Nginx를 이용한 WebSocket reverse proxy

# go run echo.go

server {
    listen 80 default_server;
    listen [::]:80 default_server;
    ......
    ......
    location /ws/ {
        proxy_pass http://localhost:8080;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "Upgrade";
    }
}

$ go run echo.go 
recv: Hello world!
read: websocket: close 1001 (going away)
upgrade:websocket: 'Origin' header value not allowed

GET /echo HTTP/1.1
Host: localhost:8080
Accept-Encoding: gzip, deflate, br
Accept-Language: ko-KR,ko;q=0.9,en-US;q=0.8,en;q=0.7
Cache-Control: no-cache
Connection: Upgrade
Cookie: _ga=GA1.1.1798860791.1500182387
Origin: http://localhost
Pragma: no-cache
Sec-Websocket-Extensions: permessage-deflate; client_max_window_bits
Sec-Websocket-Key: 03SvnEbGeWQjug0BmxXzaw==
Sec-Websocket-Version: 13
Upgrade: websocket
User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.84 Safari/537.36

    location /ws/ {
        proxy_pass http://localhost:8080;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "Upgrade";
        proxy_set_header Origin "";
    }