grpc-java springboot 同步异步调用 demo

曾经终败给现在 2021-09-21 21:10 721阅读 0赞

> 近期学习 grpc-java，从 demo 入手，进行学习

grpc 的基础知识暂不整理，后续有时间再整理一波，这一篇主要是记录一个简单的 grpc 使用 springboot 创建的 demo。

我整个 demo 分成三个 Project ：

*  grpc-springboot-demo-api：用于存放 proto 文件，生成Java 代码
 *  grpc-springboot-demo-server：服务端代码
 *  grpc-springboot-demo-consumer：客户端代码

## demo-api（proto） ##

创建一个最简单的 proto 文件，请求跟相应都只包含一个 String 的对象。

syntax = "proto3";
    
    option java_package = "grpc.springboot.demo.api";
    option java_outer_classname = "HelloWorldService";
    
    package helloworld;
    
    // 定义服务
    service HelloWorld {
        rpc SayHello (HelloRequest) returns (HelloResponse) {}
    }
    
    // 定义请求体
    message HelloRequest {
        string message = 1;
    }
    
    // 定义相应内容
    message HelloResponse {
        string message = 1;
    }

文件创建好之后，需要进行编译，pom文件中需要引入相关插件：

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
    
        <groupId>com.parallelline1996</groupId>
        <artifactId>grpc-springboot-demo-api</artifactId>
        <version>1.0.0-SNAPSHOT</version>
    
        <dependencies>
            <dependency>
                <groupId>com.google.protobuf</groupId>
                <artifactId>protobuf-java</artifactId>
                <version>3.5.1</version>
            </dependency>
            <dependency>
                <groupId>io.grpc</groupId>
                <artifactId>grpc-all</artifactId>
                <version>1.12.0</version>
            </dependency>
        </dependencies>
    
        <build>
            <extensions>
                <extension>
                    <groupId>kr.motd.maven</groupId>
                    <artifactId>os-maven-plugin</artifactId>
                    <version>1.4.1.Final</version>
                </extension>
            </extensions>
            <plugins>
                <plugin>
                    <groupId>org.xolstice.maven.plugins</groupId>
                    <artifactId>protobuf-maven-plugin</artifactId>
                    <version>0.5.0</version>
                    <configuration>
                        <protocArtifact>com.google.protobuf:protoc:3.0.0:exe:${os.detected.classifier}</protocArtifact>
                        <pluginId>grpc-java</pluginId>
                        <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.0.0:exe:${os.detected.classifier}</pluginArtifact>
                    </configuration>
                    <executions>
                        <execution>
                            <goals>
                                <goal>compile</goal>
                                <goal>compile-custom</goal>
                            </goals>
                        </execution>
                    </executions>
                </plugin>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <configuration>
                        <source>6</source>
                        <target>6</target>
                    </configuration>
                </plugin>
            </plugins>
        </build>
    </project>

完成后，直接通过 maven 工具的 install 指令，推到本地仓库即可，构建时，便会自动生成我们需要的类。

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0FwcGx5aW5n_size_16_color_FFFFFF_t_70]

## demo-server ##

服务端项目的目录结构：

*  Starter：springboot 的启动类
 *  GrpcServerConfiguration：grpc 服务端的启动类
 *  HelloServerImpl：提供服务的实现类

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0FwcGx5aW5n_size_16_color_FFFFFF_t_70 1]  
首先 pom 文件，主要是导入 springboot 的启动的依赖，以及 grpc 的依赖，以及我们上面的 api 项目。

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
    
        <groupId>com.parallelline1996</groupId>
        <artifactId>grpc-springboot-demo-server</artifactId>
        <version>1.0.0-SNAPSHOT</version>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>com.parallelline1996</groupId>
                <artifactId>grpc-springboot-demo-api</artifactId>
                <version>1.0.0-SNAPSHOT</version>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
            <dependency>
                <groupId>org.apache.httpcomponents</groupId>
                <artifactId>httpclient</artifactId>
                <version>4.5.5</version>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-actuator</artifactId>
            </dependency>
            <dependency>
                <groupId>io.grpc</groupId>
                <artifactId>grpc-all</artifactId>
                <version>1.28.1</version>
            </dependency>
            <dependency>
                <groupId>com.google.guava</groupId>
                <artifactId>guava</artifactId>
                <version>27.0-jre</version>
            </dependency>
        </dependencies>
    
        <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-dependencies</artifactId>
                    <version>1.5.21.RELEASE</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>
    </project>

Starter 启动类：

@SpringBootApplication
    public class Starter implements CommandLineRunner { 
    
        private GrpcServerConfiguration configuration;
    
        public Starter(GrpcServerConfiguration configuration) { 
            this.configuration = configuration;
        }
    
    	// 启动 grpc 服务端
        @Override
        public void run(String... args) throws Exception { 
            configuration.start();
        }
    
    	// 启动 springboot 容器
        public static void main(String[] args) { 
            SpringApplication.run(Starter.class, args);
        }
    }

