About

When caching is enabled during installation, a caching server deployment is automatically created for you and managed by Gloo Gateway. Then you must configure an HTTP or HTTPS listener on your gateway to cache responses for upstream services. When the listener routes a request to an upstream, the response from the upstream is automatically cached by the caching server if it contains a cache-control response header. All subsequent requests receive the cached response, until the cache entry expires.

For more information, see About response caching.

In this guide, you complete the following tasks:

  • Enable the Gloo Gateway caching server.
  • Deploy the Envoy caching service. You use this service to try out caching with response validation.
  • Configure caching for an HTTP listener.
  • Verify response caching:
    • You use the httpbin app from the Get started guide to test response caching without validation.
    • You use the Envoy caching app to test response caching with validation.

Before you begin

  1. Follow the Get started guide to install Gloo Gateway, set up a gateway resource, and deploy the httpbin sample app.

  2. Get the external address of the gateway and save it in an environment variable.

Deploy the caching server

  1. Get the Helm values for your current installation.

      helm get values gloo-gateway -n gloo-system -o yaml > gloo-gateway.yaml
    open gloo-gateway.yaml
      
  2. Add the following values to your Helm values file to enable the caching server.

      
    global: 
      extensions: 
        caching: 
          enabled: true # Enable the caching server. 
      
  3. Upgrade your Helm installation.

      helm upgrade -n gloo-system gloo-gateway glooe/gloo-ee \
     -f gloo-gateway.yaml \
     --version=1.17.3
      
  4. Verify that the caching server is deployed.

      kubectl --namespace gloo-system get all | grep caching
      

    Example output:

      pod/caching-service-5d7f867cdc-bhmqp                  1/1     Running   0          74s
    service/caching-service                       ClusterIP      10.76.11.242   <none>          8085/TCP                                               77s
    deployment.apps/caching-service                       1/1     1            1           77s
    replicaset.apps/caching-service-5d7f867cdc            1         1         1       76s
      

Deploy the Envoy caching service

  1. Create a namespace for the Envoy caching service.

      kubectl create ns envoy-caching
      
  2. Deploy the caching app and expose it with a Kubernetes service.

      kubectl apply -n envoy-caching -f- <<EOF
    apiVersion: v1
    kind: Pod
    metadata:
      labels:
        app: service1
      name: service1
    spec:
      containers:
      - image: ghcr.io/huzlak/caching-service:0.2
        name: service1
        ports:
        - name: http
          containerPort: 8000
        readinessProbe:
          httpGet:
            port: 8000
            path: /service/1/no-cache
    ---
    apiVersion: v1
    kind: Service
    metadata:
      name: service1
    spec:
      ports:
        - port: 8000
          name: http
          targetPort: http
      selector:
        app: service1
    EOF
      
  3. Verify that the app is up and running.

      kubectl get pods -n envoy-caching
      

    Example output:

      NAMESPACE           NAME                 READY   STATUS    RESTARTS        AGE
    envoy-caching       service1             1/1     Running   0               23h
      
  4. Create an HTTPRoute resource to route incoming requests on the caching.example.com domain to the Envoy caching service.

      kubectl apply -f- <<EOF
    apiVersion: gateway.networking.k8s.io/v1beta1
    kind: HTTPRoute
    metadata:
      name: envoy-caching-route
      namespace: envoy-caching
      labels:
        example: envoy-caching-route
    spec:
      parentRefs:
        - name: http
          namespace: gloo-system
      hostnames:
        - "caching.example.com"
      rules:
        - backendRefs:
            - name: service1
              port: 8000
    EOF
      
  5. Send a request to the Envoy caching service and verify that you get back a 200 HTTP response code.

    Example output:

      HTTP/1.1 200 OK
    content-type: text/html; charset=utf-8
    content-length: 126
    cache-control: max-age=0, no-cache
    etag: "ae3959c591c5e69e5175fbc2c8b272f15883952b"
    date: Mon, 24 Jun 2024 20:22:47 GMT
    server: envoy
    x-envoy-upstream-service-time: 6
      

Configure and verify caching for an HTTP listener

In the following example, you configure caching for the HTTP listener on the http gateway that you set up as part of the Get started guide. Alternatively, you can configure the cachingServer section in your Gloo Settings resource to enable HTTP caching for all gateways by default.

