I’m using

GCSResult

in my flow and getting errors from GCS (caused by the

GCSResults

object trying to store task results:

Unexpected error: SSLError(MaxRetryError("HTTPSConnectionPool(host='<http://storage.googleapis.com|storage.googleapis.com>', port=443): Max retries exceeded with url: /upload/storage/v1/b/prefect-bucket/o?uploadType=multipart (Caused by SSLError(OSError(24, 'Too many open files')))"))

The reason is (probably) that I have many mapped tasks, and they are running in parallel. It’s a 32-core machine, but I can’t really figure out how Prefect/Dask decides how many run in parallel. Sometimes it’s more than 32. The bigger problem here is that I think it caused the flow to get stuck, so I didn’t even have the indication for the failure and couldn’t go and restart it. Anyhow, any suggestions on how to overcome this? Or at the very least cause my flow to fail on such things so that I can restart? Does it have anything to do with the fact that these tasks have a retry option?

In your task code are you properly closing your GCS client in each task? That'd be the first thing I'd check.

hmmm… it’s possible. I’m using

fs-gcsfs

which is a pluging for pyfilesystem2 that allows me to open GCS and local files interchangeably. I have things like this in the code:

return fs.open_fs(dir_path, create=False).exists(SUCCESS)

where

dir_path

is a GCS path, so I’m probably not closing it correctly. But to my defense, to the best of my knowledge `cpython`’s garbage collector should close these cursors automatically (as opposed to

pypy

implementation). I’ll try and report back

Hooray! Glad you figured it out.

The funny thing is that this is a caching mechanism I wrote before you guys published the new

Result

architecture. I guess it’s time to decommission it but I need to find time for that 😕