Add channelz server support

include/grpc/grpc.h

@@ -483,6 +483,9 @@ GRPCAPI const grpc_arg_pointer_vtable* grpc_resource_quota_arg_vtable(void);
    The returned string is allocated and must be freed by the application. */
 GRPCAPI char* grpc_channelz_get_top_channels(intptr_t start_channel_id);
 
+/* Gets all servers that exist in the process. */
+GRPCAPI char* grpc_channelz_get_servers(intptr_t start_channel_id);
+
 /* Returns a single Channel, or else a NOT_FOUND code. The returned string
    is allocated and must be freed by the application. */
 GRPCAPI char* grpc_channelz_get_channel(intptr_t channel_id);

src/core/lib/channel/channelz.cc

@@ -48,6 +48,7 @@ BaseNode::~BaseNode() { ChannelzRegistry::Unregister(uuid_); }
 
 char* BaseNode::RenderJsonString() {
   grpc_json* json = RenderJson();
+  GPR_ASSERT(json != nullptr);
   char* json_str = grpc_json_dump_to_string(json, 0);
   grpc_json_destroy(json);
   return json_str;
@@ -146,5 +147,45 @@ RefCountedPtr<ChannelNode> ChannelNode::MakeChannelNode(
       channel, channel_tracer_max_nodes, is_top_level_channel);
 }
 
+ServerNode::ServerNode(size_t channel_tracer_max_nodes)
+    : BaseNode(EntityType::kServer), trace_(channel_tracer_max_nodes) {}
+
+ServerNode::~ServerNode() {}
+
+grpc_json* ServerNode::RenderJson() {
+  // We need to track these three json objects to build our object
+  grpc_json* top_level_json = grpc_json_create(GRPC_JSON_OBJECT);
+  grpc_json* json = top_level_json;
+  grpc_json* json_iterator = nullptr;
+  // create and fill the ref child
+  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,
+                                                    "serverId", 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;
+  // 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);
+  json = top_level_json;
+  // template method. Child classes may override this to add their specific
+  // functionality.
+  PopulateSockets(json);
+  return top_level_json;
+}
+
 }  // namespace channelz
 }  // namespace grpc_core

src/core/lib/channel/channelz.h

@@ -167,12 +167,32 @@ class ChannelNode : public BaseNode {
 };
 
 // Handles channelz bookkeeping for servers
-// TODO(ncteisen): implement in subsequent PR.
 class ServerNode : public BaseNode {
  public:
-  explicit ServerNode(size_t channel_tracer_max_nodes)
-      : BaseNode(EntityType::kServer) {}
-  ~ServerNode() override {}
+  explicit ServerNode(size_t channel_tracer_max_nodes);
+  ~ServerNode() override;
+
+  grpc_json* RenderJson() override;
+
+  void PopulateSockets(grpc_json* json) {}
+
+  // proxy methods to composed classes.
+  void AddTraceEvent(ChannelTrace::Severity severity, grpc_slice data) {
+    trace_.AddTraceEvent(severity, data);
+  }
+  void AddTraceEventWithReference(ChannelTrace::Severity severity,
+                                  grpc_slice data,
+                                  RefCountedPtr<BaseNode> referenced_channel) {
+    trace_.AddTraceEventWithReference(severity, data,
+                                      std::move(referenced_channel));
+  }
+  void RecordCallStarted() { call_counter_.RecordCallStarted(); }
+  void RecordCallFailed() { call_counter_.RecordCallFailed(); }
+  void RecordCallSucceeded() { call_counter_.RecordCallSucceeded(); }
+
+ private:
+  CallCountingHelper call_counter_;
+  ChannelTrace trace_;
 };
 
 // Handles channelz bookkeeping for sockets

src/core/lib/channel/channelz_registry.cc

@@ -111,6 +111,42 @@ char* ChannelzRegistry::InternalGetTopChannels(intptr_t start_channel_id) {
   return json_str;
 }
 
