How to Rewrite URL Paths and Hostnames with Envoy Gateway

Scenario 1: Rewrite URL Prefix Path

In a microservice architecture, the frontend may call /api/v1/who while the backend service expects /who. The goal is to let the gateway automatically rewrite /api/v1/who to /who.

cat <<'EOF' | kubectl apply -f -
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: simple
spec:
  hostnames:
  - example.local
  parentRefs:
  - group: gateway.networking.k8s.io
    kind: Gateway
    name: simple-gw
  rules:
  - matches:
    - path:
        type: PathPrefix
        value: /api/v1/who  # Browser request path
    filters:
    - type: URLRewrite
      urlRewrite:
        path:
          type: ReplacePrefixMatch
          replacePrefixMatch: /who  # Path seen by the service
    backendRefs:
    - name: simple
      port: 80
EOF

Apply the manifest with kubectl apply -f - and verify that the service receives the rewritten path.