全链路灰度实现

• 全量发布：只有实现复杂度比价低，没有其他优势
• 滚动发布：发布和回退时间比较缓慢，用户体验比较平滑
• 蓝绿发布：适合于对于资源预算比较充足的业务，或者是比较简单的单体应用，可以快速实现系统的整体变更
• 金丝雀和全链路灰度：适合需要针对特定用户或者人群进行现网请求验证的业务，可以显著减低风险

总结：
建议选择 金丝雀或者全链路灰度 进行服务的升级发布。

四、全链路灰度思路实例讲解

灰度发布架构

• 环境：springcloud-nacos-feign-loadbalancer（ribbon）
• 简单描述一下灰度发布，这里有微服务order集群和微服务user集群，每个集群未标红的是生产实例，标红的代表发布的灰度版本实例；可以看到网络流量是通过微服务网关为入口，流入微服务集群，中间有个loadbalancer负载均衡器处理版本本次流量执行那个版本的order服务，所以这里微服务网关就负责过滤流量管理灰度规则等，流量经过微服务网关后，可以看到灰度流量就指向了灰度版本，微服务order通过RPC调用微服务user时也通过loadbalancer也将灰度流量发到了微服务user的灰度实例上。

• ​ 通过上面的图和对于灰度发布架构的描述，我们可以看出实现微服务全链路灰度发布的核心是负载均衡器。

灰度发布实现思路

1. order、user服务设置版本release-1.0.0，灰度版本release-2.0.0
2. 请求header加version ：release-2.0.0 会执行灰度版本实例
3. 改造loadbalancer负载均衡策略，根据流量url获取路由服务名order从注册中心获取order服务
4. 根据流量header的version筛选order服务的版本
5. 将筛选过后的order服务负载请求
6. 流量从order服务通过feign到user服务也是通过loadbalancer负载均衡策略将流量请求到对应的版本

代码实现

• springcloud2021之后版本的openfeign取消了内置ribbon，2021版本以后的可以使用loadbalancer

• gateway、order、user 服务添加依赖包

  <dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-loadbalancer</artifactId></dependency>

• order、user服务配置文件加版本配置

spring.cloud.nacos.discovery.metadata.version=release-2.0.0

2.网关配置

• 过滤器

@Slf4j
@Configuration
public class GrayReactiveLoadBalancerClientFilter implements GlobalFilter, Ordered {private static final int LOAD_BALANCER_CLIENT_FILTER_ORDER = 100;//负载均衡工厂@Autowiredprivate LoadBalancerClientFactory clientFactory;@Overridepublic int getOrder() {return LOAD_BALANCER_CLIENT_FILTER_ORDER;}@Overridepublic Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {// 获取请求的Route对象Route route = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR);URI url = route.getUri();if (url != null && "lb".equals(url.getScheme())) {ServerWebExchangeUtils.addOriginalRequestUrl(exchange, url);if (log.isTraceEnabled()) {log.trace(ReactiveLoadBalancerClientFilter.class.getSimpleName() + " url before: " + url);}return this.choose(exchange).doOnNext((response) -> {//校验是否有服务信息if (!response.hasServer()) {throw NotFoundException.create(true, "Unable to find instance for " + url.getHost());} else {//协议 默认httpString overrideScheme = null;String schemePrefix = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR);if (schemePrefix != null) {overrideScheme = schemePrefix;}//创建一个DelegatingServiceInstance 实例, 该实例包装了选定的ServiceInstance并指定了协议DelegatingServiceInstance serviceInstance = new DelegatingServiceInstance(response.getServer(), overrideScheme);//使用DelegatingServiceInstance 实例和原始URI来构建目标请求的URIURI uri = exchange.getRequest().getURI();URI requestUrl = this.reconstructURI(serviceInstance, uri);if (log.isTraceEnabled()) {log.trace("LoadBalancerClientFilter url chosen: " + requestUrl);}// 将构建的目标请求URI存储到ServerWebExchange的属性中提供给后续的过滤器exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR, requestUrl);}}).then(chain.filter(exchange));} else {return chain.filter(exchange);}}private Mono<Response<ServiceInstance>> choose(ServerWebExchange exchange) {// 获取请求的Route对象Route route = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR);//要请求的服务名String serviceId = null;if (route != null) {// 获取Route对象中的serviceIdserviceId = route.getUri().getHost();}//通过serviceId，获取服务提供者集合ObjectProvider<ServiceInstanceListSupplier> lazyProvider = clientFactory.getLazyProvider(serviceId, ServiceInstanceListSupplier.class);//创建负载均衡对象GrayLoadBalancer loadBalancer = new GrayLoadBalancer(lazyProvider, serviceId);if (loadBalancer == null) {throw new NotFoundException("No loadbalancer available for " + serviceId);} else {//执行负载均衡的方法return loadBalancer.choose(this.createRequest(exchange));}}/*** 获取Request* @param exchange* @return*/private Request createRequest(ServerWebExchange exchange) {HttpHeaders headers = exchange.getRequest().getHeaders();Request<HttpHeaders> request = new DefaultRequest<>(headers);return request;}protected URI reconstructURI(ServiceInstance serviceInstance, URI original) {return LoadBalancerUriTools.reconstructURI(serviceInstance, original);}
}

