sample-socketio

This repo is related to miguelgrinberg/python-socketio#451 and aims to reproduce the issue easily.

Setup

One machine should run the server. One machine should run the client.

Both machines are on the same local network.

• Create a clean Python3 virtualenv (I'm personaly having Python 3.7.3)
• Install deps: pip3 install -r requirements.txt

Server side

Description

When at least one client is connected, the server sends status update through SocketIO (default namespace).

Run

python3 server.py

Client side

Description

Client connects to the server and subscribes for the status update event. Then it waits until the status received is OK.

Run

export SERVER_IP=<local_server_ip>

Check

python3 client.py

Stress test (run n clients)

python3 nclient.py --count 10

Results

After running the stress test few times (I reproduce the problem every ~8 runs), you should see one of the following errors:

$ python3 nclient.py --count 10
...
Unexpected error "[Errno 9] Bad file descriptor", aborting
...

$ python3 nclient.py --count 10
Starting 10 client
...
Exception in thread Thread-3:
Traceback (most recent call last):
  File "/usr/lib/python3.7/threading.py", line 917, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.7/threading.py", line 865, in run
    self._target(*self._args, **self._kwargs)
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/engineio/client.py", line 683, in _write_loop
    self.ws.send(encoded_packet)
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/websocket/_core.py", line 253, in send
    return self.send_frame(frame)
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/websocket/_core.py", line 279, in send_frame
    l = self._send(data)
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/websocket/_core.py", line 449, in _send
    return send(self.sock, data)
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/websocket/_socket.py", line 157, in send
    return _send()
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/websocket/_socket.py", line 139, in _send
    return sock.send(data)
  File "/usr/lib/python3.7/ssl.py", line 986, in send
    return super().send(data, flags)
OSError: [Errno 9] Bad file descriptor
...

Exception in thread Thread-3:
Traceback (most recent call last):
  File "/usr/lib/python3.7/threading.py", line 917, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.7/threading.py", line 865, in run
    self._target(*self._args, **self._kwargs)
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/engineio/client.py", line 683, in _write_loop
    self.ws.send(encoded_packet)
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/websocket/_core.py", line 253, in send
    return self.send_frame(frame)
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/websocket/_core.py", line 279, in send_frame
    l = self._send(data)
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/websocket/_core.py", line 449, in _send
    return send(self.sock, data)
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/websocket/_socket.py", line 157, in send
    return _send()
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/websocket/_socket.py", line 139, in _send
    return sock.send(data)
  File "/usr/lib/python3.7/ssl.py", line 984, in send
    return self._sslobj.write(data)
ssl.SSLError: [SSL: BAD_LENGTH] bad length (_ssl.c:2341)

Exception in thread Thread-3:
Traceback (most recent call last):
  File "/usr/lib/python3.7/threading.py", line 917, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.7/threading.py", line 865, in run
    self._target(*self._args, **self._kwargs)
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/engineio/client.py", line 683, in _write_loop
    self.ws.send(encoded_packet)
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/websocket/_core.py", line 253, in send
    return self.send_frame(frame)
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/websocket/_core.py", line 279, in send_frame
    l = self._send(data)
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/websocket/_core.py", line 449, in _send
    return send(self.sock, data)
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/websocket/_socket.py", line 157, in send
    return _send()
  File "/home/adrien/.virtualenvs/sio/lib/python3.7/site-packages/websocket/_socket.py", line 139, in _send
    return sock.send(data)
  File "/usr/lib/python3.7/ssl.py", line 984, in send
    return self._sslobj.write(data)
ssl.SSLEOFError: EOF occurred in violation of protocol (_ssl.c:2341)

Notes

With a real app, those errors are visible on various CI environment (Bitrise, CircleCI for example).

Setting enable_multithread=True here https://github.com/miguelgrinberg/python-engineio/blob/master/engineio/client.py#L377 solves the problem.