GrpcServerConfiguration grpc 服务端启动类：  
这里注意：如果不在创建 Server 指定线程池，则会使用 grpc-java 中提供的默认线程池响应从客户端发送的请求（后续关于 Server 的创建，会再写博客说明）。也可以直接指定线程池，只需调用 `ServerBuilder.executor(executor)`  
即可。

@Component
    public class GrpcServerConfiguration { 
    
        private static final Logger logger = LoggerFactory.getLogger(GrpcServerConfiguration.class);
    
        // Grpc 服务端提供的服务
        @Autowired
        private HelloServiceImpl service;
    
        // Grpc 服务端的地址
        @Value("${grpc.server.port}")
        private int port;
        private Server server;
        private ThreadPoolExecutor executor;
    
        @PostConstruct
        public void init() { 
            executor = new ThreadPoolExecutor(10, 10, 60,
                    TimeUnit.MILLISECONDS, new SynchronousQueue<>());
        }
    
        public void start() throws IOException { 
            // 构建服务端
            logger.info("Starting gRPC on port {}.", port);
    
            // 使用默认线程池
            server = ServerBuilder.forPort(port).addService(service).build().start();
    
            // 使用自定义线程池用于处理请求
    // server = ServerBuilder.forPort(port).addService(service).executor(executor).build().start();
    
            logger.info("gRPC server started, listening on {}.", port);
    
            // 添加服务端关闭的逻辑
            Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() { 
                @Override
                public void run() { 
                    logger.info("Shutting down gRPC server.");
                    GrpcServerConfiguration.this.stop();
                    logger.info("gRPC server shut down successfully.");
                }
            }));
        }
    
        private void stop() { 
            if (server != null) { 
                // 关闭服务端
                server.shutdown();
            }
        }

HelloServiceImpl：业务逻辑的实现类，继承 demo-api 中申明的 `HelloWorldGrpc.HelloWorldImplBase`，重写 `sayHello` 方法即可。

@Component
    public class HelloServiceImpl extends HelloWorldGrpc.HelloWorldImplBase { 
        
        private static final Logger logger = LoggerFactory.getLogger(HelloServiceImpl.class);
        
        @Override
        public void sayHello(HelloWorldService.HelloRequest request,
                             StreamObserver<HelloWorldService.HelloResponse> responseObserver) { 
            String message = request.getMessage();
            logger.info("Client Received message:{}", message);
    
            // 创建结果，返回响应内容
            String rsp = String.format("Hello, %s. This message have send to server", message);
            HelloWorldService.HelloResponse response = HelloWorldService.HelloResponse
                    .newBuilder()
                    .setMessage(rsp)
                    .build();
            responseObserver.onNext(response);
            responseObserver.onCompleted();
        }

## demo-consumer ##

客服端项目的目录结构：

*  Starter：springboot 的启动类
 *  GrpcClient：客户端的启动类
 *  HelloController：对外提供服务

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0FwcGx5aW5n_size_16_color_FFFFFF_t_70 2]

pom 文件，主要是导入 springboot 的启动的依赖，以及 grpc 的依赖，同样也需要引入 api 项目的依赖。

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
    
        <groupId>com.parallelline1996</groupId>
        <artifactId>grpc-springboot-demo-consumer</artifactId>
        <version>1.0.0-SNAPSHOT</version>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>com.parallelline1996</groupId>
                <artifactId>grpc-springboot-demo-api</artifactId>
                <version>1.0.0-SNAPSHOT</version>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
            <dependency>
                <groupId>org.apache.httpcomponents</groupId>
                <artifactId>httpclient</artifactId>
                <version>4.5.5</version>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-actuator</artifactId>
            </dependency>
            <dependency>
                <groupId>io.grpc</groupId>
                <artifactId>grpc-all</artifactId>
                <version>1.28.1</version>
            </dependency>
            <dependency>
                <groupId>com.google.guava</groupId>
                <artifactId>guava</artifactId>
                <version>27.0-jre</version>
            </dependency>
        </dependencies>
    
        <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-dependencies</artifactId>
                    <version>1.5.21.RELEASE</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>
    </project>

Starter，启动类，与服务端服务启动类无差异。

@SpringBootApplication
    public class Starter implements CommandLineRunner { 
    
        private GrpcClient configuration;
    
        public Starter(GrpcClient configuration) { 
            this.configuration = configuration;
        }
    
    	// 启动 grpc 客户端
        @Override
        public void run(String... args) { 
            configuration.start();
        }
    
    	// 启动 springboot 容器
        public static void main(String[] args) { 
            SpringApplication.run(Starter.class, args);
        }
    }

GrpcClient，gRPC 客户端，主要作用是监听 gRPC 服务端，开启通道。

@Component
    public class GrpcClient { 
    
        private static final Logger logger = LoggerFactory.getLogger(GrpcClient.class);
    
        // Grpc 服务端的地址
        @Value("${grpc.server.host}")
        private String host;
    
