Istio Preserve Header Case

1

Istio converts the headers’s case to lower case. But we wanted to preserve the case.
We use Istio 1.9

I am trying the following envoyfilter from:

kind: EnvoyFilter
metadata:
  name: header-casing
spec:
  configPatches:
  - applyTo: CLUSTER
    match:
      cluster:
      context: SIDECAR_INBOUND
    patch:
      operation: MERGE
      value:
        typed_extension_protocol_options:
          envoy.extensions.upstreams.http.v3.HttpProtocolOptions:
            '@type': type.googleapis.com/envoy.extensions.upstreams.http.v3.HttpProtocolOptions
            use_downstream_protocol_config:
              http_protocol_options:
                header_key_format:
                  stateful_formatter:
                    name: preserve_case
                    typed_config:
                      '@type': type.googleapis.com/envoy.extensions.http.header_formatters.preserve_case.v3.PreserveCaseFormatterConfig
  - applyTo: NETWORK_FILTER
    match:
      listener:
        filterChain:
          filter:
            name: envoy.filters.network.http_connection_manager
    patch:
      operation: MERGE
      value:
        typed_config:
          '@type': type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager
          http_protocol_options:
            header_key_format:
              stateful_formatter:
                name: preserve_case
                typed_config:
                  '@type': type.googleapis.com/envoy.extensions.http.header_formatters.preserve_case.v3.PreserveCaseFormatterConfig

I get this error:
The EnvoyFilter “header-casing” is invalid: spec.configPatches.match.cluster: Invalid value: “null”: spec.configPatches.match.cluster in body must be of type object: “null”

Any help on this would be appreciated

2 
cluster: <> is empty. Try with correct cluster name.
3

Thanks,
What would be cluster name, how can I get this details, I tried with
cluster:
name : “test”

I could apply the yaml, but header is still in lower case