Fix the muddled linkeage of channelz

21 files changed, 216 insertions, 29 deletions

diff --git a/BUILD b/BUILD
index 6db179fd3f..294ce46d41 100644
--- a/BUILD
+++ b/BUILD
@@ -1028,6 +1028,7 @@ grpc_cc_library(
         "src/core/ext/filters/client_channel/backup_poller.cc",
         "src/core/ext/filters/client_channel/channel_connectivity.cc",
         "src/core/ext/filters/client_channel/client_channel.cc",
+        "src/core/ext/filters/client_channel/client_channel_channelz.cc",
         "src/core/ext/filters/client_channel/client_channel_factory.cc",
         "src/core/ext/filters/client_channel/client_channel_plugin.cc",
         "src/core/ext/filters/client_channel/connector.cc",
@@ -1050,6 +1051,7 @@ grpc_cc_library(
     hdrs = [
         "src/core/ext/filters/client_channel/backup_poller.h",
         "src/core/ext/filters/client_channel/client_channel.h",
+        "src/core/ext/filters/client_channel/client_channel_channelz.h",
         "src/core/ext/filters/client_channel/client_channel_factory.h",
         "src/core/ext/filters/client_channel/connector.h",
         "src/core/ext/filters/client_channel/http_connect_handshaker.h",
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6b8e4f919c..7222894af6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1187,6 +1187,7 @@ add_library(grpc
   src/core/ext/filters/client_channel/backup_poller.cc
   src/core/ext/filters/client_channel/channel_connectivity.cc
   src/core/ext/filters/client_channel/client_channel.cc
+  src/core/ext/filters/client_channel/client_channel_channelz.cc
   src/core/ext/filters/client_channel/client_channel_factory.cc
   src/core/ext/filters/client_channel/client_channel_plugin.cc
   src/core/ext/filters/client_channel/connector.cc
@@ -1523,6 +1524,7 @@ add_library(grpc_cronet
   src/core/ext/filters/client_channel/backup_poller.cc
   src/core/ext/filters/client_channel/channel_connectivity.cc
   src/core/ext/filters/client_channel/client_channel.cc
+  src/core/ext/filters/client_channel/client_channel_channelz.cc
   src/core/ext/filters/client_channel/client_channel_factory.cc
   src/core/ext/filters/client_channel/client_channel_plugin.cc
   src/core/ext/filters/client_channel/connector.cc
@@ -1881,6 +1883,7 @@ add_library(grpc_test_util
   src/core/ext/filters/client_channel/backup_poller.cc
   src/core/ext/filters/client_channel/channel_connectivity.cc
   src/core/ext/filters/client_channel/client_channel.cc
+  src/core/ext/filters/client_channel/client_channel_channelz.cc
   src/core/ext/filters/client_channel/client_channel_factory.cc
   src/core/ext/filters/client_channel/client_channel_plugin.cc
   src/core/ext/filters/client_channel/connector.cc
@@ -2188,6 +2191,7 @@ add_library(grpc_test_util_unsecure
   src/core/ext/filters/client_channel/backup_poller.cc
   src/core/ext/filters/client_channel/channel_connectivity.cc
   src/core/ext/filters/client_channel/client_channel.cc
+  src/core/ext/filters/client_channel/client_channel_channelz.cc
   src/core/ext/filters/client_channel/client_channel_factory.cc
   src/core/ext/filters/client_channel/client_channel_plugin.cc
   src/core/ext/filters/client_channel/connector.cc
@@ -2508,6 +2512,7 @@ add_library(grpc_unsecure
   src/core/ext/filters/client_channel/backup_poller.cc
   src/core/ext/filters/client_channel/channel_connectivity.cc
   src/core/ext/filters/client_channel/client_channel.cc
+  src/core/ext/filters/client_channel/client_channel_channelz.cc
   src/core/ext/filters/client_channel/client_channel_factory.cc
   src/core/ext/filters/client_channel/client_channel_plugin.cc
   src/core/ext/filters/client_channel/connector.cc
@@ -3315,6 +3320,7 @@ add_library(grpc++_cronet
   src/core/ext/filters/client_channel/backup_poller.cc
   src/core/ext/filters/client_channel/channel_connectivity.cc
   src/core/ext/filters/client_channel/client_channel.cc
+  src/core/ext/filters/client_channel/client_channel_channelz.cc
   src/core/ext/filters/client_channel/client_channel_factory.cc
   src/core/ext/filters/client_channel/client_channel_plugin.cc
   src/core/ext/filters/client_channel/connector.cc
diff --git a/Makefile b/Makefile
index c0c3d239ee..47c9dc7ccd 100644
--- a/Makefile
+++ b/Makefile
@@ -3633,6 +3633,7 @@ LIBGRPC_SRC = \
     src/core/ext/filters/client_channel/backup_poller.cc \
     src/core/ext/filters/client_channel/channel_connectivity.cc \
     src/core/ext/filters/client_channel/client_channel.cc \
+    src/core/ext/filters/client_channel/client_channel_channelz.cc \
     src/core/ext/filters/client_channel/client_channel_factory.cc \
     src/core/ext/filters/client_channel/client_channel_plugin.cc \
     src/core/ext/filters/client_channel/connector.cc \
@@ -3968,6 +3969,7 @@ LIBGRPC_CRONET_SRC = \
     src/core/ext/filters/client_channel/backup_poller.cc \
     src/core/ext/filters/client_channel/channel_connectivity.cc \
     src/core/ext/filters/client_channel/client_channel.cc \
+    src/core/ext/filters/client_channel/client_channel_channelz.cc \
     src/core/ext/filters/client_channel/client_channel_factory.cc \
     src/core/ext/filters/client_channel/client_channel_plugin.cc \
     src/core/ext/filters/client_channel/connector.cc \
@@ -4324,6 +4326,7 @@ LIBGRPC_TEST_UTIL_SRC = \
     src/core/ext/filters/client_channel/backup_poller.cc \
     src/core/ext/filters/client_channel/channel_connectivity.cc \
     src/core/ext/filters/client_channel/client_channel.cc \
+    src/core/ext/filters/client_channel/client_channel_channelz.cc \
     src/core/ext/filters/client_channel/client_channel_factory.cc \
     src/core/ext/filters/client_channel/client_channel_plugin.cc \
     src/core/ext/filters/client_channel/connector.cc \
@@ -4622,6 +4625,7 @@ LIBGRPC_TEST_UTIL_UNSECURE_SRC = \
     src/core/ext/filters/client_channel/backup_poller.cc \
     src/core/ext/filters/client_channel/channel_connectivity.cc \
     src/core/ext/filters/client_channel/client_channel.cc \
+    src/core/ext/filters/client_channel/client_channel_channelz.cc \
     src/core/ext/filters/client_channel/client_channel_factory.cc \
     src/core/ext/filters/client_channel/client_channel_plugin.cc \
     src/core/ext/filters/client_channel/connector.cc \
@@ -4920,6 +4924,7 @@ LIBGRPC_UNSECURE_SRC = \
     src/core/ext/filters/client_channel/backup_poller.cc \
     src/core/ext/filters/client_channel/channel_connectivity.cc \
     src/core/ext/filters/client_channel/client_channel.cc \
+    src/core/ext/filters/client_channel/client_channel_channelz.cc \
     src/core/ext/filters/client_channel/client_channel_factory.cc \
     src/core/ext/filters/client_channel/client_channel_plugin.cc \
     src/core/ext/filters/client_channel/connector.cc \
@@ -5715,6 +5720,7 @@ LIBGRPC++_CRONET_SRC = \
     src/core/ext/filters/client_channel/backup_poller.cc \
     src/core/ext/filters/client_channel/channel_connectivity.cc \
