java版gRPC实战之六：客户端动态获取服务端地址，2021Java开发社招面试解答之性能优化

java版gRPC实战之六：客户端动态获取服务端地址，2021Java开发社招面试解答之性能优化

import static com.google.common.base.Charsets.UTF_8;

@Component(“stubWrapper”)

@Data

@Slf4j

@ConfigurationProperties(prefix = “grpc”)

public class StubWrapper {

private static final String GRPC_SERVER_INFO_KEY = “/grpc/local-server”;

private String etcdendpoints;

private SimpleGrpc.SimpleBlockingStub simpleBlockingStub;

public String[] getGrpcServerInfo() {

// 创建client类

KV kvClient = Client.builder().endpoints(etcdendpoints.split(",")).build().getKVClient();

GetResponse response = null;

// 去etcd查询/grpc/local-server这个key的值

try {

response = kvClient.get(ByteSequence.from(GRPC_SERVER_INFO_KEY, UTF_8)).get();

} catch (Exception exception) {

log.error(“get grpc key from etcd error”, exception);

}

if (null==response || response.getKvs().isEmpty()) {

log.error(“empty value of key [{}]”, GRPC_SERVER_INFO_KEY);

return null;

}

// 从response中取得值

String rawAddrInfo = response.getKvs().get(0).getValue().toString(UTF_8);

// rawAddrInfo是“192.169.0.1:8080”这样的字符串，即一个IP和一个端口，用":"分割，

// 这里用":"分割成数组返回

return null==rawAddrInfo ? null : rawAddrInfo.split(";

}

@PostConstruct

public void simpleBlockingStub() {

// 从etcd获取地址信息

String[] array = getGrpcServerInfo();

log.info(“create stub bean, array info from etcd {}”, Arrays.toString(array));

// 数组的第一个元素是gRPC服务端的IP地址，第二个元素是端口

if (null==array || array.length<2) {

log.error(“can not get valid grpc address from etcd”);

return;

}

// 数组的第一个元素是gRPC服务端的IP地址

String addr = array[0];

// 数组的第二个元素是端口

int port = Integer.parseInt(array[1]);

// 根据刚才获取的gRPC服务端的地址和端口，创建channel

Channel channel = ManagedChannelBuilder

.forAddress(addr, port)

.usePlaintext()

.build();

// 根据channel创建stub

simpleBlockingStub = SimpleGrpc.newBlockingStub(channel);

}

}

• GrpcClientService是封装了StubWrapper的服务类：

package com.bolingcavalry.dynamicrpcaddr;

import com.bolingcavalry.grpctutorials.lib.HelloReply;

import com.bolingcavalry.grpctutorials.lib.HelloRequest;

import com.bolingcavalry.grpctutorials.lib.SimpleGrpc;

import io.grpc.StatusRuntimeException;

import lombok.Setter;

import net.devh.boot.grpc.client.inject.GrpcClient;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

@Service

public class GrpcClientService {

@Autowired(required = false)

@Setter

private StubWrapper stubWrapper;

public String sendMessage(final String name) {

// 很有可能simpleStub对象为null

if (null==stubWrapper) {

return “invalid SimpleBlockingStub, please check etcd configuration”;

}

try {

final HelloReply response = stubWrapper.getSimpleBlockingStub().sayHello(HelloRequest.newBuilder().setName(name).build());

return response.getMessage();

} ca

【一线大厂Java面试题解析+后端开发学习笔记+最新架构讲解视频+实战项目源码讲义】

浏览器打开：qq.cn.hn/FTf 免费领取

tch (final StatusRuntimeException e) {

return "FAILED with " + e.getStatus().getCode().name();

}

}

}

• 新增一个controller类GrpcClientController，提供一个http接口，里面会调用GrpcClientService的方法，最终完成远程gRPC调用：

package com.bolingcavalry.dynamicrpcaddr;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.bind.annotation.RestController;

@RestController

public class GrpcClientController {

@Autowired

private GrpcClientService grpcClientService;

@RequestMapping("/")

public String printMessage(@RequestParam(defaultValue = “will”) String name) {

return grpcClientService.sendMessage(name);

}

}

• 接下来新增一个controller类RefreshStubInstanceController，对外提供一个http接口refreshstub，作用是删掉stubWrapper这个bean，再重新注册一次，这样每当外部调用refreshstub接口，就可以从etcd取得服务端信息再重新实例化SimpleBlockingStub成员变量，这样就达到了客户端动态获取服务端地址的效果：

package com.bolingcavalry.dynamicrpcaddr;

import com.bolingcavalry.grpctutorials.lib.SimpleGrpc;

import org.springframework.beans.BeansException;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.beans.factory.support.AbstractBeanDefinition;

import org.springframework.beans.factory.support.BeanDefinitionBuilder;

import org.springframework.beans.factory.support.BeanDefinitionRegistry;

import org.springframework.beans.factory.support.DefaultListableBeanFactory;

import org.springframework.context.ApplicationContext;

import org.springframework.context.ApplicationContextAware;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.bind.annotation.RestController;

