rpc框架之gRPC 学习 - hello world

grpc是google在github于2015年开源的一款RPC框架，虽然protobuf很早google就开源了，但是google一直没推出正式的开源框架，导致github上基于protobuf的rpc五花八门，国内比较著名的有百度的sofa-pbrpc，但是遗憾的是soft-pbrpc没有对应的java实现版本。rgpc还有一个独立的官网：http://www.grpc.io/，目前已经支持的语言有 C, C++, Java, Go, Node.js, Python, Ruby, Objective-C, PHP 、 C#. grpc最大的特点是基于protobuf + http2 协议，http2协议虽然还未正式定稿，但从目前得知的内容来看，潜力巨大。下面是grpc基本的hello world的示例：

一、grpc-contract

还是按老套路，把服务涉及的对象定义、接口定义抽象出来，下面是项目结构图：

pom.xml的内容如下：

 <?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>yjmyzz.grpc</groupId>
     <artifactId>grpc-contract</artifactId>
     <version>1.0</version>

     <dependencies>

         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
             <version>4.10</version>
         </dependency>

         <dependency>
             <groupId>com.google.protobuf</groupId>
             <artifactId>protobuf-java</artifactId>
             <version>3.0.0-beta-1</version>
         </dependency>

         <dependency>
             <groupId>io.grpc</groupId>
             <artifactId>grpc-all</artifactId>
             <version>0.8.0</version>
         </dependency>

     </dependencies>

     <!--下面这个节点可选-->
     <pluginRepositories>
         <pluginRepository>
             <releases>
                 <updatePolicy>never</updatePolicy>
             </releases>
             <snapshots>
                 <enabled>false</enabled>
             </snapshots>
             <id>central</id>
             <name>Central Repository</name>
             <url>https://repo.maven.apache.org/maven2</url>
         </pluginRepository>
         <pluginRepository>
             <id>protoc-plugin</id>
             <url>https://dl.bintray.com/sergei-ivanov/maven/</url>
         </pluginRepository>
     </pluginRepositories>

     <build>
         <extensions>
             <extension>
                 <groupId>kr.motd.maven</groupId>
                 <artifactId>os-maven-plugin</artifactId>
                 <version>1.4.0.Final</version>
             </extension>
         </extensions>
         <plugins>
             <!--用于根据proto文件生成java类的插件-->
             <plugin>
                 <groupId>com.google.protobuf.tools</groupId>
                 <artifactId>maven-protoc-plugin</artifactId>
                 <version>0.4.2</version>
                 <configuration>
                     <protocArtifact>com.google.protobuf:protoc:3.0.0-alpha-3.1:exe:${os.detected.classifier}
                     </protocArtifact>
                     <pluginId>grpc-java</pluginId>
                     <pluginArtifact>io.grpc:protoc-gen-grpc-java:0.8.0:exe:${os.detected.classifier}</pluginArtifact>
                 </configuration>
                 <executions>
                     <execution>
                         <goals>
                             <goal>compile</goal>
                             <goal>compile-custom</goal>
                         </goals>
                     </execution>
                 </executions>
             </plugin>

             <!--生成源代码jar包的插件（可选）-->
             <plugin>
                 <artifactId>maven-source-plugin</artifactId>
                 <version>2.4</version>
                 <executions>
                     <execution>
                         <phase>package</phase>
                         <goals>
                             <goal>jar-no-fork</goal>
                         </goals>
                     </execution>
                 </executions>
             </plugin>

         </plugins>
     </build>
 </project>

demo_service_dto.proto内容如下：

syntax = "proto3";

package yjmyzz.grpc.study.dto;

option java_multiple_files = true;
option java_outer_classname = "DemoServiceDto";

message PingRequest {
     string in=1;
}

message PingResponse {
     string out=1;
}

message QueryParameter {
     int32 ageStart = 1;
     int32 ageEnd = 2;
}

message Person {
     int32 age = 1;
     string name = 2;
     bool sex=3;
     double salary=4;
     int32 childrenCount=5;
}

message PersonList{
     repeated Person items=1;
}

注：grpc要求protobuf必须使用3.0以上版本

demo_service.proto内容如下：

syntax = "proto3";

import "demo_service_dto.proto";

package yjmyzz.grpc.study.service;

option java_multiple_files = true;
option java_outer_classname = "DemoServiceDto";

service DemoService {
    rpc Ping (yjmyzz.grpc.study.dto.PingRequest) returns (yjmyzz.grpc.study.dto.PingResponse) {}

    rpc getPersonList (yjmyzz.grpc.study.dto.QueryParameter) returns (yjmyzz.grpc.study.dto.PersonList) {}
}

mvn install 后，会自动在target下生成相应的java class类

二、grpc-server

pom.xml文件如下：

 <?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>yjmyzz.grpc</groupId>
     <artifactId>grpc-server</artifactId>
     <version>1.0</version>

