Merge pull request #6438 from y-zeng/reflection_separate_lib

Proto server reflection

3 files changed, 613 insertions, 0 deletions

diff --git a/test/cpp/end2end/proto_server_reflection_test.cc b/test/cpp/end2end/proto_server_reflection_test.cc
new file mode 100644
index 0000000000..f8fc39b553
--- /dev/null
+++ b/test/cpp/end2end/proto_server_reflection_test.cc
@@ -0,0 +1,166 @@
+/*
+ *
+ * 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 <google/protobuf/descriptor.h>
+#include <grpc++/channel.h>
+#include <grpc++/client_context.h>
+#include <grpc++/create_channel.h>
+#include <grpc++/ext/proto_server_reflection_plugin.h>
+#include <grpc++/security/credentials.h>
+#include <grpc++/security/server_credentials.h>
+#include <grpc++/server.h>
+#include <grpc++/server_builder.h>
+#include <grpc++/server_context.h>
+#include <grpc/grpc.h>
+#include <gtest/gtest.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 "test/cpp/util/proto_reflection_descriptor_database.h"
+
+namespace grpc {
+namespace testing {
+
+class ProtoServerReflectionTest : public ::testing::Test {
+ public:
+  ProtoServerReflectionTest() {}
+
+  void SetUp() GRPC_OVERRIDE {
+    port_ = grpc_pick_unused_port_or_die();
+    ref_desc_pool_ = google::protobuf::DescriptorPool::generated_pool();
+
+    ServerBuilder builder;
+    grpc::string server_address = "localhost:" + to_string(port_);
+    builder.AddListeningPort(server_address, InsecureServerCredentials());
+    server_ = builder.BuildAndStart();
+  }
+
+  void ResetStub() {
+    string target = "dns:localhost:" + to_string(port_);
+    std::shared_ptr<Channel> channel =
+        CreateChannel(target, InsecureChannelCredentials());
+    stub_ = grpc::testing::EchoTestService::NewStub(channel);
+    desc_db_.reset(new ProtoReflectionDescriptorDatabase(channel));
+    desc_pool_.reset(new google::protobuf::DescriptorPool(desc_db_.get()));
+  }
+
+  string to_string(const int number) {
+    std::stringstream strs;
+    strs << number;
+    return strs.str();
+  }
+
+  void CompareService(const grpc::string& service) {
+    const google::protobuf::ServiceDescriptor* service_desc =
+        desc_pool_->FindServiceByName(service);
+    const google::protobuf::ServiceDescriptor* ref_service_desc =
+        ref_desc_pool_->FindServiceByName(service);
+    EXPECT_TRUE(service_desc != nullptr);
+    EXPECT_TRUE(ref_service_desc != nullptr);
+    EXPECT_EQ(service_desc->DebugString(), ref_service_desc->DebugString());
+
+    const google::protobuf::FileDescriptor* file_desc = service_desc->file();
+    if (known_files_.find(file_desc->package() + "/" + file_desc->name()) !=
+        known_files_.end()) {
+      EXPECT_EQ(file_desc->DebugString(),
+                ref_service_desc->file()->DebugString());
+      known_files_.insert(file_desc->package() + "/" + file_desc->name());
+    }
+
+    for (int i = 0; i < service_desc->method_count(); ++i) {
+      CompareMethod(service_desc->method(i)->full_name());
+    }
+  }
+
+  void CompareMethod(const grpc::string& method) {
+    const google::protobuf::MethodDescriptor* method_desc =
+        desc_pool_->FindMethodByName(method);
+    const google::protobuf::MethodDescriptor* ref_method_desc =
+        ref_desc_pool_->FindMethodByName(method);
+    EXPECT_TRUE(method_desc != nullptr);
+    EXPECT_TRUE(ref_method_desc != nullptr);
+    EXPECT_EQ(method_desc->DebugString(), ref_method_desc->DebugString());
+
+    CompareType(method_desc->input_type()->full_name());
+    CompareType(method_desc->output_type()->full_name());
+  }
+
+  void CompareType(const grpc::string& type) {
+    if (known_types_.find(type) != known_types_.end()) {
+      return;
+    }
+
+    const google::protobuf::Descriptor* desc =
+        desc_pool_->FindMessageTypeByName(type);
+    const google::protobuf::Descriptor* ref_desc =
+        ref_desc_pool_->FindMessageTypeByName(type);
+    EXPECT_TRUE(desc != nullptr);
+    EXPECT_TRUE(ref_desc != nullptr);
+    EXPECT_EQ(desc->DebugString(), ref_desc->DebugString());
+  }
+
+ protected:
+  std::unique_ptr<Server> server_;
+  std::unique_ptr<grpc::testing::EchoTestService::Stub> stub_;
+  std::unique_ptr<ProtoReflectionDescriptorDatabase> desc_db_;
+  std::unique_ptr<google::protobuf::DescriptorPool> desc_pool_;
+  std::unordered_set<string> known_files_;
+  std::unordered_set<string> known_types_;
+  const google::protobuf::DescriptorPool* ref_desc_pool_;
+  int port_;
+  reflection::ProtoServerReflectionPlugin plugin_;
+};
+
+TEST_F(ProtoServerReflectionTest, CheckResponseWithLocalDescriptorPool) {
+  ResetStub();
+
+  std::vector<std::string> services;
+  desc_db_->GetServices(&services);
+  // The service list has at least one service (reflection servcie).
