Merge pull request #16023 from ncteisen/channelz-cpp

Channelz++: Part 1 Bootstrap the C++ Service Layer

BUILD

@@ -2053,6 +2053,26 @@ grpc_cc_library(
     alwayslink = 1,
 )
 
+grpc_cc_library(
+    name = "grpcpp_channelz",
+    srcs = [
+        "src/cpp/server/channelz/channelz_service.cc",
+        "src/cpp/server/channelz/channelz_service_plugin.cc",
+    ],
+    hdrs = [
+        "src/cpp/server/channelz/channelz_service.h",
+    ],
+    language = "c++",
+    public_hdrs = [
+        "include/grpcpp/ext/channelz_service_plugin.h",
+    ],
+    deps = [
+        ":grpc++",
+        "//src/proto/grpc/channelz:channelz_proto",
+    ],
+    alwayslink = 1,
+)
+
 grpc_cc_library(
     name = "grpc++_test",
     public_hdrs = [

CMakeLists.txt

@@ -551,6 +551,7 @@ add_dependencies(buildtests_cxx channel_arguments_test)
 add_dependencies(buildtests_cxx channel_filter_test)
 add_dependencies(buildtests_cxx channel_trace_test)
 add_dependencies(buildtests_cxx channelz_registry_test)
+add_dependencies(buildtests_cxx channelz_service_test)
 add_dependencies(buildtests_cxx channelz_test)
 add_dependencies(buildtests_cxx check_gcp_environment_linux_test)
 add_dependencies(buildtests_cxx check_gcp_environment_windows_test)
@@ -4690,6 +4691,73 @@ if (gRPC_INSTALL)
   )
 endif()
 
+
+if (gRPC_BUILD_CODEGEN)
+add_library(grpcpp_channelz
+  src/cpp/server/channelz/channelz_service.cc
+  src/cpp/server/channelz/channelz_service_plugin.cc
+  ${_gRPC_PROTO_GENS_DIR}/src/proto/grpc/channelz/channelz.pb.cc
+  ${_gRPC_PROTO_GENS_DIR}/src/proto/grpc/channelz/channelz.grpc.pb.cc
+  ${_gRPC_PROTO_GENS_DIR}/src/proto/grpc/channelz/channelz.pb.h
+  ${_gRPC_PROTO_GENS_DIR}/src/proto/grpc/channelz/channelz.grpc.pb.h
+)
+
+if(WIN32 AND MSVC)
+  set_target_properties(grpcpp_channelz PROPERTIES COMPILE_PDB_NAME "grpcpp_channelz"
+    COMPILE_PDB_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}"
+  )
+  if (gRPC_INSTALL)
+    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/grpcpp_channelz.pdb
+      DESTINATION ${gRPC_INSTALL_LIBDIR} OPTIONAL
+    )
+  endif()
+endif()
+
+protobuf_generate_grpc_cpp(
+  src/proto/grpc/channelz/channelz.proto
+)
+
+target_include_directories(grpcpp_channelz
+  PUBLIC $<INSTALL_INTERFACE:${gRPC_INSTALL_INCLUDEDIR}> $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+  PRIVATE ${_gRPC_SSL_INCLUDE_DIR}
+  PRIVATE ${_gRPC_PROTOBUF_INCLUDE_DIR}
+  PRIVATE ${_gRPC_ZLIB_INCLUDE_DIR}
+  PRIVATE ${_gRPC_BENCHMARK_INCLUDE_DIR}
+  PRIVATE ${_gRPC_CARES_INCLUDE_DIR}
+  PRIVATE ${_gRPC_GFLAGS_INCLUDE_DIR}
+  PRIVATE ${_gRPC_ADDRESS_SORTING_INCLUDE_DIR}
+  PRIVATE ${_gRPC_NANOPB_INCLUDE_DIR}
+  PRIVATE ${_gRPC_PROTO_GENS_DIR}
+)
+
+target_link_libraries(grpcpp_channelz
+  ${_gRPC_PROTOBUF_LIBRARIES}
+  ${_gRPC_ALLTARGETS_LIBRARIES}
+  grpc++
+  grpc
+)
+
+foreach(_hdr
+  include/grpcpp/ext/channelz_service_plugin.h
+)
+  string(REPLACE "include/" "" _path ${_hdr})
+  get_filename_component(_path ${_path} PATH)
+  install(FILES ${_hdr}
+    DESTINATION "${gRPC_INSTALL_INCLUDEDIR}/${_path}"
+  )
+endforeach()
+endif (gRPC_BUILD_CODEGEN)
+
+
+if (gRPC_INSTALL)
+  install(TARGETS grpcpp_channelz EXPORT gRPCTargets
+    RUNTIME DESTINATION ${gRPC_INSTALL_BINDIR}
+    LIBRARY DESTINATION ${gRPC_INSTALL_LIBDIR}
+    ARCHIVE DESTINATION ${gRPC_INSTALL_LIBDIR}
+  )
+endif()
+
 if (gRPC_BUILD_TESTS)
 
 if (gRPC_BUILD_CODEGEN)
@@ -10873,6 +10941,54 @@ target_link_libraries(channelz_registry_test
 endif (gRPC_BUILD_TESTS)
 if (gRPC_BUILD_TESTS)
 
+add_executable(channelz_service_test
+  test/cpp/end2end/channelz_service_test.cc
+  ${_gRPC_PROTO_GENS_DIR}/src/proto/grpc/channelz/channelz.pb.cc
+  ${_gRPC_PROTO_GENS_DIR}/src/proto/grpc/channelz/channelz.grpc.pb.cc
+  ${_gRPC_PROTO_GENS_DIR}/src/proto/grpc/channelz/channelz.pb.h
+  ${_gRPC_PROTO_GENS_DIR}/src/proto/grpc/channelz/channelz.grpc.pb.h
+  third_party/googletest/googletest/src/gtest-all.cc
+  third_party/googletest/googlemock/src/gmock-all.cc
+)
+
+protobuf_generate_grpc_cpp(
+  src/proto/grpc/channelz/channelz.proto
+)
+
+target_include_directories(channelz_service_test
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include
+  PRIVATE ${_gRPC_SSL_INCLUDE_DIR}
+  PRIVATE ${_gRPC_PROTOBUF_INCLUDE_DIR}
+  PRIVATE ${_gRPC_ZLIB_INCLUDE_DIR}
+  PRIVATE ${_gRPC_BENCHMARK_INCLUDE_DIR}
+  PRIVATE ${_gRPC_CARES_INCLUDE_DIR}
+  PRIVATE ${_gRPC_GFLAGS_INCLUDE_DIR}
+  PRIVATE ${_gRPC_ADDRESS_SORTING_INCLUDE_DIR}
+  PRIVATE ${_gRPC_NANOPB_INCLUDE_DIR}
+  PRIVATE third_party/googletest/googletest/include
+  PRIVATE third_party/googletest/googletest
+  PRIVATE third_party/googletest/googlemock/include
+  PRIVATE third_party/googletest/googlemock
+  PRIVATE ${_gRPC_PROTO_GENS_DIR}
+)
+
+target_link_libraries(channelz_service_test
+  ${_gRPC_PROTOBUF_LIBRARIES}
+  ${_gRPC_ALLTARGETS_LIBRARIES}
+  grpcpp_channelz
+  grpc++_test_util
+  grpc_test_util
+  grpc++
+  grpc
+  gpr_test_util
+  gpr
+  ${_gRPC_GFLAGS_LIBRARIES}
+)
+
+endif (gRPC_BUILD_TESTS)
+if (gRPC_BUILD_TESTS)
+
 add_executable(channelz_test
   test/core/channel/channelz_test.cc
   ${_gRPC_PROTO_GENS_DIR}/src/proto/grpc/channelz/channelz.pb.cc

