envoy-filter.yaml

apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  name: authn-filter
spec:
  workloadSelector:
    labels:
      istio: ingressgateway
  configPatches:
    - applyTo: HTTP_FILTER
      match:
        context: GATEWAY
      listener:
        filterChain:
          filter:
            name: "envoy.http_connection_manager"
            subFilter:
              name: ""
      patch:
        # For some reason, INSERT_FIRST doesn't work
        operation: INSERT_BEFORE
        value:
          # See: https://www.envoyproxy.io/docs/envoy/v1.17.0/configuration/http/http_filters/ext_authz_filter#config-http-filters-ext-authz
          name: "envoy.filters.http.ext_authz"
          typed_config:
            '@type': type.googleapis.com/envoy.extensions.filters.http.ext_authz.v3.ExtAuthz
            http_service:
              server_uri:
                uri: http://$(AUTHSERVICE_SERVICE).$(AUTHSERVICE_NAMESPACE).svc.cluster.local
                cluster: outbound|8080||$(AUTHSERVICE_SERVICE).$(AUTHSERVICE_NAMESPACE).svc.cluster.local
                timeout: 10s
              authorization_request:
                allowed_headers:
                  patterns:
                    # XXX: MUST be lowercase!
                    - exact: "authorization"
                    - exact: "cookie"
                    - exact: "x-auth-token"
              authorization_response:
                allowed_upstream_headers:
                  patterns:
                    - exact: "kubeflow-userid"