xds: add config for pick_first LB policy extension (#26952)

Signed-off-by: Easwar Swaminathan <easwars@google.com>

Mirrored from https://github.com/envoyproxy/envoy @ 7897f75a1f0cc744cbd83191fa37fb485ceabab8

BUILD

@@ -254,6 +254,7 @@ proto_library(
         "//envoy/extensions/load_balancing_policies/common/v3:pkg",
         "//envoy/extensions/load_balancing_policies/least_request/v3:pkg",
         "//envoy/extensions/load_balancing_policies/maglev/v3:pkg",
+        "//envoy/extensions/load_balancing_policies/pick_first/v3:pkg",
         "//envoy/extensions/load_balancing_policies/random/v3:pkg",
         "//envoy/extensions/load_balancing_policies/ring_hash/v3:pkg",
         "//envoy/extensions/load_balancing_policies/round_robin/v3:pkg",

envoy/extensions/load_balancing_policies/pick_first/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/load_balancing_policies/pick_first/v3/pick_first.proto

@@ -0,0 +1,22 @@
+syntax = "proto3";
+
+package envoy.extensions.load_balancing_policies.pick_first.v3;
+
+import "udpa/annotations/status.proto";
+
+option java_package = "io.envoyproxy.envoy.extensions.load_balancing_policies.pick_first.v3";
+option java_outer_classname = "PickFirstProto";
+option java_multiple_files = true;
+option go_package = "github.com/envoyproxy/go-control-plane/envoy/extensions/load_balancing_policies/pick_first/v3;pick_firstv3";
+option (udpa.annotations.file_status).package_version_status = ACTIVE;
+
+// [#protodoc-title: Pick First Load Balancing Policy]
+// [#not-implemented-hide:]
+
+// This configuration allows the built-in PICK_FIRST LB policy to be configured
+// via the LB policy extension point.
+message PickFirst {
+  // If set to true, instructs the LB policy to shuffle the list of addresses
+  // received from the name resolver before attempting to connect to them.
+  bool shuffle_address_list = 1;
+}

versioning/BUILD

@@ -193,6 +193,7 @@ proto_library(
         "//envoy/extensions/load_balancing_policies/common/v3:pkg",
         "//envoy/extensions/load_balancing_policies/least_request/v3:pkg",
         "//envoy/extensions/load_balancing_policies/maglev/v3:pkg",
+        "//envoy/extensions/load_balancing_policies/pick_first/v3:pkg",
         "//envoy/extensions/load_balancing_policies/random/v3:pkg",
         "//envoy/extensions/load_balancing_policies/ring_hash/v3:pkg",
         "//envoy/extensions/load_balancing_policies/round_robin/v3:pkg",