Proto server reflection

4 files changed, 599 insertions, 0 deletions

diff --git a/test/cpp/util/proto_reflection_descriptor_database.cc b/test/cpp/util/proto_reflection_descriptor_database.cc
new file mode 100644
index 0000000000..c2ed93c12b
--- /dev/null
+++ b/test/cpp/util/proto_reflection_descriptor_database.cc
@@ -0,0 +1,238 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "proto_reflection_descriptor_database.h"
+
+#include <vector>
+
+#include <grpc/support/log.h>
+
+namespace grpc {
+
+ProtoReflectionDescriptorDatabase::ProtoReflectionDescriptorDatabase(
+    std::unique_ptr<reflection::v1alpha::ServerReflection::Stub> stub)
+    : stub_(std::move(stub)) {}
+
+ProtoReflectionDescriptorDatabase::ProtoReflectionDescriptorDatabase(
+    std::shared_ptr<grpc::Channel> channel)
+    : stub_(reflection::v1alpha::ServerReflection::NewStub(channel)) {}
+
+ProtoReflectionDescriptorDatabase::~ProtoReflectionDescriptorDatabase() {}
+
+bool ProtoReflectionDescriptorDatabase::FindFileByName(
+    const string& filename, google::protobuf::FileDescriptorProto* output) {
+  if (cached_db_.FindFileByName(filename, output)) {
+    return true;
+  }
+
+  if (known_files_.find(filename) != known_files_.end()) {
+    return false;
+  }
+
+  ClientContext ctx;
+  reflection::v1alpha::FileNameRequest request;
+  request.set_filename(filename);
+  reflection::v1alpha::FileDescriptorProtoResponse response;
+
+  Status status = stub_->GetFileByName(&ctx, request, &response);
+  if (status.ok()) {
+    // const google::protobuf::FileDescriptorProto* file_proto =
+    //     response.mutable_file_descriptor_proto();
+    const google::protobuf::FileDescriptorProto file_proto =
+        ParseFileDescriptorProtoResponse(&response);
+    known_files_.insert(file_proto.name());
+    cached_db_.Add(file_proto);
+  } else if (status.error_code() == StatusCode::NOT_FOUND) {
+    gpr_log(GPR_INFO, "NOT_FOUND from server for FindFileByName(%s)",
+            filename.c_str());
+  } else {
+    gpr_log(GPR_INFO,
+            "Error on FindFileByName(%s)\n\tError code: %d\n"
+            "\tError Message: %s",
+            filename.c_str(), status.error_code(),
+            status.error_message().c_str());
+  }
+
+  return cached_db_.FindFileByName(filename, output);
+}
+
+bool ProtoReflectionDescriptorDatabase::FindFileContainingSymbol(
+    const string& symbol_name, google::protobuf::FileDescriptorProto* output) {
+  if (cached_db_.FindFileContainingSymbol(symbol_name, output)) {
+    return true;
+  }
+
+  if (missing_symbols_.find(symbol_name) != missing_symbols_.end()) {
+    return false;
+  }
+
+  ClientContext ctx;
+  reflection::v1alpha::SymbolRequest request;
+  request.set_symbol(symbol_name);
+  reflection::v1alpha::FileDescriptorProtoResponse response;
+
+  Status status = stub_->GetFileContainingSymbol(&ctx, request, &response);
+  if (status.ok()) {
+    const google::protobuf::FileDescriptorProto file_proto =
+        ParseFileDescriptorProtoResponse(&response);
+    if (known_files_.find(file_proto.name()) == known_files_.end()) {
+      known_files_.insert(file_proto.name());
+      cached_db_.Add(file_proto);
+    }
+  } else if (status.error_code() == StatusCode::NOT_FOUND) {
+    missing_symbols_.insert(symbol_name);
+    gpr_log(GPR_INFO, "NOT_FOUND from server for FindFileContainingSymbol(%s)",
+            symbol_name.c_str());
+  } else {
+    gpr_log(GPR_INFO,
+            "Error on FindFileContainingSymbol(%s)\n"
+            "\tError code: %d\n\tError Message: %s",
+            symbol_name.c_str(), status.error_code(),
