Nginx userspace proxy script - expose localhost service on interface IPs

expose-service.sh

#!/bin/bash

# Create temporary nginx config
CONF_FILE=$(mktemp)
trap "rm -f $CONF_FILE" EXIT

cat > "$CONF_FILE" << 'EOF'
pid /tmp/nginx.pid;
error_log /tmp/nginx-error.log;

events {
    worker_connections 1024;
}

http {
    access_log /tmp/nginx-access.log;
    client_body_temp_path /tmp/nginx-client-body;
    proxy_temp_path /tmp/nginx-proxy;
    fastcgi_temp_path /tmp/nginx-fastcgi;
    uwsgi_temp_path /tmp/nginx-uwsgi;
    scgi_temp_path /tmp/nginx-scgi;

    # WebSocket connection upgrade mapping
    map $http_upgrade $connection_upgrade {
        default upgrade;
        ''      close;
    }

    upstream backend {
        server 127.0.0.1:9090;
    }

    server {
        listen 10.5.0.5:9080;
        listen 100.79.106.85:9080;

        location / {
            proxy_pass http://backend;
            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-Proto $scheme;
            
            # WebSocket support
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection $connection_upgrade;
            proxy_cache_bypass $http_upgrade;
        }
    }
}
EOF

echo "Starting nginx proxy: localhost:9090 -> 10.5.0.5:9080, 100.79.106.85:9080"
echo "Press Ctrl+C to stop"

nginx -c "$CONF_FILE" -g 'daemon off;'