From 33a4b502c450fa05814992147679d0e77a23d4a5 Mon Sep 17 00:00:00 2001 From: Juanli Shen Date: Thu, 13 Dec 2018 15:55:20 -0800 Subject: Add LB example --- examples/BUILD | 14 ++++ examples/cpp/load_balancing/Makefile | 110 ++++++++++++++++++++++++++ examples/cpp/load_balancing/README.md | 64 +++++++++++++++ examples/cpp/load_balancing/greeter_client.cc | 90 +++++++++++++++++++++ examples/cpp/load_balancing/greeter_server.cc | 72 +++++++++++++++++ 5 files changed, 350 insertions(+) create mode 100644 examples/cpp/load_balancing/Makefile create mode 100644 examples/cpp/load_balancing/README.md create mode 100644 examples/cpp/load_balancing/greeter_client.cc create mode 100644 examples/cpp/load_balancing/greeter_server.cc (limited to 'examples') diff --git a/examples/BUILD b/examples/BUILD index 0f18cfa9ba..525e6989ee 100644 --- a/examples/BUILD +++ b/examples/BUILD @@ -51,3 +51,17 @@ cc_binary( defines = ["BAZEL_BUILD"], deps = [":helloworld", "//:grpc++"], ) + +cc_binary( + name = "lb_client", + srcs = ["cpp/load_balancing/greeter_client.cc"], + defines = ["BAZEL_BUILD"], + deps = [":helloworld", "//:grpc++"], +) + +cc_binary( + name = "lb_server", + srcs = ["cpp/load_balancing/greeter_server.cc"], + defines = ["BAZEL_BUILD"], + deps = [":helloworld", "//:grpc++"], +) diff --git a/examples/cpp/load_balancing/Makefile b/examples/cpp/load_balancing/Makefile new file mode 100644 index 0000000000..7c8d072770 --- /dev/null +++ b/examples/cpp/load_balancing/Makefile @@ -0,0 +1,110 @@ +# +# 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. +# + +HOST_SYSTEM = $(shell uname | cut -f 1 -d_) +SYSTEM ?= $(HOST_SYSTEM) +CXX = g++ +CPPFLAGS += `pkg-config --cflags protobuf grpc` +CXXFLAGS += -std=c++11 +ifeq ($(SYSTEM),Darwin) +LDFLAGS += -L/usr/local/lib `pkg-config --libs protobuf grpc++ grpc`\ + -lgrpc++_reflection\ + -ldl +else +LDFLAGS += -L/usr/local/lib `pkg-config --libs protobuf grpc++ grpc`\ + -Wl,--no-as-needed -lgrpc++_reflection -Wl,--as-needed\ + -ldl +endif +PROTOC = protoc +GRPC_CPP_PLUGIN = grpc_cpp_plugin +GRPC_CPP_PLUGIN_PATH ?= `which $(GRPC_CPP_PLUGIN)` + +PROTOS_PATH = ../../protos + +vpath %.proto $(PROTOS_PATH) + +all: system-check greeter_client greeter_server + +greeter_client: helloworld.pb.o helloworld.grpc.pb.o greeter_client.o + $(CXX) $^ $(LDFLAGS) -o $@ + +greeter_server: helloworld.pb.o helloworld.grpc.pb.o greeter_server.o + $(CXX) $^ $(LDFLAGS) -o $@ + +.PRECIOUS: %.grpc.pb.cc +%.grpc.pb.cc: %.proto + $(PROTOC) -I $(PROTOS_PATH) --grpc_out=. --plugin=protoc-gen-grpc=$(GRPC_CPP_PLUGIN_PATH) $< + +.PRECIOUS: %.pb.cc +%.pb.cc: %.proto + $(PROTOC) -I $(PROTOS_PATH) --cpp_out=. $< + +clean: + rm -f *.o *.pb.cc *.pb.h greeter_client greeter_server + + +# The following is to test your system and ensure a smoother experience. +# They are by no means necessary to actually compile a grpc-enabled software. + +PROTOC_CMD = which $(PROTOC) +PROTOC_CHECK_CMD = $(PROTOC) --version | grep -q libprotoc.3 +PLUGIN_CHECK_CMD = which $(GRPC_CPP_PLUGIN) +HAS_PROTOC = $(shell $(PROTOC_CMD) > /dev/null && echo true || echo false) +ifeq ($(HAS_PROTOC),true) +HAS_VALID_PROTOC = $(shell $(PROTOC_CHECK_CMD) 2> /dev/null && echo true || echo false) +endif +HAS_PLUGIN = $(shell $(PLUGIN_CHECK_CMD) > /dev/null && echo true || echo false) + +SYSTEM_OK = false +ifeq ($(HAS_VALID_PROTOC),true) +ifeq ($(HAS_PLUGIN),true) +SYSTEM_OK = true +endif +endif + +system-check: +ifneq ($(HAS_VALID_PROTOC),true) + @echo " DEPENDENCY ERROR" + @echo + @echo "You don't have protoc 3.0.0 installed in your path." + @echo "Please install Google protocol buffers 3.0.0 