+char* ChannelzRegistry::InternalGetServers(intptr_t start_server_id) {
+  grpc_json* top_level_json = grpc_json_create(GRPC_JSON_OBJECT);
+  grpc_json* json = top_level_json;
+  grpc_json* json_iterator = nullptr;
+  InlinedVector<BaseNode*, 10> servers;
+  // uuids index into entities one-off (idx 0 is really uuid 1, since 0 is
+  // reserved). However, we want to support requests coming in with
+  // start_server_id=0, which signifies "give me everything."
+  size_t start_idx = start_server_id == 0 ? 0 : start_server_id - 1;
+  for (size_t i = start_idx; i < entities_.size(); ++i) {
+    if (entities_[i] != nullptr &&
+        entities_[i]->type() ==
+            grpc_core::channelz::BaseNode::EntityType::kServer) {
+      servers.push_back(entities_[i]);
+    }
+  }
+  if (!servers.empty()) {
+    // create list of servers
+    grpc_json* array_parent = grpc_json_create_child(
+        nullptr, json, "server", nullptr, GRPC_JSON_ARRAY, false);
+    for (size_t i = 0; i < servers.size(); ++i) {
+      grpc_json* server_json = servers[i]->RenderJson();
+      json_iterator =
+          grpc_json_link_child(array_parent, server_json, json_iterator);
+    }
+  }
+  // For now we do not have any pagination rules. In the future we could
+  // pick a constant for max_channels_sent for a GetServers request.
+  // Tracking: https://github.com/grpc/grpc/issues/16019.
+  json_iterator = grpc_json_create_child(nullptr, json, "end", nullptr,
+                                         GRPC_JSON_TRUE, false);
+  char* json_str = grpc_json_dump_to_string(top_level_json, 0);
+  grpc_json_destroy(top_level_json);
+  return json_str;
+}
+
 }  // namespace channelz
 }  // namespace grpc_core
 
@@ -119,6 +155,10 @@ char* grpc_channelz_get_top_channels(intptr_t start_channel_id) {
       start_channel_id);
 }
 
+char* grpc_channelz_get_servers(intptr_t start_server_id) {
+  return grpc_core::channelz::ChannelzRegistry::GetServers(start_server_id);
+}
+
 char* grpc_channelz_get_channel(intptr_t channel_id) {
   grpc_core::channelz::BaseNode* channel_node =
       grpc_core::channelz::ChannelzRegistry::Get(channel_id);

src/core/lib/channel/channelz_registry.h

@@ -52,6 +52,12 @@ class ChannelzRegistry {
     return Default()->InternalGetTopChannels(start_channel_id);
   }
 
+  // Returns the allocated JSON string that represents the proto
+  // GetServersResponse as per channelz.proto.
+  static char* GetServers(intptr_t start_server_id) {
+    return Default()->InternalGetServers(start_server_id);
+  }
+
  private:
   GPRC_ALLOW_CLASS_TO_USE_NON_PUBLIC_NEW
   GPRC_ALLOW_CLASS_TO_USE_NON_PUBLIC_DELETE
@@ -74,6 +80,7 @@ class ChannelzRegistry {
   BaseNode* InternalGet(intptr_t uuid);
 
   char* InternalGetTopChannels(intptr_t start_channel_id);
+  char* InternalGetServers(intptr_t start_server_id);
 
   // protects entities_ and uuid_
   gpr_mu mu_;

