1、背景(灰度部署)
在咱们零碎公布生产环境时，有时为了确保新的服务逻辑没有问题，会让一小部分特定的用户来应用新的版本（比方客户端的内测版本），而其余的用户应用旧的版本，那么这个在Spring Cloud中该如何来实现呢？
负载平衡组件应用：Spring Cloud LoadBalancer
2、需要
3、实现思路
通过翻阅Spring Cloud的官网文档，咱们晓得，大略能够通过2种形式来达到咱们的目标。
- 实现
ReactiveLoadBalancer接口，重写负载平衡算法。 - 实现
ServiceInstanceListSupplier接口，重写get办法，返回自定义的服务列表。
ServiceInstanceListSupplier： 能够实现如下性能，比方咱们的 user-service在注册核心上存在5个，此处我能够只返回3个。
4、Spring Cloud中是否有我上方相似需要的例子
查阅Spring Cloud官网文档，发现org.springframework.cloud.loadbalancer.core.HintBasedServiceInstanceListSupplier 类能够实现相似的性能。
那可能有人会说，既然Spring Cloud曾经提供了这个性能，为什么你还要重写一个？ 此处只是为了一个记录，因为工作中的需要可能各种各样，万一前期有相似的需要，此处记录了，前期晓得怎么实现。
5、外围代码实现
5.1 灰度外围代码
5.1.1 灰度服务实例选择器实现
package com.huan.loadbalancer;import lombok.extern.slf4j.Slf4j;import org.springframework.cloud.client.ServiceInstance;import org.springframework.cloud.client.loadbalancer.Request;import org.springframework.cloud.client.loadbalancer.RequestDataContext;import org.springframework.cloud.loadbalancer.core.DelegatingServiceInstanceListSupplier;import org.springframework.cloud.loadbalancer.core.ServiceInstanceListSupplier;import org.springframework.http.HttpHeaders;import reactor.core.publisher.Flux;import java.util.List;import java.util.Objects;import java.util.stream.Collectors;/** * 自定义 依据服务名 获取服务实例 列表 * <p> * 需要： 用户通过申请拜访 网关<br /> * 1、如果申请头中的 version 值和 上游服务元数据的 version 值统一，则抉择该 服务。<br /> * 2、如果申请头中的 version 值和 上游服务元数据的 version 值不统一，且 不存在 version 的值 为 default 则间接报错。<br /> * 3、如果申请头中的 version 值和 上游服务元数据的 version 值不统一，且 存在 version 的值 为 default，则抉择该服务。<br /> * <p> * 参考: {@link org.springframework.cloud.loadbalancer.core.HintBasedServiceInstanceListSupplier} 实现 * * @author huan.fu * @date 2023/6/19 - 21:14 */@Slf4jpublic class VersionServiceInstanceListSupplier extends DelegatingServiceInstanceListSupplier { /** * 申请头的名字， 通过这个 version 字段和 服务中的元数据来version字段进行比拟， * 失去最终的实例数据 */ private static final String VERSION_HEADER_NAME = "version"; public VersionServiceInstanceListSupplier(ServiceInstanceListSupplier delegate) { super(delegate); } @Override public Flux<List<ServiceInstance>> get() { return delegate.get(); } @Override public Flux<List<ServiceInstance>> get(Request request) { return delegate.get(request).map(instances -> filteredByVersion(instances, getVersion(request.getContext()))); } private String getVersion(Object requestContext) { if (requestContext == null) { return null; } String version = null; if (requestContext instanceof RequestDataContext) { version = getVersionFromHeader((RequestDataContext) requestContext); } log.info("获取到须要申请服务[{}]的version:[{}]", getServiceId(), version); return version; } /** * 从申请中获取version */ private String getVersionFromHeader(RequestDataContext context) { if (context.getClientRequest() != null) { HttpHeaders headers = context.getClientRequest().getHeaders(); if (headers != null) { return headers.getFirst(VERSION_HEADER_NAME); } } return null; } private List<ServiceInstance> filteredByVersion(List<ServiceInstance> instances, String version) { // 1、获取 申请头中的 version 和 ServiceInstance 中 元数据中 version 统一的服务 List<ServiceInstance> selectServiceInstances = instances.stream() .filter(instance -> instance.getMetadata().get(VERSION_HEADER_NAME) != null && Objects.equals(version, instance.getMetadata().get(VERSION_HEADER_NAME))) .collect(Collectors.toList()); if (!selectServiceInstances.isEmpty()) { log.info("返回申请服务:[{}]为version:[{}]的有:[{}]个", getServiceId(), version, selectServiceInstances.size()); return selectServiceInstances; } // 2、返回 version=default 的实例 selectServiceInstances = instances.stream() .filter(instance -> Objects.equals(instance.getMetadata().get(VERSION_HEADER_NAME), "default")) .collect(Collectors.toList()); log.info("返回申请服务:[{}]为version:[{}]的有:[{}]个", getServiceId(), "default", selectServiceInstances.size()); return selectServiceInstances; }}5.1.2 灰度feign申请头传递拦截器