• 实现负载均衡算法，负载均衡策略改造

@Slf4j
public class GrayLoadBalancer implements ReactorServiceInstanceLoadBalancer {private ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider;private String serviceId;public GrayLoadBalancer(ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider, String serviceId) {this.serviceId = serviceId;this.serviceInstanceListSupplierProvider = serviceInstanceListSupplierProvider;}@Overridepublic Mono<Response<ServiceInstance>> choose(Request request) {//获取请求头信息HttpHeaders headers = (HttpHeaders) request.getContext();//校验服务提供者集合是否为空if (this.serviceInstanceListSupplierProvider != null) {//转换服务提供者集合实例ServiceInstanceListSupplier supplier = this.serviceInstanceListSupplierProvider.getIfAvailable();//执行负载return supplier.get().next().map(list -> getInstanceResponse(list, headers));}return null;}/*** 校验实体是否为空* @param instances     服务集合* @param headers       请求头信息* @return*/private Response<ServiceInstance> getInstanceResponse(List<ServiceInstance> instances, HttpHeaders headers) {if (instances.isEmpty()) {return getServiceInstanceEmptyResponse();} else {return getServiceInstanceResponseByVersion(instances, headers);}}/*** 根据版本进行选择** @param instances     服务信息* @param headers       请求头信息* @return*/private Response<ServiceInstance> getServiceInstanceResponseByVersion(List<ServiceInstance> instances, HttpHeaders headers) {//获取请求头version的值String versionNo = headers.getFirst("version");log.info("getServiceInstanceResponseByVersion--versionNo：" + this.serviceId);Map<String, String> versionMap = new HashMap<>();versionMap.put("version", versionNo);//创建不可变的Set集合final Set<Map.Entry<String, String>> attributes =Collections.unmodifiableSet(versionMap.entrySet());//校验获取符合version版本的服务ServiceInstance serviceInstance = null;for (ServiceInstance instance : instances) {Map<String, String> metadata = instance.getMetadata();if (metadata.entrySet().containsAll(attributes)) {serviceInstance = instance;break;}}//校验服务是否为空if (ObjectUtils.isEmpty(serviceInstance)) {return getServiceInstanceEmptyResponse();}//返回符合服务return new DefaultResponse(serviceInstance);}private Response<ServiceInstance> getServiceInstanceEmptyResponse() {log.warn("No servers available for service: " + this.serviceId);return new EmptyResponse();}
}

3.消费者服务通过feign到生产者服务，负载配置

• 启动类添加： 加载负载均衡配置

@LoadBalancerClients(defaultConfiguration = GllobalLoadbanlancerConfig.class)

