Hello, I am trying out prefect for the first time and am running it on my local machine. The prefect orion start was running fine, until I created a flow that does a parallel flow execution. Will appreciate any guidance on how to resolve the error.

Hi @Rohit Motiani, I just tested a sample of your code and the structure looks fine and ran for me. I replaced the generateOutputFile with a print statement so maybe there is an error with that function.

from prefect import task, flow
from prefect_dask.task_runners import DaskTaskRunner


@task 
def run_product():
    print('hello')

@task 
def run_field():
    print('hello')

@flow(task_runner=DaskTaskRunner())
def main_flow():
    result = run_product.submit()
    result = run_field.submit()

if __name__ == "__main__":
    main_flow()

Hi @Kalise Richmond. Thanks for the response. This code was working before, and I was able to see the flow on the API. However, after I ran the code, the "prefect orion start" displayed the error message posted before. The code is also unable to communicate with the API. After running with the print statement, I still get the same error (Sorry I should have posted this earlier, when I ran my original code.)

can you share your

prefect version

and

prefect config view

? did you start Orion? you can do that using

prefect orion start

if this doesn't help, could be an issue with the network i.e. Dask runner can't reach orion

@Rohit Motiani to add to what @Anna Geller said… Can you see what

prefect version

returns in your IDE and in your terminal where you’re spinning up Orion?

@Emil Christensen, here is the screen shot:

Hi @Rohit Motiani, it's worth updating your Prefect version on 2.7.6 which was released yesterday. There was a critical bug on 2.7.4 with sqlite. I'm not on Windows but based on the error your seeing, it could be related to this.

@Kalise Richmond, I get the same error after installing the latest version:

you could try resetting the database or pip uninstall

@Anna Geller I removed dask runner, but no luck. Did a database reset, uninstalled and reinstalled prefect, still the same issue / error message running prefect orion start. Highlighted in the prefect config view, which I did not share earlier.

@Rohit Motiani As per Kalise’s message, it looks like this is a Windows compatibility issue that has to do with asyncio. I’m going to open up an issue and will link it here.

Hi @Emil Christensen. I was able to get past and reproduce the issue. To get past the issue, I had to do the following. 1. Delete the file in C:\Users\<user_name>\AppData\Roaming\Python. 2. Comment the code: @flow #(task_runner=DaskTaskRunner()). To reproduce the issue, all I have to do is uncomment the DaskTaskRunner. I agree its an issue running the DaskTaskRunner on Windows.

Hi @Rohit Motiani 👋 Hope you’re doing well. Just wanted to let you know that we released a fix to your bug in version 2.7.9. Let us know if you’re able to upgrade and resolve the issue. Thank you!