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Robin

11/05/2020, 8:57 PM
Dear all, while the flow was running perfectly before and still runs locally, I suddenly get an error that seems to be related to pickle when running it on cloud:
TypeError: can't pickle _thread.lock objects
See full error message below. Any ideas, what could be the reason?
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nicholas

11/05/2020, 8:59 PM
Hi @Robin - could you delete your stack trace and put it in this thread instead?
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Robin

11/05/2020, 9:01 PM
I get the following error in the DEBUG level logging after a message saying
Checking flow run state...
...
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nicholas

11/05/2020, 10:31 PM
Thanks @Robin, it looks like this might be a bug on the Core side; would you mind opening a ticket with a short description of what version of Core you're on and when this stacktrace arose?
PS: Turns out the error does not occur when switching back to another feature branch of our own code repository. Hence, the error might be related to a code change on our side. The current assumption on our side is that we might pass an open connection or something else that is not pickable between tasks...
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nicholas

11/06/2020, 3:51 PM
@Robin that's definitely possible as well - if you find out more could you update your issue? I'm sure others have run into this as well when trying to pass around connections.
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Robin

11/06/2020, 6:48 PM
OK, will update on GitHub 🙂
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nicholas

11/06/2020, 6:57 PM
Thanks @Robin, much appreciated 😄
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Robin

11/11/2020, 5:51 PM
It was indeed related to open connection 😉 So always to all prefect users: make sure to close/teardown/dispose all open connections 🙂
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