WebAssembly

In this scenario we demonstrate how to apply a wasm extension to an HttpRoute.

You will apply an extension policy that references a simple, pre-built wasm plugin to the HttpRoute for the httpbin sample application.

The basic logic of the plugin is to inject arbitrary, configurable headers into HTTP responses on the associated route.

Context

httpbin is already deployed to the default namespace and the simple HttpRoute is already defined for it.

Instructions

1. Send a test request to the httpbin route:

    curl -v http://httpbin.esuez.org/json --resolve httpbin.esuez.org:80:$GATEWAY_IP
   

   The request should succeed, and return some json.

   Note the headers in the HTTP response.

2. Review the following extension policy:

   ---
   apiVersion: gateway.envoyproxy.io/v1alpha1
   kind: EnvoyExtensionPolicy
   metadata:
     name: wasm-plugin
   spec:
     targetRefs:
     - group: gateway.networking.k8s.io
       kind: HTTPRoute
       name: httpbin
     wasm:
     - code:
         type: Image
         image:
           url: us-central1-docker.pkg.dev/eitan-tetrate/misc-repo/wasm:v1
       config:
         header_1: my first header
         header_2: "yet another header.."
   

   Apply the policy:

   kubectl apply -f wasm/extension-policy.yaml
   

3. Repeat the request:

   curl -v http://httpbin.esuez.org/json --resolve httpbin.esuez.org:80:$GATEWAY_IP
   

   Note the response headers contain extra headers from the configuration of the wasm plugin.