+            status.error_message().c_str());
+  }
+
+  return cached_db_.FindFileContainingSymbol(symbol_name, output);
+}
+
+bool ProtoReflectionDescriptorDatabase::FindFileContainingExtension(
+    const string& containing_type, int field_number,
+    google::protobuf::FileDescriptorProto* output) {
+  if (cached_db_.FindFileContainingExtension(containing_type, field_number,
+                                             output)) {
+    return true;
+  }
+
+  if (missing_extensions_.find(containing_type) != missing_extensions_.end() &&
+      missing_extensions_[containing_type].find(field_number) !=
+          missing_extensions_[containing_type].end()) {
+    gpr_log(GPR_INFO, "nested map.");
+    return false;
+  }
+
+  ClientContext ctx;
+  reflection::v1alpha::ExtensionRequest request;
+  request.set_containing_type(containing_type);
+  request.set_extension_number(field_number);
+  reflection::v1alpha::FileDescriptorProtoResponse response;
+
+  Status status = stub_->GetFileContainingExtension(&ctx, request, &response);
+  if (status.ok()) {
+    const google::protobuf::FileDescriptorProto file_proto =
+        ParseFileDescriptorProtoResponse(&response);
+    if (known_files_.find(file_proto.name()) == known_files_.end()) {
+      known_files_.insert(file_proto.name());
+      cached_db_.Add(file_proto);
+    }
+  } else if (status.error_code() == StatusCode::NOT_FOUND) {
+    if (missing_extensions_.find(containing_type) ==
+        missing_extensions_.end()) {
+      missing_extensions_[containing_type] = {};
+    }
+    missing_extensions_[containing_type].insert(field_number);
+    gpr_log(GPR_INFO,
+            "NOT_FOUND from server for FindFileContainingExtension(%s, %d)",
+            containing_type.c_str(), field_number);
+  } else {
+    gpr_log(GPR_INFO,
+            "Error on FindFileContainingExtension(%s, %d)\n"
+            "\tError code: %d\n\tError Message: %s",
+            containing_type.c_str(), field_number, status.error_code(),
+            status.error_message().c_str());
+  }
+
+  return cached_db_.FindFileContainingExtension(containing_type, field_number,
+                                                output);
+}
+
+bool ProtoReflectionDescriptorDatabase::FindAllExtensionNumbers(
+    const string& extendee_type, std::vector<int>* output) {
+  if (cached_extension_numbers_.find(extendee_type) !=
+      cached_extension_numbers_.end()) {
+    *output = cached_extension_numbers_[extendee_type];
+    return true;
+  }
+
+  ClientContext ctx;
+  reflection::v1alpha::TypeRequest request;
+  request.set_type(extendee_type);
+  reflection::v1alpha::ExtensionNumberResponse response;
+
+  Status status = stub_->GetAllExtensionNumbers(&ctx, request, &response);
+  if (status.ok()) {
+    auto number = response.extension_number();
+    *output = std::vector<int>(number.begin(), number.end());
+    cached_extension_numbers_[extendee_type] = *output;
+    return true;
+  } else if (status.error_code() == StatusCode::NOT_FOUND) {
+    gpr_log(GPR_INFO, "NOT_FOUND from server for FindAllExtensionNumbers(%s)",
+            extendee_type.c_str());
+  } else {
+    gpr_log(GPR_INFO,
+            "Error on FindAllExtensionNumbersExtension(%s)\n"
+            "\tError code: %d\n\tError Message: %s",
+            extendee_type.c_str(), status.error_code(),
+            status.error_message().c_str());
+  }
+  return false;
+}
+
+bool ProtoReflectionDescriptorDatabase::GetServices(
+    std::vector<std::string>* output) {
+  ClientContext ctx;
+  reflection::v1alpha::EmptyRequest request;
