Migrate cron expression to another timezone

[jmrozanec]

I need something like below:

newCronExpression = convert (localCronExpresn,fromLocalTZ, "UTC")

Is it possible using cron-utils?

Let me give an example:

My local timezone is IST i.e. GMT+5.30.

Current local time is: 11:20 AM.

I want a job to run in 45 min of every hour.

So, my cron expression: 45 * * * *

Hence I am expecting my job to run after 25 min ( as starting time is 11:45 AM)

but my job is running as per UTC, because of oozie.

Current time in UTC : 05:50 AM

As per cron expression 45 * * * , the starting time will be 06:45 AM at GMT.

So, the job will be actually started after 55 min.

Expected : After 25 min

Actual : After 55 min

So,

if I am converting my local cron expression 45 ** * * to 15 * * * * at GMT, then actual waiting period will be same as expected.

This feature was originally reported at cron-utils-examples by @jrphub

[jmrozanec]

The same use case is reported at Stackoverflow

[SvenssonWeb]

Is this really supposed to be a part of this utility?
Doing the timezone conversion before building the cron expression would probably be easier for everyone.
I could see the use case for this if you are writing the cron expression by hand and plugging it into a service. But is that really how this should be done?
Adding cron expression to be run on server side, should be expected to run on server time, And if you build some UI to craft the schedules, you could do the time conversion before inserting the values into cron.

[jmrozanec]

@SvenssonWeb there may be different ways to do this - we agree on that. Nevertheless, this use case may not be that straightforward: we may have cases where converting a cron expression to another timezone involve day changes, DST, etc.
We understand this could be valuable for anyone who has servers in multiple time zones and needs to execute tasks at the same time, providing a single cron expression and without a central scheduler. Tweaking multiple cron expressions for different timezones would be tedious and error prone: if the library can provide this, we may save some work and headaches to someone.