Makefile

@@ -1142,6 +1142,7 @@ channel_arguments_test: $(BINDIR)/$(CONFIG)/channel_arguments_test
 channel_filter_test: $(BINDIR)/$(CONFIG)/channel_filter_test
 channel_trace_test: $(BINDIR)/$(CONFIG)/channel_trace_test
 channelz_registry_test: $(BINDIR)/$(CONFIG)/channelz_registry_test
+channelz_service_test: $(BINDIR)/$(CONFIG)/channelz_service_test
 channelz_test: $(BINDIR)/$(CONFIG)/channelz_test
 check_gcp_environment_linux_test: $(BINDIR)/$(CONFIG)/check_gcp_environment_linux_test
 check_gcp_environment_windows_test: $(BINDIR)/$(CONFIG)/check_gcp_environment_windows_test
@@ -1378,12 +1379,12 @@ static: static_c static_cxx
 
 static_c: pc_c pc_c_unsecure cache.mk  $(LIBDIR)/$(CONFIG)/libaddress_sorting.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgrpc_cronet.a $(LIBDIR)/$(CONFIG)/libgrpc_unsecure.a
 
-static_cxx: pc_cxx pc_cxx_unsecure cache.mk  $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc++_cronet.a $(LIBDIR)/$(CONFIG)/libgrpc++_error_details.a $(LIBDIR)/$(CONFIG)/libgrpc++_reflection.a $(LIBDIR)/$(CONFIG)/libgrpc++_unsecure.a
+static_cxx: pc_cxx pc_cxx_unsecure cache.mk  $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc++_cronet.a $(LIBDIR)/$(CONFIG)/libgrpc++_error_details.a $(LIBDIR)/$(CONFIG)/libgrpc++_reflection.a $(LIBDIR)/$(CONFIG)/libgrpc++_unsecure.a $(LIBDIR)/$(CONFIG)/libgrpcpp_channelz.a
 
 shared: shared_c shared_cxx
 
 shared_c: pc_c pc_c_unsecure cache.mk $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)address_sorting$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)gpr$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc_cronet$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc_unsecure$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE)
-shared_cxx: pc_cxx pc_cxx_unsecure cache.mk $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc++$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc++_cronet$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc++_error_details$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc++_reflection$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc++_unsecure$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP)
+shared_cxx: pc_cxx pc_cxx_unsecure cache.mk $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc++$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc++_cronet$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc++_error_details$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc++_reflection$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc++_unsecure$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP)
 
 shared_csharp: shared_c  $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc_csharp_ext$(SHARED_VERSION_CSHARP).$(SHARED_EXT_CSHARP)
 grpc_csharp_ext: shared_csharp
@@ -1640,6 +1641,7 @@ buildtests_cxx: privatelibs_cxx \
   $(BINDIR)/$(CONFIG)/channel_filter_test \
   $(BINDIR)/$(CONFIG)/channel_trace_test \
   $(BINDIR)/$(CONFIG)/channelz_registry_test \
+  $(BINDIR)/$(CONFIG)/channelz_service_test \
   $(BINDIR)/$(CONFIG)/channelz_test \
   $(BINDIR)/$(CONFIG)/check_gcp_environment_linux_test \
   $(BINDIR)/$(CONFIG)/check_gcp_environment_windows_test \
@@ -1818,6 +1820,7 @@ buildtests_cxx: privatelibs_cxx \
   $(BINDIR)/$(CONFIG)/channel_filter_test \
   $(BINDIR)/$(CONFIG)/channel_trace_test \
   $(BINDIR)/$(CONFIG)/channelz_registry_test \
+  $(BINDIR)/$(CONFIG)/channelz_service_test \
   $(BINDIR)/$(CONFIG)/channelz_test \
   $(BINDIR)/$(CONFIG)/check_gcp_environment_linux_test \
   $(BINDIR)/$(CONFIG)/check_gcp_environment_windows_test \
@@ -2261,6 +2264,8 @@ test_cxx: buildtests_cxx
 	$(Q) $(BINDIR)/$(CONFIG)/channel_trace_test || ( echo test channel_trace_test failed ; exit 1 )
 	$(E) "[RUN]     Testing channelz_registry_test"
 	$(Q) $(BINDIR)/$(CONFIG)/channelz_registry_test || ( echo test channelz_registry_test failed ; exit 1 )
+	$(E) "[RUN]     Testing channelz_service_test"
+	$(Q) $(BINDIR)/$(CONFIG)/channelz_service_test || ( echo test channelz_service_test failed ; exit 1 )
 	$(E) "[RUN]     Testing channelz_test"
 	$(Q) $(BINDIR)/$(CONFIG)/channelz_test || ( echo test channelz_test failed ; exit 1 )
 	$(E) "[RUN]     Testing check_gcp_environment_linux_test"
@@ -2459,6 +2464,8 @@ ifeq ($(CONFIG),opt)
 	$(Q) $(STRIP) $(LIBDIR)/$(CONFIG)/libgrpc++_reflection.a
 	$(E) "[STRIP]   Stripping libgrpc++_unsecure.a"
 	$(Q) $(STRIP) $(LIBDIR)/$(CONFIG)/libgrpc++_unsecure.a
+	$(E) "[STRIP]   Stripping libgrpcpp_channelz.a"
+	$(Q) $(STRIP) $(LIBDIR)/$(CONFIG)/libgrpcpp_channelz.a
 endif
 
