https://www.envoyproxy.io/docs/envoy/latest/configuration/http/http_conn_man/header_casing#config-http-conn-man-header-casing
When handling HTTP/1.1, Envoy will normalize the header keys to be all lowercase. While this is compliant with the HTTP/1.1 spec, in practice this can result in issues when migrating existing systems that might rely on specific header casing.
To support these use cases, Envoy allows configuring a formatting scheme for the headers, which will have Envoy transform the header keys during serialization.
- To configure this formatting on response headers, specify the format in the
http_protocol_options.
- To configure this for upstream request headers, specify the formatting in
http_protocol_options in the cluster’s extension_protocol_options.
Currently Envoy supports two mutually exclusive types of header key formatters:
https://www.envoyproxy.io/docs/envoy/latest/api-v3/config/core/v3/protocol.proto#config-core-v3-http1protocoloptions-headerkeyformat
https://www.envoyproxy.io/docs/envoy/latest/api-v3/extensions/http/header_formatters/preserve_case/v3/preserve_case.proto#extension-envoy-http-stateful-header-formatters-preserve-case
This extension may be referenced by the qualified name envoy.http.stateful_header_formatters.preserve_case
Istio example:
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|
apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
name: {{ include "@chartName@.name" . }}-preserve-case-header
spec:
configPatches:
- applyTo: CLUSTER
match:
context: ANY
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
|
