GRPC 是Google发布的一个开源、高性能、通用RPC（Remote Procedure Call）框架。提供跨语言、跨平台支持。以下以一个.NET Core Console项目演示如何使用GRPC框架。
一、定义服务
通过proto定义一个数学计算服务，其中包括两个服务方法（Add, Multipy）以及4个请求响应对象（AddRequest, AddReply, MultiplyRequest, MultiplyReply）。
// 文件名：mathservice.proto syntax = "proto3"; option java_multiple_files = false; option java_package = "MathServices"; option java_outer_classname = "MathServicesProto"; option objc_class_prefix = "MathServices"; package MathServices; // 数学运算服务 service MathService { rpc Add (AddRequest) returns (AddReply) {} rpc Multiply (MultiplyRequest) returns (MultiplyReply) {} } message AddRequest { double First = 1; double Second = 2; } message AddReply { double Sum = 1; } message MultiplyRequest { double First = 1; double Second = 2; } message MultiplyReply { double Result = 1; }
二、将服务编译成存根（stub）
通过以下批处理命令generate_protos.bat将服务定义生成多种语言和平台版本的客户端和服务端存根。
@rem 生成客户端和服务器端存根 setlocal @rem 进入当前目录 cd /d %~dp0 set TOOLS_PATH=C:UsersFreeman.nugetpackagesGrpc.Tools1.0.0 oolswindows_x86 %TOOLS_PATH%protoc.exe ^ --proto_path protos ^ --cpp_out=Interfaces/cpp ^ --csharp_out=Interfaces/csharp ^ --java_out=Interfaces/java ^ --js_out=Interfaces/javascript ^ --grpc_out=Interfaces/csharp ^ --plugin=protoc-gen-grpc=%TOOLS_PATH%grpc_csharp_plugin.exe ^ protos/mathservice.proto endlocal timeout 5
针对CSHARP语言，protoc.exe编译器生成了如下图几个类，其中左边4个类用于构造请求和响应对象，MathService类用于下一步构造服务和消费服务。
CSHARP STUBS
三、实现并运行服务
通过上一步的编译，自动生成了MathService类，下面通过该类构造并启动grpc服务。
通过继承基类实现服务接口
/// <summary> /// 实现RPC服务端接口。 /// </summary> public class MathServiceImpl : MathService.MathServiceBase { public override Task<AddReply> Add(AddRequest request, ServerCallContext context) { return Task.FromResult(new AddReply { Sum = request.First + request.Second }); } public override Task<MultiplyReply> Multiply(MultiplyRequest request, ServerCallContext context) { return Task.FromResult(new MultiplyReply { Result = request.First * request.Second }); } }
启动服务
const string ip = "0.0.0.0"; const int port = 50051; Server server = new Server(); server.Ports.Add(new ServerPort(ip, port, ServerCredentials.Insecure)); server.Services.Add(MathService.BindService(new MathServiceImpl())); server.Start(); server.Ports.ToList().ForEach(a => Console.WriteLine($"Server listening on port {a.Port}...")); Console.ReadLine();
四、客户端调用服务
客户端通过创建一个Channel和一个服务客户端来使用服务。
var channel = new Channel($"{"127.0.0.1"}:{port}", SslCredentials.Insecure); var client = new MathService.MathServiceClient(channel); var random = new Random(); while (true) { var first = random.NextDouble(); var second = random.NextDouble(); var reply = client.Add(new AddRequest { First = first, Second = second }); Console.WriteLine($"RPC call Add service: {first:F4} + {second:F4} = {reply.Sum:F4}"); Thread.Sleep(500); }
RPC调用
五、使用SSL实现加密通讯
grpc默认实现了基于证书的SSL加密通讯，使用中需要注意以下事项。
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在Windows上开发请安装 OpenSSL对应版本并将openssl.exe所在路径添加到环境变量中。
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通过以下样例脚本生成通讯中所需要的服务端和客户端证书，其中需要特别注意的是，Generate server signing request:中的CN=KEKYK字段如果是本机测试，请一定使用本机名称或使用localhost，如果是真实环境请使用域名，因为客户端必须通过机器名（本地测试）或域名访问该服务。如果此处CN字段不使用机器名或域名，将导致以下错误：
