istio-fev1-httpfilter-ext_authz.yaml

apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  name: ext-authz-filter
spec:
  workloadSelector:
    labels:
      app: myapp
      version: v1
  configPatches:
    - applyTo: HTTP_FILTER
      match:
        proxy:
          proxyVersion: ^1\.7.*      
        context: SIDECAR_INBOUND
        listener:
          portNumber: 8080
          filterChain:
            filter:
              name: "envoy.http_connection_manager"
              subFilter:
                name: "envoy.router"
      patch:
        operation: INSERT_BEFORE
        value:
         name: envoy.filters.http.ext_authz
         typed_config:
           "@type": type.googleapis.com/envoy.extensions.filters.http.ext_authz.v3.ExtAuthz
           grpc_service:
            google_grpc:
              target_uri: "your_grpc_server_ip:50051"
              stat_prefix: "ext_authz"