Spring Boot 2+gRPC 学习系列1:搭建Spring Boot 2+gRPC本地项目

本项目基于Spring Boot 2.0.5+yidongnan/grpc-spring-boot-starter 2.0.1.RELEASE,通过grpc-lib，grpc-server，grpc-client 3个模块来模拟grpc的服务调用。

主要参考自yidongnan/grpc-spring-boot-starter和LogNet/grpc-spring-boot-starter的官方example
yidongnan项目的主要优点有：项目使用maven和gradle两种方式，grpc-client连接grpc-server的channel通过注解自动注入，较优雅。缺点是文档没LogNet的丰富。两者功能相近，所以我使用了yidognnan的starter。

本项目已上传至GitHub：https://github.com/linshenkx/grpc-springboot-lin

一项目结构

1 项目结构

根项目（com.linshen:grpc-springboot-lin:1.0-SNAPSHOT）下有3个子模块：

grpc-lib：包含原始proto文件，并负责将其转换为java代码
grpc-server：grpc服务端
grpc-client ： grpc客户端

2 模块功能

相互关系
根项目负责依赖版本管理,grpc-server和grpc-client都依赖grpc-lib的接口,其中,grpc-server提供了接口的具体实现,而grpc-client则调用了grpc-server的实现,他们通过grpc-lib来确定使用规范(接口即契约)
对应MVC关系
- grpc-lib就是service(接口,为提供实现)
- grpc-server就相当于serviceImpl(service的实现类)
- grpc-client就是controller的角色.
框架依赖
- grpc-lib需要将proto文件转换成java类，故需依赖于protobuf-maven-plugin插件，另外还需要io.grpc下的grpc-all，否则生成的java类会提示缺少依赖
- grpc-server 负责提供rpc服务,不需要spring-web支持
- grpc-client 调用rpc服务

二项目搭建

0 编写根项目pom文件

如下，根项目主要负责定义项目子模块，全局属性和版本管理

<?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.linshen</groupId>
    <artifactId>grpc-springboot-lin</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>pom</packaging>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.5.RELEASE</version>
    </parent>

    <!--引入的子模块-->
    <modules>
        <module>grpc-lib</module>
        <module>grpc-server</module>
        <module>grpc-client</module>
    </modules>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-boot.version>2.0.5.RELEASE</spring-boot.version>
        <net-devh-grpc.version>2.0.1.RELEASE</net-devh-grpc.version>

    </properties>

    <dependencyManagement>
        <dependencies>
            <!--依赖维护平台,在添加第三方依赖的时候，不需要写版本号，它能够自动帮我们挑选一个最优的版本-->
            <dependency>
                <groupId>io.spring.platform</groupId>
                <artifactId>platform-bom</artifactId>
                <version>Cairo-RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!--公共grpc模块-->
            <dependency>
                <groupId>com.linshen</groupId>
                <artifactId>grpc-lib</artifactId>
                <version>${project.version}</version>
            </dependency>
            <!--核心grpc-spring-boot依赖-->
            <dependency>
                <groupId>net.devh</groupId>
                <artifactId>grpc-client-spring-boot-starter</artifactId>
                <version>${net-devh-grpc.version}</version>
            </dependency>
            <dependency>
                <groupId>net.devh</groupId>
                <artifactId>grpc-server-spring-boot-starter</artifactId>
                <version>${net-devh-grpc.version}</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-deploy-plugin</artifactId>
                <configuration>
                    <skip>true</skip>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

1 创建grpc-lib模块

创建maven管理的java项目，pom文件如下
proto文件目录是${project.basedir}/src/main/proto
生成的java代码在${project.basedir}/src/main/java
使用maven指令compile可完成代码生成，或直接在IDE里用proto插件运行compile和compile-custom

<?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>

    <artifactId>grpc-lib</artifactId>
    <packaging>jar</packaging>

    <name>grpc-lib</name>

    <parent>
        <groupId>com.linshen</groupId>
        <artifactId>grpc-springboot-lin</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <properties>
        <os.plugin.version>1.6.0</os.plugin.version>
        <grpc.version>1.15.1</grpc.version>
        <protoc.version>3.6.1</protoc.version>
        <protobuf.plugin.version>0.6.1</protobuf.plugin.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>io.grpc</groupId>
            <artifactId>grpc-all</artifactId>
            <version>${grpc.version}</version>
        </dependency>
    </dependencies>

    <build>
        <extensions>
            <extension>
                <groupId>kr.motd.maven</groupId>
                <artifactId>os-maven-plugin</artifactId>
                <version>${os.plugin.version}</version>
            </extension>
        </extensions>
        <plugins>
            <plugin>
                <groupId>org.xolstice.maven.plugins</groupId>
                <artifactId>protobuf-maven-plugin</artifactId>
                <version>${protobuf.plugin.version}</version>
                <extensions>true</extensions>
                <configuration>
                    <protocArtifact>com.google.protobuf:protoc:${protoc.version}:exe:${os.detected.classifier}</protocArtifact>
                    <pluginId>grpc-java</pluginId>
                    <pluginArtifact>io.grpc:protoc-gen-grpc-java:${grpc.version}:exe:${os.detected.classifier}</pluginArtifact>
                    <!--默认值-->
                    <protoSourceRoot>${project.basedir}/src/main/proto</protoSourceRoot>
                    <!--默认值-->
                    <!--<outputDirectory>${project.build.directory}/generated-sources/protobuf/java</outputDirectory>-->
                    <outputDirectory>${project.basedir}/src/main/java</outputDirectory>
                    <!--设置是否在生成java文件之前清空outputDirectory的文件，默认值为true，设置为false时也会覆盖同名文件-->
                    <clearOutputDirectory>false</clearOutputDirectory>
                    <!--更多配置信息可以查看https://www.xolstice.org/protobuf-maven-plugin/compile-mojo.html-->
                </configuration>
                <executions>
                    <execution>
                        <!--在执行mvn compile的时候会执行以下操作-->
                        <phase>compile</phase>
                        <goals>
                            <!--生成OuterClass类-->
                            <goal>compile</goal>
                            <!--生成Grpc类-->
                            <goal>compile-custom</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