and its compiler." + @echo "You can find it here:" + @echo + @echo " https://github.com/google/protobuf/releases/tag/v3.0.0" + @echo + @echo "Here is what I get when trying to evaluate your version of protoc:" + @echo + -$(PROTOC) --version + @echo + @echo +endif +ifneq ($(HAS_PLUGIN),true) + @echo " DEPENDENCY ERROR" + @echo + @echo "You don't have the grpc c++ protobuf plugin installed in your path." + @echo "Please install grpc. You can find it here:" + @echo + @echo " https://github.com/grpc/grpc" + @echo + @echo "Here is what I get when trying to detect if you have the plugin:" + @echo + -which $(GRPC_CPP_PLUGIN) + @echo + @echo +endif +ifneq ($(SYSTEM_OK),true) + @false +endif \ No newline at end of file diff --git a/examples/cpp/load_balancing/README.md b/examples/cpp/load_balancing/README.md new file mode 100644 index 0000000000..f48aca5307 --- /dev/null +++ b/examples/cpp/load_balancing/README.md @@ -0,0 +1,64 @@ +# gRPC C++ Load Balancing Tutorial + +### Prerequisite +Make sure you have run the [hello world example](../helloworld) or understood the basics of gRPC. We will not dive into the details that have been discussed in the hello world example. + +### Get the tutorial source code + +The example code for this and our other examples lives in the `examples` directory. Clone this repository to your local machine by running the following command: + + +```sh +$ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc +``` + +Change your current directory to examples/cpp/load_balancing + +```sh +$ cd examples/cpp/load_balancing/ +``` + +### Generating gRPC code + +To generate the client and server side interfaces: + +```sh +$ make helloworld.grpc.pb.cc helloworld.pb.cc +``` +Which internally invokes the proto-compiler as: + +```sh +$ protoc -I ../../protos/ --grpc_out=. --plugin=protoc-gen-grpc=grpc_cpp_plugin ../../protos/helloworld.proto +$ protoc -I ../../protos/ --cpp_out=. ../../protos/helloworld.proto +``` + +### Writing a client and a server + +The client and the server can be based on the hello world example. + +Additionally, we can configure the load balancing policy. (To see what load balancing policies are available, check out [this folder](https://github.com/grpc/grpc/tree/master/src/core/ext/filters/client_channel/lb_policy).) + +In the client, set the load balancing policy of the channel via the channel arg (to, for example, Round Robin). + +```cpp + ChannelArguments args; + // Set the load balancing policy for the channel. + args.SetLoadBalancingPolicyName("round_robin"); + GreeterClient greeter(grpc::CreateCustomChannel( + "localhost:50051", grpc::InsecureChannelCredentials(), args)); +``` + +For a working example, refer to [greeter_client.cc](greeter_client.cc) and [greeter_server.cc](greeter_server.cc). + +Build and run the client and the server with the following commands. + +```sh +make +./greeter_server +``` + +```sh +./greeter_client +``` + +(Note that the case in this example is trivial because there is only one server resolved from the name.) \ No newline at end of file diff --git a/examples/cpp/load_balancing/greeter_client.cc b/examples/cpp/load_balancing/greeter_client.cc new file mode 100644 index 0000000000..5b08204a96 --- /dev/null +++ b/examples/cpp/load_balancing/greeter_client.cc @@ -0,0 +1,90 @@ +/* + * + * Copyright 2015 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 +#include +#include + +#include + +#ifdef BAZEL_BUILD +#include "examples/protos/helloworld.grpc.pb.h" +#else +#include "helloworld.grpc.pb.h" +#endif + +using grpc::Channel; +using grpc::ChannelArguments; +using grpc::ClientContext; +using