     src/core/ext/filters/client_channel/client_channel.cc \
+    src/core/ext/filters/client_channel/client_channel_channelz.cc \
     src/core/ext/filters/client_channel/client_channel_factory.cc \
     src/core/ext/filters/client_channel/client_channel_plugin.cc \
     src/core/ext/filters/client_channel/connector.cc \
diff --git a/build.yaml b/build.yaml
index c8d4e6109d..3067ca9161 100644
--- a/build.yaml
+++ b/build.yaml
@@ -564,6 +564,7 @@ filegroups:
   headers:
   - src/core/ext/filters/client_channel/backup_poller.h
   - src/core/ext/filters/client_channel/client_channel.h
+  - src/core/ext/filters/client_channel/client_channel_channelz.h
   - src/core/ext/filters/client_channel/client_channel_factory.h
   - src/core/ext/filters/client_channel/connector.h
   - src/core/ext/filters/client_channel/http_connect_handshaker.h
@@ -586,6 +587,7 @@ filegroups:
   - src/core/ext/filters/client_channel/backup_poller.cc
   - src/core/ext/filters/client_channel/channel_connectivity.cc
   - src/core/ext/filters/client_channel/client_channel.cc
+  - src/core/ext/filters/client_channel/client_channel_channelz.cc
   - src/core/ext/filters/client_channel/client_channel_factory.cc
   - src/core/ext/filters/client_channel/client_channel_plugin.cc
   - src/core/ext/filters/client_channel/connector.cc
diff --git a/config.m4 b/config.m4
index d4af0cfd91..c277ccafc8 100644
--- a/config.m4
+++ b/config.m4
@@ -332,6 +332,7 @@ if test "$PHP_GRPC" != "no"; then
     src/core/ext/filters/client_channel/backup_poller.cc \
     src/core/ext/filters/client_channel/channel_connectivity.cc \
     src/core/ext/filters/client_channel/client_channel.cc \
+    src/core/ext/filters/client_channel/client_channel_channelz.cc \
     src/core/ext/filters/client_channel/client_channel_factory.cc \
     src/core/ext/filters/client_channel/client_channel_plugin.cc \
     src/core/ext/filters/client_channel/connector.cc \
diff --git a/config.w32 b/config.w32
index 0f219d3496..2857781dd5 100644
--- a/config.w32
+++ b/config.w32
@@ -307,6 +307,7 @@ if (PHP_GRPC != "no") {
     "src\\core\\ext\\filters\\client_channel\\backup_poller.cc " +
     "src\\core\\ext\\filters\\client_channel\\channel_connectivity.cc " +
     "src\\core\\ext\\filters\\client_channel\\client_channel.cc " +
+    "src\\core\\ext\\filters\\client_channel\\client_channel_channelz.cc " +
     "src\\core\\ext\\filters\\client_channel\\client_channel_factory.cc " +
     "src\\core\\ext\\filters\\client_channel\\client_channel_plugin.cc " +
     "src\\core\\ext\\filters\\client_channel\\connector.cc " +
diff --git a/gRPC-C++.podspec b/gRPC-C++.podspec
index 4d574fd4d6..57d58cc440 100644
--- a/gRPC-C++.podspec
+++ b/gRPC-C++.podspec
@@ -317,6 +317,7 @@ Pod::Spec.new do |s|
                       'src/core/ext/transport/chttp2/client/chttp2_connector.h',
                       'src/core/ext/filters/client_channel/backup_poller.h',
                       'src/core/ext/filters/client_channel/client_channel.h',
+                      'src/core/ext/filters/client_channel/client_channel_channelz.h',
                       'src/core/ext/filters/client_channel/client_channel_factory.h',
                       'src/core/ext/filters/client_channel/connector.h',
                       'src/core/ext/filters/client_channel/http_connect_handshaker.h',
diff --git a/gRPC-Core.podspec b/gRPC-Core.podspec
index 2789d15ec8..997617c530 100644
--- a/gRPC-Core.podspec
+++ b/gRPC-Core.podspec
@@ -328,6 +328,7 @@ Pod::Spec.new do |s|
                       'src/core/ext/transport/chttp2/client/chttp2_connector.h',
                       'src/core/ext/filters/client_channel/backup_poller.h',
                       'src/core/ext/filters/client_channel/client_channel.h',
+                      'src/core/ext/filters/client_channel/client_channel_channelz.h',
                       'src/core/ext/filters/client_channel/client_channel_factory.h',
                       'src/core/ext/filters/client_channel/connector.h',
                       'src/core/ext/filters/client_channel/http_connect_handshaker.h',
@@ -753,6 +754,7 @@ Pod::Spec.new do |s|
                       'src/core/ext/filters/client_channel/backup_poller.cc',
                       'src/core/ext/filters/client_channel/channel_connectivity.cc',
                       'src/core/ext/filters/client_channel/client_channel.cc',
+                      'src/core/ext/filters/client_channel/client_channel_channelz.cc',
                       'src/core/ext/filters/client_channel/client_channel_factory.cc',
                       'src/core/ext/filters/client_channel/client_channel_plugin.cc',
                       'src/core/ext/filters/client_channel/connector.cc',
@@ -916,6 +918,7 @@ Pod::Spec.new do |s|
                               'src/core/ext/transport/chttp2/client/chttp2_connector.h',
                               'src/core/ext/filters/client_channel/backup_poller.h',
                               'src/core/ext/filters/client_channel/client_channel.h',
+                              'src/core/ext/filters/client_channel/client_channel_channelz.h',
                               'src/core/ext/filters/client_channel/client_channel_factory.h',
                               'src/core/ext/filters/client_channel/connector.h',
                               'src/core/ext/filters/client_channel/http_connect_handshaker.h',
diff --git a/grpc.gemspec b/grpc.gemspec
index 6d0a9ced51..b69d5a7c6f 100644
--- a/grpc.gemspec
+++ b/grpc.gemspec
@@ -265,6 +265,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/ext/transport/chttp2/client/chttp2_connector.h )
   s.files += %w( src/core/ext/filters/client_channel/backup_poller.h )
   s.files += %w( src/core/ext/filters/client_channel/client_channel.h )
+  s.files += %w( src/core/ext/filters/client_channel/client_channel_channelz.h )
   s.files += %w( src/core/ext/filters/client_channel/client_channel_factory.h )
   s.files += %w( src/core/ext/filters/client_channel/connector.h )
   s.files += %w( src/core/ext/filters/client_channel/http_connect_handshaker.h )
@@ -693,6 +694,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/ext/filters/client_channel/backup_poller.cc )
   s.files += %w( src/core/ext/filters/client_channel/channel_connectivity.cc )
   s.files += %w( src/core/ext/filters/client_channel/client_channel.cc )
+  s.files += %w( src/core/ext/filters/client_channel/client_channel_channelz.cc )
   s.files += %w( src/core/ext/filters/client_channel/client_channel_factory.cc )
   s.files += %w( src/core/ext/filters/client_channel/client_channel_plugin.cc )
   s.files += %w( src/core/ext/filters/client_channel/connector.cc )
diff --git a/grpc.gyp b/grpc.gyp
index 6b3efe5c12..0db6afe468 100644
--- a/grpc.gyp
+++ b/grpc.gyp
@@ -524,6 +524,7 @@
         'src/core/ext/filters/client_channel/backup_poller.cc',
         'src/core/ext/filters/client_channel/channel_connectivity.cc',