src/core/lib/surface/call.cc

@@ -48,6 +48,7 @@
 #include "src/core/lib/surface/call_test_only.h"
 #include "src/core/lib/surface/channel.h"
 #include "src/core/lib/surface/completion_queue.h"
+#include "src/core/lib/surface/server.h"
 #include "src/core/lib/surface/validate_metadata.h"
 #include "src/core/lib/transport/error_utils.h"
 #include "src/core/lib/transport/metadata.h"
@@ -166,6 +167,8 @@ struct grpc_call {
   grpc_completion_queue* cq;
   grpc_polling_entity pollent;
   grpc_channel* channel;
+  // backpointer to owning server if this is a server side call.
+  grpc_server* server;
   gpr_timespec start_time;
   /* parent_call* */ gpr_atm parent_call_atm;
   child_call* child;
@@ -362,14 +365,11 @@ grpc_error* grpc_call_create(const grpc_call_create_args* args,
   /* Always support no compression */
   GPR_BITSET(&call->encodings_accepted_by_peer, GRPC_MESSAGE_COMPRESS_NONE);
   call->is_client = args->server_transport_data == nullptr;
-  if (call->is_client) {
-    GRPC_STATS_INC_CLIENT_CALLS_CREATED();
-  } else {
-    GRPC_STATS_INC_SERVER_CALLS_CREATED();
-  }
   call->stream_op_payload.context = call->context;
   grpc_slice path = grpc_empty_slice();
   if (call->is_client) {
+    GRPC_STATS_INC_CLIENT_CALLS_CREATED();
+    call->server = nullptr;
     GPR_ASSERT(args->add_initial_metadata_count <
                MAX_SEND_EXTRA_METADATA_COUNT);
     for (i = 0; i < args->add_initial_metadata_count; i++) {
@@ -383,6 +383,8 @@ grpc_error* grpc_call_create(const grpc_call_create_args* args,
     call->send_extra_metadata_count =
         static_cast<int>(args->add_initial_metadata_count);
   } else {
+    GRPC_STATS_INC_SERVER_CALLS_CREATED();
+    call->server = args->server;
     GPR_ASSERT(args->add_initial_metadata_count == 0);
     call->send_extra_metadata_count = 0;
   }
@@ -486,11 +488,19 @@ grpc_error* grpc_call_create(const grpc_call_create_args* args,
                                                &call->pollent);
   }
 
+  if (call->is_client) {
     grpc_core::channelz::ChannelNode* channelz_channel =
         grpc_channel_get_channelz_node(call->channel);
     if (channelz_channel != nullptr) {
       channelz_channel->RecordCallStarted();
     }
+  } else {
+    grpc_core::channelz::ServerNode* channelz_server =
+        grpc_server_get_channelz_node(call->server);
+    if (channelz_server != nullptr) {
+      channelz_server->RecordCallStarted();
+    }
+  }
 
   grpc_slice_unref_internal(path);
 
@@ -1263,11 +1273,6 @@ static void post_batch_completion(batch_control* bctl) {
                        call->final_op.client.status,
                        call->final_op.client.status_details,
                        call->final_op.client.error_string);
-    } else {
-      get_final_status(call, set_cancelled_value,
-                       call->final_op.server.cancelled, nullptr, nullptr);
-    }
-    // Record channelz data for the channel.
       grpc_core::channelz::ChannelNode* channelz_channel =
           grpc_channel_get_channelz_node(call->channel);
       if (channelz_channel != nullptr) {
@@ -1277,6 +1282,19 @@ static void post_batch_completion(batch_control* bctl) {
           channelz_channel->RecordCallSucceeded();
         }
       }
+    } else {
+      get_final_status(call, set_cancelled_value,
+                       call->final_op.server.cancelled, nullptr, nullptr);
+      grpc_core::channelz::ServerNode* channelz_server =
+          grpc_server_get_channelz_node(call->server);
+      if (channelz_server != nullptr) {
+        if (*call->final_op.server.cancelled) {
+          channelz_server->RecordCallFailed();
+        } else {
+          channelz_server->RecordCallSucceeded();
+        }
+      }
+    }
     GRPC_ERROR_UNREF(error);
     error = GRPC_ERROR_NONE;
   }

src/core/lib/surface/call.h

@@ -33,6 +33,7 @@ typedef void (*grpc_ioreq_completion_func)(grpc_call* call, int success,
 
 typedef struct grpc_call_create_args {
   grpc_channel* channel;
+  grpc_server* server;
 
   grpc_call* parent;
   uint32_t propagation_mask;

src/core/lib/surface/channel.cc

@@ -166,10 +166,11 @@ grpc_channel* grpc_channel_create_with_builder(
   }
 
   grpc_channel_args_destroy(args);
-  if (channelz_enabled) {
-    bool is_top_level_channel = channel->is_client && !internal_channel;
+  // only track client channels since server channels are held in the
+  // grpc_server channel.
+  if (channelz_enabled && channel->is_client) {
     channel->channelz_channel = channel_node_create_func(
-        channel, channel_tracer_max_nodes, is_top_level_channel);
+        channel, channel_tracer_max_nodes, !internal_channel);
     channel->channelz_channel->AddTraceEvent(
         grpc_core::channelz::ChannelTrace::Severity::Info,
         grpc_slice_from_static_string("Channel created"));

src/core/lib/surface/server.cc

@@ -219,6 +219,8 @@ struct grpc_server {
 
   /** when did we print the last shutdown progress message */
   gpr_timespec last_shutdown_message_time;
+
+  grpc_core::RefCountedPtr<grpc_core::channelz::ServerNode> channelz_server;
 };
 
