Navigation :

Directly respond to requests

Rather than routing an incoming request to an upstream service in your cluster, you can send back a pre-defined body and HTTP status response to the client. If necessary, you can also specify headers by using the Header Modification feature in the enclosing route.

For more information, see the Gloo Gateway API docs for route tables.

Create a direct response route table

Create a virtual gateway that opens up port 80 on your ingress gateway.

kubectl apply -f- <<EOF
apiVersion: networking.gloo.solo.io/v2
kind: VirtualGateway
metadata:
  name: istio-ingressgateway
  namespace: bookinfo
spec:
  workloads:
    # Matches on `spec.selector` labels for the ingress gateway service
    - selector:
        labels:
          istio: ingressgateway
        cluster: ${CLUSTER_NAME}
  listeners:
    # The port the ingress gateway listens on for incoming requests to route
    - port:
        number: 80
      http: {}
EOF

Save the external address of the ingress gateway.

LoadBalancer IP address
EKS: LoadBalancer hostname

export INGRESS_GW_IP=$(kubectl get svc -n gloo-mesh-gateways istio-ingressgateway -o jsonpath='{.status.loadBalancer.ingress[0].ip}')
echo $INGRESS_GW_IP

export INGRESS_GW_IP=$(kubectl get svc -n gloo-mesh-gateways istio-ingressgateway -o jsonpath='{.status.loadBalancer.ingress[0].hostname}')
echo $INGRESS_GW_IP

Create a direct response route table, and specify the status and optional body that is returned. In the following example, the 510 status and no longer supported message are immediately returned in response to any requests to the /unsupported-app path.

kubectl apply -n global -f- <<EOF
apiVersion: networking.gloo.solo.io/v2
kind: RouteTable
metadata:
  name: direct-response
  namespace: global
spec:
  hosts:
    - '*'
  # Selects the virtual gateway you previously created
  virtualGateways:
    - name: istio-ingressgateway
      namespace: bookinfo
      cluster: ${CLUSTER_NAME}
  http:
    - name: unsupported-app-route
      # Prefix matching
      matchers:
      - uri:
          prefix: /unsupported-app
      # Immediately returns this 510 response
      directResponse:
        body: '{"message": "no longer supported"}'
        status: 510
EOF

Verify that you receive the expected direct response by curling the ingress gateway address and, if applicable, the path. For example, the following command appends /unsupported-app.
```
curl http://$INGRESS_GW_IP/unsupported-app
```