1 files changed, 60 insertions, 0 deletions
diff --git a/src/core/ext/filters/client_channel/client_channel_channelz.cc b/src/core/ext/filters/client_channel/client_channel_channelz.cc
index 86c765df52..7e8f59bcd3 100644
--- a/src/core/ext/filters/client_channel/client_channel_channelz.cc
+++ b/src/core/ext/filters/client_channel/client_channel_channelz.cc
@@ -20,10 +20,13 @@
 
 #include "src/core/ext/filters/client_channel/client_channel.h"
 #include "src/core/ext/filters/client_channel/client_channel_channelz.h"
+#include "src/core/lib/channel/channelz_registry.h"
 #include "src/core/lib/gpr/useful.h"
 #include "src/core/lib/surface/channel.h"
 #include "src/core/lib/transport/connectivity_state.h"
 
+#include <grpc/support/string_util.h>
+
 namespace grpc_core {
 namespace channelz {
 namespace {
@@ -109,5 +112,62 @@ RefCountedPtr<ChannelNode> ClientChannelNode::MakeClientChannelNode(
                                            is_top_level_channel);
 }
 
+SubchannelNode::SubchannelNode(grpc_subchannel* subchannel,
+                               size_t channel_tracer_max_nodes)
+    : BaseNode(EntityType::kSubchannel),
+      subchannel_(subchannel),
+      target_(
+          UniquePtr<char>(gpr_strdup(grpc_subchannel_get_target(subchannel_)))),
+      trace_(channel_tracer_max_nodes) {}
+
+SubchannelNode::~SubchannelNode() {}
+
+void SubchannelNode::PopulateConnectivityState(grpc_json* json) {
+  grpc_connectivity_state state;
+  if (subchannel_ == nullptr) {
+    state = GRPC_CHANNEL_SHUTDOWN;
+  } else {
+    state = grpc_subchannel_check_connectivity(subchannel_, nullptr);
+  }
+  json = grpc_json_create_child(nullptr, json, "state", nullptr,
+                                GRPC_JSON_OBJECT, false);
+  grpc_json_create_child(nullptr, json, "state",
+                         grpc_connectivity_state_name(state), GRPC_JSON_STRING,
+                         false);
+}
+
+grpc_json* SubchannelNode::RenderJson() {
+  grpc_json* top_level_json = grpc_json_create(GRPC_JSON_OBJECT);
+  grpc_json* json = top_level_json;
+  grpc_json* json_iterator = nullptr;
+  json_iterator = grpc_json_create_child(json_iterator, json, "ref", nullptr,
+                                         GRPC_JSON_OBJECT, false);
+  json = json_iterator;
+  json_iterator = nullptr;
+  json_iterator = grpc_json_add_number_string_child(json, json_iterator,
+                                                    "subchannelId", uuid());
+  // reset json iterators to top level object
+  json = top_level_json;
+  json_iterator = nullptr;
+  // create and fill the data child.
+  grpc_json* data = grpc_json_create_child(json_iterator, json, "data", nullptr,
+                                           GRPC_JSON_OBJECT, false);
+  json = data;
+  json_iterator = nullptr;
+  PopulateConnectivityState(json);
+  GPR_ASSERT(target_.get() != nullptr);
+  grpc_json_create_child(nullptr, json, "target", target_.get(),
+                         GRPC_JSON_STRING, false);
+  // fill in the channel trace if applicable
+  grpc_json* trace_json = trace_.RenderJson();
+  if (trace_json != nullptr) {
+    trace_json->key = "trace";  // this object is named trace in channelz.proto
+    grpc_json_link_child(json, trace_json, nullptr);
+  }
+  // ask CallCountingHelper to populate trace and call count data.
+  call_counter_.PopulateCallCounts(json);
+  return top_level_json;
+}
+
 }  // namespace channelz
 }  // namespace grpc_core