Dagster does not allow specifying time zone along hour_of_day and minute_of_hour in scheduled partitioned jobs about dagster

[OmranKaddah]

Just a note to those who are reading this and wondering what to do about the time zone. This can be set in DailyPartitionsDefinition. @garethbrickman thanks for the detailed explanation.

[garethbrickman]

The reason you cannot specify both the cron_schedule/execution_timezone parameters and the day_of_month/day_of_week/hour_of_day/minute_of_hour parameters at the same time when creating a schedule from a partitioned job is due to the design of the Dagster scheduling system. The build_schedule_from_partitioned_job function is designed to create a schedule that aligns with the partitioning of the job. This means that the schedule's frequency and timing should match the intervals defined by the job's partitions.

When you define a partitioned job, you are effectively setting up a structure for how the data should be processed over time. For example, if you have a job that processes data daily, you would set up daily partitions. The schedule for this job should then naturally run once per day to process each partition.

The day_of_month, day_of_week, hour_of_day, and minute_of_hour parameters are used to specify the exact time within the partition's interval when the job should run. These parameters are meant to provide a convenient way to set the schedule based on the partition's natural frequency without having to manually calculate the corresponding cron expression.

On the other hand, the cron_schedule parameter allows you to specify a custom cron expression that defines the schedule's frequency and timing in a more granular and flexible way. The execution_timezone parameter is used in conjunction with cron_schedule to ensure that the schedule runs at the correct local time, taking into account time zone differences.

Allowing both sets of parameters to be specified would create ambiguity and potential conflicts in the scheduling logic. For instance, if you set a daily partition but then provide a cron expression that runs every hour, it would be unclear how the schedule should reconcile the hourly cron expression with the daily partitioning of the job.

To maintain clarity and prevent such conflicts, Dagster requires you to use either the partition-based parameters or the cron-based parameters , but not both. This ensures that the schedule is consistent with the partitioning of the job and that there is a single source of truth for when and how often the job should run.