Issue
We work on a product whose software development team applies patch on every 1st Friday of the month. We have written some tests that we run on the Sunday after the patch is applied. So to automate the same on Jenkins, we would need a cron that runs on 1st Sunday after the 1st Friday of the month has passed.
Right now we just update our Jenkins each month considering dates, but can we automate this?
Thanks
Solution
Naively, one would suppose that 0 3 1-7 * fri would be "3am on the Friday that falls inside the first week of each month", and then we could use the similar logic to construct 0 3 3-9 * sun, for the Sunday that follows two days after such a Friday.
Unfortunately, this does not work, because day of week and day of month are taken as a disjunction by the cron specification; which means, the above would trigger not on the Sunday following the first Friday in a month, but on every Sunday, and also every day from 3rd to 9th.
Due to this twist in cron spec, what you ask is not possible by cron alone. The easiest way to untangle this is to separate the two requirements, ask the cron to track one of them, and manually test the other: either use 0 3 3-9 * * and then manually test in your script whether the day is Sunday and exit without performing your task if it is not, or use 0 3 * * sun and manually make sure the date is between 3rd and 9th.
Answered By - Amadan Answer Checked By - Gilberto Lyons (WPSolving Admin)