Then, you try out caching with and without response validation with the following apps:

  • httpbin: The /cache/{value} endpoint is used to show how caching works without response validation. This app is deployed as part of the Get started guide.
  • Envoy caching service: The /valid-for-minute endpoint is used to show how caching works with response validation. This app is deployed as part of this guide.
  1. Create an HTTPListenerOption resource to configure response caching for all services that are served by an HTTP or HTTPS listener. Enabling caching for a specific service or upstream is currently not supported. Note that for listener-level caching to take effect, the cachingServer option of the Settings resource must be disabled.

      kubectl apply -f- <<EOF
    apiVersion: gateway.solo.io/v1
    kind: HttpListenerOption
    metadata:
      name: caching
      namespace: gloo-system
    spec:
      targetRefs:
      - group: gateway.networking.k8s.io
        kind: Gateway
        name: http
      options:
        caching:
          cachingServiceRef:
            name: caching-service
            namespace: gloo-system
    EOF
      
  2. Try out caching without response validation by using the /cache/{value} endpoint of the httpbin app.

    1. Send a request to the /cache/{value} endpoint. The {value} variable specifies the number of seconds that you want to cache the response for. In this example, the response is cached for 30 seconds. In your CLI output, verify that you get back the cache-control response header with a max-age=30 value. This response header triggers Gloo Gateway to cache the response.

      Example output:

            * Mark bundle as not supporting multiuse
            < HTTP/1.1 200 OK
            HTTP/1.1 200 OK
            < access-control-allow-credentials: true
            access-control-allow-credentials: true
            < access-control-allow-origin: *
            access-control-allow-origin: *
            < cache-control: public, max-age=30
            cache-control: public, max-age=30
            < content-type: application/json; encoding=utf-8
            content-type: application/json; encoding=utf-8
            < date: Mon, 24 Jun 2024 20:53:12 GMT
            date: Mon, 24 Jun 2024 20:53:12 GMT
            < content-length: 603
            content-length: 603
            < x-envoy-upstream-service-time: 2
            x-envoy-upstream-service-time: 2
            < server: envoy
            server: envoy
            < x-envoy-decorator-operation: httpbin.httpbin.svc.cluster.local:8000/*
            x-envoy-decorator-operation: httpbin.httpbin.svc.cluster.local:8000/*
      
            {
              "args": {},
              "headers": {
                "Accept": [
                "*/*"
                ],
                "Host": [
                "www.example.com:8080"
                ],
                "If-Modified-Since": [
                "Mon, 24 Jun 2024 20:40:41 GMT"
                ],
                "User-Agent": [
                "curl/7.77.0"
                ],
                "X-B3-Sampled": [
                "0"
                ],
                "X-B3-Spanid": [
                "939316d334cefd4b"
                ],
                "X-B3-Traceid": [
                "6b20a80619a46d1b939316d334cefd4b"
                ],
                "X-Forwarded-Proto": [
                "http"
                ],
                "X-Request-Id": [
                "62dfa4c8-0155-4b9a-8ee1-69250ebdc71a"
                ]
            }
            

    2. Send another request to the same endpoint within the 30s timeframe. In your CLI output, verify that you get back the original response. In addition, check that an age response header is returned indicating the age of the cached response, and that the date header uses the date and time of the original response.

      Example output:

            * Mark bundle as not supporting multiuse
            < HTTP/1.1 200 OK
            HTTP/1.1 200 OK
            < access-control-allow-origin: *
            access-control-allow-origin: *
            < server: envoy
            server: envoy
            < date: Mon, 24 Jun 2024 20:53:12 GMT
            date: Mon, 24 Jun 2024 20:53:12 GMT
            < x-envoy-upstream-service-time: 2
            x-envoy-upstream-service-time: 2
            < cache-control: public, max-age=30
            cache-control: public, max-age=30
            < x-envoy-decorator-operation: httpbin.httpbin.svc.cluster.local:8000/*
            x-envoy-decorator-operation: httpbin.httpbin.svc.cluster.local:8000/*
            < content-length: 603
            content-length: 603
            < access-control-allow-credentials: true
            access-control-allow-credentials: true
            < content-type: application/json; encoding=utf-8
            content-type: application/json; encoding=utf-8
            < age: 21
            age: 21
            ...
            

    3. Wait until the 30 seconds pass and the cached response becomes stale. Send another request to the same endpoint. Verify that you get back a fresh response and that no age header is returned.

      Example output:

            * Mark bundle as not supporting multiuse
            < HTTP/1.1 200 OK
            HTTP/1.1 200 OK
            < access-control-allow-credentials: true
            access-control-allow-credentials: true
            < access-control-allow-origin: *
            access-control-allow-origin: *
            < cache-control: public, max-age=30
            cache-control: public, max-age=30
            < content-type: application/json; encoding=utf-8
            content-type: application/json; encoding=utf-8
            < date: Mon, 24 Jun 2024 21:05:45 GMT
            date: Mon, 24 Jun 2024 21:05:45 GMT
            < content-length: 603
            content-length: 603
            < x-envoy-upstream-service-time: 2
            x-envoy-upstream-service-time: 2
            < server: envoy
            server: envoy
            < x-envoy-decorator-operation: httpbin.httpbin.svc.cluster.local:8000/*
            x-envoy-decorator-operation: httpbin.httpbin.svc.cluster.local:8000/*
            

  3. Try out caching with response validation by using the Envoy caching service. Response validation must be implemented in the upstream service directly. The service must be capable of reading the date and time that is sent in the If-Modified-Since request header and to check if the response has changed since then.