         'src/core/ext/filters/client_channel/client_channel.cc',
+        'src/core/ext/filters/client_channel/client_channel_channelz.cc',
         'src/core/ext/filters/client_channel/client_channel_factory.cc',
         'src/core/ext/filters/client_channel/client_channel_plugin.cc',
         'src/core/ext/filters/client_channel/connector.cc',
@@ -783,6 +784,7 @@
         'src/core/ext/filters/client_channel/backup_poller.cc',
         'src/core/ext/filters/client_channel/channel_connectivity.cc',
         'src/core/ext/filters/client_channel/client_channel.cc',
+        'src/core/ext/filters/client_channel/client_channel_channelz.cc',
         'src/core/ext/filters/client_channel/client_channel_factory.cc',
         'src/core/ext/filters/client_channel/client_channel_plugin.cc',
         'src/core/ext/filters/client_channel/connector.cc',
@@ -1015,6 +1017,7 @@
         'src/core/ext/filters/client_channel/backup_poller.cc',
         'src/core/ext/filters/client_channel/channel_connectivity.cc',
         'src/core/ext/filters/client_channel/client_channel.cc',
+        'src/core/ext/filters/client_channel/client_channel_channelz.cc',
         'src/core/ext/filters/client_channel/client_channel_factory.cc',
         'src/core/ext/filters/client_channel/client_channel_plugin.cc',
         'src/core/ext/filters/client_channel/connector.cc',
@@ -1259,6 +1262,7 @@
         'src/core/ext/filters/client_channel/backup_poller.cc',
         'src/core/ext/filters/client_channel/channel_connectivity.cc',
         'src/core/ext/filters/client_channel/client_channel.cc',
+        'src/core/ext/filters/client_channel/client_channel_channelz.cc',
         'src/core/ext/filters/client_channel/client_channel_factory.cc',
         'src/core/ext/filters/client_channel/client_channel_plugin.cc',
         'src/core/ext/filters/client_channel/connector.cc',
diff --git a/package.xml b/package.xml
index 5589167474..a9dc2dc79a 100644
--- a/package.xml
+++ b/package.xml
@@ -270,6 +270,7 @@
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/client/chttp2_connector.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/backup_poller.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/client_channel.h" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/filters/client_channel/client_channel_channelz.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/client_channel_factory.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/connector.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/http_connect_handshaker.h" role="src" />
@@ -698,6 +699,7 @@
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/backup_poller.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/channel_connectivity.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/client_channel.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/filters/client_channel/client_channel_channelz.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/client_channel_factory.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/client_channel_plugin.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/connector.cc" role="src" />
diff --git a/src/core/ext/filters/client_channel/client_channel_channelz.cc b/src/core/ext/filters/client_channel/client_channel_channelz.cc
new file mode 100644
index 0000000000..df78dd5932
--- /dev/null
+++ b/src/core/ext/filters/client_channel/client_channel_channelz.cc
@@ -0,0 +1,62 @@
+/*
+ *
+ * Copyright 2018 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#include "src/core/ext/filters/client_channel/client_channel_channelz.h"
+#include "src/core/lib/gpr/useful.h"
+
+namespace grpc_core {
+namespace channelz {
+
+static void* client_channel_channelz_copy(void* p) { return p; }
+
+static void client_channel_channelz_destroy(void* p) {}
+
+static int client_channel_channelz_cmp(void* a, void* b) {
+  return GPR_ICMP(a, b);
+}
+
+static const grpc_arg_pointer_vtable client_channel_channelz_vtable = {
+    client_channel_channelz_copy, client_channel_channelz_destroy,
+    client_channel_channelz_cmp};
+
+bool ClientChannelNode::GetConnectivityState(grpc_connectivity_state* state) {
+  if (channel()) {
+    *state = grpc_channel_check_connectivity_state(channel(), false);
+  } else {
+    *state = GRPC_CHANNEL_SHUTDOWN;
+  }
+  return true;
+}
+
+grpc_arg ClientChannelNode::CreateArg() {
+  return grpc_channel_arg_pointer_create(
+      const_cast<char*>(GRPC_ARG_CHANNELZ_CHANNEL_NODE_CREATION_FUNC),
+      reinterpret_cast<void*>(MakeClientChannelNode),
+      &client_channel_channelz_vtable);
+}
+
+RefCountedPtr<ChannelNode> MakeClientChannelNode(
+    grpc_channel* channel, size_t channel_tracer_max_nodes) {
+  return RefCountedPtr<ChannelNode>(
+      New<ClientChannelNode>(channel, channel_tracer_max_nodes));
+}
+
+}  // namespace channelz
+}  // namespace grpc_core
diff --git a/src/core/ext/filters/client_channel/client_channel_channelz.h b/src/core/ext/filters/client_channel/client_channel_channelz.h
new file mode 100644
index 0000000000..7d05cda7da
--- /dev/null
+++ b/src/core/ext/filters/client_channel/client_channel_channelz.h
@@ -0,0 +1,55 @@
+/*
+ *
+ * Copyright 2018 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.
+ *
+ */
+
+#ifndef GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_CLIENT_CHANNEL_CHANNELZ_H
+#define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_CLIENT_CHANNEL_CHANNELZ_H
+
+#include <grpc/support/port_platform.h>
+
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/channel/channelz.h"
+
+namespace grpc_core {
+namespace channelz {
+
+// Subtype of ChannelNode that overrides and provides client_channel specific
+// functionality like querying for connectivity_state and subchannel data.
+class ClientChannelNode : public ChannelNode {
+ public:
+  ClientChannelNode(grpc_channel* channel, size_t channel_tracer_max_nodes)
+      : ChannelNode(channel, channel_tracer_max_nodes) {}
+  virtual ~ClientChannelNode() {}
+
+  // Override this functionality since client_channels have a notion of
+  // channel connectivity.
+  bool GetConnectivityState(grpc_connectivity_state* state) override;
+
+  // Helper to create a channel arg to ensure this type of ChannelNode is
+  // created.
+  static grpc_arg CreateArg();
+};
+
+RefCountedPtr<ChannelNode> MakeClientChannelNode(
+    grpc_channel* channel, size_t channel_tracer_max_nodes);
+
+grpc_arg BlahBlah();
+
+}  // namespace channelz
+}  // namespace grpc_core
+
+#endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_CLIENT_CHANNEL_CHANNELZ_H */
diff --git a/src/core/ext/transport/chttp2/client/insecure/channel_create.cc b/src/core/ext/transport/chttp2/client/insecure/channel_create.cc
index e6c8c38260..420629f6b7 100644
--- a/src/core/ext/transport/chttp2/client/insecure/channel_create.cc
+++ b/src/core/ext/transport/chttp2/client/insecure/channel_create.cc
@@ -26,6 +26,7 @@
 #include <grpc/support/string_util.h>
 