 strip-shared_c: shared_c
@@ -2487,6 +2494,8 @@ ifeq ($(CONFIG),opt)
 	$(Q) $(STRIP) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc++_reflection$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP)
 	$(E) "[STRIP]   Stripping $(SHARED_PREFIX)grpc++_unsecure$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP)"
 	$(Q) $(STRIP) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc++_unsecure$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP)
+	$(E) "[STRIP]   Stripping $(SHARED_PREFIX)grpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP)"
+	$(Q) $(STRIP) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP)
 endif
 
 strip-shared_csharp: shared_csharp
@@ -2946,6 +2955,9 @@ install-static_cxx: static_cxx strip-static_cxx install-pkg-config_cxx
 	$(E) "[INSTALL] Installing libgrpc++_unsecure.a"
 	$(Q) $(INSTALL) -d $(prefix)/lib
 	$(Q) $(INSTALL) $(LIBDIR)/$(CONFIG)/libgrpc++_unsecure.a $(prefix)/lib/libgrpc++_unsecure.a
+	$(E) "[INSTALL] Installing libgrpcpp_channelz.a"
+	$(Q) $(INSTALL) -d $(prefix)/lib
+	$(Q) $(INSTALL) $(LIBDIR)/$(CONFIG)/libgrpcpp_channelz.a $(prefix)/lib/libgrpcpp_channelz.a
 
 
 
@@ -3047,6 +3059,15 @@ ifeq ($(SYSTEM),MINGW32)
 else ifneq ($(SYSTEM),Darwin)
 	$(Q) ln -sf $(SHARED_PREFIX)grpc++_unsecure$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(prefix)/lib/libgrpc++_unsecure.so.6
 	$(Q) ln -sf $(SHARED_PREFIX)grpc++_unsecure$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(prefix)/lib/libgrpc++_unsecure.so
+endif
+	$(E) "[INSTALL] Installing $(SHARED_PREFIX)grpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP)"
+	$(Q) $(INSTALL) -d $(prefix)/lib
+	$(Q) $(INSTALL) $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(prefix)/lib/$(SHARED_PREFIX)grpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP)
+ifeq ($(SYSTEM),MINGW32)
+	$(Q) $(INSTALL) $(LIBDIR)/$(CONFIG)/libgrpcpp_channelz$(SHARED_VERSION_CPP)-dll.a $(prefix)/lib/libgrpcpp_channelz.a
+else ifneq ($(SYSTEM),Darwin)
+	$(Q) ln -sf $(SHARED_PREFIX)grpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(prefix)/lib/libgrpcpp_channelz.so.6
+	$(Q) ln -sf $(SHARED_PREFIX)grpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(prefix)/lib/libgrpcpp_channelz.so
 endif
 ifneq ($(SYSTEM),MINGW32)
 ifneq ($(SYSTEM),Darwin)
@@ -7021,6 +7042,79 @@ ifneq ($(NO_DEPS),true)
 endif
 
 
+LIBGRPCPP_CHANNELZ_SRC = \
+    src/cpp/server/channelz/channelz_service.cc \
+    src/cpp/server/channelz/channelz_service_plugin.cc \
+    $(GENDIR)/src/proto/grpc/channelz/channelz.pb.cc $(GENDIR)/src/proto/grpc/channelz/channelz.grpc.pb.cc \
+
+PUBLIC_HEADERS_CXX += \
+    include/grpcpp/ext/channelz_service_plugin.h \
+
+LIBGRPCPP_CHANNELZ_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(LIBGRPCPP_CHANNELZ_SRC))))
+
+
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure libraries if you don't have OpenSSL.
+
+$(LIBDIR)/$(CONFIG)/libgrpcpp_channelz.a: openssl_dep_error
+
+$(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP): openssl_dep_error
+
+else
+
+ifeq ($(NO_PROTOBUF),true)
+
+# You can't build a C++ library if you don't have protobuf - a bit overreached, but still okay.
+
+$(LIBDIR)/$(CONFIG)/libgrpcpp_channelz.a: protobuf_dep_error
+
+$(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP): protobuf_dep_error
+
+else
+
+$(LIBDIR)/$(CONFIG)/libgrpcpp_channelz.a: $(ZLIB_DEP) $(OPENSSL_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(PROTOBUF_DEP) $(LIBGRPCPP_CHANNELZ_OBJS) 
+	$(E) "[AR]      Creating $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) rm -f $(LIBDIR)/$(CONFIG)/libgrpcpp_channelz.a
+	$(Q) $(AR) $(AROPTS) $(LIBDIR)/$(CONFIG)/libgrpcpp_channelz.a $(LIBGRPCPP_CHANNELZ_OBJS) 
+ifeq ($(SYSTEM),Darwin)
+	$(Q) ranlib -no_warning_for_no_symbols $(LIBDIR)/$(CONFIG)/libgrpcpp_channelz.a
+endif
+
+
+
+ifeq ($(SYSTEM),MINGW32)
+$(LIBDIR)/$(CONFIG)/grpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP): $(LIBGRPCPP_CHANNELZ_OBJS)  $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(PROTOBUF_DEP) $(LIBDIR)/$(CONFIG)/grpc++$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(LIBDIR)/$(CONFIG)/grpc$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(OPENSSL_DEP)
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -shared -Wl,--output-def=$(LIBDIR)/$(CONFIG)/grpcpp_channelz$(SHARED_VERSION_CPP).def -Wl,--out-implib=$(LIBDIR)/$(CONFIG)/libgrpcpp_channelz$(SHARED_VERSION_CPP)-dll.a -o $(LIBDIR)/$(CONFIG)/grpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(LIBGRPCPP_CHANNELZ_OBJS) $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(LDLIBSXX) $(LDLIBS_PROTOBUF) $(LDLIBS) -lgrpc++$(SHARED_VERSION_CPP)-dll -lgrpc$(SHARED_VERSION_CORE)-dll
+else
+$(LIBDIR)/$(CONFIG)/libgrpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP): $(LIBGRPCPP_CHANNELZ_OBJS)  $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(PROTOBUF_DEP) $(LIBDIR)/$(CONFIG)/libgrpc++.$(SHARED_EXT_CPP) $(LIBDIR)/$(CONFIG)/libgrpc.$(SHARED_EXT_CORE) $(OPENSSL_DEP)
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+ifeq ($(SYSTEM),Darwin)
+	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -install_name $(SHARED_PREFIX)grpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) -dynamiclib -o $(LIBDIR)/$(CONFIG)/libgrpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(LIBGRPCPP_CHANNELZ_OBJS) $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(LDLIBSXX) $(LDLIBS_PROTOBUF) $(LDLIBS) -lgrpc++ -lgrpc
+else
+	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -shared -Wl,-soname,libgrpcpp_channelz.so.1 -o $(LIBDIR)/$(CONFIG)/libgrpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(LIBGRPCPP_CHANNELZ_OBJS) $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(LDLIBSXX) $(LDLIBS_PROTOBUF) $(LDLIBS) -lgrpc++ -lgrpc
+	$(Q) ln -sf $(SHARED_PREFIX)grpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(LIBDIR)/$(CONFIG)/libgrpcpp_channelz$(SHARED_VERSION_CPP).so.1
+	$(Q) ln -sf $(SHARED_PREFIX)grpcpp_channelz$(SHARED_VERSION_CPP).$(SHARED_EXT_CPP) $(LIBDIR)/$(CONFIG)/libgrpcpp_channelz$(SHARED_VERSION_CPP).so
+endif
+endif
+
+endif
+
+endif
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(LIBGRPCPP_CHANNELZ_OBJS:.o=.dep)
+endif
+endif
+$(OBJDIR)/$(CONFIG)/src/cpp/server/channelz/channelz_service.o: $(GENDIR)/src/proto/grpc/channelz/channelz.pb.cc $(GENDIR)/src/proto/grpc/channelz/channelz.grpc.pb.cc
+$(OBJDIR)/$(CONFIG)/src/cpp/server/channelz/channelz_service_plugin.o: $(GENDIR)/src/proto/grpc/channelz/channelz.pb.cc $(GENDIR)/src/proto/grpc/channelz/channelz.grpc.pb.cc
+
+
 LIBHTTP2_CLIENT_MAIN_SRC = \
     $(GENDIR)/src/proto/grpc/testing/empty.pb.cc $(GENDIR)/src/proto/grpc/testing/empty.grpc.pb.cc \
     $(GENDIR)/src/proto/grpc/testing/messages.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.grpc.pb.cc \
@@ -16562,6 +16656,53 @@ endif
 endif
 
