# 网关示例：静态前端 + /api 反向代理 + /ai/stream SSE 流式代理 + 限流 + 按 Cookie 灰度
# 运行 test_gateway.py 时会把 {{...}} 占位符替换成临时端口和目录
worker_processes 1;
error_log {{PREFIX}}/error.log warn;
pid {{PREFIX}}/nginx.pid;
events { worker_connections 256; }

http {
    access_log off;
    # 非 root 运行时，把临时文件目录放到可写位置
    client_body_temp_path {{PREFIX}}/client_body;
    proxy_temp_path {{PREFIX}}/proxy;
    fastcgi_temp_path {{PREFIX}}/fastcgi;
    uwsgi_temp_path {{PREFIX}}/uwsgi;
    scgi_temp_path {{PREFIX}}/scgi;

    # 每个 IP 每秒 5 个请求，突发最多 5 个
    limit_req_zone $binary_remote_addr zone=api_limit:10m rate=5r/s;
    limit_req_status 429;

    upstream api_stable { server 127.0.0.1:{{STABLE_PORT}}; keepalive 16; }
    upstream api_canary { server 127.0.0.1:{{CANARY_PORT}}; keepalive 16; }

    # Cookie canary=1 的用户走新版本，其余走稳定版本
    map $cookie_canary $api_backend {
        default api_stable;
        "1"     api_canary;
    }

    server {
        listen 127.0.0.1:{{LISTEN_PORT}};

        # 前端单页应用：找不到文件时回退到 index.html，交给前端路由
        location / {
            root {{PREFIX}}/html;
            try_files $uri $uri/ /index.html;
        }

        location /api/ {
            limit_req zone=api_limit burst=5 nodelay;
            proxy_pass http://$api_backend;
            proxy_http_version 1.1;
            proxy_set_header Connection "";
            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 3s;
            proxy_read_timeout 30s;
        }

        # 大模型流式输出（SSE）：关闭缓冲，否则 Nginx 攒满缓冲区才发给浏览器
        location /ai/stream {
            proxy_pass http://api_stable;
            proxy_http_version 1.1;
            proxy_set_header Connection "";
            proxy_buffering off;
            proxy_cache off;
            proxy_read_timeout 300s;       # 生成时间长，读超时要放宽
            add_header X-Accel-Buffering no;
        }
    }
}