 #include "src/core/ext/filters/client_channel/client_channel.h"
+#include "src/core/ext/filters/client_channel/client_channel_channelz.h"
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
 #include "src/core/ext/transport/chttp2/client/authority.h"
 #include "src/core/ext/transport/chttp2/client/chttp2_connector.h"
@@ -92,10 +93,11 @@ grpc_channel* grpc_insecure_channel_create(const char* target,
       "grpc_insecure_channel_create(target=%s, args=%p, reserved=%p)", 3,
       (target, args, reserved));
   GPR_ASSERT(reserved == nullptr);
-  // Add channel arg containing the client channel factory.
-  grpc_arg arg =
-      grpc_client_channel_factory_create_channel_arg(&client_channel_factory);
-  grpc_channel_args* new_args = grpc_channel_args_copy_and_add(args, &arg, 1);
+  grpc_arg args_to_add[] = {
+      grpc_client_channel_factory_create_channel_arg(&client_channel_factory),
+      grpc_core::channelz::ClientChannelNode::CreateArg()};
+  grpc_channel_args* new_args = grpc_channel_args_copy_and_add(
+      args, args_to_add, GPR_ARRAY_SIZE(args_to_add));
   // Create channel.
   grpc_channel* channel = client_channel_factory_create_channel(
       &client_channel_factory, target, GRPC_CLIENT_CHANNEL_TYPE_REGULAR,
diff --git a/src/core/ext/transport/chttp2/client/secure/secure_channel_create.cc b/src/core/ext/transport/chttp2/client/secure/secure_channel_create.cc
index 5ce73a95d7..82691d4e25 100644
--- a/src/core/ext/transport/chttp2/client/secure/secure_channel_create.cc
+++ b/src/core/ext/transport/chttp2/client/secure/secure_channel_create.cc
@@ -26,6 +26,7 @@
 #include <grpc/support/string_util.h>
 