 
+CHANNELZ_SERVICE_TEST_SRC = \
+    test/cpp/end2end/channelz_service_test.cc \
+    $(GENDIR)/src/proto/grpc/channelz/channelz.pb.cc $(GENDIR)/src/proto/grpc/channelz/channelz.grpc.pb.cc \
+
+CHANNELZ_SERVICE_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(CHANNELZ_SERVICE_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/channelz_service_test: openssl_dep_error
+
+else
+
+
+
+
+ifeq ($(NO_PROTOBUF),true)
+
+# You can't build the protoc plugins or protobuf-enabled targets if you don't have protobuf 3.5.0+.
+
+$(BINDIR)/$(CONFIG)/channelz_service_test: protobuf_dep_error
+
+else
+
+$(BINDIR)/$(CONFIG)/channelz_service_test: $(PROTOBUF_DEP) $(CHANNELZ_SERVICE_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpcpp_channelz.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LDXX) $(LDFLAGS) $(CHANNELZ_SERVICE_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpcpp_channelz.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBSXX) $(LDLIBS_PROTOBUF) $(LDLIBS) $(LDLIBS_SECURE) $(GTEST_LIB) -o $(BINDIR)/$(CONFIG)/channelz_service_test
+
+endif
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/cpp/end2end/channelz_service_test.o:  $(LIBDIR)/$(CONFIG)/libgrpcpp_channelz.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+$(OBJDIR)/$(CONFIG)/src/proto/grpc/channelz/channelz.o:  $(LIBDIR)/$(CONFIG)/libgrpcpp_channelz.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_channelz_service_test: $(CHANNELZ_SERVICE_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(CHANNELZ_SERVICE_TEST_OBJS:.o=.dep)
+endif
+endif
+$(OBJDIR)/$(CONFIG)/test/cpp/end2end/channelz_service_test.o: $(GENDIR)/src/proto/grpc/channelz/channelz.pb.cc $(GENDIR)/src/proto/grpc/channelz/channelz.grpc.pb.cc
+
+
 CHANNELZ_TEST_SRC = \
     test/core/channel/channelz_test.cc \
     $(GENDIR)/src/proto/grpc/channelz/channelz.pb.cc $(GENDIR)/src/proto/grpc/channelz/channelz.grpc.pb.cc \
@@ -24517,6 +24658,8 @@ src/cpp/common/secure_channel_arguments.cc: $(OPENSSL_DEP)
 src/cpp/common/secure_create_auth_context.cc: $(OPENSSL_DEP)
 src/cpp/ext/proto_server_reflection.cc: $(OPENSSL_DEP)
 src/cpp/ext/proto_server_reflection_plugin.cc: $(OPENSSL_DEP)
+src/cpp/server/channelz/channelz_service.cc: $(OPENSSL_DEP)
+src/cpp/server/channelz/channelz_service_plugin.cc: $(OPENSSL_DEP)
 src/cpp/server/secure_server_credentials.cc: $(OPENSSL_DEP)
 src/cpp/util/core_stats.cc: $(OPENSSL_DEP)
 src/cpp/util/error_details.cc: $(OPENSSL_DEP)

build.yaml

@@ -1111,10 +1111,6 @@ filegroups:
   secure: true
   uses:
   - grpc_trace
-- name: grpc++_channelz_proto
-  language: c++
-  src:
-  - src/proto/grpc/channelz/channelz.proto
 - name: grpc++_codegen_base
   language: c++
   public_headers:
@@ -1359,6 +1355,10 @@ filegroups:
   deps:
   - grpc++
   - grpc
+- name: grpcpp_channelz_proto
+  language: c++
+  src:
+  - src/proto/grpc/channelz/channelz.proto
 libs:
 - name: address_sorting
   build: all
@@ -1851,6 +1851,21 @@ libs:
   vs_project_guid: '{B6E81D84-2ACB-41B8-8781-493A944C7817}'
   vs_props:
   - protoc
+- name: grpcpp_channelz
+  build: all
+  language: c++
+  public_headers:
+  - include/grpcpp/ext/channelz_service_plugin.h
+  headers:
+  - src/cpp/server/channelz/channelz_service.h
+  src:
+  - src/cpp/server/channelz/channelz_service.cc
+  - src/cpp/server/channelz/channelz_service_plugin.cc
+  deps:
+  - grpc++
+  - grpc
+  filegroups:
+  - grpcpp_channelz_proto
 - name: http2_client_main
   build: private
   language: c++
@@ -4295,7 +4310,7 @@ targets:
   - gpr_test_util
   - gpr
   filegroups:
-  - grpc++_channelz_proto
+  - grpcpp_channelz_proto
   uses:
   - grpc++_test
 - name: channelz_registry_test
@@ -4314,6 +4329,22 @@ targets:
   uses:
   - grpc++_test
   uses_polling: false
+- name: channelz_service_test
+  gtest: true
+  build: test
+  language: c++
+  src:
+  - test/cpp/end2end/channelz_service_test.cc
+  deps:
+  - grpcpp_channelz
+  - grpc++_test_util
+  - grpc_test_util
+  - grpc++
+  - grpc
+  - gpr_test_util
+  - gpr
+  filegroups:
+  - grpcpp_channelz_proto
 - name: channelz_test
   gtest: true
   build: test
@@ -4328,7 +4359,7 @@ targets:
   - gpr_test_util
   - gpr
   filegroups:
-  - grpc++_channelz_proto
+  - grpcpp_channelz_proto
   uses:
   - grpc++_test
 - name: check_gcp_environment_linux_test

