目标

实践 gRPC 与 springboot 的整合方式，实现 springboot 版本的 gRPC helloworld，通过编写 springboot 测试用例进行测试。

创建项目

项目文件夹 grpc-spring-boot-helloworld，pom.xml：

<?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.codenotfound</groupId>
    <artifactId>grpc-spring-boot-helloworld</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>grpc-spring-boot-helloworld</name>
    <description>gRPC - Spring Boot Hello World Example</description>
    <url>https://www.codenotfound.com/grpc-spring-boot-example.html</url>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.1.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>

        <grpc-spring-boot-starter.version>2.3.2</grpc-spring-boot-starter.version>

        <os-maven-plugin.version>1.6.0</os-maven-plugin.version>
        <protobuf-maven-plugin.version>0.5.1</protobuf-maven-plugin.version>
    </properties>

    <repositories>
        <repository>
            <id>jcenter</id>
            <url>https://jcenter.bintray.com/</url>
        </repository>
    </repositories>

    <dependencies>
        <!-- spring-boot -->
        <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.lognet</groupId>
            <artifactId>grpc-spring-boot-starter</artifactId>
            <version>${grpc-spring-boot-starter.version}</version>
        </dependency>
    </dependencies>

    <build>
        <extensions>
            <!-- os-maven-plugin -->
            <extension>
                <groupId>kr.motd.maven</groupId>
                <artifactId>os-maven-plugin</artifactId>
                <version>${os-maven-plugin.version}</version>
            </extension>
        </extensions>
        <plugins>
            <!-- spring-boot-maven-plugin -->
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <!-- protobuf-maven-plugin -->
            <plugin>
                <groupId>org.xolstice.maven.plugins</groupId>
                <artifactId>protobuf-maven-plugin</artifactId>
                <version>${protobuf-maven-plugin.version}</version>
                <configuration>
                    <protocArtifact>com.google.protobuf:protoc:3.5.1-1:exe:${os.detected.classifier}</protocArtifact>
                    <pluginId>grpc-java</pluginId>
                    <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.11.0:exe:${os.detected.classifier}</pluginArtifact>
                    <outputDirectory>${project.build.sourceDirectory}</outputDirectory>
                    <clearOutputDirectory>false</clearOutputDirectory>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>compile</goal>
                            <goal>compile-custom</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

springboot 主文件 src/main/java/com/codenotfound/grpc/DemoApplication.java

package com.codenotfound.grpc;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

创建 proto 文件

src/main/proto/HelloWorld.proto

syntax = "proto3";

option java_multiple_files = true;
package com.codenotfound.grpc.helloworld;

message Person {
  string first_name = 1;
  string last_name = 2;
}

message Greeting {
  string message = 1;
}

service HelloWorldService {
  rpc sayHello (Person) returns (Greeting);
}

编译

mvn compile

编译后自动生成 proto 描述的相关代码。

实现 service

src/main/java/com/codenotfound/grpc/HelloWorldServiceImpl.java

package com.codenotfound.grpc;

import org.lognet.springboot.grpc.GRpcService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.codenotfound.grpc.helloworld.Greeting;
import com.codenotfound.grpc.helloworld.HelloWorldServiceGrpc;
import com.codenotfound.grpc.helloworld.Person;

import io.grpc.stub.StreamObserver;

@GRpcService
public class HelloWorldServiceImpl
    extends HelloWorldServiceGrpc.HelloWorldServiceImplBase {

  private static final Logger LOGGER =
      LoggerFactory.getLogger(HelloWorldServiceImpl.class);

  @Override
  public void sayHello(Person request,
      StreamObserver<Greeting> responseObserver) {
    LOGGER.info("server received {}", request);

