Chaining websockets from an url to server to other services

[datnguyen219]

Hi, I am new to flask_socketio. I am attempting to stream live stock data from finnhub websocket url to a client and potentially more services. The reason I'm chaining this is because finnhub websocket only allows 1 connection at a time. Initially the code does not work until I put it socketio.sleep(0), which enable concurrency ? I really wanted to know why this suddenly work because I was stuck with this for 3 days. Here is the code

def on_message(ws, message):
    print(message)
    socketio.sleep(0)
    #why does adding a sleep here make it works ?
    socketio.emit('live_stock', message)

def live_stock_stream():
    global ws_app
    websocket.enableTrace(True)
    ws_app = websocket.WebSocketApp(
        "wss://ws.finnhub.io?token=mytoken",
        on_message=on_message,
        on_error=on_error,
        on_close=on_close,
        on_open=on_open
    )
    ws_app.run_forever(sslopt={"cert_reqs": ssl.CERT_NONE})

  
@socketio.on('connect')
def connect():
  global ws_thread
  with thread_lock:
      if ws_thread is None:
          ws_thread = socketio.start_background_task(live_stock_stream)

[miguelgrinberg]

Are you using eventlet or gevent for concurrency? If yes, I suggest you uninstall them and use the regular threads, which would not need you to sleep to achieve concurrency.