Nginx 리버스 프록시 설정

upstream app_servers {
    least_conn;
    server app:3000 max_fails=3 fail_timeout=30s;
    keepalive 32;
}

server {
    listen 80;
    server_name example.com www.example.com;
    return 301 https://$host$request_uri;
}

server {
    listen 443 ssl http2;
    server_name example.com www.example.com;

    ssl_certificate     /etc/ssl/certs/example.com.crt;
    ssl_certificate_key /etc/ssl/private/example.com.key;
    ssl_session_timeout 1d;
    ssl_session_cache   shared:SSL:50m;
    ssl_protocols       TLSv1.2 TLSv1.3;
    ssl_ciphers         ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384;
    ssl_prefer_server_ciphers off;
    add_header Strict-Transport-Security "max-age=63072000; includeSubDomains; preload" always;

    gzip on;
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_types text/plain text/css application/json application/javascript text/xml application/xml image/svg+xml;

    add_header X-Frame-Options           "SAMEORIGIN"    always;
    add_header X-Content-Type-Options    "nosniff"       always;
    add_header X-XSS-Protection          "1; mode=block" always;
    add_header Referrer-Policy           "strict-origin-when-cross-origin" always;
    add_header Permissions-Policy        "camera=(), microphone=(), geolocation=()" always;

    client_max_body_size 50M;
    keepalive_timeout    65;
    proxy_read_timeout   120s;

    location /static/ {
        alias /var/www/static/;
        expires 1y;
        add_header Cache-Control "public, immutable";
        access_log off;
    }

    location /api/ {
        proxy_pass         http://app_servers;
        proxy_http_version 1.1;
        proxy_set_header   Upgrade $http_upgrade;
        proxy_set_header   Connection "upgrade";
        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;
        proxy_cache_bypass $http_upgrade;
        proxy_buffering    off;
    }

    location / {
        proxy_pass         http://app_servers;
        proxy_http_version 1.1;
        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;

        location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg|woff2?)$ {
            expires 30d;
            add_header Cache-Control "public";
        }
    }

    location /health {
        access_log off;
        return 200 "healthy\n";
        add_header Content-Type text/plain;
    }
}