Nginx rate limiting and caching configuration

# /etc/nginx/nginx.conf or /etc/nginx/conf.d/default.conf

# Rate limiting zones (define at http level)
limit_req_zone $binary_remote_addr zone=api_limit:10m rate=60r/m;
limit_req_zone $binary_remote_addr zone=write_limit:10m rate=20r/m;

# Cache zone
proxy_cache_path /tmp/nginx_cache levels=1:2 keys_zone=api_cache:10m max_size=100m inactive=60m;

server {
    listen 80;
    server_name api.example.com;

    gzip on;
    gzip_types application/json text/plain;
    gzip_min_length 1024;

    # Apply rate limit to all routes
    limit_req zone=api_limit burst=20 nodelay;

    location /api/v1/traces/search {
        # Stricter limit for expensive search endpoint
        limit_req zone=api_limit burst=10 nodelay;
        limit_req_status 429;

        # Cache GET search responses for 30 seconds
        proxy_cache api_cache;
        proxy_cache_key "$request_uri$http_x_api_key";
        proxy_cache_valid 200 30s;
        proxy_cache_bypass $http_pragma;
        add_header X-Cache-Status $upstream_cache_status;

        proxy_pass http://api:8000;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }

    location /api/v1/traces {
        # Stricter write limit
        limit_req zone=write_limit burst=5 nodelay;
        proxy_pass http://api:8000;
    }

    location / {
        proxy_pass http://api:8000;
        proxy_read_timeout 30s;
    }
}