Lua filter logging is not working

1

I am new in this field. Trying to implement lua filter with OPA [ open policy agent and istio ]

to implement a simple poc, i have created following following filter

 ############################################################
# Envoy External Authorization filter that will query OPA.
############################################################
apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  name: ext-authz
  namespace: istio-system
spec:
  filters:
  - insertPosition:
      index: FIRST
    listenerMatch:
      listenerType: GATEWAY
      listenerProtocol: HTTP
    filterType: HTTP
    filterName: envoy.lua
    filterConfig:
      inlineCode: |
        function envoy_on_request(request_handle)
            request_handle:logWarn("envoy_on_request")
        end

        function envoy_on_response(response_handle)
            response_handle:logWarn("envoy_on_response")
            response_handle:headers():add("x-this","It works")
        end
---

When i am executing my api I am able to get the updated header value in output. [ seems lua filter is invoked in filter chain ]

but my problem is, i am not able to find the log “envoy_on_request” anywhere in the container logs.

need you suggestion to find the log…