 #define SERVER_FROM_CALL_ELEM(elem) \
@@ -364,6 +366,7 @@ static void server_ref(grpc_server* server) {
 static void server_delete(grpc_server* server) {
   registered_method* rm;
   size_t i;
+  server->channelz_server.reset();
   grpc_channel_args_destroy(server->channel_args);
   gpr_mu_destroy(&server->mu_global);
   gpr_mu_destroy(&server->mu_call);
@@ -779,6 +782,7 @@ static void accept_stream(void* cd, grpc_transport* transport,
   args.channel = chand->channel;
   args.server_transport_data = transport_server_data;
   args.send_deadline = GRPC_MILLIS_INF_FUTURE;
+  args.server = chand->server;
   grpc_call* call;
   grpc_error* error = grpc_call_create(&args, &call);
   grpc_call_element* elem =
@@ -941,6 +945,7 @@ void grpc_server_register_completion_queue(grpc_server* server,
 }
 
 grpc_server* grpc_server_create(const grpc_channel_args* args, void* reserved) {
+  grpc_core::ExecCtx exec_ctx;
   GRPC_API_TRACE("grpc_server_create(%p, %p)", 2, (args, reserved));
 
   grpc_server* server =
@@ -957,6 +962,20 @@ grpc_server* grpc_server_create(const grpc_channel_args* args, void* reserved) {
 
   server->channel_args = grpc_channel_args_copy(args);
 
+  const grpc_arg* arg = grpc_channel_args_find(args, GRPC_ARG_ENABLE_CHANNELZ);
+  if (grpc_channel_arg_get_bool(arg, false)) {
+    arg = grpc_channel_args_find(args,
+                                 GRPC_ARG_MAX_CHANNEL_TRACE_EVENTS_PER_NODE);
+    size_t trace_events_per_node =
+        grpc_channel_arg_get_integer(arg, {0, 0, INT_MAX});
+    server->channelz_server =
+        grpc_core::MakeRefCounted<grpc_core::channelz::ServerNode>(
+            trace_events_per_node);
+    server->channelz_server->AddTraceEvent(
+        grpc_core::channelz::ChannelTrace::Severity::Info,
+        grpc_slice_from_static_string("Server created"));
+  }
+
   return server;
 }
 
@@ -1459,3 +1478,8 @@ int grpc_server_has_open_connections(grpc_server* server) {
   gpr_mu_unlock(&server->mu_global);
   return r;
 }
+
+grpc_core::channelz::ServerNode* grpc_server_get_channelz_node(
+    grpc_server* server) {
+  return server->channelz_server.get();
+}

src/core/lib/surface/server.h

@@ -23,6 +23,7 @@
 
 #include <grpc/grpc.h>
 #include "src/core/lib/channel/channel_stack.h"
+#include "src/core/lib/channel/channelz.h"
 #include "src/core/lib/debug/trace.h"
 #include "src/core/lib/transport/transport.h"
 
@@ -46,6 +47,9 @@ void grpc_server_setup_transport(grpc_server* server, grpc_transport* transport,
                                  grpc_pollset* accepting_pollset,
                                  const grpc_channel_args* args);
 
+grpc_core::channelz::ServerNode* grpc_server_get_channelz_node(
+    grpc_server* server);
+
 const grpc_channel_args* grpc_server_get_channel_args(grpc_server* server);
 
 int grpc_server_has_open_connections(grpc_server* server);

test/core/channel/channelz_test.cc

@@ -31,6 +31,7 @@
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/json/json.h"
 #include "src/core/lib/surface/channel.h"
+#include "src/core/lib/surface/server.h"
 
 #include "test/core/util/test_config.h"
 #include "test/cpp/util/channel_trace_proto_helper.h"
@@ -102,6 +103,25 @@ void ValidateGetTopChannels(size_t expected_channels) {
   gpr_free(core_api_json_str);
 }
 
