@Marvin how are we supposed to enable the heartbeat mechanism? Set

PREFECT_RUNNER_HEARTBEAT_FREQUENCY

on the server? On the runner? On both?

To enable the heartbeat mechanism in Prefect 3.x, you should set the

PREFECT_RUNNER_HEARTBEAT_FREQUENCY

environment variable. This setting should be applied on the runner, not the server. The heartbeat mechanism helps monitor the health of your flow runs by sending regular heartbeat events. If a certain number of heartbeats are missed, it can trigger automations to handle potentially "zombie" runs. For more detailed instructions, you can refer to the Prefect documentation on automations and triggers. If you're transitioning from Prefect 2.x to 3.x, remember that several architectural changes have been made, such as replacing agents with workers and work pools. For more common gotchas in Prefect 3.x, you might want to check the 3.x migration guide. If you have any other questions, feel free to ask.

@Marvin this does not seem to work. How do I debug this?

Debugging issues with the heartbeat mechanism in Prefect 3.x can be tricky. Here are some steps and considerations based on recent discussions and documentation: 1. Check Environment Variable: Ensure that the

PREFECT_RUNNER_HEARTBEAT_FREQUENCY

is correctly set in your environment. You can verify this by running

prefect config view

to see if the setting is picked up correctly. 2. Worker Type: Note that some worker types might not emit heartbeats as expected. For instance, the

ProcessWorker

had issues with not emitting flow run heartbeats, which was addressed in a recent update. Ensure your Prefect version includes this fix or consider using a different worker type. More details can be found in this GitHub issue. 3. Automation Configuration: Double-check your automation setup. The automation should be configured to trigger based on missed heartbeats. Ensure that the conditions are set correctly to detect "zombie" runs. 4. Logs and Monitoring: Use the Prefect Cloud dashboard or local logs to monitor the heartbeats and check if they are being emitted as expected. Look for any errors or warnings that might indicate why heartbeats aren't being sent. 5. Version and Compatibility: Make sure you are using a compatible version of Prefect that supports the heartbeat feature. The issue with

ProcessWorker

was resolved in a pull request, so updating to the latest version might help. For more detailed information on debugging, you can refer to the Prefect debugging tutorial. If these steps don't resolve the issue, consider reaching out to the Prefect community or filing an issue on their GitHub repository.