Python threading.Thread join hangs

Question

We've got a Lambda function that runs in a Docker container (built from `public.ecr.aws/lambda/python:3.8`) that was working until we recently (02/11) deployed some minor changes to another Lambda function (CI redeploys everything). After some debugging, it looks like the code is stuck waiting for the `threading.Thread` `join`:

```
    thread_queue = queue.Queue()
    our_thread = threading.Thread(target=our_func, args=(thread_queue,))
  
    our_thread.start()
    print("Thread started and waiting...")
  
    our_thread.join()
    print("Thread completed")
```

The `our_func` updates our RDS database and writes to S3....both are working as expected.

We're not seeing *"Thread completed"* in the logs.

Why is the Lambda function hanging?

Answer

Maybe something in the thread itself that doesn't finish somehow?

If this is actually your code, why are you creating a thread?

Python threading.Thread join hangs

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