Flask Issue of "Address already in use" in PythonAnywhere Cloud

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Project Setup X:

Issue of: "Address already in use"

* Serving Flask app '__main__' (lazy loading)
* Environment: production
  WARNING: This is a development server. Do not use it in a production deployment.
  Use a production WSGI server instead.
* Debug mode: on
Address already in use
Port 5000 is in use by another program. Either identify and stop that program, or start the server with a different port.
Traceback (most recent call last):
  File "/usr/local/lib/python3.10/site-packages/werkzeug/serving.py", line 908, in prepare_socket
    s.bind(server_address)
OSError: [Errno 98] Address already in use


FIX:
if __name__ == '__main__':
    app.run(debug=True, port=5002, use_reloader=False)


Project Setup For ASR

04:47 ~ $ python app_pt.py 
2025-03-09 04:49:18.556050: W tensorflow/stream_executor/platform/default/dso_loader.cc:64] Could not load dynamic library 'libcudart.so.11.0'; dlerror: libcudart.so.11.0: cannot open shared object file: No such file or directory; LD_LIBRARY_PATH: /usr/local/lib/python3.10/site-packages/cv2/../../lib64:
2025-03-09 04:49:18.556080: I tensorflow/stream_executor/cuda/cudart_stub.cc:29] Ignore above cudart dlerror if you do not have a GPU set up on your machine.
    * Serving Flask app 'app_pt' (lazy loading)
    * Environment: production
    WARNING: This is a development server. Do not use it in a production deployment.
    Use a production WSGI server instead.
    * Debug mode: on
Address already in use
Port 5000 is in use by another program. Either identify and stop that program, or start the server with a different port.



05:08 ~ $ tail -3 app_pt.py 
if __name__ == "__main__":
    # Run the server on port 5000 and listen on all interfaces.
    app.run(host="0.0.0.0", port=5001, debug=False)


04:59 ~ $ python app_pt.py 
2025-03-09 05:01:13.156268: W tensorflow/stream_executor/platform/default/dso_loader.cc:64] Could not load dynamic library 'libcudart.so.11.0'; dlerror: libcudart.so.11.0: cannot open shared object file: No such file or directory; LD_LIBRARY_PATH: /usr/local/lib/python3.10/site-packages/cv2/../../lib64:
2025-03-09 05:01:13.156294: I tensorflow/stream_executor/cuda/cudart_stub.cc:29] Ignore above cudart dlerror if you do not have a GPU set up on your machine.
    * Serving Flask app 'app_pt' (lazy loading)
    * Environment: production
    WARNING: This is a development server. Do not use it in a production deployment.
    Use a production WSGI server instead.
    * Debug mode: off
Address already in use
Port 5001 is in use by another program. Either identify and stop that program, or start the server with a different port.
05:03 ~ $ 



05:09 ~ $ tail -3 app_pt.py 
if __name__ == "__main__":
    # Run the server on port 5000 and listen on all interfaces.
    app.run(host="0.0.0.0", port=5001, debug=False, use_reloader=False)




05:09 ~ $ python app_pt.py 
2025-03-09 05:11:43.255847: W tensorflow/stream_executor/platform/default/dso_loader.cc:64] Could not load dynamic library 'libcudart.so.11.0'; dlerror: libcudart.so.11.0: cannot open shared object file: No such file or directory; LD_LIBRARY_PATH: /usr/local/lib/python3.10/site-packages/cv2/../../lib64:
2025-03-09 05:11:43.255871: I tensorflow/stream_executor/cuda/cudart_stub.cc:29] Ignore above cudart dlerror if you do not have a GPU set up on your machine.
    * Serving Flask app 'app_pt' (lazy loading)
    * Environment: production
    WARNING: This is a development server. Do not use it in a production deployment.
    Use a production WSGI server instead.
    * Debug mode: off
Address already in use
Port 5001 is in use by another program. Either identify and stop that program, or start the server with a different port.
05:13 ~

The way to resolve this is to not attempt to run a 'flask app' as a Python Script. Rather use 'Web' app configuration of PythonAnywhere as shown below:

Below screen is not the actual one but only for demo purpose...

Tags: Python,Cloud,Technology,Web Development,