Triple 协议

    Triple 协议是 Dubbo3 的主力协议，完整兼容 gRPC over HTTP/2，并在协议层面扩展了负载均衡和流量控制相关机制。本文档旨在指导用户正确的使用 Triple 协议。

    在开始前，需要决定服务使用的序列化方式，如果为新服务，推荐使用 protobuf 作为默认序列化，在性能和跨语言上的效果都会更好。如果是原有服务想进行协议升级，Triple 协议也已经支持其他序列化方式，如 Hessian / JSON 等

    1. 编写 IDL 文件

    2. 添加编译 protobuf 的 extension 和 plugin (以 maven 为例)

      2.             <extension>
      3.                 <groupId>kr.motd.maven</groupId>
      4.                 <artifactId>os-maven-plugin</artifactId>
      5.                 <version>1.6.1</version>
      6.             </extension>
      7.         </extensions>
      8.         <plugins>
      9.             <plugin>
      10.                 <groupId>org.xolstice.maven.plugins</groupId>
      11.                 <artifactId>protobuf-maven-plugin</artifactId>
      12.                 <version>0.6.1</version>
      13.                 <configuration>
      14.                     <protocArtifact>com.google.protobuf:protoc:3.7.1:exe:${os.detected.classifier}</protocArtifact>
      15.                     <pluginId>triple-java</pluginId>
      16.                     <outputDirectory>build/generated/source/proto/main/java</outputDirectory>
      17.                 </configuration>
      18.                 <executions>
      19.                     <execution>
      20.                         <goals>
      21.                             <goal>compile</goal>
      22.                             <goal>test-compile</goal>
      23.                         </goals>
      24.                     </execution>
      25.                 </executions>
      26.             </plugin>
      27.         </plugins>

    3. 构建/ 编译生成 protobuf Message 类

      1. $ mvn clean install

    2. 创建 Provider

      1.     public static void main(String[] args) throws InterruptedException {
      2.         ServiceConfig<IGreeter> service = new ServiceConfig<>();
      3.         service.setInterface(IGreeter.class);
      4.         service.setRef(new IGreeter1Impl());
      5.         service.setProtocol(new ProtocolConfig(CommonConstants.TRIPLE, 50051));
      6.         service.setApplication(new ApplicationConfig("demo-provider"));
      7.         service.setRegistry(new RegistryConfig("zookeeper://127.0.0.1:2181"));
      8.         service.export();
      10.         new CountDownLatch(1).await();
      11.     }

    3. 创建 Consumer

      1. public static void main(String[] args) throws IOException {
      2.     ReferenceConfig<IGreeter> ref = new ReferenceConfig<>();
      3.     ref.setInterface(IGreeter.class);
      4.     ref.setCheck(false);
      5.     ref.setInterface(IGreeter.class);
      6.     ref.setCheck(false);
      7.     ref.setProtocol(CommonConstants.TRIPLE);
      8.     ref.setLazy(true);
      9.     ref.setTimeout(100000);
      10.     ref.setApplication(new ApplicationConfig("demo-consumer"));
      11.     ref.setRegistry(new RegistryConfig("zookeeper://127.0.0.1:2181"));
      12.     final IGreeter iGreeter = ref.get();
      14.     System.out.println("dubbo ref started");
      15.     try {
      16.         final HelloReply reply = iGreeter.sayHello(HelloRequest.newBuilder()
      17.                 .setName("name")
      18.                 .build());
      19.         TimeUnit.SECONDS.sleep(1);
      20.         System.out.println("Reply:" + reply);
      21.     } catch (Throwable t) {
      22.         t.printStackTrace();
      23.     }
      24.     System.in.read();
      25. }

    4. 运行 Provider 和 Consumer ,可以看到请求正常返回了

    1. 编写 Java 接口

      1. public class IStreamGreeterImpl implements IStreamGreeter {
      3.     @Override
      4.     public StreamObserver<HelloRequest> sayHello(StreamObserver<HelloReply> replyObserver) {
      6.         return new StreamObserver<HelloRequest>() {
      8.             @Override
      10.                 System.out.println("onNext receive request name:" + helloRequest.getName());
      11.                 replyList.add(HelloReply.newBuilder()
      12.                     .setMessage("receive name:" + helloRequest.getName())
      13.                     .build());
      14.             }
      16.             @Override
      17.             public void onError(Throwable cause) {
      18.                 System.out.println("onError");
      19.                 replyObserver.onError(cause);
      20.             }
      22.             @Override
      23.             public void onCompleted() {
      24.                 System.out.println("onComplete receive request size:" + replyList.size());
      25.                 for (HelloReply reply : replyList) {
      26.                     replyObserver.onNext(reply);
      27.                 }
      28.                 replyObserver.onCompleted();
      29.             }
      30.         };
      31.     }
      32. }

    3. 创建 Provider

      1. public class StreamProvider {
      2.    public static void main(String[] args) throws InterruptedException {
      3.        ServiceConfig<IStreamGreeter> service = new ServiceConfig<>();
      4.        service.setInterface(IStreamGreeter.class);
      5.        service.setRef(new IStreamGreeterImpl());
      6.        service.setProtocol(new ProtocolConfig(CommonConstants.TRIPLE, 50051));
      7.        service.setApplication(new ApplicationConfig("stream-provider"));
      8.        service.setRegistry(new RegistryConfig("zookeeper://127.0.0.1:2181"));
      9.        service.export();
      10.        System.out.println("dubbo service started");
      11.        new CountDownLatch(1).await();
      12.    }
      13. }

    4. 创建 Consumer

    5. 运行 Provider 和 Consumer ,可以看到请求正常返回了

    省略上文中的 1-3 步，指定 Provider 和 Consumer 使用的协议即可完成协议升级。