CN字段不使用主机名或域名时产生的错误 -
生成服务端和客户端证书脚本generate_ssl.bat
@echo off set OPENSSL_CONF=c:OpenSSL-Win64inopenssl.cfg echo Generate CA key: openssl genrsa -passout pass:1111 -des3 -out ca.key 4096 echo Generate CA certificate: openssl req -passin pass:1111 -new -x509 -days 365 -key ca.key -out ca.crt -subj "/C=US/ST=CA/L=Cupertino/O=YourCompany/OU=YourApp/CN=MyRootCA" echo Generate server key: openssl genrsa -passout pass:1111 -des3 -out server.key 4096 echo Generate server signing request: openssl req -passin pass:1111 -new -key server.key -out server.csr -subj "/C=US/ST=CA/L=Cupertino/O=YourCompany/OU=YourApp/CN=kekyk" echo Self-sign server certificate: openssl x509 -req -passin pass:1111 -days 365 -in server.csr -CA ca.crt -CAkey ca.key -set_serial 01 -out server.crt echo Remove passphrase from server key: openssl rsa -passin pass:1111 -in server.key -out server.key echo Generate client key openssl genrsa -passout pass:1111 -des3 -out client.key 4096 echo Generate client signing request: openssl req -passin pass:1111 -new -key client.key -out client.csr -subj "/C=US/ST=CA/L=Cupertino/O=YourCompany/OU=YourApp/CN=client" echo Self-sign client certificate: openssl x509 -passin pass:1111 -req -days 365 -in client.csr -CA ca.crt -CAkey ca.key -set_serial 01 -out client.crt echo Remove passphrase from client key: openssl rsa -passin pass:1111 -in client.key -out client.key pause
- 基于SSL的服务端启动如下，创建服务的时候请使用主机名（开发环境）或域名（生产环境），不要使用IP地址。
public static void RpcServerSsl() { var cacert = File.ReadAllText(CombinePath("ca.crt")); var servercert = File.ReadAllText(CombinePath("server.crt")); var serverkey = File.ReadAllText(CombinePath("server.key")); var keypair = new KeyCertificatePair(servercert, serverkey); var sslCredentials = new SslServerCredentials(new List<KeyCertificatePair>() { keypair }, cacert, false); var server = new Server { Services = { MathService.BindService(new MathServiceImpl()) }, Ports = { new ServerPort("KEKYK", sslPort, sslCredentials) } }; server.Start(); server.Ports.ToList().ForEach(a => Console.WriteLine($"Server (SSL) listening on port {a.Port}...")); Console.ReadLine(); }
- 基于SSL的客户端使用如下，注意测试环境中使用主机名，生产环境中使用域名来，不要使用任何形式的IP地址。
public static void RpcClientSsl() { var cacert = File.ReadAllText(CombinePath("ca.crt")); var clientcert = File.ReadAllText(CombinePath("client.crt")); var clientkey = File.ReadAllText(CombinePath("client.key")); var ssl = new SslCredentials(cacert, new KeyCertificatePair(clientcert, clientkey)); var channel = new Channel("KEKYK", sslPort, ssl); var client = new MathService.MathServiceClient(channel); var random = new Random(); while (true) { var first = random.NextDouble(); var second = random.NextDouble(); var reply = client.AddAsync(new AddRequest { First = first, Second = second }, new CallOptions()).ResponseAsync.Result; Console.WriteLine($"RPC call Add service: {first:F4} + {second:F4} = {reply.Sum:F4}"); Thread.Sleep(1000); } }
https://www.jianshu.com/p/f5e1c002047a