envoyfilter writing authorization header in the response and setting cookie values

envoyfilter.yml

---

apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  name: lua-filter
  namespace: dev
spec:
  workloadSelector:
    labels:
      app: bff
  configPatches:
    - applyTo: HTTP_FILTER
      match:
        context: SIDECAR_INBOUND
        listener:
          filterChain:
            filter:
              name: "envoy.http_connection_manager"
              subFilter:
                name: "envoy.router"
      patch:
        operation: INSERT_BEFORE
        value:
          name: envoy.lua
          typed_config:
            "@type": "type.googleapis.com/envoy.config.filter.http.lua.v2.Lua"
            inlineCode: |
              function stringSplit(inputstr, sep)
                if sep == nil then
                  sep = "%s"
                end
                local t={}
                for str in string.gmatch(inputstr, "([^"..sep.."]+)") do
                  print (str)
                  table.insert(t, str)
                end
                return t
              end

              function envoy_on_request(request_handle)
                headers = request_handle:headers()
                for key, value in pairs(headers) do
                  request_handle:logWarn("key: " .. key .. " <--> value: " .. value)
                end

                request_handle:streamInfo():dynamicMetadata():set("request_headers", "request_authority", headers:get("x-custom-header-authz"))
                request_handle:streamInfo():dynamicMetadata():set("envoy.filters.http.lua", "cookies", headers:get("cookie"))
              end

              function envoy_on_response(response_handle)
                local meta = response_handle:streamInfo():dynamicMetadata():get("request_headers")
                for key, value in pairs(meta) do
                  response_handle:headers():add("Authorization", "Bearer " .. value)
                  response_handle:headers():add("set-cookie", "x-jwt=" .. value)
                end

                local cookies = response_handle:streamInfo():dynamicMetadata():get("envoy.filters.http.lua")
                local sep = ";"
                for key, value in pairs(cookies) do
                  splits = stringSplit(value, sep)
                  for k, v in pairs(splits) do
                    response_handle:headers():add("set-cookie", v)
                    response_handle:logWarn("COOKIESkey: " .. k .. " <--> COOKIESvalue: " .. v)
                  end

                end
              end

---