     <dependencies>
         <dependency>
             <groupId>com.google.protobuf</groupId>
             <artifactId>protobuf-java</artifactId>
             <version>3.0.0-beta-1</version>
         </dependency>

         <dependency>
             <groupId>yjmyzz.grpc</groupId>
             <artifactId>grpc-contract</artifactId>
             <version>1.0</version>
         </dependency>

         <dependency>
             <groupId>io.grpc</groupId>
             <artifactId>grpc-all</artifactId>
             <version>0.8.0</version>
         </dependency>

         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
             <version>4.10</version>
         </dependency>

     </dependencies>

 </project>

先对服务接口提供实现：

package yjmyzz.grpc.study.service.impl;

import io.grpc.stub.StreamObserver;
import yjmyzz.grpc.study.dto.*;
import yjmyzz.grpc.study.service.DemoServiceGrpc;

import java.util.ArrayList;
import java.util.List;

public class DemoServiceImpl implements DemoServiceGrpc.DemoService {
    public void ping(PingRequest pingRequest, StreamObserver<PingResponse> streamObserver) {
        PingResponse reply = PingResponse.newBuilder().setOut("pong => " + pingRequest.getIn()).build();
        streamObserver.onValue(reply);
        streamObserver.onCompleted();
    }

    public void getPersonList(QueryParameter queryParameter, StreamObserver<PersonList> streamObserver) {
        //System.out.println(queryParameter.getAgeStart() + "-" + queryParameter.getAgeEnd());
        PersonList.Builder personListBuilder = PersonList.newBuilder();
        Person.Builder builder = Person.newBuilder();
        List<Person> list = new ArrayList<Person>();
        for (short i = 0; i < 10; i++) {
            list.add(builder.setAge(i).setChildrenCount(i).setName("test" + i).setSex(true).build());
        }
        personListBuilder.addAllItems(list);
        streamObserver.onValue(personListBuilder.build());
        streamObserver.onCompleted();
    }
}

和前面thrift、avro的helloworld一样，这里的实现只是意思一下，方便测试而已。

grpc的server端是基于Netty的（当然还有OKHttp的实现，详情见github项目主页），下面是server端的代码：

package yjmyzz.grpc.study.server;

import io.grpc.ServerImpl;
import io.grpc.inprocess.InProcessServerBuilder;
import io.grpc.netty.NettyServerBuilder;
import yjmyzz.grpc.study.service.DemoServiceGrpc;
import yjmyzz.grpc.study.service.impl.DemoServiceImpl;

public class DemoServiceServer {

    private int port = 50051;
    private ServerImpl server;

    private void start() throws Exception {
        server = NettyServerBuilder.forPort(port)
                .addService(DemoServiceGrpc.bindService(new DemoServiceImpl()))
                .build().start();

        server = InProcessServerBuilder.forName("testServer")
                .addService(DemoServiceGrpc.bindService(new DemoServiceImpl()))
                .build().start();

        System.out.println("Server started, listening on " + port);
        Runtime.getRuntime().addShutdownHook(new Thread() {
            @Override
            public void run() {
                System.out.println("*** shutting down gRPC server since JVM is shutting down");
                DemoServiceServer.this.stop();
                System.out.println("*** server shut down");
            }
        });
    }

    private void stop() {
        if (server != null) {
            server.shutdown();
        }
    }

    public static void main(String[] args) throws Exception {
        final DemoServiceServer server = new DemoServiceServer();
        server.start();
    }

}

三、grpc-client

pom.xml内容：

 <?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>yjmyzz.grpc</groupId>
     <artifactId>grpc-client</artifactId>
     <version>1.0</version>

     <dependencies>

         <dependency>
             <groupId>com.google.protobuf</groupId>
             <artifactId>protobuf-java</artifactId>
             <version>3.0.0-beta-1</version>
         </dependency>

         <dependency>
             <groupId>yjmyzz.grpc</groupId>
             <artifactId>grpc-contract</artifactId>
             <version>1.0</version>
         </dependency>

