I'm struggling to preserve proper_case in headers (1.19)

[Adam Davis]

I have a service widely used, and after fronting with envoy I had a few clients complain that the header cases changes (default in envoy is lowercase, RFC says it shouldn't matter, but I'm not trying to cause extra work for anyone)

For the life of me I can't get proper_case_words to work. 

When I curl my service, the header is Subject-Token, from envoy it's subject-token.

https://www.envoyproxy.io/docs/envoy/latest/api-v3/config/core/v3/protocol.proto#envoy-v3-api-field-config-core-v3-http1protocoloptions-headerkeyformat-proper-case-words

Is what i'm trying to use, but figuring out how to stuff it into envoy config is beyond my current grasp.

I've tried the following with no luck. Any tips on keeping proper_case headers:

  clusters:

  - name: default

    typed_extension_protocol_options:

      envoy.extensions.upstreams.http.v3.HttpProtocolOptions:

        "@type": type.googleapis.com/envoy.extensions.upstreams.http.v3.HttpProtocolOptions

        explicit_http_config:

          http_protocol_options: 

            header_key_format:

              proper_case_words: {}

    connect_timeout: 15.0s

    type: STRICT_DNS

    lb_policy: ROUND_ROBIN

    load_assignment:

      cluster_name: default

      endpoints:

        - lb_endpoints:

            - endpoint:

                address:

                  socket_address:

                    address: authentication-service

                    port_value: 8087

[Adam Davis]

of course, I fight with this for a full day and then immediately after sending this I get it figured out :)

Instead of having it on the cluster, per this page it is needed on the listener itself 

https://www.envoyproxy.io/docs/envoy/latest/configuration/http/http_conn_man/header_casing

This is what got this working:

static_resources:

  listeners:

  - name: listener_0

    address:

      socket_address: { address: 0.0.0.0, port_value: 10000 }

    filter_chains:

    - filters:

      - name: envoy.filters.network.http_connection_manager

        typed_config:

          "@type": type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager

          stat_prefix: ingress_http

          http_protocol_options: 

            header_key_format:

              proper_case_words: {}

          codec_type: AUTO

          route_config:

             [..] all of my routes