+void ValidateGetServers(size_t expected_servers) {
+  char* json_str = ChannelzRegistry::GetServers(0);
+  grpc::testing::ValidateGetServersResponseProtoJsonTranslation(json_str);
+  grpc_json* parsed_json = grpc_json_parse_string(json_str);
+  // This check will naturally have to change when we support pagination.
+  // tracked: https://github.com/grpc/grpc/issues/16019.
+  ValidateJsonArraySize(parsed_json, "server", expected_servers);
+  grpc_json* end = GetJsonChild(parsed_json, "end");
+  ASSERT_NE(end, nullptr);
+  EXPECT_EQ(end->type, GRPC_JSON_TRUE);
+  grpc_json_destroy(parsed_json);
+  gpr_free(json_str);
+  // also check that the core API formats this correctly
+  char* core_api_json_str = grpc_channelz_get_servers(0);
+  grpc::testing::ValidateGetServersResponseProtoJsonTranslation(
+      core_api_json_str);
+  gpr_free(core_api_json_str);
+}
+
 class ChannelFixture {
  public:
   ChannelFixture(int max_trace_nodes = 0) {
@@ -124,6 +144,27 @@ class ChannelFixture {
   grpc_channel* channel_;
 };
 
+class ServerFixture {
+ public:
+  ServerFixture(int max_trace_nodes = 0) {
+    grpc_arg server_a[2];
+    server_a[0] = grpc_channel_arg_integer_create(
+        const_cast<char*>(GRPC_ARG_MAX_CHANNEL_TRACE_EVENTS_PER_NODE),
+        max_trace_nodes);
+    server_a[1] = grpc_channel_arg_integer_create(
+        const_cast<char*>(GRPC_ARG_ENABLE_CHANNELZ), true);
+    grpc_channel_args server_args = {GPR_ARRAY_SIZE(server_a), server_a};
+    server_ = grpc_server_create(&server_args, nullptr);
+  }
+
+  ~ServerFixture() { grpc_server_destroy(server_); }
+
+  grpc_server* server() { return server_; }
+
+ private:
+  grpc_server* server_;
+};
+
 struct validate_channel_data_args {
   int64_t calls_started;
   int64_t calls_failed;
@@ -163,6 +204,13 @@ void ValidateChannel(ChannelNode* channel, validate_channel_data_args args) {
   gpr_free(core_api_json_str);
 }
 
+void ValidateServer(ServerNode* server, validate_channel_data_args args) {
+  char* json_str = server->RenderJsonString();
+  grpc::testing::ValidateServerProtoJsonTranslation(json_str);
+  ValidateCounters(json_str, args);
+  gpr_free(json_str);
+}
+
 grpc_millis GetLastCallStartedMillis(CallCountingHelper* channel) {
   CallCountingHelperPeer peer(channel);
   return peer.last_call_started_millis();
@@ -237,7 +285,7 @@ TEST_P(ChannelzChannelTest, LastCallStartedMillis) {
   EXPECT_NE(millis1, millis4);
 }
 
-TEST(ChannelzGetTopChannelsTest, BasicTest) {
+TEST(ChannelzGetTopChannelsTest, BasicGetTopChannelsTest) {
   grpc_core::ExecCtx exec_ctx;
   ChannelFixture channel;
   ValidateGetTopChannels(1);
@@ -273,9 +321,49 @@ TEST(ChannelzGetTopChannelsTest, InternalChannelTest) {
   grpc_channel_destroy(internal_channel);
 }
 