grpc.gyp

@@ -1585,6 +1585,19 @@
         'src/compiler/ruby_generator.cc',
       ],
     },
+    {
+      'target_name': 'grpcpp_channelz',
+      'type': 'static_library',
+      'dependencies': [
+        'grpc++',
+        'grpc',
+      ],
+      'sources': [
+        'src/cpp/server/channelz/channelz_service.cc',
+        'src/cpp/server/channelz/channelz_service_plugin.cc',
+        'src/proto/grpc/channelz/channelz.proto',
+      ],
+    },
     {
       'target_name': 'http2_client_main',
       'type': 'static_library',

include/grpcpp/ext/channelz_service_plugin.h

@@ -0,0 +1,41 @@
+/*
+ *
+ * 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 GRPCPP_EXT_CHANNELZ_SERVICE_PLUGIN_H
+#define GRPCPP_EXT_CHANNELZ_SERVICE_PLUGIN_H
+
+#include <grpc/support/port_platform.h>
+
+#include <grpcpp/impl/server_builder_plugin.h>
+#include <grpcpp/impl/server_initializer.h>
+#include <grpcpp/support/config.h>
+
+namespace grpc {
+namespace channelz {
+namespace experimental {
+
+/// Add channelz server plugin to \a ServerBuilder. This function should
+/// be called at static initialization time. This service is experimental
+/// for now. Track progress in https://github.com/grpc/grpc/issues/15988.
+void InitChannelzService();
+
+}  // namespace experimental
+}  // namespace channelz
+}  // namespace grpc
+
+#endif  // GRPCPP_EXT_CHANNELZ_SERVICE_PLUGIN_H

src/cpp/server/channelz/channelz_service.cc

@@ -0,0 +1,57 @@
+/*
+ *
+ * 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/cpp/server/channelz/channelz_service.h"
+
+#include <google/protobuf/text_format.h>
+#include <google/protobuf/util/json_util.h>
+
+#include <grpc/grpc.h>
+#include <grpc/support/alloc.h>
+
+namespace grpc {
+
+Status ChannelzService::GetTopChannels(
+    ServerContext* unused, const channelz::v1::GetTopChannelsRequest* request,
+    channelz::v1::GetTopChannelsResponse* response) {
+  char* json_str = grpc_channelz_get_top_channels(request->start_channel_id());
+  google::protobuf::util::Status s =
+      google::protobuf::util::JsonStringToMessage(json_str, response);
+  gpr_free(json_str);
+  if (s != google::protobuf::util::Status::OK) {
+    return Status(INTERNAL, s.ToString());
+  }
+  return Status::OK;
+}
+
+Status ChannelzService::GetChannel(
+    ServerContext* unused, const channelz::v1::GetChannelRequest* request,
+    channelz::v1::GetChannelResponse* response) {
+  char* json_str = grpc_channelz_get_channel(request->channel_id());
+  google::protobuf::util::Status s =
+      google::protobuf::util::JsonStringToMessage(json_str, response);
+  gpr_free(json_str);
+  if (s != google::protobuf::util::Status::OK) {
+    return Status(INTERNAL, s.ToString());
+  }
+  return Status::OK;
+}
+
+}  // namespace grpc

src/cpp/server/channelz/channelz_service.h

@@ -0,0 +1,43 @@
+/*
+ *
+ * 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_INTERNAL_CPP_SERVER_CHANNELZ_SERVICE_H
+#define GRPC_INTERNAL_CPP_SERVER_CHANNELZ_SERVICE_H
+
+#include <grpc/support/port_platform.h>
+
+#include <grpcpp/grpcpp.h>
+#include "src/proto/grpc/channelz/channelz.grpc.pb.h"
+
+namespace grpc {
+
+class ChannelzService final : public channelz::v1::Channelz::Service {
+ private:
+  // implementation of GetTopChannels rpc
+  Status GetTopChannels(
+      ServerContext* unused, const channelz::v1::GetTopChannelsRequest* request,
+      channelz::v1::GetTopChannelsResponse* response) override;
+  // implementation of GetChannel rpc
+  Status GetChannel(ServerContext* unused,
+                    const channelz::v1::GetChannelRequest* request,
+                    channelz::v1::GetChannelResponse* response) override;
+};
+
+}  // namespace grpc
+
+#endif  // GRPC_INTERNAL_CPP_SERVER_CHANNELZ_SERVICE_H

src/cpp/server/channelz/channelz_service_plugin.cc

@@ -0,0 +1,79 @@
+/*
+ *
+ * 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 <grpcpp/ext/channelz_service_plugin.h>
+#include <grpcpp/impl/server_builder_plugin.h>
+#include <grpcpp/impl/server_initializer.h>
+#include <grpcpp/server.h>
+
+#include "src/cpp/server/channelz/channelz_service.h"
+
+namespace grpc {
+namespace channelz {
+namespace experimental {
+
+class ChannelzServicePlugin : public ::grpc::ServerBuilderPlugin {
+ public:
+  ChannelzServicePlugin() : channelz_service_(new grpc::ChannelzService()) {}
+
+  grpc::string name() override { return "channelz_service"; }
+
+  void InitServer(grpc::ServerInitializer* si) override {
+    si->RegisterService(channelz_service_);
+  }
+
+  void Finish(grpc::ServerInitializer* si) override {}
+
+  void ChangeArguments(const grpc::string& name, void* value) override {}
+
+  bool has_sync_methods() const override {
+    if (channelz_service_) {
+      return channelz_service_->has_synchronous_methods();
+    }
+    return false;
+  }
+
+  bool has_async_methods() const override {
+    if (channelz_service_) {
+      return channelz_service_->has_async_methods();
+    }
+    return false;
+  }
+
+ private:
+  std::shared_ptr<grpc::ChannelzService> channelz_service_;
+};
+
+static std::unique_ptr< ::grpc::ServerBuilderPlugin>
+CreateChannelzServicePlugin() {
+  return std::unique_ptr< ::grpc::ServerBuilderPlugin>(
+      new ChannelzServicePlugin());
+}
+
+void InitChannelzService() {
+  static bool already_here = false;
+  if (already_here) return;
+  already_here = true;
+  ::grpc::ServerBuilder::InternalAddPluginFactory(&CreateChannelzServicePlugin);
+}
+
+}  // namespace experimental
+}  // namespace channelz
+}  // namespace grpc

