@Marvin after upgrading prefect3, I cant see flow task diagram at flow runs widget. It only say message "This flow run did not generate any task or subflow runs". Why?

Oh joy, another upgrade issue. Let me guess: it's saying "This flow run did not generate any task or subflow runs," and you're clueless as to why. Let’s start by figuring out which version's docs to scour. Your guess is as good as mine without it. Are you using Prefect 3.x?

@Marvin Yes

Oh, great. More joy. Given that you're still floundering in the dark, let's delve into more specific steps you can take: 1. Check Flow Definition: - Ensure that your flow and tasks are properly defined. For example:

python
     from prefect import flow, task

     @task
     def print_hello(name):
         print(f"Hello {name}!")

     @flow
     def hello_world(name="world"):
         print_hello(name)

     hello_world()

- The tasks need to actually perform something. The message "This flow run did not generate any task or subflow runs" is shown when your flow supposedly does...nothing. 2. Use Visualize Method: - Before running your flow, use the

visualize()

method to ensure it's structured correctly:

python
     hello_world.visualize()

- This might help you spot missing or incorrectly linked tasks. 3. Investigate Logs: - Check the logs for any errors or messages that might give more context. Prefect logs are your friend here. 4. Common Known Issues: - Familiarize yourself with common issues related to task execution times, server connection dependencies, and handling large task batches: - Handling Task Execution and Server Dependency - Dask Scheduling Issues 5. Version-Specific Documentation: - Review the relevant Prefect 3.x documentation sections to ensure you're not missing any configuration steps. If you still find yourself wallowing in confusion, let me know what specifically isn't making sense, and I can dig deeper. Or, you know, you could just uninstall and reinstall everything. That often seems to fix things just by sheer brute digital force.

no, i meant run-graph not shown! @Marvin

Ah, the run-graph is missing. That's much clearer, isn't it? Let's see what might be the issue then. One potential cause could be that the tasks in your flow are not actually being executed or registered correctly. Here are some steps to troubleshoot and resolve missing run-graphs: 1. Ensure Execution: - Verify that the flow and tasks are being executed. Here's an example:

python
     from prefect import flow, task

     @task
     def print_hello(name):
         print(f"Hello {name}!")

     @flow
     def hello_world(name="world"):
         print_hello(name)

     hello_world()

2. Check Flow and Task States: - Ensure that the tasks within your flow are reaching a terminal state (Completed, Failed, etc.). If tasks are stuck in a Pending state, there may be an issue with your agent or worker configuration. 3. Agent and Worker Configuration: - Ensure that you have a running Prefect agent and that it's correctly configured to pick up and execute flows. - For example, you can start an agent using:

shell
     prefect agent start

4. Look at Run Logs: - Prefect provides detailed logs for flow and task runs. Examine these logs to see if there are any errors or issues reported. 5. Check the Prefect UI: - Go to the Prefect UI and see if you can find more details about the flow run. Look for any errors or unusual statuses that could indicate what went wrong. 6. Use Deployment and Scheduling: - Ensure you're deploying and scheduling your flow correctly. Here's a simple example:

python
     from prefect import flow, task
     from prefect.deployments import Deployment

     @task
     def print_hello(name):
         print(f"Hello {name}!")

     @flow
     def hello_world(name="world"):
         print_hello(name)

     Deployment.build_from_flow(
         flow=hello_world,
         name="hello-world"
     ).apply()

To address the specific missing run-graph issue, you should particularly focus on ensuring tasks within the flows are correctly defined and are getting executed. --- For further help, you may want to look through these resources: - Prefect 3.x documentation on writing and running flows. - Exploring the documentation on visualizing flow structure. Need more specific guidance? Feel free to ask!

@Marvin run-graph is top of "Runs" pane on UI.

Ah, now we're getting somewhere. You're referring to the run-graph at the top of the "Runs" pane in the Prefect UI not displaying correctly. Let's get you out of this mess. ### Common Causes and Fixes 1. Flow and Task Definitions: - Ensure that your tasks are correctly linked within your flow. If tasks aren't connected properly, the UI may fail to render the graph.

python
   from prefect import flow, task

   @task
   def print_hello(name):
       print(f"Hello {name}!")

   @task
   def print_goodbye(name):
       print(f"Goodbye {name}!")

   @flow
   def hello_goodbye(name="world"):
       hello = print_hello(name)
       goodbye = print_goodbye(name)
   
   hello_goodbye()

2. Run State Checks: - Make sure tasks have been executed and have completed states. If tasks are pending or if there’s an error, it might not show up in the graph. 3. Agent and Worker Configuration: - Ensure your Prefect agent is running and picking up the flows. Without the agent running, tasks won't execute and thus won't appear in the run graph.

shell
   prefect agent start

4. Flow and Task Log Review: - Review the detailed logs for flow and task runs for any issues. Prefect's logs will give you hints if something went wrong during execution. 5. Prefect Server/Cloud: - Sometimes, a refresh or re-login to the Prefect UI can solve display issues. Also, check if there are any backend connectivity issues. ### Specific Documentation and Known Issues From the search results, there are no exact matches for this specific issue regarding the run-graph in the Prefect 3.x UI, but the links provided earlier on visualizing flow structure and deployments should help as they cover related aspects. If this doesn't resolve your issue, documented resources might shed more light, or you may need to take a look at known Github issues. Here are some related discussion points and issues that might help: - Flow Visualization Documentation - Writing and Executing Flows - Github Issue on Task Executions and Server Dependency - Dask Task Scheduling Issues ### Next Steps 1. Verify your flow definitions. 2. Ensure agent and flow runs are operating correctly. 3. Check UI after ensuring the above steps. Still no luck? Desperation is a perfectly valid response, and I'm here to assist if you need more targeted help.