package com.huan.loadbalancer;import feign.RequestInterceptor;import feign.RequestTemplate;import lombok.extern.slf4j.Slf4j;import org.springframework.stereotype.Component;import org.springframework.web.context.request.RequestContextHolder;import org.springframework.web.context.request.ServletRequestAttributes;/** * 将version申请头通过feign传递到上游 * * @author huan.fu * @date 2023/6/20 - 08:27 */@Component@Slf4jpublic class VersionRequestInterceptor implements RequestInterceptor { @Override public void apply(RequestTemplate requestTemplate) { String version = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest() .getHeader("version"); log.info("feign 中传递的 version 申请头的值为:[{}]", version); requestTemplate .header("version", version); }}留神： 此处全局配置了，配置了一个feign的全局拦截器，进行申请头version的传递。
5.1.3 灰度服务实例选择器配置
package com.huan.loadbalancer;import lombok.extern.slf4j.Slf4j;import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;import org.springframework.cloud.client.discovery.DiscoveryClient;import org.springframework.cloud.client.discovery.ReactiveDiscoveryClient;import org.springframework.cloud.loadbalancer.annotation.LoadBalancerClients;import org.springframework.cloud.loadbalancer.core.ServiceInstanceListSupplier;import org.springframework.context.ConfigurableApplicationContext;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;/** * 此处抉择全局配置 * * @author huan.fu * @date 2023/6/19 - 22:16 */@Configuration@Slf4j@LoadBalancerClients(defaultConfiguration = VersionServiceInstanceListSupplierConfiguration.class)public class VersionServiceInstanceListSupplierConfiguration { @Bean @ConditionalOnClass(name = "org.springframework.web.servlet.DispatcherServlet") public VersionServiceInstanceListSupplier versionServiceInstanceListSupplierV1( ConfigurableApplicationContext context) { log.error("===========> versionServiceInstanceListSupplierV1"); ServiceInstanceListSupplier delegate = ServiceInstanceListSupplier.builder() .withBlockingDiscoveryClient() .withCaching() .build(context); return new VersionServiceInstanceListSupplier(delegate); } @Bean @ConditionalOnClass(name = "org.springframework.web.reactive.DispatcherHandler") public VersionServiceInstanceListSupplier versionServiceInstanceListSupplierV2( ConfigurableApplicationContext context) { log.error("===========> versionServiceInstanceListSupplierV2"); ServiceInstanceListSupplier delegate = ServiceInstanceListSupplier.builder() .withDiscoveryClient() .withCaching() .build(context); return new VersionServiceInstanceListSupplier(delegate); }}此处偷懒全局配置了
`
@Configuration
@Slf4j
@LoadBalancerClients(defaultConfiguration = VersionServiceInstanceListSupplierConfiguration.class)
`
5.2 网关外围代码
5.2.1 网关配置文件
spring: application: name: lobalancer-gateway-8001 cloud: nacos: discovery: # 配置 nacos 的服务地址 server-addr: localhost:8848 group: DEFAULT_GROUP config: server-addr: localhost:8848 gateway: discovery: locator: enabled: trueserver: port: 8001logging: level: root: info5.3 服务提供者外围代码
5.3.1 向外提供一个办法
package com.huan.loadbalancer.controller;import com.alibaba.cloud.nacos.NacosDiscoveryProperties;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RestController;import javax.annotation.Resource;/** * 提供者控制器 * * @author huan.fu * @date 2023/3/6 - 21:58 */@RestControllerpublic class ProviderController { @Resource private NacosDiscoveryProperties nacosDiscoveryProperties; /** * 获取服务信息 * * @return ip:port */ @GetMapping("serverInfo") public String serverInfo() { return nacosDiscoveryProperties.getIp() + ":" + nacosDiscoveryProperties.getPort(); }}5.3.2 提供者端口8005配置信息
spring: application: name: provider cloud: nacos: discovery: # 配置 nacos 的服务地址 server-addr: localhost:8848 # 配置元数据 metadata: version: v1 config: server-addr: localhost:8848server: port: 8005留神 metadata中version的值
5.3.2 提供者端口8006配置信息
spring: application: name: provider cloud: nacos: discovery: # 配置 nacos 的服务地址 server-addr: localhost:8848 # 配置元数据 metadata: version: v1 config: server-addr: localhost:8848server: port: 8006留神 metadata中version的值
5.3.3 提供者端口8007配置信息
