Direct Response

Direct responses are valuable in cases where you want the gateway itself to handle certain requests without forwarding them to backend services. This task shows you how to configure them.

Installation

Follow the steps from the Quickstart to install Envoy Gateway and the example manifest. Before proceeding, you should be able to query the example backend using HTTP.

Testing Direct Response

cat <<EOF | kubectl apply -f -
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: direct-response
spec:
  parentRefs:
  - name: eg
  hostnames:
  - "www.example.com"    
  rules:
  - matches:
    - path:
        type: PathPrefix
        value: /inline
    filters:
    - type: ExtensionRef
      extensionRef:
        group: gateway.envoyproxy.io
        kind: HTTPRouteFilter
        name: direct-response-inline
  - matches:
    - path:
        type: PathPrefix
        value: /value-ref
    filters:
    - type: ExtensionRef
      extensionRef:
        group: gateway.envoyproxy.io
        kind: HTTPRouteFilter
        name: direct-response-value-ref
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: value-ref-response
data:
  response.body: '{"error": "Internal Server Error"}'
---
apiVersion: gateway.envoyproxy.io/v1alpha1
kind: HTTPRouteFilter
metadata:
  name: direct-response-inline
spec:
  directResponse:
    contentType: text/plain
    statusCode: 503
    body:
      type: Inline
      inline: "Oops! Your request is not found."
---
apiVersion: gateway.envoyproxy.io/v1alpha1
kind: HTTPRouteFilter
metadata:
  name: direct-response-value-ref
spec:
  directResponse:
    contentType: application/json
    statusCode: 500
    body:
      type: ValueRef
      valueRef:
        group: ""
        kind: ConfigMap
        name: value-ref-response
EOF

Save and apply the following resource to your cluster:

---
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: direct-response
spec:
  parentRefs:
  - name: eg
  hostnames:
  - "www.example.com"    
  rules:
  - matches:
    - path:
        type: PathPrefix
        value: /inline
    filters:
    - type: ExtensionRef
      extensionRef:
        group: gateway.envoyproxy.io
        kind: HTTPRouteFilter
        name: direct-response-inline
  - matches:
    - path:
        type: PathPrefix
        value: /value-ref
    filters:
    - type: ExtensionRef
      extensionRef:
        group: gateway.envoyproxy.io
        kind: HTTPRouteFilter
        name: direct-response-value-ref
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: value-ref-response
data:
  response.body: '{"error": "Internal Server Error"}'
---
apiVersion: gateway.envoyproxy.io/v1alpha1
kind: HTTPRouteFilter
metadata:
  name: direct-response-inline
spec:
  directResponse:
    contentType: text/plain
    statusCode: 503
    body:
      type: Inline
      inline: "Oops! Your request is not found."
---
apiVersion: gateway.envoyproxy.io/v1alpha1
kind: HTTPRouteFilter
metadata:
  name: direct-response-value-ref
spec:
  directResponse:
    contentType: application/json
    statusCode: 500
    body:
      type: ValueRef
      valueRef:
        group: ""
        kind: ConfigMap
        name: value-ref-response
curl --verbose --header "Host: www.example.com" http://$GATEWAY_HOST/inline
*   Trying 127.0.0.1:80...
* Connected to 127.0.0.1 (127.0.0.1) port 80
> GET /inline HTTP/1.1
> Host: www.example.com
> User-Agent: curl/8.4.0
> Accept: */*
> 
< HTTP/1.1 503 Service Unavailable
< content-type: text/plain
< content-length: 32
< date: Sat, 02 Nov 2024 00:35:48 GMT
< 
* Connection #0 to host 127.0.0.1 left intact
Oops! Your request is not found.
curl --verbose --header "Host: www.example.com" http://$GATEWAY_HOST/value-ref
*   Trying 127.0.0.1:80...
* Connected to 127.0.0.1 (127.0.0.1) port 80
> GET /value-ref HTTP/1.1
> Host: www.example.com
> User-Agent: curl/8.4.0
> Accept: */*
> 
< HTTP/1.1 500 Internal Server Error
< content-type: application/json
< content-length: 34
< date: Sat, 02 Nov 2024 00:35:55 GMT
< 
* Connection #0 to host 127.0.0.1 left intact
{"error": "Internal Server Error"}

Last modified November 14, 2024: docs: fix api doc (#4711) (639a441)