配置类：负载均衡配置类

public class GllobalLoadbanlancerConfig {@Beanpublic ReactorLoadBalancer<ServiceInstance> reactorServiceInstanceLoadBalancer(Environment environment, LoadBalancerClientFactory loadBalancerClientFactory) {String name = environment.getProperty(LoadBalancerClientFactory.PROPERTY_NAME);return new GrayLoadBalancer(loadBalancerClientFactory.getLazyProvider(name, ServiceInstanceListSupplier.class), name);}
}

实现负载均衡算法，负载均衡策略改造

@Slf4jpublic class GrayLoadBalancer implements ReactorServiceInstanceLoadBalancer {private ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider;private String serviceId;public GrayLoadBalancer(ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider, String serviceId) {this.serviceId = serviceId;this.serviceInstanceListSupplierProvider = serviceInstanceListSupplierProvider;}@Overridepublic Mono<Response<ServiceInstance>> choose(Request request) {//        HttpHeaders headers = (HttpHeaders) request.getContext();RequestDataContext context = (RequestDataContext) request.getContext();RequestData clientRequest = context.getClientRequest();HttpHeaders headers = clientRequest.getHeaders();if (this.serviceInstanceListSupplierProvider != null) {//获取调用的服务信息列表ServiceInstanceListSupplier supplier = this.serviceInstanceListSupplierProvider.getIfAvailable();//执行负载分发return supplier.get().next().map(list -> getInstanceResponse(list, headers));}return null;}/*** 校验实体是否为空* @param instances     服务信息* @param headers       请求头信息* @return*/private Response<ServiceInstance> getInstanceResponse(List<ServiceInstance> instances, HttpHeaders headers) {if (instances.isEmpty()) {return getServiceInstanceEmptyResponse();} else {return getServiceInstanceResponseByVersion(instances, headers);}}/*** 根据版本进行分发** @param instances     服务信息* @param headers       请求头信息* @return*/private Response<ServiceInstance> getServiceInstanceResponseByVersion(List<ServiceInstance> instances, HttpHeaders headers) {//获取请求头version的值String versionNo = headers.getFirst("version");log.info("getServiceInstanceResponseByVersion--versionNo：" + this.serviceId);Map<String, String> versionMap = new HashMap<>();versionMap.put("version", versionNo);//创建不可变的Set集合final Set<Map.Entry<String, String>> attributes =Collections.unmodifiableSet(versionMap.entrySet());//校验获取符合version版本的服务ServiceInstance serviceInstance = null;for (ServiceInstance instance : instances) {Map<String, String> metadata = instance.getMetadata();if (metadata.entrySet().containsAll(attributes)) {serviceInstance = instance;break;}}//校验服务是否为空if (ObjectUtils.isEmpty(serviceInstance)) {return getServiceInstanceEmptyResponse();}//返回符合服务return new DefaultResponse(serviceInstance);}private Response<ServiceInstance> getServiceInstanceEmptyResponse() {log.warn("No servers available for service: " + this.serviceId);return new EmptyResponse();}}

请求头信息带入

@Component
public class FeignRequestInterceptor implements RequestInterceptor {//相当于是一个前置操作 处理请求头信息，记录请求日志、实现认证授权@Overridepublic void apply(RequestTemplate requestTemplate) {//获取请求参数ServletRequestAttributes attributes = (ServletRequestAttributes)RequestContextHolder.getRequestAttributes();//拿到请求HttpServletRequest request = attributes.getRequest();//获取请求头参数  当然调用上面这条代码的 request是一样的Enumeration<String> headerNames = attributes.getRequest().getHeaderNames();//将获取的请求中的所有参数while(headerNames.hasMoreElements()){//将key先获取String key=headerNames.nextElement();//通过key 获得 valueString value=request.getHeader(key);//将获取的参数 放到header头中采用键值 key:value 放到请求模板中requestTemplate.header(key,value);}}
}

五、探讨内容

• 灰度部署需要更新配置文件如何解决

apollo配置也支持灰度拉取配置，不同的服务端节点拉取不同版本的apollo配置

• 灰度部署需要更新改表结构如何解决

表删除和变更先保留老字段，等发布完成后再删除老字段

• 灰度场景，按照用户灰度、按照ip灰度如何实现

拦截器中配置相对应的策略