gRPC SkyLB

gRPC 作為一款高性能悲雳、通用的 RPC 框架殿怜，相比傳統(tǒng)的RPC框架有著自己天然的優(yōu)勢：

1. protobuf二進制消息坠韩，性能好/效率高（空間和時間效率都很不錯）；
2. proto文件生成目標代碼右犹，簡單易用急侥；
3. 序列化反序列化直接對應(yīng)程序中的數(shù)據(jù)類砌滞，不需要解析后在進行映射(XML,JSON都是這種方式)侮邀；
4. 支持向前兼容（新加字段采用默認值）和向后兼容（忽略新加字段）坏怪，簡化升級；
5. 支持多種語言（可以把proto文件看做IDL文件）绊茧；
6. Netty等一些框架集成铝宵；

服務(wù)注冊/發(fā)現(xiàn) 是RPC框架的核心組件，但是gRPC 作為企業(yè)級框架华畏，他的開源組件官方并未直接提供服務(wù)注冊與發(fā)現(xiàn)的功能實現(xiàn)鹏秋。而是在設(shè)計文檔(load-balancing.md)中提供了實現(xiàn)的思路，并在不同語言的gRPC代碼API中提供了命名解析和負載均衡接口供擴展亡笑。

關(guān)于gRPC 服務(wù)發(fā)現(xiàn)&負載均衡的介紹侣夷，可以參見我之前寫的一篇文章 gRPC服務(wù)發(fā)現(xiàn)&負載均衡

Overview

gRPC SkyLB 采用獨立LB進程（External Load Balancing Service）負載均衡方式，支持輪詢仑乌、一致性哈希兩種負載均衡策略百拓，并支持服務(wù)端權(quán)重琴锭。采用etcd作為注冊中心。

項目地址：

https://github.com/binchencoder/grpc-skylb

Architecture of SkyLB

architecture.png

服務(wù)提供者起來后向注冊中心(SkyLB) 注冊自己的信息衙传，ip决帖、端口、權(quán)重等蓖捶，并保持心跳地回。客戶端監(jiān)聽注冊中心俊鱼，獲取服務(wù)器列表刻像，一旦服務(wù)器發(fā)生變化，客戶端馬上更新本地的服務(wù)器列表并闲∫锼伲客戶端每個請求都通過負載均衡策略選擇一個合適的服務(wù)器去訪問。

Usage

1. Dependency

   Install skylb-client local repository

   chenbindeMacBook-Pro:grpc-skylb chenbin$ mvn clean install
   

   <dependency>
    <groupId>com.binchencoder.skylb</groupId>
    <artifactId>skylb-client</artifactId>
    <version>1.0-SNAPSHOT</version>
   </dependency>
   

2. Implements gRPC API

   public class DemoGrpcImpl extends DemoGrpc.DemoImplBase {
     private final Logger LOGGER = LoggerFactory.getLogger(DemoGrpcImpl.class);
   
     private Random rand = new Random(System.currentTimeMillis());
     private int port;
     public DemoGrpcImpl(int port_) {
       this.port = port_;
     }
   
     @Override
     public void greeting(GreetingProtos.GreetingRequest request,
         StreamObserver<GreetingProtos.GreetingResponse> responseObserver) {
       LOGGER.info("Got req: {}", request);
   
       // 隨機耗時350~550毫秒.
       int elapse = 350 + rand.nextInt(200);
       try {
         TimeUnit.MILLISECONDS.sleep(elapse);
       } catch (InterruptedException ie) {
         LOGGER.warn("sleep interrupted");
       }
   
       GreetingResponse reply = GreetingResponse.newBuilder().setGreeting(
           "Hello " + request.getName() + ", from :" + port + ", elapse " + elapse + "ms").build();
       responseObserver.onNext(reply);
       responseObserver.onCompleted();
     }
   
     @Override
     public void greetingForEver(GreetingProtos.GreetingRequest request,
         StreamObserver<GreetingProtos.GreetingResponse> responseObserver) {
       super.greetingForEver(request, responseObserver);
     }
   }
   

3. Register gRPC Server to SkyLB Server

   Server server = ServerTemplate.create(
            {port} 9090, 
            {bindableService} new DemoGrpcImpl(), 
            {serviceName} "shared-test-client-service")
     .build()
     .start();
   
   SkyLBServiceReporter reporter = ServerTemplate.reportLoad(
            {skylbUri} "skylb://127.0.0.1:1900/",
            {serviceName} ServiceNameUtil.toString(ServiceId.CUSTOM_EASE_GATEWAY_TEST),
            {portName} "grpc",
            {port} 9090);
   