grpc::Status; +using helloworld::HelloRequest; +using helloworld::HelloReply; +using helloworld::Greeter; + +class GreeterClient { + public: + GreeterClient(std::shared_ptr channel) + : stub_(Greeter::NewStub(channel)) {} + + // Assembles the client's payload, sends it and presents the response back + // from the server. + std::string SayHello(const std::string& user) { + // Data we are sending to the server. + HelloRequest request; + request.set_name(user); + + // Container for the data we expect from the server. + HelloReply reply; + + // Context for the client. It could be used to convey extra information to + // the server and/or tweak certain RPC behaviors. + ClientContext context; + + // The actual RPC. + Status status = stub_->SayHello(&context, request, &reply); + + // Act upon its status. + if (status.ok()) { + return reply.message(); + } else { + std::cout << status.error_code() << ": " << status.error_message() + << std::endl; + return "RPC failed"; + } + } + + private: + std::unique_ptr stub_; +}; + +int main(int argc, char** argv) { + // Instantiate the client. It requires a channel, out of which the actual RPCs + // are created. This channel models a connection to an endpoint (in this case, + // localhost at port 50051). We indicate that the channel isn't authenticated + // (use of InsecureChannelCredentials()). + ChannelArguments args; + // Set the load balancing policy for the channel. + args.SetLoadBalancingPolicyName("round_robin"); + GreeterClient greeter(grpc::CreateCustomChannel( + "localhost:50051", grpc::InsecureChannelCredentials(), args)); + std::string user("world"); + std::string reply = greeter.SayHello(user); + std::cout << "Greeter received: " << reply << std::endl; + + return 0; +} diff --git a/examples/cpp/load_balancing/greeter_server.cc b/examples/cpp/load_balancing/greeter_server.cc new file mode 100644 index 0000000000..f36ad906a2 --- /dev/null +++ b/examples/cpp/load_balancing/greeter_server.cc @@ -0,0 +1,72 @@ +/* + * + * Copyright 2015 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 +#include +#include + +#include + +#ifdef BAZEL_BUILD +#include "examples/protos/helloworld.grpc.pb.h" +#else +#include "helloworld.grpc.pb.h" +#endif + +using grpc::Server; +using grpc::ServerBuilder; +using grpc::ServerContext; +using grpc::Status; +using helloworld::HelloRequest; +using helloworld::HelloReply; +using helloworld::Greeter; + +// Logic and data behind the server's behavior. +class GreeterServiceImpl final : public Greeter::Service { + Status SayHello(ServerContext* context, const HelloRequest* request, + HelloReply* reply) override { + std::string prefix("Hello "); + reply->set_message(prefix + request->name()); + return Status::OK; + } +}; + +void RunServer() { + std::string server_address("0.0.0.0:50051"); + GreeterServiceImpl service; + + ServerBuilder builder; + // Listen on the given address without any authentication mechanism. + builder.AddListeningPort(server_address, grpc::InsecureServerCredentials()); + // Register "service" as the instance through which we'll communicate with + // clients. In this case it corresponds to an *synchronous* service. + builder.RegisterService(&service); + // Finally assemble the server. + std::unique_ptr server(builder.BuildAndStart()); + std::cout << "Server listening on " << server_address << std::endl; + + // Wait for the server to shutdown. Note that some other thread must be + // responsible for shutting down the server for this call to ever return. + server->Wait(); +} + +int main(int argc, char** argv) { + RunServer(); + + return 0; +} -- cgit v1.2.3