        // Grpc 服务端暴露的接口
        @Value("${grpc.server.port}")
        private int port;
    
        private HelloWorldGrpc.HelloWorldBlockingStub stub;
        private HelloWorldGrpc.HelloWorldFutureStub futureStub;
    
        public void start() { 
            // 开启channel
            ManagedChannel channel = ManagedChannelBuilder.forAddress(host, port).usePlaintext().build();
    
            // 通过 channel 获取服务端 blocking-stub
            stub = HelloWorldGrpc.newBlockingStub(channel);
            // 通过 channel 获取服务端 future-stub
            futureStub = HelloWorldGrpc.newFutureStub(channel);
    
            logger.info("gRPC client start, server address: host:{}, port:{}", host, port);
        }
    
        public HelloWorldGrpc.HelloWorldBlockingStub getStub() { 
            return this.stub;
        }
    
        public HelloWorldGrpc.HelloWorldFutureStub getFutureStub() { 
            return this.futureStub;
        }
    }

gRPC 的客户端支持三种调用方式：

*  同步调用
 *  基于 Future 的异步调用
 *  基于回调的异步调用

下面的代码分别对应三种调用方式：

@RestController
    public class HelloController { 
    
        private static final Logger logger = LoggerFactory.getLogger(HelloController.class);
    
        @Autowired
        GrpcClient configuration;
    
        /** * 同步调用，阻塞 */
        @GetMapping("/hello")
        public String hello(@RequestParam(name = "name", defaultValue = "test", required = false) String name) { 
            logger.info("Server received request.name={}", name);
            // 构建一个请求
            HelloWorldService.HelloRequest request = HelloWorldService.HelloRequest
                    .newBuilder()
                    .setMessage(name)
                    .build();
    
            // 使用stub发送请求至服务端
            try { 
    			// 这里获取了一个 blocking-stub
                HelloWorldGrpc.HelloWorldBlockingStub stub = configuration.getStub();
                // 同步发送，将阻塞等待请求结果
                HelloWorldService.HelloResponse response = stub.sayHello(request);
                logger.info("Server response received: [{}]", response.toString());
                return response.getMessage();
            } catch (StatusRuntimeException e) { 
                logger.info(" Error Received - Error code : {}", e.getStatus().getCode());
            }
            return "error";
        }
    
        /** * 基于 Future 的异步调用 */
        @GetMapping("/hello-async-future")
        public String helloAsyncFuture(@RequestParam(name = "name", defaultValue = "test", required = false) String name) { 
            logger.info("Server received request.name={}", name);
            // 构建一个请求
            HelloWorldService.HelloRequest request = HelloWorldService.HelloRequest
                    .newBuilder()
                    .setMessage(name)
                    .build();
    
            // 使用stub发送请求至服务端
            try { 
                // 获取 future-stub 对象，调用请求后，将获取 future
                ListenableFuture<HelloWorldService.HelloResponse> listenableFuture = configuration.getFutureStub().sayHello(request);
                // 通过 future 对象的 get 请求获取结果
                // 由于在同一线程中调用，并没有实现真正的异步，仍为同步阻塞
                HelloWorldService.HelloResponse response = listenableFuture.get();
                logger.info("Server response received: [{}]", response.toString());
                return response.getMessage();
            } catch (StatusRuntimeException e) { 
                logger.info(" Error Received - Error code : {}", e.getStatus().getCode());
            } catch (Exception e) { 
                logger.error("error ", e);
            }
            return "error";
        }
    
        /** * 基于回调的异步调用 */
        @GetMapping("/hello-async-callback")
        public String helloAsyncCallback(@RequestParam(name = "name", defaultValue = "test", required = false) String name) { 
            logger.info("Server received request.name={}", name);
            // 构建一个请求
            HelloWorldService.HelloRequest request = HelloWorldService.HelloRequest
                    .newBuilder()
                    .setMessage(name)
                    .build();
    
            // 使用stub发送请求至服务端
            try { 
                HelloWorldGrpc.HelloWorldFutureStub futureStub = configuration.getFutureStub();
                ListenableFuture<HelloWorldService.HelloResponse> listenableFuture = futureStub.sayHello(request);
    
    			// 通过设备监听器，同时指定回调线程池的方式进行
                listenableFuture.addListener(() -> { 
                    try { 
                        HelloWorldService.HelloResponse response = listenableFuture.get();
                        logger.info("Server response received: [{}]", response.toString());
                    } catch (Exception e) { 
                        e.printStackTrace();
                    }
                }, new ThreadPoolExecutor(1, 1, 60,
                        TimeUnit.MILLISECONDS, new SynchronousQueue<>()));
    
                return "async";
            } catch (StatusRuntimeException e) { 
                logger.info(" Error Received - Error code : {}", e.getStatus().getCode());
            } catch (Exception e) { 
                logger.error("error ", e);
            }
            return "error";
        }
    }

完整的代码连接：https://github.com/Parallelline1996/Daily-Learning/tree/master/gRPC/code-repository/grpc-springboot-demo

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