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：
1 <?xml version="1.0" encoding="UTF-8"?> 2 <project xmlns="http://maven.apache.org/POM/4.0.0" 3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 4 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> 5 <modelVersion>4.0.0</modelVersion> 6 7 <groupId>yjmyzz.grpc</groupId> 8 <artifactId>grpc-contract</artifactId> 9 <version>1.0</version> 10 11 12 <dependencies> 13 14 <dependency> 15 <groupId>junit</groupId> 16 <artifactId>junit</artifactId> 17 <version>4.10</version> 18 </dependency> 19 20 <dependency> 21 <groupId>com.google.protobuf</groupId> 22 <artifactId>protobuf-java</artifactId> 23 <version>3.0.0-beta-1</version> 24 </dependency> 25 26 <dependency> 27 <groupId>io.grpc</groupId> 28 <artifactId>grpc-all</artifactId> 29 <version>0.8.0</version> 30 </dependency> 31 32 </dependencies> 33 34 <!--下面这个节点可选--> 35 <pluginRepositories> 36 <pluginRepository> 37 <releases> 38 <updatePolicy>never</updatePolicy> 39 </releases> 40 <snapshots> 41 <enabled>false</enabled> 42 </snapshots> 43 <id>central</id> 44 <name>Central Repository</name> 45 <url>https://repo.maven.apache.org/maven2</url> 46 </pluginRepository> 47 <pluginRepository> 48 <id>protoc-plugin</id> 49 <url>https://dl.bintray.com/sergei-ivanov/maven/</url> 50 </pluginRepository> 51 </pluginRepositories> 52 53 54 <build> 55 <extensions> 56 <extension> 57 <groupId>kr.motd.maven</groupId> 58 <artifactId>os-maven-plugin</artifactId> 59 <version>1.4.0.Final</version> 60 </extension> 61 </extensions> 62 <plugins> 63 <!--用于根据proto文件生成java类的插件--> 64 <plugin> 65 <groupId>com.google.protobuf.tools</groupId> 66 <artifactId>maven-protoc-plugin</artifactId> 67 <version>0.4.2</version> 68 <configuration> 69 <protocArtifact>com.google.protobuf:protoc:3.0.0-alpha-3.1:exe:${os.detected.classifier} 70 </protocArtifact> 71 <pluginId>grpc-java</pluginId> 72 <pluginArtifact>io.grpc:protoc-gen-grpc-java:0.8.0:exe:${os.detected.classifier}</pluginArtifact> 73 </configuration> 74 <executions> 75 <execution> 76 <goals> 77 <goal>compile</goal> 78 <goal>compile-custom</goal> 79 </goals> 80 </execution> 81 </executions> 82 </plugin> 83 84 <!--生成源代码jar包的插件（可选）--> 85 <plugin> 86 <artifactId>maven-source-plugin</artifactId> 87 <version>2.4</version> 88 <executions> 89 <execution> 90 <phase>package</phase> 91 <goals> 92 <goal>jar-no-fork</goal> 93 </goals> 94 </execution> 95 </executions> 96 </plugin> 97 98 </plugins> 99 </build> 100 </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：
1 <?xml version="1.0" encoding="UTF-8"?> 2 <project xmlns="http://maven.apache.org/POM/4.0.0" 3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 4 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> 5 <modelVersion>4.0.0</modelVersion> 6 7 <groupId>yjmyzz.grpc</groupId> 8 <artifactId>grpc-server</artifactId> 9 <version>1.0</version> 10 11 12 <dependencies> 13 <dependency> 14 <groupId>com.google.protobuf</groupId> 15 <artifactId>protobuf-java</artifactId> 16 <version>3.0.0-beta-1</version> 17 </dependency> 18 19 <dependency> 20 <groupId>yjmyzz.grpc</groupId> 21 <artifactId>grpc-contract</artifactId> 22 <version>1.0</version> 23 </dependency> 24 25 <dependency> 26 <groupId>io.grpc</groupId> 27 <artifactId>grpc-all</artifactId> 28 <version>0.8.0</version> 29 </dependency> 30 31 <dependency> 32 <groupId>junit</groupId> 33 <artifactId>junit</artifactId> 34 <version>4.10</version> 35 </dependency> 36 37 </dependencies> 38 39 40 </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：
1 <?xml version="1.0" encoding="UTF-8"?> 2 <project xmlns="http://maven.apache.org/POM/4.0.0" 3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 4 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> 5 <modelVersion>4.0.0</modelVersion> 6 7 <groupId>yjmyzz.grpc</groupId> 8 <artifactId>grpc-client</artifactId> 9 <version>1.0</version> 10 11 <dependencies> 12 13 <dependency> 14 <groupId>com.google.protobuf</groupId> 15 <artifactId>protobuf-java</artifactId> 16 <version>3.0.0-beta-1</version> 17 </dependency> 18 19 <dependency> 20 <groupId>yjmyzz.grpc</groupId> 21 <artifactId>grpc-contract</artifactId> 22 <version>1.0</version> 23 </dependency> 24 25 <dependency> 26 <groupId>io.grpc</groupId> 27 <artifactId>grpc-all</artifactId> 28 <version>0.8.0</version> 29 </dependency> 30 31 <dependency> 32 <groupId>junit</groupId> 33 <artifactId>junit</artifactId> 34 <version>4.10</version> 35 </dependency> 36 37 </dependencies> 38 39 </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：
Schema evolution in Avro, Protocol Buffers and Thrift