 #include "src/core/ext/filters/client_channel/client_channel.h"
+#include "src/core/ext/filters/client_channel/client_channel_channelz.h"
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
 #include "src/core/ext/filters/client_channel/uri_parser.h"
 #include "src/core/ext/transport/chttp2/client/chttp2_connector.h"
@@ -213,7 +214,8 @@ grpc_channel* grpc_secure_channel_create(grpc_channel_credentials* creds,
     // credentials.
     grpc_arg args_to_add[] = {
         grpc_client_channel_factory_create_channel_arg(&client_channel_factory),
-        grpc_channel_credentials_to_arg(creds)};
+        grpc_channel_credentials_to_arg(creds),
+        grpc_core::channelz::ClientChannelNode::CreateArg()};
     grpc_channel_args* new_args = grpc_channel_args_copy_and_add(
         args, args_to_add, GPR_ARRAY_SIZE(args_to_add));
     // Create channel.
diff --git a/src/core/lib/channel/channelz.cc b/src/core/lib/channel/channelz.cc
index a49271c3a1..62bc4d4330 100644
--- a/src/core/lib/channel/channelz.cc
+++ b/src/core/lib/channel/channelz.cc
@@ -109,15 +109,8 @@ void ChannelNode::RecordCallStarted() {
                            (gpr_atm)ExecCtx::Get()->Now());
 }
 