+  EXPECT_TRUE(services.size() > 0);
+
+  for (auto it = services.begin(); it != services.end(); ++it) {
+    CompareService(*it);
+  }
+}
+
+}  // namespace testing
+}  // namespace grpc
+
+int main(int argc, char** argv) {
+  grpc_test_init(argc, argv);
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
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..6907d97bd5
--- /dev/null
+++ b/test/cpp/util/proto_reflection_descriptor_database.cc
@@ -0,0 +1,316 @@
+/*
+ *
+ * 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 "test/cpp/util/proto_reflection_descriptor_database.h"
+
+#include <vector>
+
+#include <grpc/support/log.h>
+
+using grpc::reflection::v1alpha::ServerReflection;
+using grpc::reflection::v1alpha::ServerReflectionRequest;
+using grpc::reflection::v1alpha::ServerReflectionResponse;
+using grpc::reflection::v1alpha::ListServiceResponse;
+using grpc::reflection::v1alpha::ErrorResponse;
+
+namespace grpc {
+
+ProtoReflectionDescriptorDatabase::ProtoReflectionDescriptorDatabase(
+    std::unique_ptr<ServerReflection::Stub> stub)
+    : stub_(std::move(stub)) {}
+
+ProtoReflectionDescriptorDatabase::ProtoReflectionDescriptorDatabase(
+    std::shared_ptr<grpc::Channel> channel)
+    : stub_(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;
+  }
+
+  ServerReflectionRequest request;
+  request.set_file_by_filename(filename);
+  ServerReflectionResponse response;
+
+  DoOneRequest(request, response);
+
+  if (response.message_response_case() ==
+      ServerReflectionResponse::MessageResponseCase::kFileDescriptorResponse) {
+    AddFileFromResponse(response.file_descriptor_response());
+  } else if (response.message_response_case() ==
+             ServerReflectionResponse::MessageResponseCase::kErrorResponse) {
+    const ErrorResponse error = response.error_response();
+    if (error.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(), error.error_code(),
+              error.error_message().c_str());
+    }
+  } else {
+    gpr_log(
+        GPR_INFO,
+        "Error on FindFileByName(%s) response type\n"
+        "\tExpecting: %d\n\tReceived: %d",
+        filename.c_str(),
+        ServerReflectionResponse::MessageResponseCase::kFileDescriptorResponse,
+        response.message_response_case());
+  }
+
+  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;
+  }
+
+  ServerReflectionRequest request;
+  request.set_file_containing_symbol(symbol_name);
+  ServerReflectionResponse response;
+
+  DoOneRequest(request, response);
+
+  if (response.message_response_case() ==
+      ServerReflectionResponse::MessageResponseCase::kFileDescriptorResponse) {
+    AddFileFromResponse(response.file_descriptor_response());
+  } else if (response.message_response_case() ==
+             ServerReflectionResponse::MessageResponseCase::kErrorResponse) {
+    const ErrorResponse error = response.error_response();
+    if (error.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(), error.error_code(),
+              error.error_message().c_str());
+    }
+  } else {
+    gpr_log(
+        GPR_INFO,
+        "Error on FindFileContainingSymbol(%s) response type\n"
+        "\tExpecting: %d\n\tReceived: %d",
+        symbol_name.c_str(),
+        ServerReflectionResponse::MessageResponseCase::kFileDescriptorResponse,
+        response.message_response_case());
+  }
+  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;
+  }
+
+  ServerReflectionRequest request;
+  request.mutable_file_containing_extension()->set_containing_type(
+      containing_type);
+  request.mutable_file_containing_extension()->set_extension_number(
+      field_number);
+  ServerReflectionResponse response;
+
+  DoOneRequest(request, response);
+
+  if (response.message_response_case() ==
+      ServerReflectionResponse::MessageResponseCase::kFileDescriptorResponse) {
+    AddFileFromResponse(response.file_descriptor_response());
+  } else if (response.message_response_case() ==
+             ServerReflectionResponse::MessageResponseCase::kErrorResponse) {
+    const ErrorResponse error = response.error_response();
+    if (error.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, error.error_code(),