         <dependency>
             <groupId>io.grpc</groupId>
             <artifactId>grpc-all</artifactId>
             <version>0.8.0</version>
         </dependency>

         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
             <version>4.10</version>
         </dependency>

     </dependencies>

 </project>

Client端代码：

package yjmyzz.grpc.study.client;

import io.grpc.ChannelImpl;
import io.grpc.netty.NegotiationType;
import io.grpc.netty.NettyChannelBuilder;
import yjmyzz.grpc.study.dto.PersonList;
import yjmyzz.grpc.study.dto.PingRequest;
import yjmyzz.grpc.study.dto.PingResponse;
import yjmyzz.grpc.study.dto.QueryParameter;
import yjmyzz.grpc.study.service.DemoServiceGrpc;

import java.util.concurrent.TimeUnit;

public class DemoServiceClient {

    private final ChannelImpl channel;
    private final DemoServiceGrpc.DemoServiceBlockingStub blockingStub;

    public DemoServiceClient(String host, int port) {
        channel =
                NettyChannelBuilder.forAddress(host, port).negotiationType(NegotiationType.PLAINTEXT)
                        .build();

        blockingStub = DemoServiceGrpc.newBlockingStub(channel);
    }

    public void shutdown() throws InterruptedException {
        channel.shutdown().awaitTermination(5, TimeUnit.SECONDS);
    }

    public void ping(String name) {
        try {
            System.out.println("Will try to ping " + name + " ...");
            PingRequest request = PingRequest.newBuilder().setIn(name).build();
            PingResponse response = blockingStub.ping(request);
            System.out.println("ping: " + response.getOut());
        } catch (RuntimeException e) {
            System.out.println("RPC failed:" + e.getMessage());
            return;
        }
    }

    public void getPersonList(QueryParameter parameter) {
        try {
            //System.out.println("Will try to getPersonList " + parameter + " ...");
            PersonList response = blockingStub.getPersonList(parameter);
            //System.out.println("items count: " + response.getItemsCount());
//            for (Person p : response.getItemsList()) {
//                System.out.println(p);
//            }
        } catch (RuntimeException e) {
            System.out.println("RPC failed:" + e.getMessage());
            return;
        }
    }

    public static void main(String[] args) throws Exception {
        DemoServiceClient client = new DemoServiceClient("localhost", 50051);
        try {
            client.ping("a");

            int max = 100000;
            Long start = System.currentTimeMillis();

            for (int i = 0; i < max; i++) {
                client.getPersonList(getParameter());
            }
            Long end = System.currentTimeMillis();
            Long elapse = end - start;
            int perform = Double.valueOf(max / (elapse / 1000d)).intValue();

            System.out.print("rgpc " + max + " 次NettyServer调用，耗时：" + elapse + "毫秒，平均" + perform + "次/秒");
        } finally {
            client.shutdown();
        }
    }

    private static QueryParameter getParameter() {
        return QueryParameter.newBuilder().setAgeStart(5).setAgeEnd(50).build();
    }
}

在笔记本测试的结果：

Will try to ping a ...
ping: pong => a
rgpc 100000 次NettyServer调用，耗时：36409毫秒，平均2746次/秒

基本上在每秒3k次的数量级，相对thrift（1w+）、avro(5k+)来讲，目前的差距还是很明显的，但是新事物成长总是需要时间，再给google一段时间，相信以后会让大家感到惊艳的。

在序列化方面，也做了一个跟之前thrift、avro类似的测试：

    @Test
    public void test() throws InvalidProtocolBufferException {

        QueryParameter queryParameter = QueryParameter.newBuilder().setAgeStart(1).setAgeEnd(5).build();
        byte[] bytes1 = queryParameter.toByteArray();
        System.out.println("Protobuf 3.0 二进制序列后的byte数组长度：" + bytes1.length);

        QueryParameter result = QueryParameter.parseFrom(bytes1);
        System.out.println(queryParameter.getAgeStart() + " - " + result.getAgeStart());

    }

输出：

Protobuf 3.0 二进制序列后的byte数组长度：4
1 - 1

在2进制序列化后的大小方面，protobuf 3大体跟thrift的TCompactProtocal（大小5）接近，比avro（大小2）略差。

文中示例源码下载：http://code.taobao.org/svn/grpc-demo/

参考文章：

RPC框架性能基本比较测试

Schema evolution in Avro, Protocol Buffers and Thrift

jvm-serializers

RPC综述 - PB, Thrift, Avro