Java连接EKS上容器化gRPC服务的实践指南

syntax = "proto3"; // 指定ProtoBuf语法版本

option java_multiple_files = true; // 为每个顶级消息和枚举生成单独的Java文件
option java_package = "io.grpc.examples.helloworld"; // 指定生成的Java类的包名
option java_outer_classname = "HelloWorldProto"; // 指定包含所有其他类的外部类名

package helloworld; // 定义ProtoBuf包名

// 定义Greeter服务
service Greeter {
  // 定义一个SayHello RPC方法，接收HelloRequest，返回HelloReply
  rpc SayHello (HelloRequest) returns (HelloReply) {}
}

// 定义HelloRequest消息
message HelloRequest {
  string name = 1; // 字段类型为字符串，字段编号为1
}

// 定义HelloReply消息
message HelloReply {
  string message = 1; // 字段类型为字符串，字段编号为1
}

<build>
    <extensions>
        <extension>
            <groupId>kr.motd.maven</groupId>
            <artifactId>os-maven-plugin</artifactId>
            <version>1.7.1</version>
        </extension>
    </extensions>
    <plugins>
        <plugin>
            <groupId>org.xolstice.maven.plugins</groupId>
            <artifactId>protobuf-maven-plugin</artifactId>
            <version>0.6.1</version>
            <configuration>
                <protocArtifact>com.google.protobuf:protoc:3.21.7:exe:${os.detected.classifier}</protocArtifact>
                <pluginId>grpc-java</pluginId>
                <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.50.2:exe:${os.detected.classifier}</pluginArtifact>
                <protoSourceRoot>${project.basedir}/src/main/proto</protoSourceRoot>
            </configuration>
            <executions>
                <execution>
                    <goals>
                        <goal>compile</goal>
                        <goal>compile-custom</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

package io.grpc.examples.helloworld;

import io.grpc.ManagedChannel;
import io.grpc.ManagedChannelBuilder;
import io.grpc.StatusRuntimeException;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;
import java.util.logging.Logger;

public class HelloWorldClient {
    private static final Logger logger = Logger.getLogger(HelloWorldClient.class.getName());

    private final ManagedChannel channel;
    private final GreeterGrpc.GreeterBlockingStub blockingStub; // 阻塞式存根

    /**
     * 构造客户端，用于访问gRPC服务。
     * @param host gRPC服务的主机名或IP地址
     * @param port gRPC服务的端口
     */
    public HelloWorldClient(String host, int port) {
        // 创建一个ManagedChannel，用于管理与gRPC服务器的连接
        // .usePlaintext() 表示使用非加密连接。生产环境中应使用TLS/SSL。
        this(ManagedChannelBuilder.forAddress(host, port)
                .usePlaintext()
                .build());
    }

    HelloWorldClient(ManagedChannel channel) {
        this.channel = channel;
        // 使用ManagedChannel创建阻塞式存根
        blockingStub = GreeterGrpc.newBlockingStub(channel);
    }

    /**
     * 关闭ManagedChannel，释放资源。
     * @throws InterruptedException 如果等待关闭时线程被中断
     */
    public void shutdown() throws InterruptedException {
        channel.shutdown().awaitTermination(5, TimeUnit.SECONDS);
    }

    /**
     * 调用SayHello RPC方法。
     * @param name 要问候的名字
     */
    public void greet(String name) {
        logger.info("尝试问候: " + name + " ...");
        HelloRequest request = HelloRequest.newBuilder().setName(name).build();
        HelloReply response;
        try {
            // 发起RPC调用
            response = blockingStub.SayHello(request);
        } catch (StatusRuntimeException e) {
            logger.log(Level.WARNING, "RPC 调用失败: {0}", e.getStatus());
            return;
        }
        logger.info("收到问候: " + response.getMessage());
    }

    public static void main(String[] args) throws Exception {
        // 替换为您的EKS服务或Pod的实际IP/域名和端口
        // 例如：client = new HelloWorldClient("my-grpc-service.my-namespace.svc.cluster.local", 50051);
        // 或者：client = new HelloWorldClient("your-eks-loadbalancer-ip", 50051);
        HelloWorldClient client = new HelloWorldClient("localhost", 50051); // 示例：本地测试
        try {
            String user = "world";
            if (args.length > 0) {
                user = args[0];
            }
            client.greet(user);
        } finally {
            client.shutdown(); // 确保在程序退出时关闭连接
        }
    }
}

apiVersion: v1
kind: Service
metadata:
  name: grpc-greeter-service
  namespace: default # 替换为您的命名空间
spec:
  selector:
    app: greeter # 匹配您的gRPC服务Pod的标签
  ports:
    - protocol: TCP
      port: 50051 # Service暴露的端口
      targetPort: 50051 # Pod中gRPC容器监听的端口
  type: LoadBalancer # 使用LoadBalancer类型暴露服务