Superskyyy commented on issue #9071:
URL: https://github.com/apache/skywalking/issues/9071#issuecomment-1308948811

   > ## Use case
   > 
[skywalking.apache.org/docs/skywalking-python/next/en/setup/faq/how-to-use-with-uwsgi](https://skywalking.apache.org/docs/skywalking-python/next/en/setup/faq/how-to-use-with-uwsgi/)
 But start the application by cli as showd below
   > 
   > ```
   > sw-python uwsgi --die-on-term \
   >     --http 0.0.0.0:5000 \
   >     --http-manage-expect \
   >     --master --workers 3 \
   >     --enable-threads \
   >     --threads 3 \
   >     --manage-script-name \
   >     --mount /=main:app
   > ```
   > 
   > ## Potential cause
   > I've done a small amount of research, and this might be caused by the 
inherent property of Linux's `fork`. In Python Agent, we use a global variable 
[_started](https://github.com/apache/skywalking-python/blob/11a74be39b07d55290c2df3de2b499bb126de048/skywalking/agent/__init__.py#L39)
 to prevent redundant initialization.
   > 
   > In `preforking mode` of `uWsgi`,
   > 
   > 1. At first, `uWsgi` spawns a master process in which the Agent will be 
initialized for the first time and `_started` will be set as `True`.
   > 2. Then the master process spawns n worker processes in which `_started` 
remains `True`. So the necessary reporting threads will not be created here and 
nothing will be sent to `oap`.
   > 
   > Commenting this 
[line](https://github.com/apache/skywalking-python/blob/11a74be39b07d55290c2df3de2b499bb126de048/skywalking/bootstrap/loader/sitecustomize.py#L147)
 preventing initialization inside the master process, then each worker 
processes will have its own Agent initialized successfully.
   
   Thank you, I see where the problem is, maybe adding PID info to the 
`__started` flag so upon fork we can allow a safe restart.


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