# Nginx Load Balancer Configuration for lokistack Production
# Simple round-robin load balancing between two app instances

events {
    worker_connections 1024;
}

http {
    # Upstream for lokistack app instances
    # ⚠️ 只保留一个后端：平台是 JSON 文件 DB（单写者），
    # 多实例各挂各的数据卷会互相覆盖数据，不是高可用。
    # 详见 docker-compose.prod.yml 顶部说明。
    upstream lokistack_backend {
        server lokistack:8080 max_fails=3 fail_timeout=30s;

        # Health check for upstream servers (nginx-plus) or passive checks
        keepalive 32;
    }

    # Rate limiting zone
    limit_req_zone $binary_remote_addr zone=api_limit:10m rate=10r/s;
    limit_req_zone $binary_remote_addr zone=auth_limit:10m rate=5r/m;

    # Logging format
    log_format main '$remote_addr - $remote_user [$time_local] "$request" '
                    '$status $body_bytes_sent "$http_referer" '
                    '"$http_user_agent" rt=$request_time';

    access_log /var/log/nginx/access.log main;
    error_log /var/log/nginx/error.log warn;

    # Security headers
    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;

    # Gzip compression
    gzip on;
    gzip_types text/plain text/css application/json application/javascript;

    server {
        listen 8080;
        server_name _;

        # Health check endpoint for nginx itself
        location /health {
            access_log off;
            return 200 "healthy\n";
            add_header Content-Type text/plain;
        }

        # Stricter rate limit for authentication
        location /api/v1/auth/login {
            limit_req zone=auth_limit burst=3 nodelay;
            proxy_pass http://lokistack_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;
            proxy_connect_timeout 5s;
            proxy_send_timeout 10s;
            proxy_read_timeout 30s;
        }

        # General API rate limiting
        location /api/ {
            limit_req zone=api_limit burst=20 nodelay;
            proxy_pass http://lokistack_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;
            proxy_connect_timeout 5s;
            proxy_send_timeout 10s;
            proxy_read_timeout 30s;
        }

        # Static files and all other routes
        location / {
            proxy_pass http://lokistack_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;
            proxy_connect_timeout 5s;
            proxy_send_timeout 10s;
            proxy_read_timeout 30s;
            proxy_http_version 1.1;
            proxy_set_header Connection "";
        }
    }
}