JAVA面试题分享四百六十：Spring Cloud Gateway + Nacos 灰度发布
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前言
环境搭建
父项目
服务提供者 provider
网关 gateway
动态路由
灰度发布
依赖配置
负载均衡策略
过滤器加载负载均衡
注入过滤器
发布灰度服务
测试
仓库地址
前言
本文将会使用 SpringCloud Gateway 网关组件配合 Nacos 实现灰度发布（金丝雀发布）
环境搭建
创建子模块服务提供者 provider，网关模块 gateway
父项目
pom.xml 配置
4.0.0 com.example spring-gateway-demo 0.0.1-SNAPSHOT pom spring-gateway-demo spring-gateway-demo 11 11 11 3.8.1 2.3.7.RELEASE 2.2.2.RELEASE Hoxton.SR9 2.2.0.RELEASE provider gateway com.alibaba.cloud spring-cloud-starter-alibaba-nacos-config com.alibaba.cloud spring-cloud-starter-alibaba-nacos-discovery org.springframework.cloud spring-cloud-dependencies ${spring-cloud.version} pom import org.springframework.boot spring-boot-dependencies ${spring-boot.version} pom import com.alibaba.cloud spring-cloud-alibaba-dependencies ${spring-cloud-alibaba.version} pom import
服务提供者 provider
这里我们计划引入 nacos, 所以先创建一个 nacos 配置文件 dataId 为 provider.properties, 这里用默认的命名空间 public, 默认分组 DEFAULT_GROUP
version=2
provider 的 pom 配置依赖
org.springframework.boot spring-boot-starter-web org.springframework.boot spring-boot-starter-test test org.junit.vintage junit-vintage-engine
application.yml
server: port: 9001 spring: application: name: provider cloud: nacos: config: server-addr: 127.0.0.1:8848 discovery: server-addr: 127.0.0.1:8848
启动类上添加 @EnableDiscoveryClient 注解
@EnableDiscoveryClient @SpringBootApplication public class ProviderApplication { public static void main(String[] args) { SpringApplication.run(ProviderApplication.class, args); } }
然后添加测试 controller
@RefreshScope @RestController @RequestMapping("/test") public class TestController { @Autowired private Environment env; @Value("${version:0}") private String version; @GetMapping("/port") public Object port() { return String.format("port=%s, version=%s", env.getProperty("local.server.port"), version); } }
注意，这里配置 nacos 的时候需要配置下面两个文件 provider.properties 和 provider，然后实际配置最终 nacos 是采用的 provider 文件，否则后端控制台就会持续输出 400 错误，可能是新版本问题，其他版本暂时不清楚（后面网关配置也是同理）
后端控制台输出，也可以看出需要两个
[fixed-localhost_8848] [subscribe] provider.properties+DEFAULT_GROUP [fixed-localhost_8848] [add-listener] ok, tenant=, dataId=provider.properties, group=DEFAULT_GROUP, cnt=1 [fixed-localhost_8848] [subscribe] provider+DEFAULT_GROUP [fixed-localhost_8848] [add-listener] ok, tenant=, dataId=provider, group=DEFAULT_GROUP, cnt=1
Nacos 版本：2.3.0-BETA
网关 gateway
gateway 服务的 pom 依赖配置如下:
org.springframework.cloud spring-cloud-starter-gateway org.projectlombok lombok true org.springframework.boot spring-boot-starter-test test org.junit.vintage junit-vintage-engine org.springframework.boot spring-boot-starter-actuator
application.yml
# 应用服务 WEB 访问端口 server: port: 9000 # 应用名称 spring: application: name: gateway cloud: nacos: config: server-addr: 127.0.0.1:8848 discovery: server-addr: 127.0.0.1:8848 gateway: routes: # http://127.0.0.1:9000/actuator/gateway/routes - id: provider # 路由 ID，保持唯一 uri: lb://provider # uri指目标服务地址，lb代表从注册中心获取服务 predicates: - Path=/provider/** # http://127.0.0.1:9000/provider/port 会转发到 http://localhost:9001/provider/port, 和预期不符合, 需要StripPrefix来处理 filters: - StripPrefix=1 # StripPrefix=1就代表截取路径的个数为1, 这样请求 http://127.0.0.1:9000/provider/test/port 会转发到 http://localhost:9001/test/port management: endpoint: gateway: enabled: true endpoints: web: exposure: include: gateway
同样启动类上添加 @EnableDiscoveryClient 注解
查看所有路由：/actuator/gateway/routes 查看指定路由（GET）：/actuator/gateway/routes/{id} 查看全局过滤器：/actuator/gateway/globalfilters 查看路由过滤器：/actuator/gateway/routefilters POST 方式刷新路由缓存：/actuator/gateway/refresh
测试
curl http://127.0.0.1:9001/test/port port=9001, version=2 curl http://127.0.0.1:9000/provider/test/port port=9001, version=2
动态路由
实现动态路由有两种方式，一个是改写 RouteDefinitionRepository（实测失败），一个是基于 nacos 的监听器给 RouteDefinitionRepository 动态更新值。实现逻辑大同小异
Spring Cloud Gateway 中加载路由信息分别由以下几个类负责 1、PropertiesRouteDefinitionLocator：从配置文件中读取路由信息 (如 YML、Properties 等) 2、RouteDefinitionRepository：从存储器中读取路由信息 (如内存、配置中心、Redis、MySQL 等) 3、DiscoveryClientRouteDefinitionLocator：从注册中心中读取路由信息(如 Nacos、Eurka、Zookeeper 等)
下面使用 RouteDefinitionRepository 配置动态路由
gateway-router.json
[{ "id": "provider", "predicates": [{ "name": "Path", "args": { "_genkey_0": "/provider/**" } }], "filters": [{ "name": "StripPrefix", "args": { "_genkey_0": "1" } }], "uri": "lb://provider", "order": 0 }]
