spring-cloud-gateway動態路由

概述

線上項目發布一般有以下幾種方案:

1. 停機發布
2. 藍綠部署
3. 滾動部署
4. 灰度發布

停機發布 這種發布一般在夜里或者進行大版本升級的時候發布，因為需要停機，所以現在大家都在研究 Devops 方案。

藍綠部署 需要准備兩個相同的環境。一個環境新版本，一個環境舊版本，通過負載均衡進行切換與回滾，目的是為了減少服務停止時間。

滾動部署 就是在升級過程中，並不一下子啟動所有新版本，是先啟動一台新版本，再停止一台老版本，然后再啟動一台新版本，再停止一台老版本，直到升級完成。基於 k8s 的升級方案默認就是滾動部署。

灰度發布 也叫金絲雀發布，灰度發布中，常常按照用戶設置路由權重，例如 90%的用戶維持使用老版本，10%的用戶嘗鮮新版本。不同版本應用共存，經常與 A/B 測試一起使用，用於測試選擇多種方案。

上邊介紹的幾種發布方案，主要是引出我們接下來介紹的 spring-cloud-gateway 動態路由，我們可以基於動態路由、負載均衡和策略加載去實現 灰度發布。當然現在有很多開源的框架可以實現 灰度發布，這里只是研究學習。

動態路由

spring-cloud-gateway 默認將路由加載在內存中。具體可以參見 InMemoryRouteDefinitionRepository 類的實現。

這里我們基於 Redis 實現動態路由。基礎項目見 spring-cloud-gateway 簡介

1. 將 actuator 的端點暴露出來。

management:  endpoints:  web:  exposure:  include: "*"

2. redis 配置

@Configuration public class RedisConfig { @Bean(name = {"redisTemplate", "stringRedisTemplate"}) public StringRedisTemplate stringRedisTemplate(RedisConnectionFactory factory) { StringRedisTemplate redisTemplate = new StringRedisTemplate(); redisTemplate.setConnectionFactory(factory); return redisTemplate; } }

3. 將原內存路由持久化到 redis

@Component public class RedisRouteDefinitionRepository implements RouteDefinitionRepository { /** * hash存儲的key */ public static final String GATEWAY_ROUTES = "gateway_dynamic_route"; @Resource private StringRedisTemplate redisTemplate; /** * 獲取路由信息 * @return */ @Override public Flux<RouteDefinition> getRouteDefinitions() { List<RouteDefinition> routeDefinitions = new ArrayList<>(); redisTemplate.opsForHash().values(GATEWAY_ROUTES).stream() .forEach(routeDefinition -> routeDefinitions.add(JSON.parseObject(routeDefinition.toString(), RouteDefinition.class))); return Flux.fromIterable(routeDefinitions); } @Override public Mono<Void> save(Mono<RouteDefinition> route) { return route.flatMap(routeDefinition -> { redisTemplate.opsForHash().put(GATEWAY_ROUTES, routeDefinition.getId(), JSONObject.toJSONString(routeDefinition)); return Mono.empty(); }); } @Override public Mono<Void> delete(Mono<String> routeId) { return routeId.flatMap(id -> { if (redisTemplate.opsForHash().hasKey(GATEWAY_ROUTES, id)) { redisTemplate.opsForHash().delete(GATEWAY_ROUTES, id); return Mono.empty(); } return Mono.defer(() -> Mono.error(new NotFoundException("route definition is not found, routeId:" + routeId))); }); } }

4. 重寫動態路由服務

@Service public class GatewayDynamicRouteService implements ApplicationEventPublisherAware { @Resource private RedisRouteDefinitionRepository redisRouteDefinitionRepository; private ApplicationEventPublisher applicationEventPublisher; /** * 增加路由 * @param routeDefinition * @return */ public int add(RouteDefinition routeDefinition) { redisRouteDefinitionRepository.save(Mono.just(routeDefinition)).subscribe(); applicationEventPublisher.publishEvent(new RefreshRoutesEvent(this)); return 1; } /** * 更新 * @param routeDefinition * @return */ public int update(RouteDefinition routeDefinition) { redisRouteDefinitionRepository.delete(Mono.just(routeDefinition.getId())); redisRouteDefinitionRepository.save(Mono.just(routeDefinition)).subscribe(); applicationEventPublisher.publishEvent(new RefreshRoutesEvent(this)); return 1; } /** * 刪除 * @param id * @return */ public Mono<ResponseEntity<Object>> delete(String id) { return redisRouteDefinitionRepository.delete(Mono.just(id)).then(Mono.defer(() -> Mono.just(ResponseEntity.ok().build()))) .onErrorResume(t -> t instanceof NotFoundException, t -> Mono.just(ResponseEntity.notFound().build())); } @Override public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) { this.applicationEventPublisher = applicationEventPublisher; } }