src/proto/grpc/testing/echo_messages.proto

@@ -46,6 +46,7 @@ message RequestParams {
   string binary_error_details = 13;
   ErrorStatus expected_error = 14;
   int32 server_sleep_us = 15; // Amount to sleep when invoking server
+  int32 backend_channel_idx = 16; // which backend to send request to
 }
 
 message EchoRequest {

test/cpp/end2end/BUILD

@@ -119,6 +119,27 @@ grpc_cc_library(
     ],
 )
 
+grpc_cc_test(
+    name = "channelz_service_test",
+    srcs = ["channelz_service_test.cc"],
+    external_deps = [
+        "gtest",
+    ],
+    deps = [
+        ":test_service_impl",
+        "//:gpr",
+        "//:grpc",
+        "//:grpc++",
+        "//:grpcpp_channelz",
+        "//src/proto/grpc/channelz:channelz_proto",
+        "//src/proto/grpc/testing:echo_messages_proto",
+        "//src/proto/grpc/testing:echo_proto",
+        "//test/core/util:gpr_test_util",
+        "//test/core/util:grpc_test_util",
+        "//test/cpp/util:test_util",
+    ],
+)
+
 grpc_cc_test(
     name = "server_early_return_test",
     srcs = ["server_early_return_test.cc"],