NacosRouteDefinitionRepository 配置类
@Component public class NacosRouteDefinitionRepository implements RouteDefinitionRepository, ApplicationEventPublisherAware { private static final Logger log = LoggerFactory.getLogger(NacosRouteDefinitionRepository.class); @Autowired private NacosConfigManager nacosConfigManager; // 更新路由信息需要的 private ApplicationEventPublisher applicationEventPublisher; private String dataId = "gateway-router.json"; private String group = "DEFAULT_GROUP"; @Value("${spring.cloud.nacos.config.server-addr}") private String serverAddr; private ObjectMapper objectMapper = new ObjectMapper(); @PostConstruct public void dynamicRouteByNacosListener() { try { nacosConfigManager.getConfigService().addListener(dataId, group, new Listener() { public void receiveConfigInfo(String configInfo) { log.info("自动更新配置...\r\n{}", configInfo); applicationEventPublisher.publishEvent(new RefreshRoutesEvent(this)); } public Executor getExecutor() { return null; } }); } catch (NacosException e) { e.printStackTrace(); } } @Override public Flux getRouteDefinitions() { try { String configInfo = nacosConfigManager.getConfigService().getConfig(dataId, group, 5000); List gatewayRouteDefinitions = objectMapper.readValue(configInfo, new TypeReference() { }); return Flux.fromIterable(gatewayRouteDefinitions); } catch (NacosException e) { e.printStackTrace(); } catch (JsonMappingException e) { e.printStackTrace(); } catch (JsonProcessingException e) { e.printStackTrace(); } return Flux.fromIterable(Lists.newArrayList()); } @Override public Mono save(Mono route) { return null; } @Override public Mono delete(Mono routeId) { return null; } @Override public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) { this.applicationEventPublisher = applicationEventPublisher; } }
然后重启网关，访问 http://127.0.0.1:9000/actuator/gateway/routes ，查看是否生效
[ { "predicate": "Paths: [/provider/**], match trailing slash: true", "route_id": "provider", "filters": [ "[[StripPrefix parts = 1], order = 1]" ], "uri": "lb://provider", "order": 0 } ]
灰度发布
首先需要明白灰度的场景, 因为有不同版本的服务需要共存, 所以新的节点升级的时候必然代码及配置会存在差别, 所以我们根据这种差别来判断服务版本是新版本还是线上稳定版本。这里我们用 prod 和 gray 来标识 2 个版本。
实现的整体思路：
-
编写带版本号的灰度路由(负载均衡策略)
-
编写自定义 filter
-
nacos 服务配置需要灰度发布的服务的元数据信息以及权重(在服务 jar 中配置)
注意, 应该先修改 nacos 配置实现动态路由, 然后再升级灰度节点. 本案例只是简单示例灰度原理。
下面进行网关配置
依赖配置
首先排除掉默认的 ribbon 依赖
com.alibaba.cloud spring-cloud-starter-alibaba-nacos-discovery org.springframework.cloud spring-cloud-starter-netflix-ribbon
引入官方新的负载均衡包
org.springframework.cloud spring-cloud-starter-loadbalancer
负载均衡策略
public class VersionGrayLoadBalancer implements ReactorServiceInstanceLoadBalancer { private ObjectProvider serviceInstanceListSupplierProvider; private String serviceId; private final AtomicInteger position; public VersionGrayLoadBalancer(ObjectProvider serviceInstanceListSupplierProvider, String serviceId) { this(serviceInstanceListSupplierProvider, serviceId, new Random().nextInt(1000)); } public VersionGrayLoadBalancer(ObjectProvider serviceInstanceListSupplierProvider, String serviceId, int seedPosition) { this.serviceId = serviceId; this.serviceInstanceListSupplierProvider = serviceInstanceListSupplierProvider; this.position = new AtomicInteger(seedPosition); } @Override public Mono choose(Request request) { HttpHeaders headers = (HttpHeaders) request.getContext(); ServiceInstanceListSupplier supplier = this.serviceInstanceListSupplierProvider.getIfAvailable(NoopServiceInstanceListSupplier::new); return ((Flux) supplier.get()).next().map(list -> processInstanceResponse((List) list, headers)); } private Response processInstanceResponse(List instances, HttpHeaders headers) { if (instances.isEmpty()) { return new EmptyResponse(); } else { String reqVersion = headers.getFirst("version"); if (StringUtils.isEmpty(reqVersion)) { return processRibbonInstanceResponse(instances); } List serviceInstances = instances.stream() .filter(instance -> reqVersion.equals(instance.getMetadata().get("version"))) .collect(Collectors.toList()); if (serviceInstances.size() > 0) { return processRibbonInstanceResponse(serviceInstances); } else { return processRibbonInstanceResponse(instances); } } } private Response processRibbonInstanceResponse(List instances) { int pos = Math.abs(this.position.incrementAndGet()); ServiceInstance instance = instances.get(pos % instances.size()); return new DefaultResponse(instance); } }
