 3:15 (AM) and this is the result: 15 3 * * *

Unfortunately for me, in Azure Portal this does not work, but if I add a leading 0 to my expression as such, 0 15 3 * * *, Azure will accept it, while crontab.guru will tell me it is wrong. The specification according to crontab.guru is: minute hour date month weekday.

The questions..

• From where comes the discrepancy?
• Is it Microsoft that in their traditional ways have a proprietary implementation with a leading zero?
• If the standard is minute hour date month weekday, what does the leading zero describe?

Kalbli

Answer 1

Have a look at the documentation:

• Create a scheduled WebJob using a CRON NCRONTAB expression
• Timer trigger for Azure Functions

The NCRONTAB expression is composed of 6 fields: {second} {minute} {hour} {day} {month} {day of the week}. A CRON expression has only 5, without the seconds.

So the first 0 describes the seconds.

*    *    *    *    *    *  command to be executed
┬    ┬    ┬    ┬    ┬    ┬
│    │    │    │    │    │
│    │    │    │    │    │
│    │    │    │    │    └───── day of week (0 - 7) (0 or 7 are Sunday, or    use names)
│    │    │    │    └────────── month (1 - 12)
│    │    │    └─────────────── day of month (1 - 31)
│    |    └──────────────────── hour (0 - 23)
│    └───────────────────────── min (0 - 59)
└────────────────────────────── second(0 - 59)

Eightieth

Thank you! I realized that it was seconds after a while, but why does it differ from place to place? Are there different standards? Transitional/Strict ? :) – Kalbli

sorry Marcus I don't really know, hopefully someone from the Microsoft team will add a comment ^^ – Eightieth

i have created a webjob recently but it is not triggering automatically even setting correctly the CRON expression, i have also tried creating a settings.job file. What should i do to make it work? – Uprear

Can you create a new question and post your code please ? – Eightieth

Yes there are different standards. See for instance another cronmaker that assumes the seconds is the first: cronmaker.com – Germane

Use this one which follows the same standarts as in webjobs: cronexpressiondescriptor.azurewebsites.net – Germane

This page has better documentation: learn.microsoft.com/en-au/azure/azure-functions/… – Holbein

The second docs page linked has been recently updated (my PR was accepted, yay) to specifically state that these are 6 part NCRONTAB expressions and not the usual 5 part CRON expressions. I've asked for the first link to be corrected in the same way. If the snippet in your answer was from one of those two pages, you may want to update it to match any docs updates. – Exaltation