    1. Send a request to the /valid-for-minute endpoint. The endpoint is configured to cache the response for 1 minute (cache-control: max-age=60). When the response becomes stale after 1 minute, the request validation process starts.

      Example output:

            * Mark bundle as not supporting multiuse
            < HTTP/1.1 200 OK
            HTTP/1.1 200 OK
            < content-type: text/html; charset=utf-8
            content-type: text/html; charset=utf-8
            < content-length: 99
            content-length: 99
            < cache-control: max-age=60
            cache-control: max-age=60
            < custom-header: any value
            custom-header: any value
            < etag: "324ce9104e113743300a847331bb942ab7ace81a"
            etag: "324ce9104e113743300a847331bb942ab7ace81a"
            < date: Mon, 24 Jun 2024 21:35:55 GMT
            date: Mon, 24 Jun 2024 21:35:55 GMT
            < server: envoy
            server: envoy
            < x-envoy-upstream-service-time: 5
            x-envoy-upstream-service-time: 5
      
            < 
            This response will stay fresh for one minute
        
            Response generated at: Mon, 24 Jun 2024 21:35:55 GMT
            

    2. Send another request to the same endpoint within the 1 minute timeframe. Because the response is cached for 1 minute, the original response is returned with an age header indicating the number of seconds that passed since the original response was sent. Make sure that the date header and response body include the same information as in the original response.

      Example output:

            * Mark bundle as not supporting multiuse
            < HTTP/1.1 200 OK
            HTTP/1.1 200 OK
            < server: envoy
            server: envoy
            < date: Mon, 24 Jun 2024 21:35:55 GMT
            date: Mon, 24 Jun 2024 21:35:55 GMT
            < content-length: 99
            content-length: 99
            < cache-control: max-age=60
            cache-control: max-age=60
            < etag: "324ce9104e113743300a847331bb942ab7ace81a"
            etag: "324ce9104e113743300a847331bb942ab7ace81a"
            < x-envoy-upstream-service-time: 5
            x-envoy-upstream-service-time: 5
            < custom-header: any value
            custom-header: any value
            < content-type: text/html; charset=utf-8
            content-type: text/html; charset=utf-8
            < age: 3
            age: 3
      
            < 
            This response will stay fresh for one minute
      
            Response generated at: Mon, 24 Jun 2024 21:35:55 GMT
            

    3. After the 1 minute passes and the cached response becomes stale, send another request to the same endpoint. The Envoy caching app is configured to automatically add the If-Modified-Since header to each request to trigger the response validation process. In addition, the app is configured to always return a 304 Not Modified HTTP response code to indicate that the response has not changed. When the 304 HTTP response code is received by the Gloo Gateway caching server, the caching server fetches the original response from Redis, and sends it back to the client.

      You can verify that the response validation succeeded when the date response header is updated with the time and date of your new request, the age response header is removed, and the response body contains the same information as in the original response.

      Example output:

            * Mark bundle as not supporting multiuse
            < HTTP/1.1 200 OK
            HTTP/1.1 200 OK
            < cache-control: max-age=60
            cache-control: max-age=60
            < custom-header: any value
            custom-header: any value
            < etag: "324ce9104e113743300a847331bb942ab7ace81a"
            etag: "324ce9104e113743300a847331bb942ab7ace81a"
            < date: Mon, 24 Jun 2024 21:46:40 GMT
            date: Mon, 24 Jun 2024 21:46:40 GMT
            < server: envoy
            server: envoy
            < x-envoy-upstream-service-time: 6
            x-envoy-upstream-service-time: 6
            < content-length: 99
            content-length: 99
            < content-type: text/html; charset=utf-8
            content-type: text/html; charset=utf-8
      
            < 
            This response will stay fresh for one minute
       
            Response generated at: Mon, 24 Jun 2024 21:35:55 GMT
            

Cleanup

You can remove the resources that you created in this guide.

  kubectl delete pod service1 -n envoy-caching
kubectl delete service service1 -n envoy-caching
kubectl delete httproute envoy-caching-route -n envoy-caching
kubectl delete namespace envoy-caching
kubectl delete HttpListenerOption caching -n gloo-system