WebSocket Chat Async Example Crash

Question

I have been trying to run the websocket chat example provided here on an Apple Mac. https://github.com/unbit/uwsgi/blob/master/tests/websockets_chat_async.py

But running this example results in a segfault in uwsgi.

I have copied pasted this example in websocket.py and am running the server with the following command

uwsgi --http :8080 --http-websockets --wsgi-file websocket.py --venv ../../python2-wow

When I access the URL, I get the proper message for connection establishing. But then the server crashes with this segfault

!!! uWSGI process 29129 got Segmentation Fault !!!
*** backtrace of 29129 ***
0   uwsgi                               0x00000001078b5ec0 uwsgi_backtrace + 48
1   uwsgi                               0x00000001078b6371 uwsgi_segfault + 49
2   libsystem_platform.dylib            0x00007fff96b2c5aa _sigtramp + 26
3   ???                                 0x0000000000000000 0x0 + 0
4   uwsgi                               0x0000000107897b4e async_add_fd_read + 206
5   uwsgi                               0x00000001078c8979 py_eventfd_read + 89
6   Python                              0x00000001079d214d PyEval_EvalFrameEx + 8080
7   Python                              0x00000001079d0093 PyEval_EvalCodeEx + 1641
8   Python                              0x0000000107977796 PyFunction_SetClosure + 809
9   Python                              0x0000000107959f72 PyObject_Call + 101
10  Python                              0x00000001079d601f PyEval_CallObjectWithKeywords + 93
11  uwsgi                               0x00000001078c6dc7 python_call + 23
12  uwsgi                               0x00000001078c8df9 uwsgi_request_wsgi + 889
13  uwsgi                               0x000000010787b7e3 wsgi_req_recv + 291
14  uwsgi                               0x00000001078b38a5 simple_loop_run + 229
15  uwsgi                               0x00000001078ba6e2 uwsgi_ignition + 226
16  uwsgi                               0x00000001078ba5ae uwsgi_worker_run + 670
17  uwsgi                               0x00000001078b9d26 uwsgi_start + 5078
18  uwsgi                               0x00000001078b81a3 main + 7331
19  libdyld.dylib                       0x00007fff8c6ce5fd start + 1
*** end of backtrace ***

Apparantly the crash is on this line

uwsgi.wait_fd_read(websocket_fd, 3)

Stumped here. Need help.

Answer 1

I made it to work with --async=100 and --ugreen options.

Note that there are newer API's that you can use: native WebSocket support and generic gevent-based async support.