+              error.error_message().c_str());
+    }
+  } else {
+    gpr_log(
+        GPR_INFO,
+        "Error on FindFileContainingExtension(%s, %d) response type\n"
+        "\tExpecting: %d\n\tReceived: %d",
+        containing_type.c_str(), field_number,
+        ServerReflectionResponse::MessageResponseCase::kFileDescriptorResponse,
+        response.message_response_case());
+  }
+
+  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;
+  }
+
+  ServerReflectionRequest request;
+  request.set_all_extension_numbers_of_type(extendee_type);
+  ServerReflectionResponse response;
+
+  DoOneRequest(request, response);
+
+  if (response.message_response_case() ==
+      ServerReflectionResponse::MessageResponseCase::
+          kAllExtensionNumbersResponse) {
+    auto number = response.all_extension_numbers_response().extension_number();
+    *output = std::vector<int>(number.begin(), number.end());
+    cached_extension_numbers_[extendee_type] = *output;
+    return true;
+  } else if (response.message_response_case() ==
+             ServerReflectionResponse::MessageResponseCase::kErrorResponse) {
+    const ErrorResponse error = response.error_response();
+    if (error.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(), error.error_code(),
+              error.error_message().c_str());
+    }
+  }
+  return false;
+}
+
+bool ProtoReflectionDescriptorDatabase::GetServices(
+    std::vector<std::string>* output) {
+  ServerReflectionRequest request;
+  request.set_list_services("");
+  ServerReflectionResponse response;
+
+  DoOneRequest(request, response);
+
+  if (response.message_response_case() ==
+      ServerReflectionResponse::MessageResponseCase::kListServicesResponse) {
+    const ListServiceResponse ls_response = response.list_services_response();
+    for (int i = 0; i < ls_response.service_size(); ++i) {
+      (*output).push_back(ls_response.service(i).name());
+    }
+    return true;
+  } else if (response.message_response_case() ==
+             ServerReflectionResponse::MessageResponseCase::kErrorResponse) {
+    const ErrorResponse error = response.error_response();
+    gpr_log(GPR_INFO,
+            "Error on GetServices()\n\tError code: %d\n"
+            "\tError Message: %s",
+            error.error_code(), error.error_message().c_str());
+  } else {
+    gpr_log(
+        GPR_INFO,
+        "Error on GetServices() response type\n\tExpecting: %d\n\tReceived: %d",
+        ServerReflectionResponse::MessageResponseCase::kListServicesResponse,
+        response.message_response_case());
+  }
+  return false;
+}
+
+const google::protobuf::FileDescriptorProto
+ProtoReflectionDescriptorDatabase::ParseFileDescriptorProtoResponse(
+    const std::string& byte_fd_proto) {
+  google::protobuf::FileDescriptorProto file_desc_proto;
+  file_desc_proto.ParseFromString(byte_fd_proto);
+  return file_desc_proto;
+}
+
+void ProtoReflectionDescriptorDatabase::AddFileFromResponse(
+    const grpc::reflection::v1alpha::FileDescriptorResponse& response) {
+  for (int i = 0; i < response.file_descriptor_proto_size(); ++i) {
+    const google::protobuf::FileDescriptorProto file_proto =
+        ParseFileDescriptorProtoResponse(response.file_descriptor_proto(i));
+    if (known_files_.find(file_proto.name()) == known_files_.end()) {
+      known_files_.insert(file_proto.name());
+      cached_db_.Add(file_proto);
+    }
+  }
+}
+
+const std::shared_ptr<ProtoReflectionDescriptorDatabase::ClientStream>
+ProtoReflectionDescriptorDatabase::GetStream() {
+  if (stream_ == nullptr) {
+    stream_ = stub_->ServerReflectionInfo(&ctx_);
+  }
+  return stream_;
+}
+
+void ProtoReflectionDescriptorDatabase::DoOneRequest(
+    const ServerReflectionRequest& request,
+    ServerReflectionResponse& response) {
+  stream_mutex_.lock();
+  GetStream()->Write(request);
+  GetStream()->Read(&response);
+  stream_mutex_.unlock();
+}
+
+}  // 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..99c00675bb
--- /dev/null
+++ b/test/cpp/util/proto_reflection_descriptor_database.h
@@ -0,0 +1,131 @@
+/*
+ *
+ * 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.