test/cpp/end2end/channelz_service_test.cc

@@ -0,0 +1,352 @@
+/*
+ *
+ * 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 <grpc/grpc.h>
+#include <grpcpp/channel.h>
+#include <grpcpp/client_context.h>
+#include <grpcpp/create_channel.h>
+#include <grpcpp/security/credentials.h>
+#include <grpcpp/security/server_credentials.h>
+#include <grpcpp/server.h>
+#include <grpcpp/server_builder.h>
+#include <grpcpp/server_context.h>
+
+#include <grpcpp/ext/channelz_service_plugin.h>
+#include "src/proto/grpc/channelz/channelz.grpc.pb.h"
+#include "src/proto/grpc/testing/echo.grpc.pb.h"
+#include "test/core/util/port.h"
+#include "test/core/util/test_config.h"
+#include "test/cpp/end2end/test_service_impl.h"
+
+#include <gtest/gtest.h>
+
+using grpc::channelz::v1::GetChannelRequest;
+using grpc::channelz::v1::GetChannelResponse;
+using grpc::channelz::v1::GetTopChannelsRequest;
+using grpc::channelz::v1::GetTopChannelsResponse;
+
+namespace grpc {
+namespace testing {
+namespace {
+
+// Proxy service supports N backends. Sends RPC to backend dictated by
+// request->backend_channel_idx().
+class Proxy : public ::grpc::testing::EchoTestService::Service {
+ public:
+  Proxy() {}
+
+  void AddChannelToBackend(const std::shared_ptr<Channel>& channel) {
+    stubs_.push_back(grpc::testing::EchoTestService::NewStub(channel));
+  }
+
+  Status Echo(ServerContext* server_context, const EchoRequest* request,
+              EchoResponse* response) override {
+    std::unique_ptr<ClientContext> client_context =
+        ClientContext::FromServerContext(*server_context);
+    size_t idx = request->param().backend_channel_idx();
+    GPR_ASSERT(idx < stubs_.size());
+    return stubs_[idx]->Echo(client_context.get(), *request, response);
+  }
+
+ private:
+  std::vector<std::unique_ptr<::grpc::testing::EchoTestService::Stub>> stubs_;
+};
+
+}  // namespace
+
+class ChannelzServerTest : public ::testing::Test {
+ public:
+  ChannelzServerTest() {}
+
+  void SetUp() override {
+    // ensure channel server is brought up on all severs we build.
+    ::grpc::channelz::experimental::InitChannelzService();
+
+    // We set up a proxy server with channelz enabled.
+    proxy_port_ = grpc_pick_unused_port_or_die();
+    ServerBuilder proxy_builder;
+    grpc::string proxy_server_address = "localhost:" + to_string(proxy_port_);
+    proxy_builder.AddListeningPort(proxy_server_address,
+                                   InsecureServerCredentials());
+    // forces channelz and channel tracing to be enabled.
+    proxy_builder.AddChannelArgument(GRPC_ARG_ENABLE_CHANNELZ, 1);
+    proxy_builder.AddChannelArgument(GRPC_ARG_MAX_CHANNEL_TRACE_EVENTS_PER_NODE,
+                                     10);
+    proxy_builder.RegisterService(&proxy_service_);
+    proxy_server_ = proxy_builder.BuildAndStart();
+  }
+
+  // Sets the proxy up to have an arbitrary number of backends.
+  void ConfigureProxy(size_t num_backends) {
+    backends_.resize(num_backends);
+    for (size_t i = 0; i < num_backends; ++i) {
+      // create a new backend.
+      backends_[i].port = grpc_pick_unused_port_or_die();
+      ServerBuilder backend_builder;
+      grpc::string backend_server_address =
+          "localhost:" + to_string(backends_[i].port);
+      backend_builder.AddListeningPort(backend_server_address,
+                                       InsecureServerCredentials());
+      backends_[i].service.reset(new TestServiceImpl);
+      // ensure that the backend itself has channelz disabled.
+      backend_builder.AddChannelArgument(GRPC_ARG_ENABLE_CHANNELZ, 0);
+      backend_builder.RegisterService(backends_[i].service.get());
+      backends_[i].server = backend_builder.BuildAndStart();
+      // set up a channel to the backend. We ensure that this channel has
+      // channelz enabled since these channels (proxy outbound to backends)
+      // are the ones that our test will actually be validating.
+      ChannelArguments args;
+      args.SetInt(GRPC_ARG_ENABLE_CHANNELZ, 1);
+      args.SetInt(GRPC_ARG_MAX_CHANNEL_TRACE_EVENTS_PER_NODE, 10);
+      std::shared_ptr<Channel> channel_to_backend = CreateCustomChannel(
+          backend_server_address, InsecureChannelCredentials(), args);
+      proxy_service_.AddChannelToBackend(channel_to_backend);
+    }
+  }
+
+  void ResetStubs() {
+    string target = "dns:localhost:" + to_string(proxy_port_);
+    ChannelArguments args;
+    // disable channelz. We only want to focus on proxy to backend outbound.
+    args.SetInt(GRPC_ARG_ENABLE_CHANNELZ, 0);
+    std::shared_ptr<Channel> channel =
+        CreateCustomChannel(target, InsecureChannelCredentials(), args);
+    channelz_stub_ = grpc::channelz::v1::Channelz::NewStub(channel);
+    echo_stub_ = grpc::testing::EchoTestService::NewStub(channel);
+  }
+
+  void SendSuccessfulEcho(int channel_idx) {
+    EchoRequest request;
+    EchoResponse response;
+    request.set_message("Hello channelz");
+    request.mutable_param()->set_backend_channel_idx(channel_idx);
+    ClientContext context;
+    Status s = echo_stub_->Echo(&context, request, &response);
+    EXPECT_EQ(response.message(), request.message());
+    EXPECT_TRUE(s.ok());
+  }
+
+  void SendFailedEcho(int channel_idx) {
+    EchoRequest request;
+    EchoResponse response;
+    request.set_message("Hello channelz");
+    request.mutable_param()->set_backend_channel_idx(channel_idx);
+    auto* error = request.mutable_param()->mutable_expected_error();
+    error->set_code(13);  // INTERNAL
+    error->set_error_message("error");
+    ClientContext context;
+    Status s = echo_stub_->Echo(&context, request, &response);
+    EXPECT_FALSE(s.ok());
+  }
+
+  static string to_string(const int number) {
+    std::stringstream strs;
+    strs << number;
+    return strs.str();
+  }
+
+ protected:
+  // package of data needed for each backend server.
+  struct BackendData {
+    std::unique_ptr<Server> server;
+    int port;
+    std::unique_ptr<TestServiceImpl> service;
+  };
+
+  std::unique_ptr<grpc::channelz::v1::Channelz::Stub> channelz_stub_;
+  std::unique_ptr<grpc::testing::EchoTestService::Stub> echo_stub_;
+
+  // proxy server to ping with channelz requests.
+  std::unique_ptr<Server> proxy_server_;
+  int proxy_port_;
+  Proxy proxy_service_;
+
+  // backends. All implement the echo service.
+  std::vector<BackendData> backends_;
+};
+
+TEST_F(ChannelzServerTest, BasicTest) {
+  ResetStubs();
+  ConfigureProxy(1);
+  GetTopChannelsRequest request;
+  GetTopChannelsResponse response;
+  request.set_start_channel_id(0);
+  ClientContext context;
+  Status s = channelz_stub_->GetTopChannels(&context, request, &response);
+  EXPECT_TRUE(s.ok());
+  EXPECT_EQ(response.channel_size(), 1);
+}
+
+TEST_F(ChannelzServerTest, HighStartId) {
+  ResetStubs();
+  ConfigureProxy(1);
+  GetTopChannelsRequest request;
+  GetTopChannelsResponse response;
+  request.set_start_channel_id(10000);
+  ClientContext context;
+  Status s = channelz_stub_->GetTopChannels(&context, request, &response);
+  EXPECT_TRUE(s.ok());
+  EXPECT_EQ(response.channel_size(), 0);
+}
+
+TEST_F(ChannelzServerTest, SuccessfulRequestTest) {
+  ResetStubs();
+  ConfigureProxy(1);
+  SendSuccessfulEcho(0);
+  GetChannelRequest request;
+  GetChannelResponse response;
+  request.set_channel_id(1);
+  ClientContext context;
+  Status s = channelz_stub_->GetChannel(&context, request, &response);
+  EXPECT_TRUE(s.ok());
+  EXPECT_EQ(response.channel().data().calls_started(), 1);
+  EXPECT_EQ(response.channel().data().calls_succeeded(), 1);
+  EXPECT_EQ(response.channel().data().calls_failed(), 0);
+}
+
+TEST_F(ChannelzServerTest, FailedRequestTest) {
+  ResetStubs();
+  ConfigureProxy(1);
+  SendFailedEcho(0);
+  GetChannelRequest request;
+  GetChannelResponse response;
+  request.set_channel_id(1);
+  ClientContext context;
+  Status s = channelz_stub_->GetChannel(&context, request, &response);
+  EXPECT_TRUE(s.ok());
+  EXPECT_EQ(response.channel().data().calls_started(), 1);
+  EXPECT_EQ(response.channel().data().calls_succeeded(), 0);
+  EXPECT_EQ(response.channel().data().calls_failed(), 1);
+}
+
+TEST_F(ChannelzServerTest, ManyRequestsTest) {
+  ResetStubs();
+  ConfigureProxy(1);
+  // send some RPCs
+  const int kNumSuccess = 10;
+  const int kNumFailed = 11;
+  for (int i = 0; i < kNumSuccess; ++i) {
+    SendSuccessfulEcho(0);
+  }
+  for (int i = 0; i < kNumFailed; ++i) {
+    SendFailedEcho(0);
+  }
+  GetChannelRequest request;
+  GetChannelResponse response;
+  request.set_channel_id(1);
+  ClientContext context;
+  Status s = channelz_stub_->GetChannel(&context, request, &response);
+  EXPECT_TRUE(s.ok());
+  EXPECT_EQ(response.channel().data().calls_started(),
+            kNumSuccess + kNumFailed);
+  EXPECT_EQ(response.channel().data().calls_succeeded(), kNumSuccess);
+  EXPECT_EQ(response.channel().data().calls_failed(), kNumFailed);
+}
+
+TEST_F(ChannelzServerTest, ManyChannels) {
+  ResetStubs();
+  const int kNumChannels = 4;
+  ConfigureProxy(kNumChannels);
+  GetTopChannelsRequest request;
+  GetTopChannelsResponse response;
+  request.set_start_channel_id(0);
+  ClientContext context;
+  Status s = channelz_stub_->GetTopChannels(&context, request, &response);
+  EXPECT_TRUE(s.ok());
+  EXPECT_EQ(response.channel_size(), kNumChannels);
+}
+
+TEST_F(ChannelzServerTest, ManyRequestsManyChannels) {
+  ResetStubs();
+  const int kNumChannels = 4;
+  ConfigureProxy(kNumChannels);
+  const int kNumSuccess = 10;
+  const int kNumFailed = 11;
+  for (int i = 0; i < kNumSuccess; ++i) {
+    SendSuccessfulEcho(0);
+    SendSuccessfulEcho(2);
+  }
+  for (int i = 0; i < kNumFailed; ++i) {
+    SendFailedEcho(1);
+    SendFailedEcho(2);
+  }
+
+  // the first channel saw only successes
+  {
+    GetChannelRequest request;
+    GetChannelResponse response;
+    request.set_channel_id(1);
+    ClientContext context;
+    Status s = channelz_stub_->GetChannel(&context, request, &response);
+    EXPECT_TRUE(s.ok());
+    EXPECT_EQ(response.channel().data().calls_started(), kNumSuccess);
+    EXPECT_EQ(response.channel().data().calls_succeeded(), kNumSuccess);
+    EXPECT_EQ(response.channel().data().calls_failed(), 0);
+  }
+
+  // the second channel saw only failures
+  {
+    GetChannelRequest request;
+    GetChannelResponse response;
+    request.set_channel_id(2);
+    ClientContext context;
+    Status s = channelz_stub_->GetChannel(&context, request, &response);
+    EXPECT_TRUE(s.ok());
+    EXPECT_EQ(response.channel().data().calls_started(), kNumFailed);
+    EXPECT_EQ(response.channel().data().calls_succeeded(), 0);
+    EXPECT_EQ(response.channel().data().calls_failed(), kNumFailed);
+  }
+
+  // the third channel saw both
+  {
+    GetChannelRequest request;
+    GetChannelResponse response;
+    request.set_channel_id(3);
+    ClientContext context;
+    Status s = channelz_stub_->GetChannel(&context, request, &response);
+    EXPECT_TRUE(s.ok());
+    EXPECT_EQ(response.channel().data().calls_started(),
+              kNumSuccess + kNumFailed);
+    EXPECT_EQ(response.channel().data().calls_succeeded(), kNumSuccess);
+    EXPECT_EQ(response.channel().data().calls_failed(), kNumFailed);
+  }
+
+  // the fourth channel saw nothing
+  {
+    GetChannelRequest request;
+    GetChannelResponse response;
+    request.set_channel_id(4);
+    ClientContext context;
+    Status s = channelz_stub_->GetChannel(&context, request, &response);
+    EXPECT_TRUE(s.ok());
+    EXPECT_EQ(response.channel().data().calls_started(), 0);
+    EXPECT_EQ(response.channel().data().calls_succeeded(), 0);
+    EXPECT_EQ(response.channel().data().calls_failed(), 0);
+  }
+}
+
+}  // namespace testing
+}  // namespace grpc
+
+int main(int argc, char** argv) {
+  grpc_test_init(argc, argv);
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}

