service.yaml

apiVersion: cloud.google.com/v1
kind: BackendConfig
metadata:
  name: api-gateway-backend
spec:
  securityPolicy:
    name: waf-policy
  customRequestHeaders:
{{/*https://cloud.google.com/kubernetes-engine/docs/how-to/ingress-features#request_headers*/}}
{{/*https://cloud.google.com/load-balancing/docs/https/custom-headers*/}}
    headers:
      - "X-Client-Region:{client_region}"
      - "X-Client-State:{client_region_subdivision}"
      - "X-Client-City:{client_city}"