One of my fargate services keeps spinning up Dagit tasks that are erroring out with this error:

2021-09-03 11:40:15Traceback (most recent call last):
2021-09-03 11:40:15File "/usr/local/bin/dagit", line 5, in <module>
2021-09-03 11:40:15from dagit.cli import main
2021-09-03 11:40:15File "/usr/local/lib/python3.7/site-packages/dagit/cli.py", line 22, in <module>
2021-09-03 11:40:15from .app import create_app_from_workspace_process_context
2021-09-03 11:40:15File "/usr/local/lib/python3.7/site-packages/dagit/app.py", line 23, in <module>
2021-09-03 11:40:15from .subscription_server import DagsterSubscriptionServer
2021-09-03 11:40:15File "/usr/local/lib/python3.7/site-packages/dagit/subscription_server.py", line 4, in <module>
2021-09-03 11:40:15from graphql_ws.gevent import GeventSubscriptionServer, SubscriptionObserver
2021-09-03 11:40:15ImportError: cannot import name 'SubscriptionObserver' from 'graphql_ws.gevent' (/usr/local/lib/python3.7/site-packages/graphql_ws/gevent.py)

I have one run (been running for about 10 hours) that is currently running in a separate container, and this error seemed to occur when I tried to execute a second distinct pipeline.

Looks to be the same as https://github.com/dagster-io/dagster/issues/4628 The fix is to either upgrade to

dagster >= 0.12.8

or to set your own pin for

graphql-ws