Flask+uWSGI+Nginx环境下WebSocket连接失败问题求助

问题场景 #

开发Flask API时集成WebSocket，使用flask-uwsgi-websocket包，常规HTTP路由正常，但WebSocket路由/api/websocket/echo返回404，连接迅速断开。相关配置如下：

main.py代码 #

from gevent.monkey import patch_all
patch_all()
# pylint: disable=wrong-import-position
from flask_uwsgi_websocket import GeventWebSocket  # noqa: E402
# More imports...
# pylint: enable=wrong-import-position

from flask import Flask

app = Flask(__name__)
websocket = GeventWebSocket(app)

# 常规HTTP路由定义

@websocket.route('/api/websocket/echo')
def echo(w_s):
    """WebSocket echo服务"""
    print(1)
    print(w_s)
    print(2)
    while True:
        msg = w_s.receive()
        w_s.send(msg)

if __name__ == '__main__':
    app.run(debug=True, threaded=True, gevent=100)

config-uwsgi.ini配置 #

[uwsgi]

app = main
module = %(app)
callable = app

socket = /tmp/module_name.sock
chdir = /path_to_module
chmod-socket = 666
virtualenv = /path_to_module/venv
enable-threads = true
http-websockets = true

master = true
processes = 1
die-on-term = true

config-nginx.conf配置 #

server {
    listen 80;
    listen [::]:80;
    listen 443 ssl;
    server_name some.server.com;

    ssl_certificate   /etc/letsencrypt/live/some.server.com/fullchain.pem;
    ssl_certificate_key  /etc/letsencrypt/live/some.server.com/privkey.pem;
    server_tokens off;

    location / {
        include uwsgi_params;
        uwsgi_pass unix:/tmp/module_name.sock;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "Upgrade";
        proxy_read_timeout 3600s;
        proxy_send_timeout 3600s;
    }
}

错误日志 #

Jan 09 22:23:25 ip-192-168-1-50 uwsgi[242836]: [pid: 242836|app: 0|req: 5/5] 189.XXX.XXX.XXX () {52 vars in 914 bytes} [Mon Jan  9 22:23:25 2023] GET /api/websocket/echo => generated 207 bytes in 0 msecs (HTTP/1.1 404) 2 headers in 87 bytes (1 switches on core 0)

修复步骤 #

1. 修正Nginx的头传递指令 #

当前Nginx使用proxy_set_header，但该指令仅适配proxy_pass场景，而你使用的是uwsgi_pass，需替换为uwsgi_set_header，同时建议单独为WebSocket路径配置规则，避免影响常规路由：

修改后的config-nginx.conf：

server {
    listen 80;
    listen [::]:80;
    listen 443 ssl;
    server_name some.server.com;

    ssl_certificate   /etc/letsencrypt/live/some.server.com/fullchain.pem;
    ssl_certificate_key  /etc/letsencrypt/live/some.server.com/privkey.pem;
    server_tokens off;

    # 单独处理WebSocket路由
    location /api/websocket/ {
        include uwsgi_params;
        uwsgi_pass unix:/tmp/module_name.sock;
        uwsgi_set_header Upgrade $http_upgrade;
        uwsgi_set_header Connection "Upgrade";
        uwsgi_read_timeout 3600s;
        uwsgi_send_timeout 3600s;
    }

    # 处理常规HTTP路由
    location / {
        include uwsgi_params;
        uwsgi_pass unix:/tmp/module_name.sock;
    }
}

2. 完善uWSGI的Gevent支持 #

确保uWSGI启用Gevent事件循环，在config-uwsgi.ini中添加gevent参数：

[uwsgi]
# 原有配置保留
gevent = 100
http-websockets = true
enable-threads = true
master = true
processes = 1
# 原有配置保留

同时确认安装带Gevent支持的uWSGI：

pip install uwsgi[gevent]

3. 确认代码导入顺序 #

确保gevent.monkey.patch_all()在所有其他导入之前执行（你的代码已符合要求，无需修改），这是Gevent协程正常工作的必要前提。

测试验证 #

使用wscat工具测试WebSocket连接：

# 安装wscat
npm install -g wscat
# 发起WebSocket连接
wscat -c wss://some.server.com/api/websocket/echo

连接成功后发送消息，应收到对应的echo返回。

内容的提问来源于stack exchange，提问作者Dykeiichi