spring: application: name: provider cloud: nacos: discovery: # 配置 nacos 的服务地址 server-addr: localhost:8848 # 配置元数据 metadata: version: default config: server-addr: localhost:8848server: port: 8007留神 metadata中version的值
5.4 服务消费者代码
5.4.1 通过 feign 调用提供者办法
/** * @author huan.fu * @date 2023/6/19 - 22:21 */@FeignClient(value = "provider")public interface FeignProvider { /** * 获取服务信息 * * @return ip:port */ @GetMapping("serverInfo") String fetchServerInfo();}5.4.2 向外提供一个办法
package com.huan.loadbalancer.controller;import com.alibaba.cloud.nacos.NacosDiscoveryProperties;import com.huan.loadbalancer.feign.FeignProvider;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RestController;import javax.annotation.Resource;import java.util.HashMap;import java.util.Map;/** * 消费者控制器 * * @author huan.fu * @date 2023/6/19 - 22:21 */@RestControllerpublic class ConsumerController { @Resource private FeignProvider feignProvider; @Resource private NacosDiscoveryProperties nacosDiscoveryProperties; @GetMapping("fetchProviderServerInfo") public Map<String, String> fetchProviderServerInfo() { Map<String, String> ret = new HashMap<>(4); ret.put("consumer信息", nacosDiscoveryProperties.getIp() + ":" + nacosDiscoveryProperties.getPort()); ret.put("provider信息", feignProvider.fetchServerInfo()); return ret; }}消费者端口 8002 配置信息
spring: application: name: consumer cloud: nacos: discovery: # 配置 nacos 的服务地址 server-addr: localhost:8848 register-enabled: true service: nacos-feign-consumer group: DEFAULT_GROUP metadata: version: v1 config: server-addr: localhost:8848server: port: 8002留神 metadata中version的值
消费者端口 8003 配置信息
spring: application: name: consumer cloud: nacos: discovery: # 配置 nacos 的服务地址 server-addr: localhost:8848 register-enabled: true service: nacos-feign-consumer group: DEFAULT_GROUP metadata: version: v2 config: server-addr: localhost:8848server: port: 8003留神 metadata中version的值
消费者端口 8004 配置信息
spring: application: name: consumer cloud: nacos: discovery: # 配置 nacos 的服务地址 server-addr: localhost:8848 register-enabled: true service: nacos-feign-consumer group: DEFAULT_GROUP metadata: version: default config: server-addr: localhost:8848server: port: 8003留神 metadata中version的值
6、测试
6.1 申请头中携带 version=v1
从上图中能够看到，当version=v1时，服务消费者为consumer-8002, 提供者为provider-8005和provider-8006
➜ ~ curl --location --request GET 'http://localhost:8001/nacos-feign-consumer/fetchProviderServerInfo' \--header 'version: v1'{"consumer信息":"192.168.8.168:8002","provider信息":"192.168.8.168:8005"}%➜ ~ curl --location --request GET 'http://localhost:8001/nacos-feign-consumer/fetchProviderServerInfo' \--header 'version: v1'{"consumer信息":"192.168.8.168:8002","provider信息":"192.168.8.168:8006"}%➜ ~ curl --location --request GET 'http://localhost:8001/nacos-feign-consumer/fetchProviderServerInfo' \--header 'version: v1'{"consumer信息":"192.168.8.168:8002","provider信息":"192.168.8.168:8005"}%➜ ~ curl --location --request GET 'http://localhost:8001/nacos-feign-consumer/fetchProviderServerInfo' \--header 'version: v1'{"consumer信息":"192.168.8.168:8002","provider信息":"192.168.8.168:8006"}%➜ ~能够看到，消费者返回的端口是8002，提供者返回的端口是8005|8006是合乎预期的。
6.2 不传递version
从上图中能够看到，当不携带时，服务消费者为consumer-8004, 提供者为provider-8007和
➜ ~ curl --location --request GET 'http://localhost:8001/nacos-feign-consumer/fetchProviderServerInfo'{"consumer信息":"192.168.8.168:8004","provider信息":"192.168.8.168:8007"}%➜ ~ curl --location --request GET 'http://localhost:8001/nacos-feign-consumer/fetchProviderServerInfo'{"consumer信息":"192.168.8.168:8004","provider信息":"192.168.8.168:8007"}%➜ ~ curl --location --request GET 'http://localhost:8001/nacos-feign-consumer/fetchProviderServerInfo'{"consumer信息":"192.168.8.168:8004","provider信息":"192.168.8.168:8007"}%➜ ~能够看到，消费者返回的端口是8004，提供者返回的端口是8007是合乎预期的。
7、残缺代码
https://gitee.com/huan1993/spring-cloud-alibaba-parent/tree/master/loadbalancer-supply-service-instance
8、参考文档
1、https://docs.spring.io/spring-cloud-commons/docs/current/reference/html/#spring-cloud-loadbalancer