code: def gateway_default_host(service: str) -> dict:
      domains = [f"{service}.{DOMAIN}"]
      if service == "www":
          domains.append(DOMAIN)
  
      if service == "ukbb-rg":
          return {
              "@type": "type.googleapis.com/envoy.config.route.v3.VirtualHost",
              "name": service,
              "domains": domains,
              "routes": [
                  {
                      "match": {"prefix": "/rg_browser"},
                      "route": route_to_cluster("ukbb-rg-browser"),
                      "typed_per_filter_config": {
                          "envoy.filters.http.ext_authz": auth_check_exemption(),
                      },
                  },
                  {
                      "match": {"prefix": "/"},
                      "route": route_to_cluster("ukbb-rg-static"),
                      "typed_per_filter_config": {
                          "envoy.filters.http.ext_authz": auth_check_exemption(),
                      },
                  },
              ],
          }
  
      return {
          "@type": "type.googleapis.com/envoy.config.route.v3.VirtualHost",
          "name": service,
          "domains": domains,
          "routes": [
              {
                  "match": {"prefix": "/"},
                  "route": route_to_cluster(service),
                  "typed_per_filter_config": {
                      "envoy.filters.http.local_ratelimit": rate_limit_config(
                          service
                      ),
                      "envoy.filters.http.ext_authz": auth_check_exemption(),
                  },
              }
          ],
      }
  
file_path: hail/ci/ci/envoy.py
imports: import os
  import sys
  from typing import Dict, List
  import yaml
label_desc: Use image node_id 3 for calling a global function with example usage: gateway_default_host(service) and returns: dict, dict