@Marvin what are the limitations of chron scheduling in the prefect gui? I am trying to implement the following in order to schedule a deployment to run at at 9:00 AM on first Sunday of every month:

00 09 * * 7 [ $(date +\%d) -le 07 ]

Prefect uses the

croniter

library to handle cron-like scheduling, which supports most standard cron features. However, Prefect does not support certain advanced cron features, such as "R" (random) or "H" (hashed) keyword expressions and schedule jittering that some cron implementations offer. Your specific cron expression

00 09 * * 7 [ $(date +\%d) -le 07 ]

is not directly supported as it uses a shell command to check the day of the month. Prefect's cron scheduling in the GUI requires a valid cron string without such shell command extensions. To schedule a deployment to run at 9:00 AM on the first Sunday of every month, you may need to use a combination of cron and some additional logic in your flow to verify the first Sunday condition. Alternatively, consider using Prefect's RRule scheduling, which might offer more flexibility for complex recurrence patterns. For more information on scheduling in Prefect, you can refer to the Prefect documentation on scheduling.

@Marvin Thank you for the info. Can I apply an RRule schedule to an existing deployment? if so, how?

Yes, you can apply an RRule schedule to an existing deployment in Prefect. Here's how you can do it: 1. Using the Prefect CLI: You can update the deployment's schedule by modifying the

prefect.yaml

file associated with the deployment. Add an

rrule

schedule in the

schedules

section of the YAML file. Then, use the

prefect deploy

command to apply the changes. 2. Via the Prefect UI: If you prefer using the Prefect UI, you can navigate to the deployment settings and update the schedule there, selecting the RRule option and specifying your desired recurrence rule. For more details on RRule syntax and examples, you might find it helpful to use an RRule string generator like the iCalendar.org RRule Tool. For comprehensive guidance, refer to the Prefect documentation on scheduling.

@Marvin how can I retrieve a prefect.yaml file for an existing deployment?

To retrieve a

prefect.yaml

file for an existing deployment, you typically need to manually recreate it based on the deployment's current configuration. Prefect does not directly export a

prefect.yaml

from an existing deployment through the CLI or UI. However, you can achieve this by: 1. Reviewing the Deployment Configuration: Check the deployment's settings in the Prefect UI to understand its current configuration, including schedules, parameters, and infrastructure settings. 2. Creating a

prefect.yaml

File: - Use the

prefect init

command in your flow's directory to create a new

prefect.yaml

file. - Manually populate the

prefect.yaml

with the observed settings from the UI. This includes defining your deployment configuration, schedules, and any environment variables or parameters used. 3. Using Recipes: Prefect provides deployment configuration recipes that can help structure your

prefect.yaml

. You can specify a recipe during initialization with the

--recipe

flag. For more detailed guidance on creating and managing

prefect.yaml

files, refer to the Prefect documentation on deployment configurations.