-grpc_connectivity_state ChannelNode::GetConnectivityState() {
-  if (channel_ == nullptr) {
-    return GRPC_CHANNEL_SHUTDOWN;
-  } else {
-    // TODO(ncteisen): re-enable this once we have cleaned up all of the
-    // internal dependency issues.
-    // return grpc_channel_check_connectivity_state(channel_, false);
-    return GRPC_CHANNEL_IDLE;
-  }
+bool ChannelNode::GetConnectivityState(grpc_connectivity_state* state) {
+  return false;
 }
 
 char* ChannelNode::RenderJSON() {
@@ -140,15 +133,17 @@ char* ChannelNode::RenderJSON() {
   json = data;
   json_iterator = nullptr;
   // create and fill the connectivity state child.
-  grpc_connectivity_state connectivity_state = GetConnectivityState();
-  json_iterator = grpc_json_create_child(json_iterator, json, "state", nullptr,
-                                         GRPC_JSON_OBJECT, false);
-  json = json_iterator;
-  grpc_json_create_child(nullptr, json, "state",
-                         grpc_connectivity_state_name(connectivity_state),
-                         GRPC_JSON_STRING, false);
-  // reset the parent to be the data object.
-  json = data;
+  grpc_connectivity_state connectivity_state;
+  if (GetConnectivityState(&connectivity_state)) {
+    json_iterator = grpc_json_create_child(json_iterator, json, "state",
+                                           nullptr, GRPC_JSON_OBJECT, false);
+    json = json_iterator;
+    grpc_json_create_child(nullptr, json, "state",
+                           grpc_connectivity_state_name(connectivity_state),
+                           GRPC_JSON_STRING, false);
+    // reset the parent to be the data object.
+    json = data;
+  }
   json_iterator = grpc_json_create_child(
       json_iterator, json, "target", target_.get(), GRPC_JSON_STRING, false);
   // fill in the channel trace if applicable
@@ -184,5 +179,11 @@ char* ChannelNode::RenderJSON() {
   return json_str;
 }
 
