server {
    listen       ${PORT};
    server_name  _;

    root /opt/excalidraw/build;
    index index.html;

    # React single-page app
    location / {
        try_files $uri /index.html;
    }

    # WebSocket collaboration server
    location /room/ {
        proxy_pass         http://127.0.0.1:${ROOM_PORT}/;
        proxy_http_version 1.1;
        proxy_set_header   Upgrade $http_upgrade;
        proxy_set_header   Connection "Upgrade";
        proxy_set_header   Host $host;
    }

    # HTTP storage backend
    location /api/ {
        proxy_pass http://127.0.0.1:${STORAGE_PORT}/;
        proxy_set_header Host $host;
    }
}