+class ChannelzServerTest : public ::testing::TestWithParam<size_t> {};
+
+TEST_P(ChannelzServerTest, BasicServerAPIFunctionality) {
+  grpc_core::ExecCtx exec_ctx;
+  ServerFixture server(10);
+  ServerNode* channelz_server = grpc_server_get_channelz_node(server.server());
+  channelz_server->RecordCallStarted();
+  channelz_server->RecordCallFailed();
+  channelz_server->RecordCallSucceeded();
+  ValidateServer(channelz_server, {1, 1, 1});
+  channelz_server->RecordCallStarted();
+  channelz_server->RecordCallFailed();
+  channelz_server->RecordCallSucceeded();
+  channelz_server->RecordCallStarted();
+  channelz_server->RecordCallFailed();
+  channelz_server->RecordCallSucceeded();
+  ValidateServer(channelz_server, {3, 3, 3});
+}
+
+TEST(ChannelzGetServersTest, BasicGetServersTest) {
+  grpc_core::ExecCtx exec_ctx;
+  ServerFixture server;
+  ValidateGetServers(1);
+}
+
+TEST(ChannelzGetServersTest, NoServersTest) {
+  grpc_core::ExecCtx exec_ctx;
+  ValidateGetServers(0);
+}
+
+TEST(ChannelzGetServersTest, ManyServersTest) {
+  grpc_core::ExecCtx exec_ctx;
+  ServerFixture servers[10];
+  (void)servers;  // suppress unused variable error
+  ValidateGetServers(10);
+}
+
 INSTANTIATE_TEST_CASE_P(ChannelzChannelTestSweep, ChannelzChannelTest,
                         ::testing::Values(0, 1, 2, 6, 10, 15));
 
+INSTANTIATE_TEST_CASE_P(ChannelzServerTestSweep, ChannelzServerTest,
+                        ::testing::Values(0, 1, 2, 6, 10, 15));
+
 }  // namespace testing
 }  // namespace channelz
 }  // namespace grpc_core

test/core/end2end/tests/channelz.cc

@@ -22,6 +22,7 @@
 #include <string.h>
 
 #include "src/core/lib/surface/channel.h"
+#include "src/core/lib/surface/server.h"
 
 #include <grpc/byte_buffer.h>
 #include <grpc/grpc.h>
@@ -198,17 +199,21 @@ static void run_one_request(grpc_end2end_test_config config,
 static void test_channelz(grpc_end2end_test_config config) {
   grpc_end2end_test_fixture f;
 
-  grpc_arg client_a;
-  client_a.type = GRPC_ARG_INTEGER;
-  client_a.key = const_cast<char*>(GRPC_ARG_ENABLE_CHANNELZ);
-  client_a.value.integer = true;
-  grpc_channel_args client_args = {1, &client_a};
+  grpc_arg arg;
+  arg.type = GRPC_ARG_INTEGER;
+  arg.key = const_cast<char*>(GRPC_ARG_ENABLE_CHANNELZ);
+  arg.value.integer = true;
+  grpc_channel_args args = {1, &arg};
 
-  f = begin_test(config, "test_channelz", &client_args, nullptr);
+  f = begin_test(config, "test_channelz", &args, &args);
   grpc_core::channelz::ChannelNode* channelz_channel =
       grpc_channel_get_channelz_node(f.client);
-
   GPR_ASSERT(channelz_channel != nullptr);
+
+  grpc_core::channelz::ServerNode* channelz_server =
+      grpc_server_get_channelz_node(f.server);
+  GPR_ASSERT(channelz_server != nullptr);
+
   char* json = channelz_channel->RenderJsonString();
   GPR_ASSERT(json != nullptr);
   // nothing is present yet
@@ -241,6 +246,18 @@ static void test_channelz(grpc_end2end_test_config config) {
   GPR_ASSERT(nullptr == strstr(json, "\"severity\":\"CT_INFO\""));
   gpr_free(json);
 
+  json = channelz_server->RenderJsonString();
+  GPR_ASSERT(json != nullptr);
+  gpr_log(GPR_INFO, "%s", json);
+  GPR_ASSERT(nullptr != strstr(json, "\"callsStarted\":\"2\""));
+  GPR_ASSERT(nullptr != strstr(json, "\"callsFailed\":\"1\""));
+  GPR_ASSERT(nullptr != strstr(json, "\"callsSucceeded\":\"1\""));
+  // channel tracing is not enables, so these should not be preset.
+  GPR_ASSERT(nullptr == strstr(json, "\"trace\""));
+  GPR_ASSERT(nullptr == strstr(json, "\"description\":\"Channel created\""));
+  GPR_ASSERT(nullptr == strstr(json, "\"severity\":\"CT_INFO\""));
+  gpr_free(json);
+
   end_test(&f);
   config.tear_down_data(&f);
 }
@@ -248,22 +265,24 @@ static void test_channelz(grpc_end2end_test_config config) {
 static void test_channelz_with_channel_trace(grpc_end2end_test_config config) {
   grpc_end2end_test_fixture f;
 
