I m just starting with prefect v2 and when I try to run a de

Question

I m just starting with prefect v2 and when I try to run a deployment from Prefect cloud to a local agent running on a Windows server the agent raises a NotImplementedError

Khuyen Tran · Answer

Can you show a sample of your code

Jeff Hale · Answer

Thanks for your question Could you please move the traceback to the thread to help keep the main channel tidy It looks like you have a similar issue to question Prefect uses FastAPI under the hood It looks like

Andrew Stewart · Answer

Traceback ```09 12 49 068 | INFO | prefect agent Submitting flow run f42cb8fc a952 4fa0 8b5f 3af70a33aaaa 09 12 49 302 | INFO | prefect infrastructure process Opening process enigmatic piculet 09 12 49 306 | ERROR | prefect agent Failed to submit flow run f42cb8fc a952 4fa0 8b5f 3af70a33aaaa to infrastructure Traceback most recent call last File C ProgramData Miniconda3 envs prefect2 lib site packages prefect agent py line 206 in submit run await self task group start submit flow run flow run infrastructure File C ProgramData Miniconda3 envs prefect2 lib site packages anyio backends asyncio py line 807 in start return await future File C ProgramData Miniconda3 envs prefect2 lib site packages anyio backends asyncio py line 702 in run wrapped task await coro File C ProgramData Miniconda3 envs prefect2 lib site packages prefect infrastructure submission py line 48 in submit flow run return await infrastructure run task status=task status File C ProgramData Miniconda3 envs prefect2 lib site packages prefect infrastructure process py line 79 in run cwd=tmp dir File C ProgramData Miniconda3 envs prefect2 lib site packages prefect utilities processutils py line 69 in run process kwargs File C ProgramData Miniconda3 envs prefect2 lib contextlib py line 170 in aenter return await self gen anext File C ProgramData Miniconda3 envs prefect2 lib site packages prefect utilities processutils py line 28 in open process process = await anyio open process command kwargs File C ProgramData Miniconda3 envs prefect2 lib site packages anyio core subprocesses py line 135 in open process start new session=start new session File C ProgramData Miniconda3 envs prefect2 lib site packages anyio backends asyncio py line 1102 in open process start new session=start new session File C ProgramData Miniconda3 envs prefect2 lib asyncio subprocess py line 202 in create subprocess shell stderr=stderr kwds File C ProgramData Miniconda3 envs prefect2 lib asyncio base events py line 1514 in subprocess shell protocol cmd True stdin stdout stderr bufsize kwargs File C ProgramData Miniconda3 envs prefect2 lib asyncio base events py line 462 in make subprocess transport raise NotImplementedError NotImplementedError``` ``` prefect2 C Windows system32 gt prefect version Version 2 3 1 API version 0 8 0 Python version 3 7 12 Git commit 1d485b1d Built Thu Sep 1 2022 3 53 PM OS Arch win32 AMD64 Profile cloud gestamp us default Server type cloud```

Andrew Stewart · Answer

The flow I m trying to run is a parent flow with a subflow ``` flow def sap material documents by plant and date plant query date mat docs = extract sap material documents plant query date if not mat docs empty mat docs = transform sap material documents mat docs load to database mat docs flow def sap material documents engine = sqlalchemy create engine r <mssql+pyodbc localhost data warehouse driver=ODBC+Driver+18+for+SQL+Server amp trusted connection=yes> sap mat docs max dates df = pd read sql SELECT plant CAST MAX datetime entered AS DATE AS max date entered FROM sap material documents GROUP BY plant engine date extracted = datetime date today for row dict in sap mat docs max dates df to dict orient= records plant = row dict plant query date = row dict max date entered while True query date += datetime timedelta days=1 sap material documents by plant and date plant=plant query date=query date if query date gt = date extracted datetime timedelta days=1 break```

Andrew Stewart · Answer

Here is the full file and the deployment

Jeff Hale · Answer

I don t think it s something specific to your code looks like it might be a Windows async issue that you can work around by setting the event loop policy like in the above SO answer

Andrew Stewart · Answer

Unfortunately I m running on Windows an uvloop doesn t run on Windows so that SO answer doesn t help

Jeff Hale · Answer

You might want to try upgrading to Python 3 8 if possible I saw that as a suggestion somewhere

Andrew Stewart · Answer

It works on 3 10 for me I figured out how to upgrade my dependency that was keeping me on 3 7 and upgraded to 3 10 It looks like anyio doesn t have a way to do <https anyio readthedocs io en stable subprocesses html|subprocesses on Windows with Python 3 7> and that s the crux of the issue