+RefCountedPtr<ChannelNode> MakeChannelNode(grpc_channel* channel,
+                                           size_t channel_tracer_max_nodes) {
+  return MakeRefCounted<grpc_core::channelz::ChannelNode>(
+      channel, channel_tracer_max_nodes);
+}
+
 }  // namespace channelz
 }  // namespace grpc_core
diff --git a/src/core/lib/channel/channelz.h b/src/core/lib/channel/channelz.h
index 2aad1e82f4..5c91658dd1 100644
--- a/src/core/lib/channel/channelz.h
+++ b/src/core/lib/channel/channelz.h
@@ -31,6 +31,10 @@
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/json/json.h"
 
+// Channel arg key for client channel factory.
+#define GRPC_ARG_CHANNELZ_CHANNEL_NODE_CREATION_FUNC \
+  "grpc.channelz_channel_node_creation_func"
+
 namespace grpc_core {
 namespace channelz {
 
@@ -41,7 +45,7 @@ class ChannelNodePeer;
 class ChannelNode : public RefCounted<ChannelNode> {
  public:
   ChannelNode(grpc_channel* channel, size_t channel_tracer_max_nodes);
-  ~ChannelNode();
+  virtual ~ChannelNode();
 
   void RecordCallStarted();
   void RecordCallFailed() {
@@ -53,6 +57,13 @@ class ChannelNode : public RefCounted<ChannelNode> {
 
   char* RenderJSON();
 
+  // helper for getting connectivity state. It is virtual because it allows
+  // the client_channel code to live in ext/ instead of lib/
+  //
+  // returns true if the channel has a notion of a connectivity state. In that
+  // case it also sets state to the correct connectivity state.
+  virtual bool GetConnectivityState(grpc_connectivity_state* state);
+
   ChannelTrace* trace() { return trace_.get(); }
 
   void set_channel_destroyed() {
@@ -62,13 +73,13 @@ class ChannelNode : public RefCounted<ChannelNode> {
 
   intptr_t channel_uuid() { return channel_uuid_; }
 
+ protected:
+  grpc_channel* channel() { return channel_; }
+
  private:
   // testing peer friend.
   friend class testing::ChannelNodePeer;
 
-  // helper for getting connectivity state.
-  grpc_connectivity_state GetConnectivityState();
-
   grpc_channel* channel_ = nullptr;
   UniquePtr<char> target_;
   gpr_atm calls_started_ = 0;
@@ -79,6 +90,14 @@ class ChannelNode : public RefCounted<ChannelNode> {
   ManualConstructor<ChannelTrace> trace_;
 };
 
+// Creation functions
+
+typedef RefCountedPtr<ChannelNode> (*ChannelNodeCreationFunc)(grpc_channel*,
+                                                              size_t);
+
+RefCountedPtr<ChannelNode> MakeChannelNode(grpc_channel* channel,
+                                           size_t channel_tracer_max_nodes);
+
 }  // namespace channelz
 }  // namespace grpc_core
 
diff --git a/src/core/lib/surface/channel.cc b/src/core/lib/surface/channel.cc
index d5d75fcb2a..a17fde015f 100644
--- a/src/core/lib/surface/channel.cc
+++ b/src/core/lib/surface/channel.cc
@@ -105,6 +105,10 @@ grpc_channel* grpc_channel_create_with_builder(
   channel->is_client = grpc_channel_stack_type_is_client(channel_stack_type);
   size_t channel_tracer_max_nodes = 0;  // default to off
   bool channelz_enabled = false;
+  // this creates the default ChannelNode. Different types of channels may
+  // override this to ensure a correct ChannelNode is created.
+  grpc_core::channelz::ChannelNodeCreationFunc channel_node_create_func =
+      grpc_core::channelz::MakeChannelNode;
   gpr_mu_init(&channel->registered_call_mu);
   channel->registered_calls = nullptr;
 