+  reflection::v1alpha::ListServiceResponse response;
+
+  Status status = stub_->ListService(&ctx, request, &response);
+  if (status.ok()) {
+    for (int i = 0; i < response.services_size(); ++i) {
+      (*output).push_back(response.services(i));
+    }
+    return true;
+  } else {
+    gpr_log(GPR_INFO,
+            "Error on GetServices()\n\tError code: %d\n"
+            "\tError Message: %s",
+            status.error_code(), status.error_message().c_str());
+  }
+  return false;
+}
+
+const google::protobuf::FileDescriptorProto
+ProtoReflectionDescriptorDatabase::ParseFileDescriptorProtoResponse(
+    reflection::v1alpha::FileDescriptorProtoResponse* response) {
+  google::protobuf::FileDescriptorProto file_desc_proto;
+  file_desc_proto.ParseFromString(response->file_descriptor_proto());
+  return file_desc_proto;
+}
+
+}  // namespace grpc
diff --git a/test/cpp/util/proto_reflection_descriptor_database.h b/test/cpp/util/proto_reflection_descriptor_database.h
new file mode 100644
index 0000000000..bf94654c3d
--- /dev/null
+++ b/test/cpp/util/proto_reflection_descriptor_database.h
@@ -0,0 +1,95 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <memory>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
+
+#include <google/protobuf/descriptor.h>
+#include <google/protobuf/descriptor.pb.h>
+#include <google/protobuf/descriptor_database.h>
+#include <grpc++/grpc++.h>
+#include <grpc++/impl/reflection.grpc.pb.h>
+
+// #include "reflection.grpc.pb.h"
+
+namespace grpc {
+
+class ProtoReflectionDescriptorDatabase
+    : public google::protobuf::DescriptorDatabase {
+ public:
+  explicit ProtoReflectionDescriptorDatabase(
+      std::unique_ptr<reflection::v1alpha::ServerReflection::Stub> stub);
+
+  explicit ProtoReflectionDescriptorDatabase(
+      std::shared_ptr<grpc::Channel> channel);
+
+  virtual ~ProtoReflectionDescriptorDatabase();
+
+  // DescriptorDatabase methods
+  bool FindFileByName(const string& filename,
+                      google::protobuf::FileDescriptorProto* output)
+      GRPC_OVERRIDE;
+
+  bool FindFileContainingSymbol(const string& symbol_name,
+                                google::protobuf::FileDescriptorProto* output)
+      GRPC_OVERRIDE;
+
+  bool FindFileContainingExtension(
+      const string& containing_type, int field_number,
+      google::protobuf::FileDescriptorProto* output) GRPC_OVERRIDE;
+
+  bool FindAllExtensionNumbers(const string& extendee_type,
+                               std::vector<int>* output) GRPC_OVERRIDE;
+
+  bool GetServices(std::vector<std::string>* output);
+
+  grpc::reflection::v1alpha::ServerReflection::Stub* stub() {
+    return stub_.get();
+  }
+
+ private:
+  const google::protobuf::FileDescriptorProto ParseFileDescriptorProtoResponse(
+      reflection::v1alpha::FileDescriptorProtoResponse* response);
+
+  std::unique_ptr<grpc::reflection::v1alpha::ServerReflection::Stub> stub_;
+  std::unordered_set<string> known_files_;
+  std::unordered_set<string> missing_symbols_;
+  std::unordered_map<string, std::unordered_set<int>> missing_extensions_;
+  std::unordered_map<string, std::vector<int>> cached_extension_numbers_;
+
+  google::protobuf::SimpleDescriptorDatabase cached_db_;
+};
+
+}  // namespace grpc
diff --git a/test/cpp/util/reflection_debug/Makefile b/test/cpp/util/reflection_debug/Makefile
new file mode 100644
index 0000000000..9eea5ae734
--- /dev/null
+++ b/test/cpp/util/reflection_debug/Makefile
@@ -0,0 +1,50 @@
+
+# Copyright 2015-2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+
+CXX = g++
+INCLUDES += -I. -I..
