Configuración para Nginx + Webapp + API Express + SocketIO

default.conf

upstream spa {
  server webapp:2000;
}

upstream api {
  server api:3000;
}

server {

  listen       80 default_server;
  server_name  _;
  root /var/html/www;

  location / {
    include /etc/nginx/proxy_reverse.conf;
    proxy_pass         http://spa/;
  }

  location /api/ {
    include /etc/nginx/proxy_reverse.conf;
    proxy_pass         http://api/;
  }

  location /socket.io/ {
    include /etc/nginx/websocket.conf;
    proxy_pass         http://api/socket.io/;
  }

}

proxy_reverse.conf

proxy_redirect     off;
proxy_set_header   Host $host;
proxy_set_header   X-Real-IP $remote_addr;
proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header   X-Forwarded-Host $server_name;

websocket.conf

proxy_http_version 1.1;
proxy_buffering    off;
proxy_redirect     off;

proxy_set_header   Host $host;
proxy_set_header   X-Real-IP $remote_addr;
proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;

proxy_set_header   Upgrade $http_upgrade;
proxy_set_header   Connection "Upgrade";