-  grpc_arg client_a[2];
-  client_a[0].type = GRPC_ARG_INTEGER;
-  client_a[0].key =
-      const_cast<char*>(GRPC_ARG_MAX_CHANNEL_TRACE_EVENTS_PER_NODE);
-  client_a[0].value.integer = 5;
-  client_a[1].type = GRPC_ARG_INTEGER;
-  client_a[1].key = const_cast<char*>(GRPC_ARG_ENABLE_CHANNELZ);
-  client_a[1].value.integer = true;
-  grpc_channel_args client_args = {GPR_ARRAY_SIZE(client_a), client_a};
-
-  f = begin_test(config, "test_channelz_with_channel_trace", &client_args,
-                 nullptr);
+  grpc_arg arg[2];
+  arg[0].type = GRPC_ARG_INTEGER;
+  arg[0].key = const_cast<char*>(GRPC_ARG_MAX_CHANNEL_TRACE_EVENTS_PER_NODE);
+  arg[0].value.integer = 5;
+  arg[1].type = GRPC_ARG_INTEGER;
+  arg[1].key = const_cast<char*>(GRPC_ARG_ENABLE_CHANNELZ);
+  arg[1].value.integer = true;
+  grpc_channel_args args = {GPR_ARRAY_SIZE(arg), arg};
+
+  f = begin_test(config, "test_channelz_with_channel_trace", &args, &args);
   grpc_core::channelz::ChannelNode* channelz_channel =
       grpc_channel_get_channelz_node(f.client);
-
   GPR_ASSERT(channelz_channel != nullptr);
+
+  grpc_core::channelz::ServerNode* channelz_server =
+      grpc_server_get_channelz_node(f.server);
+  GPR_ASSERT(channelz_server != nullptr);
+
   char* json = channelz_channel->RenderJsonString();
   GPR_ASSERT(json != nullptr);
   gpr_log(GPR_INFO, "%s", json);
@@ -272,6 +291,14 @@ static void test_channelz_with_channel_trace(grpc_end2end_test_config config) {
   GPR_ASSERT(nullptr != strstr(json, "\"severity\":\"CT_INFO\""));
   gpr_free(json);
 
+  json = channelz_server->RenderJsonString();
+  GPR_ASSERT(json != nullptr);
+  gpr_log(GPR_INFO, "%s", json);
+  GPR_ASSERT(nullptr != strstr(json, "\"trace\""));
+  GPR_ASSERT(nullptr != strstr(json, "\"description\":\"Server created\""));
+  GPR_ASSERT(nullptr != strstr(json, "\"severity\":\"CT_INFO\""));
+  gpr_free(json);
+
   end_test(&f);
   config.tear_down_data(&f);
 }

test/cpp/util/channel_trace_proto_helper.cc

@@ -86,5 +86,14 @@ void ValidateSubchannelProtoJsonTranslation(char* json_c_str) {
   VaidateProtoJsonTranslation<grpc::channelz::v1::Subchannel>(json_c_str);
 }
 
+void ValidateServerProtoJsonTranslation(char* json_c_str) {
+  VaidateProtoJsonTranslation<grpc::channelz::v1::Server>(json_c_str);
+}
+
+void ValidateGetServersResponseProtoJsonTranslation(char* json_c_str) {
+  VaidateProtoJsonTranslation<grpc::channelz::v1::GetServersResponse>(
+      json_c_str);
+}
+
 }  // namespace testing
 }  // namespace grpc

test/cpp/util/channel_trace_proto_helper.h

@@ -27,6 +27,8 @@ void ValidateChannelProtoJsonTranslation(char* json_c_str);
 void ValidateGetTopChannelsResponseProtoJsonTranslation(char* json_c_str);
 void ValidateGetChannelResponseProtoJsonTranslation(char* json_c_str);
 void ValidateSubchannelProtoJsonTranslation(char* json_c_str);
+void ValidateServerProtoJsonTranslation(char* json_c_str);
+void ValidateGetServersResponseProtoJsonTranslation(char* json_c_str);
 
 }  // namespace testing
 }  // namespace grpc