Envoy Wasm filters with Gloo Gateway

1. Get the configuration for your gateway-proxy gateway.

   kubectl get -n gloo-system gateways.gateway.solo.io gateway-proxy -o yaml > gateway-proxy.yaml
   open gateway-proxy.yaml
   

2. Add the reference to your Wasm filter in the httpGateway section as follows.

     httpGateway:
       options:
         wasm:
           filters:
           - config:
               '@type': type.googleapis.com/google.protobuf.StringValue
               value: "world"
             image: gcr.io/solo-public/docs/assemblyscript-test:istio-1.8
             name: add-header
             rootId: add_header
   

3. Update the gateway-proxy gateway.

   kubectl apply -n gloo-system -f gateway-proxy.yaml
   

1. Get the configuration for your gateway-proxy gateway.

   kubectl get -n gloo-system gateways.gateway.solo.io gateway-proxy -o yaml  > gateway-proxy.yaml
   

2. Add the filepath reference to your .wasm file in the httpGateway section as follows.

    httpGateway:
      options:
        wasm:
          filters:
          - config:
              '@type': type.googleapis.com/google.protobuf.StringValue
              value: "world"
            filePath: filters-dir/my-filter.wasm
            name: add-header
            rootId: add_header
   

3. Update the gateway-proxy gateway.

   kubectl apply -n gloo-system -f gateway-proxy.yaml
   

Build a Docker image that has the Wasm filter image you previously created and use this image in an init container that runs alongside the gateway proxy.

1. Create a Dockerfile in the same location as your Wasm filter. The Dockerfile makes an image that has your Wasm filter, and copies the filter to the /wasm-filters/ directory when the image runs. Later, you mount this directory in a shared volume. Note: In the previous section, your Wasm file is called filter.wasm and is located at .wasmstore/<uniqueId>/filter.wasm. If built your filter with a different tool than wasme (such as bazel), your filter location might differ.

   FROM alpine
   COPY filter.wasm filter.wasm
   CMD ["cp", "filter.wasm", "/wasm-filters/"]
   

2. Build and tag a Docker image from this Dockerfile. Replace the example values with your repository URL and preferred image name in the following example command.

   docker build . -t localhost:8888/myorg/my-wasm-getter:1.0.0
   

3. Push the Docker image to an image repository that your enterprise network can access.

   docker push localhost:8888/myorg/my-wasm-getter:1.0.0
   

4. Edit your gateway-proxy deployment to add an init container and mount a shared volume. For a full example, see this gateway-proxy-wasm.yaml file.
   1. Get the configuration for the gateway-proxy deployment.

      kubectl get -n gloo-system deployment gateway-proxy -o yaml > gateway-proxy-wasm.yaml
      

   2. In the spec.template.spec.volumes section, add a volume named wasm-filters that all the containers in the template can access.

            volumes:
            - configMap:
                defaultMode: 420
                name: gateway-proxy-envoy-config
              name: envoy-config
            - name: wasm-filters
      

   3. In the spec.template.spec.containers section, add a mount path to the wasm-filters volume that you just configured.

            containers:
              volumeMounts:
              - mountPath: /etc/envoy
                name: envoy-config
              - mountPath: /wasm-filters
                name: wasm-filters
      

   4. In the spec.template.spec section, add the following init container stanza, which refers to the Wasm image that you just built and mounts the volume.

            initContainers:
            - name: wasm-image
              image: localhost:8888/myorg/my-wasm-getter:1.0.0
              imagePullPolicy: IfNotPresent
              volumeMounts:
              - mountPath: /wasm-filters
                name: wasm-filters
      

   5. Apply the updated gateway-proxy deployment.

      kubectl apply -n gloo-system -f gateway-proxy-wasm.yaml
      

5. Now that the Wasm filter is in a shared mount filepath accessible by Envoy, get the configuration for your gateway-proxy gateway.

   kubectl get -n gloo-system gateways.gateway.solo.io gateway-proxy -o yaml  > gateway-proxy.yaml
   

6. Add the filepath reference to your .wasm file in the httpGateway section as follows.

    httpGateway:
      options:
        wasm:
          filters:
          - config:
              '@type': type.googleapis.com/google.protobuf.StringValue
              value: "my test config"
            filePath: /wasm-filters/filter.wasm
            name: add-header
            rootId: add_header
   

7. Update the gateway-proxy gateway.

   kubectl apply -n gloo-system -f gateway-proxy.yaml