[channelz-v2] Place down the basic protobufs (grpc#39871)

Per grpc/proposal#493 (sans service just yet) - just getting the basic protobufs in place to start working on implementation

Closes grpc#39871

PiperOrigin-RevId: 772476936

Author: ctiller

BUILD

@@ -5168,6 +5168,16 @@ grpc_upb_proto_reflection_library(
     deps = ["//src/proto/grpc/lookup/v1:rls_config_proto"],
 )
 
+grpc_upb_proto_library(
+    name = "channelz_upb",
+    deps = ["//src/proto/grpc/channelz/v2:channelz_proto"],
+)
+
+grpc_upb_proto_reflection_library(
+    name = "channelz_upbdefs",
+    deps = ["//src/proto/grpc/channelz/v2:channelz_proto"],
+)
+
 WELL_KNOWN_PROTO_TARGETS = [
     "any",
     "duration",

bazel/grpc_build_system.bzl

@@ -745,6 +745,8 @@ def grpc_package(name, visibility = "private", features = []):
         visibility = ["//visibility:public"]
     elif visibility == "private":
         visibility = []
+    elif visibility == "grpc":
+        visibility = ["//:__subpackages__"]
     else:
         fail("Unknown visibility " + visibility)
 

src/core/ext/upb-gen/src/proto/grpc/channelz/v2/channelz.upb.h

@@ -0,0 +1,31 @@
+# Copyright 2025 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+load("//bazel:grpc_build_system.bzl", "grpc_internal_proto_library", "grpc_package")
+
+licenses(["notice"])
+
+grpc_package(
+    name = "src/proto/grpc/channelz/v2",
+    visibility = "grpc",
+)
+
+grpc_internal_proto_library(
+    name = "channelz_proto",
+    srcs = ["channelz.proto"],
+    deps = [
+        "@com_google_protobuf//:any_proto",
+        "@com_google_protobuf//:timestamp_proto",
+    ],
+)

src/core/ext/upb-gen/src/proto/grpc/channelz/v2/channelz.upb_minitable.c

@@ -0,0 +1,57 @@
+// Copyright 2025 The gRPC Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+
+///////////////////////////////////////////////////////////////////////////////
+// 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨
+//
+// This protocol is under active development, and will change in backwards
+// incompatible ways in the future.
+//
+// DO NOT take a dependency on this without contacting the gRPC authors
+// (who will advise against taking such a dependency in as strong a fashion
+// as they are able)
+//
+// 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨 🚨
+///////////////////////////////////////////////////////////////////////////////
+
+package grpc.channelz.v2;
+
+import "google/protobuf/any.proto";
+import "google/protobuf/timestamp.proto";
+
+message Entity {
+    // The identifier for this entity.
+    int64 id = 1;
+    // The kind of this entity.
+    string kind = 2;
+    // Parents for this entity.
+    repeated int64 parents = 3;
+    // Has this entity been orphaned?
+    bool orphaned = 4;
+    // Instantaneous data for this entity.
+    repeated google.protobuf.Any data = 5;
+    // Historical trace information for the entity.
+    repeated TraceEvent trace = 6;
+}
+
+message TraceEvent {
+    // High level description of the event.
+    string description = 1;
+    // When this event occurred.
+    google.protobuf.Timestamp timestamp = 2;
+    // Any additional supporting data.
+    repeated google.protobuf.Any data = 3;
+}