+ *
+ */
+#ifndef GRPC_TEST_CPP_PROTO_SERVER_REFLECTION_DATABSE_H
+#define GRPC_TEST_CPP_PROTO_SERVER_REFLECTION_DATABSE_H
+
+#include <mutex>
+#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++/ext/reflection.grpc.pb.h>
+#include <grpc++/grpc++.h>
+
+namespace grpc {
+
+// ProtoReflectionDescriptorDatabase takes a stub of ServerReflection and
+// provides the methods defined by DescriptorDatabase interfaces. It can be used
+// to feed a DescriptorPool instance.
+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();
+
+  // The following four methods implement DescriptorDatabase interfaces.
+  //
+  // Find a file by file name.  Fills in in *output and returns true if found.
+  // Otherwise, returns false, leaving the contents of *output undefined.
+  bool FindFileByName(const string& filename,
+                      google::protobuf::FileDescriptorProto* output)
+      GRPC_OVERRIDE;
+
+  // Find the file that declares the given fully-qualified symbol name.
+  // If found, fills in *output and returns true, otherwise returns false
+  // and leaves *output undefined.
+  bool FindFileContainingSymbol(const string& symbol_name,
+                                google::protobuf::FileDescriptorProto* output)
+      GRPC_OVERRIDE;
+
+  // Find the file which defines an extension extending the given message type
+  // with the given field number.  If found, fills in *output and returns true,
+  // otherwise returns false and leaves *output undefined.  containing_type
+  // must be a fully-qualified type name.
+  bool FindFileContainingExtension(
+      const string& containing_type, int field_number,
+      google::protobuf::FileDescriptorProto* output) GRPC_OVERRIDE;
+
+  // Finds the tag numbers used by all known extensions of
+  // extendee_type, and appends them to output in an undefined
+  // order. This method is best-effort: it's not guaranteed that the
+  // database will find all extensions, and it's not guaranteed that
+  // FindFileContainingExtension will return true on all of the found
+  // numbers. Returns true if the search was successful, otherwise
+  // returns false and leaves output unchanged.
+  bool FindAllExtensionNumbers(const string& extendee_type,
+                               std::vector<int>* output) GRPC_OVERRIDE;
+
+  // Provide a list of full names of registered services
+  bool GetServices(std::vector<std::string>* output);
+
+ private:
+  typedef ClientReaderWriter<
+      grpc::reflection::v1alpha::ServerReflectionRequest,
+      grpc::reflection::v1alpha::ServerReflectionResponse>
+      ClientStream;
+
+  const google::protobuf::FileDescriptorProto ParseFileDescriptorProtoResponse(
+      const std::string& byte_fd_proto);
+
+  void AddFileFromResponse(
+      const grpc::reflection::v1alpha::FileDescriptorResponse& response);
+
+  const std::shared_ptr<ClientStream> GetStream();
+
+  void DoOneRequest(
+      const grpc::reflection::v1alpha::ServerReflectionRequest& request,
+      grpc::reflection::v1alpha::ServerReflectionResponse& response);
+
+  std::shared_ptr<ClientStream> stream_;
+  grpc::ClientContext ctx_;
+  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_;
+  std::mutex stream_mutex_;
+
+  google::protobuf::SimpleDescriptorDatabase cached_db_;
+};
+
+}  // namespace grpc
+
+#endif  // GRPC_TEST_CPP_METRICS_SERVER_H