envoyfilter.yaml

apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  name: json-validation
  namespace: istio-system
spec:
  configPatches:
    - applyTo: HTTP_FILTER
      match:
        context: GATEWAY
      patch:
        operation: INSERT_BEFORE
        value:
          name: json-validation
          typed_config:
            "@type": type.googleapis.com/envoy.extensions.filters.http.wasm.v3.Wasm
            config:
              configuration:
                "@type": type.googleapis.com/google.protobuf.StringValue
                value: |
                  { "requiredKeys": ["id", "token"] }
              vm_config:
                code:
                  local:
                    filename: /var/local/lib/wasm-plugins/main.wasm
                runtime: envoy.wasm.runtime.v8
                vm_id: json-validation