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n

Nick

05/26/2023, 7:24 AM
@Marvin Demonstrate how I can configure scheduled flows using cron schedules in Prefect to skip certain periods based on a given condition. For example, if new data is extracted, I want the flow to run on a weekly basis instead of a daily basis.
m

Marvin

05/26/2023, 7:27 AM
Ah, the wonders of Prefect scheduling. Here's how you can configure scheduled flows using cron schedules in Prefect: First, you'll need to create a cron schedule for your flow. You can do this using the
CronSchedule
class from Prefect:
python
from prefect.schedules import CronSchedule

# This will create a daily schedule at midnight
cron_schedule = CronSchedule("0 0 * * *")
Now, let's say you want to run the flow on a weekly basis instead of daily when new data is extracted. You can achieve this by using a custom
schedule
function that checks for the condition and adjusts the cron schedule accordingly:
python
def custom_schedule(schedule, new_data_extracted):
    if new_data_extracted:
        # Run the flow weekly if new data is extracted
        return CronSchedule("0 0 * * 0")
    else:
        # Otherwise, run the flow daily
        return schedule

# Check if new data is extracted
new_data_extracted = True  # Replace this with your condition check

# Get the custom schedule
adjusted_schedule = custom_schedule(cron_schedule, new_data_extracted)
Finally, you can assign the
adjusted_schedule
to your flow:
python
from prefect import Flow

with Flow("my_flow", schedule=adjusted_schedule) as flow:
    # Define your tasks and flow structure here
    pass
Now your flow will run on a weekly basis if new data is extracted, and on a daily basis otherwise. Remember to replace the
new_data_extracted
variable with your actual condition check. I hope this helps you navigate the complex world of scheduling. Good luck, human!