AWS ECS Fargate中Traefik代理WSS服务出现502 Bad Gateway错误求助

1. 补充WebSocket服务协议配置 #

Traefik默认支持WebSocket转发，但需明确指定后端服务的协议类型，避免连接时出现EOF错误。给Container1添加服务关联及协议配置的Docker标签：

"traefik.http.routers.container1-router.service": "container1-service",
"traefik.http.services.container1-service.loadbalancer.server.port": "1234",
"traefik.http.services.container1-service.loadbalancer.server.scheme": "ws"

由于Traefik已在websecure入口处理TLS加密，后端服务使用ws协议即可，Traefik会自动将外部的WSS请求转为内部WS请求转发。

2. 排查StripPrefix中间件的影响 #

WebSocket连接依赖Upgrade请求头，StripPrefix中间件可能干扰请求路径或头信息。可先临时移除中间件测试：

// 注释或删除以下标签
// "traefik.http.middlewares.container1-strip.stripprefix.prefixes": "/container1",
// "traefik.http.middlewares.container1-strip.stripprefix.forceSlash": "false",
// "traefik.http.routers.container1-router.middlewares": "container1-strip"

若移除后WSS连接正常，需确认后端服务能处理去掉前缀后的路径（即根路径/），再重新启用中间件。

3. 验证任务内容器网络连通性 #

进入Traefik容器，执行命令测试与Container1的WebSocket连接：

curl -i -N -H "Connection: Upgrade" -H "Upgrade: websocket" -H "Sec-WebSocket-Version: 13" -H "Sec-WebSocket-Key: test" http://localhost:1234

若返回HTTP/1.1 101 Switching Protocols，说明后端服务正常响应；若返回EOF或连接失败，需检查Container1的WSS服务是否正常监听1234端口，或服务是否启动异常。

4. 查看Traefik详细日志定位问题 #

已启用--log.level=DEBUG，重点关注以下日志内容：

• Traefik是否成功发现Container1的服务实例
• 转发请求到Container1时的连接建立细节
• 是否存在TLS握手或证书相关错误（即使已设置insecureSkipVerify=true）

修复后的Container1 Docker标签示例 #

"dockerLabels": {
  "traefik.enable": "true",
  "traefik.http.routers.container1-router.tls": "true",
  "traefik.http.routers.container1-router.rule": "PathPrefix(`/container1`)",
  "traefik.http.routers.container1-router.entrypoints": "websecure",
  "traefik.http.routers.container1-router.service": "container1-service",
  "traefik.http.services.container1-service.loadbalancer.server.port": "1234",
  "traefik.http.services.container1-service.loadbalancer.server.scheme": "ws",
  "traefik.http.middlewares.container1-strip.stripprefix.prefixes": "/container1",
  "traefik.http.middlewares.container1-strip.stripprefix.forceSlash": "false",
  "traefik.http.routers.container1-router.middlewares": "container1-strip"
}

内容的提问来源于stack exchange，提问作者JulienChamp