5. 對外暴露接口

@RestController @RequestMapping("/gateway") public class GatewayDynamicRouteController { @Resource private GatewayDynamicRouteService gatewayDynamicRouteService; @PostMapping("/add") public String create(@RequestBody RouteDefinition entity) { int result = gatewayDynamicRouteService.add(entity); return String.valueOf(result); } @PostMapping("/update") public String update(@RequestBody RouteDefinition entity) { int result = gatewayDynamicRouteService.update(entity); return String.valueOf(result); } @DeleteMapping("/delete/{id}") public Mono<ResponseEntity<Object>> delete(@PathVariable String id) { return gatewayDynamicRouteService.delete(id); } }

測試

測試前刪除我們配置的靜態路由，因為靜態路由和 redis 動態路由同時存在時取並集。

1. 訪問 http://localhost:2000/actuato... , 可以看到只有默認路由。

[
    {
        "route_id": "CompositeDiscoveryClient_consul", "route_definition": { "id": "CompositeDiscoveryClient_consul", "predicates": [ { "name": "Path", "args": { "pattern": "/consul/**" } } ], "filters": [ { "name": "RewritePath", "args": { "regexp": "/consul/(?<remaining>.*)", "replacement": "/${remaining}" } } ], "uri": "lb://consul", "order": 0 }, "order": 0 }, { "route_id": "CompositeDiscoveryClient_idc-gateway", "route_definition": { "id": "CompositeDiscoveryClient_idc-gateway", "predicates": [ { "name": "Path", "args": { "pattern": "/idc-gateway/**" } } ], "filters": [ { "name": "RewritePath", "args": { "regexp": "/idc-gateway/(?<remaining>.*)", "replacement": "/${remaining}" } } ], "uri": "lb://idc-gateway", "order": 0 }, "order": 0 }, { "route_id": "CompositeDiscoveryClient_idc-provider1", "route_definition": { "id": "CompositeDiscoveryClient_idc-provider1", "predicates": [ { "name": "Path", "args": { "pattern": "/idc-provider1/**" } } ], "filters": [ { "name": "RewritePath", "args": { "regexp": "/idc-provider1/(?<remaining>.*)", "replacement": "/${remaining}" } } ], "uri": "lb://idc-provider1", "order": 0 }, "order": 0 }, { "route_id": "CompositeDiscoveryClient_idc-provider2", "route_definition": { "id": "CompositeDiscoveryClient_idc-provider2", "predicates": [ { "name": "Path", "args": { "pattern": "/idc-provider2/**" } } ], "filters": [ { "name": "RewritePath", "args": { "regexp": "/idc-provider2/(?<remaining>.*)", "replacement": "/${remaining}" } } ], "uri": "lb://idc-provider2", "order": 0 }, "order": 0 } ]

這個時候訪問 http://192.168.124.5:2000/idc... 根據結果可以推測能正確路由到 provider1， 測試結果一致。

1. 創建 provider1 路由，將路徑設置為 /p1/**，測試是否生效。

POST 請求 http://localhost:2000/gateway...

{
   "id":"provider1", "predicates":[ { "name":"Path", "args":{ "_genkey_0":"/p1/**" } }, { "name":"RemoteAddr", "args":{ "_genkey_0":"192.168.124.5/16" } } ], "filters":[ { "name":"StripPrefix", "args":{ "_genkey_0":"1" } } ], "uri":"lb://idc-provider1", "order":0 }

查看 redis 存儲，或者請求 http://localhost:2000/actuato... , 都可以看到配置成功。

訪問

curl http://localhost:2000/p1/provider1/1

結果輸出 2001，與期望一致。

由此可見動態路由已經生效。

結語

本文到此結束。感興趣的小伙伴后續可以通過加載配置文件，基於權重進行灰度。歡迎大家關注公眾號【當我遇上你】。

 轉自：https://segmentfault.com/a/1190000022264058