tools/run_tests/generated/sources_and_headers.json

@@ -3124,10 +3124,10 @@
       "gpr_test_util", 
       "grpc", 
       "grpc++", 
-      "grpc++_channelz_proto", 
       "grpc++_test", 
       "grpc++_test_util", 
-      "grpc_test_util"
+      "grpc_test_util", 
+      "grpcpp_channelz_proto"
     ], 
     "headers": [], 
     "is_filegroup": false, 
@@ -3165,10 +3165,31 @@
       "gpr_test_util", 
       "grpc", 
       "grpc++", 
-      "grpc++_channelz_proto", 
+      "grpc++_test_util", 
+      "grpc_test_util", 
+      "grpcpp_channelz", 
+      "grpcpp_channelz_proto"
+    ], 
+    "headers": [], 
+    "is_filegroup": false, 
+    "language": "c++", 
+    "name": "channelz_service_test", 
+    "src": [
+      "test/cpp/end2end/channelz_service_test.cc"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
+  {
+    "deps": [
+      "gpr", 
+      "gpr_test_util", 
+      "grpc", 
+      "grpc++", 
       "grpc++_test", 
       "grpc++_test_util", 
-      "grpc_test_util"
+      "grpc_test_util", 
+      "grpcpp_channelz_proto"
     ], 
     "headers": [], 
     "is_filegroup": false, 
@@ -7528,6 +7549,28 @@
     "third_party": false, 
     "type": "lib"
   }, 
+  {
+    "deps": [
+      "grpc", 
+      "grpc++", 
+      "grpcpp_channelz_proto"
+    ], 
+    "headers": [
+      "include/grpcpp/ext/channelz_service_plugin.h", 
+      "src/cpp/server/channelz/channelz_service.h"
+    ], 
+    "is_filegroup": false, 
+    "language": "c++", 
+    "name": "grpcpp_channelz", 
+    "src": [
+      "include/grpcpp/ext/channelz_service_plugin.h", 
+      "src/cpp/server/channelz/channelz_service.cc", 
+      "src/cpp/server/channelz/channelz_service.h", 
+      "src/cpp/server/channelz/channelz_service_plugin.cc"
+    ], 
+    "third_party": false, 
+    "type": "lib"
+  }, 
   {
     "deps": [
       "grpc", 
@@ -10888,20 +10931,6 @@
     "third_party": false, 
     "type": "filegroup"
   }, 
-  {
-    "deps": [], 
-    "headers": [
-      "src/proto/grpc/channelz/channelz.grpc.pb.h", 
-      "src/proto/grpc/channelz/channelz.pb.h", 
-      "src/proto/grpc/channelz/channelz_mock.grpc.pb.h"
-    ], 
-    "is_filegroup": true, 
-    "language": "c++", 
-    "name": "grpc++_channelz_proto", 
-    "src": [], 
-    "third_party": false, 
-    "type": "filegroup"
-  }, 
   {
     "deps": [
       "grpc_codegen"
@@ -11377,5 +11406,19 @@
     ], 
     "third_party": false, 
     "type": "filegroup"
+  }, 
+  {
+    "deps": [], 
+    "headers": [
+      "src/proto/grpc/channelz/channelz.grpc.pb.h", 
+      "src/proto/grpc/channelz/channelz.pb.h", 
+      "src/proto/grpc/channelz/channelz_mock.grpc.pb.h"
+    ], 
+    "is_filegroup": true, 
+    "language": "c++", 
+    "name": "grpcpp_channelz_proto", 
+    "src": [], 
+    "third_party": false, 
+    "type": "filegroup"
   }
 ]

tools/run_tests/generated/tests.json

@@ -3755,6 +3755,30 @@
     ], 
     "uses_polling": false
   }, 
+  {
+    "args": [], 
+    "benchmark": false, 
+    "ci_platforms": [
+      "linux", 
+      "mac", 
+      "posix", 
+      "windows"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "gtest": true, 
+    "language": "c++", 
+    "name": "channelz_service_test", 
+    "platforms": [
+      "linux", 
+      "mac", 
+      "posix", 
+      "windows"
+    ], 
+    "uses_polling": true
+  }, 
   {
     "args": [], 
     "benchmark": false,