Set-Metadata HTTP filter (#16400)

This extension simply allows to add user-defined dynamic metadata. This is intended to be used with matchers, so that the "result" of a matching process can imply specific metadata.

See issue #16266

Risk Level: Medium
Testing: Unit tests for the extension are added
Docs Changes: A small documentation for the extension is added in docs/root/configuration/http/http_filters

Signed-off-by: Adrien Guinet <adrien@reblaze.com>

Mirrored from https://github.com/envoyproxy/envoy @ cbe08bbe33005c1832964f7c9e657d6dbe105bbb

BUILD

@@ -209,6 +209,7 @@ proto_library(
         "//envoy/extensions/filters/http/ratelimit/v3:pkg",
         "//envoy/extensions/filters/http/rbac/v3:pkg",
         "//envoy/extensions/filters/http/router/v3:pkg",
+        "//envoy/extensions/filters/http/set_metadata/v3:pkg",
         "//envoy/extensions/filters/http/squash/v3:pkg",
         "//envoy/extensions/filters/http/tap/v3:pkg",
         "//envoy/extensions/filters/http/wasm/v3:pkg",

envoy/extensions/filters/http/set_metadata/v3/BUILD

@@ -0,0 +1,9 @@
+# DO NOT EDIT. This file is generated by tools/proto_format/proto_sync.py.
+
+load("@envoy_api//bazel:api_build_system.bzl", "api_proto_package")
+
+licenses(["notice"])  # Apache 2
+
+api_proto_package(
+    deps = ["@com_github_cncf_udpa//udpa/annotations:pkg"],
+)

envoy/extensions/filters/http/set_metadata/v3/set_metadata.proto

@@ -0,0 +1,31 @@
+syntax = "proto3";
+
+package envoy.extensions.filters.http.set_metadata.v3;
+
+import "google/protobuf/struct.proto";
+
+import "udpa/annotations/status.proto";
+import "udpa/annotations/versioning.proto";
+import "validate/validate.proto";
+
+option java_package = "io.envoyproxy.envoy.extensions.filters.http.set_metadata.v3";
+option java_outer_classname = "SetMetadataProto";
+option java_multiple_files = true;
+option (udpa.annotations.file_status).package_version_status = ACTIVE;
+
+// [#protodoc-title: Set-Metadata Filter]
+//
+// This filters adds or updates dynamic metadata with static data.
+//
+// [#extension: envoy.filters.http.set_metadata]
+
+message Config {
+  // The metadata namespace.
+  string metadata_namespace = 1 [(validate.rules).string = {min_len: 1}];
+
+  // The value to update the namespace with. See
+  // :ref:`the filter documentation <config_http_filters_set_metadata>` for
+  // more information on how this value is merged with potentially existing
+  // ones.
+  google.protobuf.Struct value = 2;
+}

versioning/BUILD

@@ -92,6 +92,7 @@ proto_library(
         "//envoy/extensions/filters/http/ratelimit/v3:pkg",
         "//envoy/extensions/filters/http/rbac/v3:pkg",
         "//envoy/extensions/filters/http/router/v3:pkg",
+        "//envoy/extensions/filters/http/set_metadata/v3:pkg",
         "//envoy/extensions/filters/http/squash/v3:pkg",
         "//envoy/extensions/filters/http/tap/v3:pkg",
         "//envoy/extensions/filters/http/wasm/v3:pkg",