@RestController

public class RefreshStubInstanceController implements ApplicationContextAware {

private ApplicationContext applicationContext;

@Autowired

private GrpcClientService grpcClientService;

@Override

public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {

this.applicationContext = applicationContext;

}

@RequestMapping("/refreshstub")

public String refreshstub() {

String beanName = “stubWrapper”;

//获取BeanFactory

DefaultListableBeanFactory defaultListableBeanFactory = (DefaultListableBeanFactory) applicationContext.getAutowireCapableBeanFactory();

// 删除已有bean

defaultListableBeanFactory.removeBeanDefinition(beanName);

//创建bean信息.

BeanDefinitionBuilder beanDefinitionBuilder = BeanDefinitionBuilder.genericBeanDefinition(StubWrapper.class);

//动态注册bean.

defaultListableBeanFactory.registerBeanDefinition(beanName, beanDefinitionBuilder.getBeanDefinition());

// 更新引用关系(注意，applicationContext.getBean方法很重要，会触发StubWrapper实例化 *** 作)

grpcClientService.setStubWrapper(applicationContext.getBean(StubWrapper.class));

return “Refresh success”;

}

}

• 编码完成，开始验证；

部署gRPC服务端应用

部署gRPC服务端应用很简单，启动local-server应用即可：

部署etcd

• 为了简化 *** 作，我这里的etcd集群是用docker部署的，对应的docker-compose.yml文件内容如下：

version: ‘3’

services:

etcd1:

image: “quay.io/coreos/etcd:v3.4.7”

entrypoint: /usr/local/bin/etcd

command:

• ‘–name=etcd1’

• ‘–data-dir=/etcd_data’

• ‘–initial-advertise-peer-urls=http://etcd1:2380’

• ‘–listen-peer-urls=http://0.0.0.0:2380’

• ‘–listen-client-urls=http://0.0.0.0:2379’

• ‘–advertise-client-urls=http://etcd1:2379’

• ‘–initial-cluster-token=etcd-cluster’

• ‘–heartbeat-interval=250’

• ‘–election-timeout=1250’

• ‘–initial-cluster=etcd1=http://etcd1:2380,etcd2=http://etcd2:2380,etcd3=http://etcd3:2380’

• ‘–initial-cluster-state=new’

ports:

• 2379:2379

volumes:

• ./store/etcd1/data:/etcd_data

etcd2:

image: “quay.io/coreos/etcd:v3.4.7”

entrypoint: /usr/local/bin/etcd

command:

• ‘–name=etcd2’

• ‘–data-dir=/etcd_data’

• ‘–initial-advertise-peer-urls=http://etcd2:2380’

• ‘–listen-peer-urls=http://0.0.0.0:2380’

• ‘–listen-client-urls=http://0.0.0.0:2379’

• ‘–advertise-client-urls=http://etcd2:2379’

• ‘–initial-cluster-token=etcd-cluster’

• ‘–heartbeat-interval=250’

• ‘–election-timeout=1250’

• ‘–initial-cluster=etcd1=http://etcd1:2380,etcd2=http://etcd2:2380,etcd3=http://etcd3:2380’

• ‘–initial-cluster-state=new’

ports:

• 2380:2379

volumes:

• ./store/etcd2/data:/etcd_data

etcd3:

image: “quay.io/coreos/etcd:v3.4.7”

entrypoint: /usr/local/bin/etcd

command:

• ‘–name=etcd3’

• ‘–data-dir=/etcd_data’

• ‘–initial-advertise-peer-urls=http://etcd3:2380’

• ‘–listen-peer-urls=http://0.0.0.0:2380’

• ‘–listen-client-urls=http://0.0.0.0:2379’

• ‘–advertise-client-urls=http://etcd3:2379’

• ‘–initial-cluster-token=etcd-cluster’

• ‘–heartbeat-interval=250’

• ‘–election-timeout=1250’

• ‘–initial-cluster=etcd1=http://etcd1:2380,etcd2=http://etcd2:2380,etcd3=http://etcd3:2380’

• ‘–initial-cluster-state=new’

ports:

• 2381:2379

volumes:

• ./store/etcd3/data:/etcd_data