@@ -145,14 +149,20 @@ grpc_channel* grpc_channel_create_with_builder(
           (size_t)grpc_channel_arg_get_integer(&args->args[i], options);
     } else if (0 == strcmp(args->args[i].key, GRPC_ARG_ENABLE_CHANNELZ)) {
       channelz_enabled = grpc_channel_arg_get_bool(&args->args[i], false);
+    } else if (0 == strcmp(args->args[i].key,
+                           GRPC_ARG_CHANNELZ_CHANNEL_NODE_CREATION_FUNC)) {
+      GPR_ASSERT(args->args[i].type == GRPC_ARG_POINTER);
+      GPR_ASSERT(args->args[i].value.pointer.p != nullptr);
+      channel_node_create_func =
+          reinterpret_cast<grpc_core::channelz::ChannelNodeCreationFunc>(
+              args->args[i].value.pointer.p);
     }
   }
 
   grpc_channel_args_destroy(args);
   if (channelz_enabled) {
     channel->channelz_channel =
-        grpc_core::MakeRefCounted<grpc_core::channelz::ChannelNode>(
-            channel, channel_tracer_max_nodes);
+        channel_node_create_func(channel, channel_tracer_max_nodes);
     channel->channelz_channel->trace()->AddTraceEvent(
         grpc_core::channelz::ChannelTrace::Severity::Info,
         grpc_slice_from_static_string("Channel created"));
diff --git a/src/python/grpcio/grpc_core_dependencies.py b/src/python/grpcio/grpc_core_dependencies.py
index 1746020b72..49185cc648 100644
--- a/src/python/grpcio/grpc_core_dependencies.py
+++ b/src/python/grpcio/grpc_core_dependencies.py
@@ -306,6 +306,7 @@ CORE_SOURCE_FILES = [
     'src/core/ext/filters/client_channel/backup_poller.cc',
     'src/core/ext/filters/client_channel/channel_connectivity.cc',
     'src/core/ext/filters/client_channel/client_channel.cc',
+    'src/core/ext/filters/client_channel/client_channel_channelz.cc',
     'src/core/ext/filters/client_channel/client_channel_factory.cc',
     'src/core/ext/filters/client_channel/client_channel_plugin.cc',
     'src/core/ext/filters/client_channel/connector.cc',
diff --git a/tools/doxygen/Doxyfile.core.internal b/tools/doxygen/Doxyfile.core.internal
index 397b8e0c96..1a5dfb902b 100644
--- a/tools/doxygen/Doxyfile.core.internal
+++ b/tools/doxygen/Doxyfile.core.internal
@@ -872,6 +872,8 @@ src/core/ext/filters/client_channel/backup_poller.h \
 src/core/ext/filters/client_channel/channel_connectivity.cc \
 src/core/ext/filters/client_channel/client_channel.cc \
 src/core/ext/filters/client_channel/client_channel.h \
+src/core/ext/filters/client_channel/client_channel_channelz.cc \
+src/core/ext/filters/client_channel/client_channel_channelz.h \
 src/core/ext/filters/client_channel/client_channel_factory.cc \
 src/core/ext/filters/client_channel/client_channel_factory.h \
 src/core/ext/filters/client_channel/client_channel_plugin.cc \
diff --git a/tools/run_tests/generated/sources_and_headers.json b/tools/run_tests/generated/sources_and_headers.json
index 5610dfbf66..7953fa3772 100644
--- a/tools/run_tests/generated/sources_and_headers.json
+++ b/tools/run_tests/generated/sources_and_headers.json
@@ -9873,6 +9873,7 @@
     "headers": [
       "src/core/ext/filters/client_channel/backup_poller.h", 
       "src/core/ext/filters/client_channel/client_channel.h", 
+      "src/core/ext/filters/client_channel/client_channel_channelz.h", 
       "src/core/ext/filters/client_channel/client_channel_factory.h", 
       "src/core/ext/filters/client_channel/connector.h", 
       "src/core/ext/filters/client_channel/http_connect_handshaker.h", 
@@ -9901,6 +9902,8 @@
       "src/core/ext/filters/client_channel/channel_connectivity.cc", 
       "src/core/ext/filters/client_channel/client_channel.cc", 
       "src/core/ext/filters/client_channel/client_channel.h", 
+      "src/core/ext/filters/client_channel/client_channel_channelz.cc", 
+      "src/core/ext/filters/client_channel/client_channel_channelz.h", 
       "src/core/ext/filters/client_channel/client_channel_factory.cc", 
       "src/core/ext/filters/client_channel/client_channel_factory.h", 
       "src/core/ext/filters/client_channel/client_channel_plugin.cc",