过滤器加载负载均衡
public class GrayReactiveLoadBalancerClientFilter implements GlobalFilter, Ordered { private static final Log log = LogFactory.getLog(ReactiveLoadBalancerClientFilter.class); private static final int LOAD_BALANCER_CLIENT_FILTER_ORDER = 10150; private final LoadBalancerClientFactory clientFactory; private LoadBalancerProperties properties; public GrayReactiveLoadBalancerClientFilter(LoadBalancerClientFactory clientFactory, LoadBalancerProperties properties) { this.clientFactory = clientFactory; this.properties = properties; } @Override public int getOrder() { return LOAD_BALANCER_CLIENT_FILTER_ORDER; } @Override public Mono filter(ServerWebExchange exchange, GatewayFilterChain chain) { URI url = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR); String schemePrefix = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR); if (url != null && ("grayLb".equals(url.getScheme()) || "grayLb".equals(schemePrefix))) { ServerWebExchangeUtils.addOriginalRequestUrl(exchange, url); if (log.isTraceEnabled()) { log.trace(ReactiveLoadBalancerClientFilter.class.getSimpleName() + " url before: " + url); } return this.choose(exchange).doOnNext((response) -> { if (!response.hasServer()) { throw NotFoundException.create(this.properties.isUse404(), "Unable to find instance for " + url.getHost()); } else { URI uri = exchange.getRequest().getURI(); String overrideScheme = null; if (schemePrefix != null) { overrideScheme = url.getScheme(); } DelegatingServiceInstance serviceInstance = new DelegatingServiceInstance((ServiceInstance) response.getServer(), overrideScheme); URI requestUrl = this.reconstructURI(serviceInstance, uri); if (log.isTraceEnabled()) { log.trace("LoadBalancerClientFilter url chosen: " + requestUrl); } exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR, requestUrl); } }).then(chain.filter(exchange)); } else { return chain.filter(exchange); } } protected URI reconstructURI(ServiceInstance serviceInstance, URI original) { return LoadBalancerUriTools.reconstructURI(serviceInstance, original); } private Mono choose(ServerWebExchange exchange) { URI uri = (URI) exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR); VersionGrayLoadBalancer loadBalancer = new VersionGrayLoadBalancer(clientFactory.getLazyProvider(uri.getHost(), ServiceInstanceListSupplier.class), uri.getHost()); if (loadBalancer == null) { throw new NotFoundException("No loadbalancer available for " + uri.getHost()); } else { return loadBalancer.choose(this.createRequest(exchange)); } } private Request createRequest(ServerWebExchange exchange) { HttpHeaders headers = exchange.getRequest().getHeaders(); Request request = new DefaultRequest(headers); return request; } }
注入过滤器
@Configuration public class GrayGatewayReactiveLoadBalancerClientAutoConfiguration { @Bean @ConditionalOnMissingBean({GrayReactiveLoadBalancerClientFilter.class}) public GrayReactiveLoadBalancerClientFilter grayReactiveLoadBalancerClientFilter(LoadBalancerClientFactory clientFactory, LoadBalancerProperties properties) { return new GrayReactiveLoadBalancerClientFilter(clientFactory, properties); } }
发布灰度服务
生产环境配置文件 application-prod.yml
server: port: 9002 spring: application: name: provider cloud: nacos: config: server-addr: 127.0.0.1:8848 discovery: metadata: version: prod server-addr: 127.0.0.1:8848
灰度环境配置文件 application-gray.yml
server: port: 9003 spring: application: name: provider cloud: nacos: config: server-addr: 127.0.0.1:8848 discovery: metadata: version: gray server-addr: 127.0.0.1:8848
idea 启动参数指定配置文件
同时注意配置两个环境的 nacos 文件（prod version: 4，gray version: 5）
测试
然后分别启动三个服务：9000 端口网关 gateway 服务，9002 端口生产环境 provider-prod 服务，9003 端口灰度环境 provider-gray 服务
E:\Nacos\nacos>curl http://127.0.0.1:9000/provider/test/port port=9003, version=5 E:\Nacos\nacos>curl -X GET -H "version:prod" http://127.0.0.1:9000/provider/test/port port=9003, version=5 E:\Nacos\nacos>curl -X GET -H "version:gray" http://127.0.0.1:9000/provider/test/port port=9002, version=4
仓库地址
如果对于文章中代码有疑问，可以直接查看下方作者仓库
仓库地址：ReturnTmp/spring-gateway-demo: 网关配置 + 灰度发布 + 配置中心 示例仓库 (github.com)[1]
The End