4. Call gRPC Server

   Create gRPC Stub

   ManagedChannel channel = ClientTemplate.createChannel(
            {skylbAddr} "skylb://127.0.0.1:1900/",
            {calleeServiceName} ServiceNameUtil.toString(ServiceId.CUSTOM_EASE_GATEWAY_TEST),
            {calleePortName} "grpc", 
            {calleeNamespace} null,                                   
            {callerServiceName} ServiceNameUtil.toString(ServiceId.SERVICE_NONE)).getOriginChannel();
   
   DemoGrpc.DemoBlockingStub blockingStub = DemoGrpc.newBlockingStub(channel);
   

   GreetingRequest request = GreetingRequest.newBuilder()
     .setName("GC " + Calendar.getInstance().get(Calendar.SECOND))
     .build();
   GreetingResponse response = blockingStub
     .withDeadlineAfter(2000, TimeUnit.MILLISECONDS)
     .greeting(request);
   

Run Demo

1. Build SkyLB Server

   chenbindeMacBook-Pro:grpc-skylb chenbin$ cd skylb-server
   chenbindeMacBook-Pro:skylb-server chenbin$ mvn clean package
   

   最終skylb.jar 打包到 skylb-server/target 目錄下

2. Start SkyLB Server

   Start ETCD3

   yum install etcd -y
   
   systemctl enable etcd && systemctl start etcd
   

   NOTE

   部署ETCD遇到問題可參考 https://www.cnblogs.com/shawhe/p/10640820.html

   chenbindeMacBook-Pro:skylb-server chenbin$ cd target/skylblib
   
   chenbindeMacBook-Pro:skylblib chenbin$ java -jar skylb.jar -h
    Usage: java -jar skylb.jar [options] [command] [command options]
     Options:
       --auto-disconn-timeout, -auto-disconn-timeout
         The timeout to automatically disconnect the resolve RPC. e.g. 10s(10 
         Seconds), 10m(10 Minutes)
         Default: PT5M
     Commands:
       etcd      Help for etcd options
         Usage: etcd [options]
           Options:
             --etcd-endpoints, -etcd-endpoints
               The comma separated ETCD endpoints. e.g., 
               http://etcd1:2379,http://etcd2:2379 
               Default: [http://127.0.0.1:2379]
             --etcd-key-ttl, -etcd-key-ttl
               The etcd key time-to-live. e.g. 10s(10 Seconds), 10m(10 Minutes)
               Default: PT10S
   
   chenbindeMacBook-Pro:skylblib chenbin$ java -jar skylb.jar -etcd-endpoints=http://127.0.0.1:2379
   

3. Start gRPC Server

   https://github.com/binchencoder/grpc-skylb/blob/master/examples/demo/src/main/java/com/binchencoder/skylb/demo/grpc/server/GreetingServer.java

   Run com/binchencoder/skylb/demo/grpc/server/GreetingServer#main

4. Start gRPC Client

   https://github.com/binchencoder/grpc-skylb/blob/master/examples/demo/src/main/java/com/binchencoder/skylb/demo/grpc/client/GreetingClient.java

   Run com/binchencoder/skylb/demo/grpc/client/GreetingClient#main

More Examples

grpc-skylb/examples/echo

該示例采用SpringBoot腳手架焙蚓，在spring-boot-grpc-common.jar中封裝好了注冊服務(wù)的邏輯纹冤，啟動方式比較簡單

@GrpcService(applyGlobalInterceptors = true) // Default use Global Interceptor
public class EchoGrpcService extends EchoServiceGrpc.EchoServiceImplBase {
}

1. 使用@GrpcService 注解方式標示gRPC Service

2. 在 spring-boot-grpc-common.jar 中默認配置兩個Global Interceptor(ExceptionInterceptor, AuthenticationInterceptor)

3. 使用者可通過注解不使用Global Interceptor，實現(xiàn)自己的Interceptor

   @GrpcService(applyGlobalInterceptors = false, interceptors = ExceptionInterceptor.class)
   

Features

• @GrpcService Annotation
• 支持配置全局攔截器
• 將來計劃支持skylb-client Golang版本

References

• gRPC服務(wù)發(fā)現(xiàn)&負載均衡
• https://github.com/binchencoder/grpc-skylb
• https://github.com/grpc/grpc/blob/master/doc/load-balancing.md
• 部署ETCD3集群

本人現(xiàn)在正在找工作购公，有合適的伯樂可隨時騷擾