URL Rewriting

Convert the NGINX rewrite-target annotation to a Gateway API HTTPRoute URLRewrite filter.

Path rewriting is common when backends expect a different path than what is exposed publicly. NGINX uses the rewrite-target annotation, while Gateway API uses the URLRewrite filter in an HTTPRoute.

Before: Ingress with Rewrite Target

In this example, requests to /api/v1/users are rewritten to /users before reaching the backend:

cat <<'EOF' > rewrite-ingress.yaml
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: rewrite-demo
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /$2
spec:
  ingressClassName: nginx
  rules:
  - host: api.example.com
    http:
      paths:
      - path: /api/v1(/|$)(.*)
        pathType: ImplementationSpecific
        backend:
          service:
            name: backend-svc
            port:
              number: 80
EOF

Convert

ingress2gateway print --providers=ingress-nginx --emitter=kgateway \
  --input-file rewrite-ingress.yaml > rewrite-kgateway.yaml

After: HTTPRoute with URLRewrite Filter

Gateway API’s URLRewrite filter handles the path transformation:

apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: rewrite-demo-api-example-com
spec:
  hostnames:
  - api.example.com
  parentRefs:
  - name: nginx
  rules:
  - matches:
    - path:
        type: PathPrefix
        value: /api/v1
    filters:
    - type: URLRewrite
      urlRewrite:
        path:
          type: ReplacePrefixMatch
          replacePrefixMatch: /
    backendRefs:
    - name: backend-svc
      port: 80

Note

Edge case: a request to /api/v1 (no trailing slash) matches the PathPrefix of /api/v1, and ReplacePrefixMatch: / leaves an empty replacement — the backend sees a request to an empty path. If clients can send a bare /api/v1, add a second match for /api/v1/ or normalize on the backend.

Apply and verify

kubectl apply -f rewrite-kgateway.yaml
kubectl get httproutes

Timeouts Request Buffering

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