@Marvin Hi! Is there a way to stop the run flow from a child task?

I can help you with that! Could you please let me know which version of Prefect you are using? This will ensure I provide you with the most accurate information.

@Marvin 3.0.10

To stop a flow run from a child task in Prefect 3.x, you may consider using the built-in

pause_flow_run()

or

cancel_flow_run()

functions, depending on your requirement to pause or cancel the flow run. Here are some options: 1. Pause a Flow Run: You can pause a flow run using the

pause_flow_run()

function. This can be triggered based on specific conditions in your task. Example:

python
   from prefect import task, flow, pause_flow_run

   @task
   def task_one():
       # Your task logic here
       return True

   @flow(log_prints=True)
   def my_flow():
       terminal_state = task_one.submit(return_state=True)
       if terminal_state.type == StateType.COMPLETED:
           print("Pausing flow run...")
           pause_flow_run(timeout=2)

2. Cancel a Flow Run: Prefect provides utilities and patterns to cancel a flow run if the infrastructure supports cancellation. Ensure the infrastructure (like a cloud worker) allows for such actions. Keep in mind that cancellation might be restricted by the type of infrastructure you're using. If you need further control or want to stop the flow's execution programmatically and your infrastructure supports it, ensure you're following best practices for those environments. For more details, you can refer to the Prefect 3.x documentation: - Pausing Flow Runs - Cancelling Flow Runs If you have any further questions or need additional assistance, feel free to ask!

@Marvin I got StateType is not defined

In Prefect, it's generally recommended to keep tasks separate and not nest one task within another. Each task should independently encapsulate a specific piece of logic for better modularity, testing, and reusability. Here's why deeply nested task structures can be problematic: 1. Complexity: Nesting tasks can make the flow logic unnecessarily complex and harder to understand or debug. 2. State Management: Prefect manages the state of each task, ensuring retries, logging, and error handling are handled seamlessly. Nesting tasks may complicate state management. 3. Independence: Each task should ideally perform a single operation or function, which aligns with the single responsibility principle. However, if you have a use case where you need to execute additional logic conditionally within a task (e.g., pausing or canceling a flow based on certain conditions), it's better to encapsulate that logic in separate functions or leverage flow control within the flow rather than nesting tasks. If you still need conditional handling within tasks, consider the following: - Define the conditional logic inside the task, and use the task's outcome to make flow-level decisions. - Use Prefect's flow control primitives (like conditional branching within flows) instead of deeply nesting tasks. If you would like, I can help provide some example patterns for handling conditional logic in Prefect flows without nesting tasks. Let me know if you'd like some examples or further explanation!

@Marvin why Am i getting timeout Flow run was paused and never resumed?

The error message "Flow run was paused and never resumed" typically occurs when a flow run is paused using the

pause_flow_run

function but is not resumed within the default timeout period. Here's why this might happen and how you can address it: 1. Default Timeout: When a flow run is paused, it has a default timeout period of one hour. If not resumed within this time, the flow run will fail with a timeout error. 2. Manual Resumption: The flow needs to be manually resumed either via the Prefect UI or by calling the

resume_flow_run

function with the appropriate flow run ID. 3. Infrastructure Considerations: Ensure that any infrastructure you're using (like cloud workers or Docker containers) is properly set up to handle long-running processes if necessary. ### How to Fix This: - Increase Timeout: You can increase the timeout duration when pausing the flow to give yourself more time for manual interventions. Example:

python
  pause_flow_run(timeout=3600 * 2)  # Sets timeout to 2 hours

- Ensure Manual Resume: Make sure there's a clear process to resume the flow. This can be set up through triggers in the UI or scripted commands if automation is required. - Review Infrastructure: Double-check that the environment where the flow runs supports suspending and resuming operations. For more detailed guidance, you can refer to the Prefect 3.x pause and resume documentation here. If you continue to face issues, let me know, and I'll be happy to help troubleshoot further!