+CPPFLAGS += -I/usr/local/include -pthread
+CXXFLAGS += -std=c++11 ${INCLUDES}
+LDFLAGS += -L/usr/local/lib -lgrpc++_unsecure -lgrpc -lgrpc++_reflection -lprotobuf -lpthread -ldl
+VPATH = ..
+
+# PROTOS_PATH = ../../../src/cpp/plugin/reflection
+
+vpath %.proto $(PROTOS_PATH)
+
+all: reflection_client
+
+reflection_client: proto_reflection_descriptor_database.o reflection_client.o
+	$(CXX) $(INCLUDES) $^ $(LDFLAGS) -o $@
+
+
+clean:
+	rm -f *.o reflection_client
diff --git a/test/cpp/util/reflection_debug/reflection_client.cc b/test/cpp/util/reflection_debug/reflection_client.cc
new file mode 100644
index 0000000000..fb40627514
--- /dev/null
+++ b/test/cpp/util/reflection_debug/reflection_client.cc
@@ -0,0 +1,216 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <iomanip>
+#include <iostream>
+#include <memory>
+#include <string>
+
+#include <google/protobuf/descriptor.h>
+#include <google/protobuf/descriptor.pb.h>
+#include <grpc++/grpc++.h>
+
+#include "proto_reflection_descriptor_database.h"
+// #include "reflection.grpc.pb.h"
+
+using grpc::Channel;
+using grpc::ClientContext;
+using grpc::Status;
+using grpc::ProtoReflectionDescriptorDatabase;
+using grpc::reflection::v1alpha::ServerReflection;
+using grpc::reflection::v1alpha::EmptyRequest;
+using grpc::reflection::v1alpha::ListServiceResponse;
+using google::protobuf::FileDescriptorProto;
+using google::protobuf::DescriptorPool;
+using google::protobuf::ServiceDescriptor;
+using google::protobuf::MethodDescriptor;
+using google::protobuf::Descriptor;
+using google::protobuf::FieldDescriptor;
+
+class ReflectionClient {
+ public:
+  ReflectionClient(std::shared_ptr<Channel> channel)
+      : db_(new ProtoReflectionDescriptorDatabase(
+            ServerReflection::NewStub(channel))),
+        desc_pool_(new DescriptorPool(db_.get())) {}
+
+  void PrintInfo() {
+    EmptyRequest request;
+    ListServiceResponse response;
+    ClientContext context;
+    Status status = db_->stub()->ListService(&context, request, &response);
+    if (status.ok()) {
+      std::string padding = "";
+      std::cout << "Service amount:" << response.services_size() << std::endl;
+      for (int i = 0; i < response.services_size(); ++i) {
+        if (i != response.services_size() - 1) {
+          std::cout << padding << "│ " << std::endl;
+          std::cout << padding << "├─" << response.services(i) << std::endl;
+          PrintService(desc_pool_->FindServiceByName(response.services(i)),
+                       padding + "│ ");
+        } else {
+          std::cout << padding << "│ " << std::endl;
+          std::cout << padding << "└─" << response.services(i) << std::endl;
+          PrintService(desc_pool_->FindServiceByName(response.services(i)),
+                       padding + "  ");
+        }
+      }
+    } else {
+      std::cout << status.error_message();
+    }
+  }
+
+  void PrintService(const ServiceDescriptor* service_desc,
+                    const std::string padding) {
+    if (service_desc != nullptr) {
+      std::cout << padding << "│ Method amount:" << service_desc->method_count()
+                << std::endl;
+      for (int i = 0; i < service_desc->method_count(); ++i) {
+        if (i != service_desc->method_count() - 1) {
+          std::cout << padding << "├─" << service_desc->method(i)->name()
+                    << std::endl;
+          PrintMethod(service_desc->method(i), padding + "│ ");
+        } else {
+          std::cout << padding << "└─" << service_desc->method(i)->name()
+                    << std::endl;
+          PrintMethod(service_desc->method(i), padding + "  ");
+        }
+      }
+    }
+  }
+
+  void PrintMethod(const MethodDescriptor* method_desc,
+                   const std::string padding) {