2 创建grpc-server模块

<?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>

    <artifactId>grpc-server</artifactId>
    <packaging>jar</packaging>

    <name>grpc-server</name>

    <parent>
        <groupId>com.linshen</groupId>
        <artifactId>grpc-springboot-lin</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>com.linshen</groupId>
            <artifactId>grpc-lib</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <dependency>
            <groupId>net.devh</groupId>
            <artifactId>grpc-server-spring-boot-starter</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>  
</project>

3 创建grpc-client模块

可以看到，这里比grpc-server多了spring-web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>

    <artifactId>grpc-client</artifactId>
    <packaging>jar</packaging>

    <name>grpc-client</name>

    <parent>
        <groupId>com.linshen</groupId>
        <artifactId>grpc-springboot-lin</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>com.linshen</groupId>
            <artifactId>grpc-lib</artifactId>
        </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.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <dependency>
            <groupId>net.devh</groupId>
            <artifactId>grpc-client-spring-boot-starter</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

三功能实现

1 在grpc-lib模块利用proto文件生成java代码

（1）编写proto文件

这里用的greeter.proto内容如下

syntax = "proto3";

option java_package = "com.linshen.grpc.lib";

// The greeter service definition.
service Greeter {
    // Sends a greeting
    rpc SayHello ( HelloRequest) returns (  HelloReply) {}

}
// The request message containing the user's name.
message HelloRequest {
    string name = 1;
}
// The response message containing the greetings
message HelloReply {
    string message = 1;
}

（2）生成java代码

根据上文pom文件的设置，将proto文件放到src/main/proto目录下，运行protobuf插件的compile和compile-custom功能，生成java代码到src/main/java目录下。
生成后文件目录如下
grpc

2 在grpc-server模块实现接口

（1）编写application文件

首先在application.yml文件指定应用名和grpc端口，如下

spring:
  application:
    name: local-grpc-server
grpc:
  server:
    port: 9898

（2）编写GreeterService类

@Slf4j
@GrpcService(GreeterOuterClass.class)
public class GreeterService extends GreeterGrpc.GreeterImplBase {
    @Override
    public void sayHello(GreeterOuterClass.HelloRequest request, StreamObserver<GreeterOuterClass.HelloReply> responseObserver) {
        String message = "Hello " + request.getName();
        final GreeterOuterClass.HelloReply.Builder replyBuilder = GreeterOuterClass.HelloReply.newBuilder().setMessage(message);
        responseObserver.onNext(replyBuilder.build());
        responseObserver.onCompleted();
        log.info("Returning " +message);
    }
}

3 在grpc-client模块调用服务

（1）编写application文件

grpc需要开放接口，故需在application.yml指定端口，另外还需指定grpc-server地址和端口，这里将grpc-server的地址以环境变量的方式开放出来，默认在本地。yml文件如下

server:
  port: 9090
spring:
  application:
    name: local-grpc-client
grpc:
  client:
    local-grpc-server:
      host:
      - ${LOCAL-GRPC-HOST:127.0.0.1}
      port:
      - 9898
      enableKeepAlive: true
      keepAliveWithoutCalls: true

（2）编写GrpcClientService服务类

注意，@GrpcClient根据value将yml文件里的配置绑定到Channel

@Service
public class GrpcClientService {

    @GrpcClient("local-grpc-server")
    private Channel serverChannel;

    public String sendMessage(String name) {
        GreeterGrpc.GreeterBlockingStub stub= GreeterGrpc.newBlockingStub(serverChannel);
        GreeterOuterClass.HelloReply response = stub.sayHello(GreeterOuterClass.HelloRequest.newBuilder().setName(name).build());
        return response.getMessage();
    }
}

（3）编写GrpcClientController类

@RestController
public class GrpcClientController {

    @Autowired
    private GrpcClientService grpcClientService;

    @RequestMapping("/")
    public String printMessage(@RequestParam(defaultValue = "Michael") String name) {
        return grpcClientService.sendMessage(name);
    }
}

四项目启动并测试

依次启动grpc-server和grpc-client,打开http://localhost:8080/或http://localhost:8080/?name=lin即可看到结果
在这里插入图片描述
同时grpc-server项目日志输出如下

需要注意的是，如果想要执行插件的jar打包，run启动等命令，需要先在根项目下运行mvn install，注意不是mvn install-install，否则会出现·Failed to collect dependencies·问题

五其他

gRPC-Java指导：https://grpc.io/docs/tutorials/basic/java.html
gRPC-Java的GitHub地址：https://github.com/grpc/grpc-java
yidongnan/grpc-spring-boot-starter的GitHub地址：https://github.com/yidongnan/grpc-spring-boot-starter
LogNet/grpc-spring-boot-starter的GitHub地址：https://github.com/LogNet/grpc-spring-boot-starter
gRPC 官方文档中文版1.0：https://doc.oschina.net/grpc
Maven Protocol Buffers Plugin 插件指南：https://www.xolstice.org/protobuf-maven-plugin/index.html