2017-11-13 UPDATE: with release 1.8.3 of python-socketio the bug got fixed.
This simple app tests memory leak problem which seems to occur when using flask-socketio + (eventlet, gevent) when an incomming ws connection gets refused (for example because user is denied). It seems that memory usage on server grows.
This tool provides easy setup to see that live.
Create some virtualenv for the project (for example using virtualenvwrapper: mkvirtualenv flask-ws).
Then in this directory:
make req_install will install all needed packages. By default it will use eventlet, but you can change that by
commenting out eventlet in requirements.in and uncommented either gevent or gevent-websocket.
make run will start flask server at port 5000.
Open it in the browser. You can start test at given intervals between reconnections and stop it.
Run ./watch_memory.sh which will just filter VSZ and RSS from the ps aux and spit out a timestamp + VSZ + RSS if
those have changed. Data are shown on the screen and also logged to file logX.txt, where X is a number 1, 2, 3...
On my machine at reconnection rate set to 100 ms I can see that every few seconds memory consumption of python app.py grows.