+    if (method_desc != nullptr) {
+      std::cout << padding
+                << "├─input type: " << method_desc->input_type()->name()
+                << std::endl;
+      PrintMessageType(method_desc->input_type(), padding + "│ ");
+      std::cout << padding
+                << "└─output type: " << method_desc->output_type()->name()
+                << std::endl;
+      PrintMessageType(method_desc->output_type(), padding + "  ");
+    }
+  }
+
+  void PrintMessageType(const Descriptor* type_desc,
+                        const std::string padding) {
+    if (type_desc != nullptr) {
+      if (type_desc->field_count() > 0) {
+        std::cout << padding << "│ Field amount:" << type_desc->field_count()
+                  << std::endl;
+      }
+      for (int i = 0; i < type_desc->field_count(); ++i) {
+        if (i != type_desc->field_count() - 1) {
+          const FieldDescriptor* field = type_desc->field(i);
+          std::cout << padding << "├─ " << std::left << std::setw(15)
+                    << kLabelToName[field->label()] << std::setw(30)
+                    << " name: " + field->name() << std::setw(50)
+                    << " type: " +
+                           (field->type() == FieldDescriptor::Type::TYPE_MESSAGE
+                                ? field->message_type()->name()
+                                : field->type_name())
+                    << std::endl;
+        } else {
+          const FieldDescriptor* field = type_desc->field(i);
+          std::cout << padding << "└─ " << std::left << std::setw(15)
+                    << kLabelToName[field->label()] << std::setw(30)
+                    << " name: " + field->name() << std::setw(50)
+                    << " type: " +
+                           (field->type() == FieldDescriptor::Type::TYPE_MESSAGE
+                                ? field->message_type()->name()
+                                : field->type_name())
+                    << std::endl;
+        }
+      }
+    }
+  }
+
+  void Test() {
+    {
+      FileDescriptorProto output;
+      bool found = db_->FindFileByName("helloworld.proto", &output);
+      if (found) std::cout << output.name() << std::endl;
+    }
+    {
+      FileDescriptorProto output;
+      bool found =
+          db_->FindFileContainingSymbol("helloworld.Greeter.SayHello", &output);
+      if (found) std::cout << output.name() << std::endl;
+    }
+    {
+      FileDescriptorProto output;
+      bool found = db_->FindFileContainingExtension(
+          "helloworld.Greeter.HelloRequest", 1, &output);
+      found = db_->FindFileContainingExtension(
+          "helloworld.Greeter.HelloRequest", 1, &output);
+      if (found) std::cout << output.name() << std::endl;
+    }
+    DescriptorPool pool(db_.get());
+    std::cout << pool.FindServiceByName("helloworld.Greeter")->name()
+              << std::endl;
+  }
+
+ private:
+  const char* const kLabelToName[FieldDescriptor::Label::MAX_LABEL + 1] = {
+      "ERROR",  // 0 is reserved for errors
+
+      "optional",  // LABEL_OPTIONAL
+      "required",  // LABEL_REQUIRED
+      "repeated",  // LABEL_REPEATED
+  };
+
+  std::unique_ptr<ProtoReflectionDescriptorDatabase> db_;
+  std::unique_ptr<DescriptorPool> desc_pool_;
+};
+
+int main(int argc, char** argv) {
+  int port = 50051;
+  if (argc == 2) {
+    try {
+      port = std::stoi(argv[1]);
+      if (port > 65535 || port < 1024) {
+        throw std::out_of_range("Port number out of range.");
+      }
+    } catch (std::invalid_argument&) {
+    } catch (std::out_of_range&) {
+    }
+  }
+
+  ReflectionClient reflection_client(grpc::CreateChannel(
+      "localhost:" + std::to_string(port), grpc::InsecureChannelCredentials()));
+
+  reflection_client.PrintInfo();
+
+  return 0;
+}