    String message = "Hello " + request.getFirstName() + " "
        + request.getLastName() + "!";
    Greeting greeting =
        Greeting.newBuilder().setMessage(message).build();
    LOGGER.info("server responded {}", greeting);

    responseObserver.onNext(greeting);
    responseObserver.onCompleted();
  }
}

创建 client

src/main/java/com/codenotfound/grpc/HelloWorldClient.java

package com.codenotfound.grpc;

import javax.annotation.PostConstruct;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import com.codenotfound.grpc.helloworld.Greeting;
import com.codenotfound.grpc.helloworld.HelloWorldServiceGrpc;
import com.codenotfound.grpc.helloworld.Person;

import io.grpc.ManagedChannel;
import io.grpc.ManagedChannelBuilder;

@Component
public class HelloWorldClient {

  private static final Logger LOGGER =
      LoggerFactory.getLogger(HelloWorldClient.class);

  private HelloWorldServiceGrpc.HelloWorldServiceBlockingStub helloWorldServiceBlockingStub;

  @PostConstruct
  private void init() {
    ManagedChannel managedChannel = ManagedChannelBuilder
        .forAddress("localhost", 6565).usePlaintext().build();

    helloWorldServiceBlockingStub =
        HelloWorldServiceGrpc.newBlockingStub(managedChannel);
  }

  public String sayHello(String firstName, String lastName) {
    Person person = Person.newBuilder().setFirstName(firstName)
        .setLastName(lastName).build();
    LOGGER.info("client sending {}", person);

    Greeting greeting =
        helloWorldServiceBlockingStub.sayHello(person);
    LOGGER.info("client received {}", greeting);

    return greeting.getMessage();
  }

}

测试代码

src/test/java/com/codenotfound/grpc/GRPCApplicationTests.java

package com.codenotfound.grpc;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import com.codenotfound.grpc.HelloWorldClient;

import static org.assertj.core.api.Assertions.assertThat;

@RunWith(SpringRunner.class)
@SpringBootTest
public class GRPCApplicationTests {
    @Autowired
    private HelloWorldClient helloWorldClient;

    @Test
    public void testSayHello() {
        assertThat(helloWorldClient.sayHello("John", "Doe")).isEqualTo("Hello John Doe!");
    }
}

运行测试

mvn test

运行效果：

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.0.1.RELEASE)

......
2018-09-25 10:55:52.491  INFO 55173 --- [           main] o.l.springboot.grpc.GRpcServerRunner     : Starting gRPC Server ...
2018-09-25 10:55:52.504  INFO 55173 --- [           main] o.l.springboot.grpc.GRpcServerRunner     : 'com.example.grpc.demo.HelloWorldServiceImpl' service has been registered.
2018-09-25 10:55:52.602  INFO 55173 --- [           main] o.l.springboot.grpc.GRpcServerRunner     : gRPC Server started, listening on port 6565.
2018-09-25 10:55:52.679  INFO 55173 --- [           main] com.example.grpc.demo.HelloWorldClient   : client sending first_name: "John"
last_name: "Doe"

2018-09-25 10:55:52.951  INFO 55173 --- [ault-executor-0] c.e.grpc.demo.HelloWorldServiceImpl      : server received first_name: "John"
last_name: "Doe"

2018-09-25 10:55:52.953  INFO 55173 --- [ault-executor-0] c.e.grpc.demo.HelloWorldServiceImpl      : server responded message: "Hello John Doe!"

2018-09-25 10:55:52.962  INFO 55173 --- [           main] com.example.grpc.demo.HelloWorldClient   : client received message: "Hello John Doe!"

[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 3.05 s - in com.example.grpc.demo.GRPCApplicationTests
2018-09-25 10:55:53.032  INFO 55173 --- [       Thread-2] o.s.w.c.s.GenericWebApplicationContext   : Closing org.springframework.web.context.support.GenericWebApplicationContext@2e385cce: startup date [Tue Sep 25 10:55:50 CST 2018]; root of context hierarchy
2018-09-25 10:55:53.034  INFO 55173 --- [       Thread-2] o.l.springboot.grpc.GRpcServerRunner     : Shutting down gRPC server ...
2018-09-25 10:55:53.036  INFO 55173 --- [       Thread-2] o.l.springboot.grpc.GRpcServerRunner     : gRPC server stopped.

参考文章：

https://www.codenotfound.com/grpc-spring-boot-example.html