nginx.conf

server {
    listen 80;
    server_name __DOMAIN__;

    location /.well-known/acme-challenge/ {
        root /var/www/certbot;
    }

    location / {
        return 301 https://$host$request_uri;
    }
}

server {
    listen 443 ssl http2;
    server_name __DOMAIN__;

    ssl_certificate /etc/letsencrypt/live/__DOMAIN__/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/__DOMAIN__/privkey.pem;

    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers HIGH:!aNULL:!MD5;
    ssl_prefer_server_ciphers on;

    # Allow large request bodies for API calls
    client_max_body_size 100M;

    # Timeouts for long-running LLM requests
    proxy_read_timeout 300s;
    proxy_send_timeout 300s;
    proxy_connect_timeout 10s;

    # Session affinity: extract session_id from request body
    set $session_id '';

    location / {
        access_by_lua_file /etc/nginx/extract_session.lua;

        proxy_pass http://127.0.0.1:4000;
        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_set_header x-litellm-session-id $session_id;

        # SSE support for streaming responses
        proxy_buffering off;
        proxy_cache off;
        proxy_set_header Connection '';
        chunked_transfer_encoding on;
    }
}