Spring-Cloud-Gateway之RouteDefinition初始化加載

RouteDefinition路由定義，Spring-Cloud-Gateway通過RouteDefinition來轉換生成具體的路由信息。RouteDefinition的信息是怎么加載初始化到網關系統中的，接下來閱讀Spring-Cloud-Gateway的RouteDefinitionLocator（路由定義信息加載器）接口，學習RouteDefinition初始化加載

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首先查看RouteDefinitionLocator源碼

/** * 路由定義信息的定位器， * 負責讀取路由配置( org.springframework.cloud.gateway.route.RouteDefinition * 子類實現類 * 1.CachingRouteDefinitionLocator -RouteDefinitionLocator包裝類， 緩存目標RouteDefinitionLocator 為routeDefinitions提供緩存功能 * 2.CompositeRouteDefinitionLocator -RouteDefinitionLocator包裝類，組合多種 RouteDefinitionLocator 的實現，為 routeDefinitions提供統一入口 * 3.PropertiesRouteDefinitionLocator-從配置文件(GatewayProperties 例如，YML / Properties 等 ) 讀取RouteDefinition * 4.DiscoveryClientRouteDefinitionLocator-從注冊中心( 例如，Eureka / Consul / Zookeeper / Etcd 等 )讀取RouteDefinition * 5.RouteDefinitionRepository-從存儲器( 例如，內存 / Redis / MySQL 等 )讀取RouteDefinition * @author Spencer Gibb */ public interface RouteDefinitionLocator { /** * 獲取RouteDefinition * @return */ Flux<RouteDefinition> getRouteDefinitions(); } 

RouteDefinitionLocator接口有且僅有一個方法getRouteDefinitions，此方法獲取RouteDefinition的核心方法，返回Flux<RouteDefinition>

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RouteDefinitionLocator 類圖如下：

graph TD RouteDefinitionLocator-->CachingRouteDefinitionLocator RouteDefinitionLocator-->CompositeRouteDefinitionLocator RouteDefinitionLocator-->PropertiesRouteDefinitionLocator RouteDefinitionLocator-->DiscoveryClientRouteDefinitionLocator RouteDefinitionLocator-->RouteDefinitionRepository 

子類功能描述：

• CachingRouteDefinitionLocator：RouteDefinitionLocator包裝類， 緩存目標RouteDefinitionLocator 為routeDefinitions提供緩存功能
• CompositeRouteDefinitionLocator -RouteDefinitionLocator包裝類，組合多種 RouteDefinitionLocator 的實現，為 routeDefinitions提供統一入口
• PropertiesRouteDefinitionLocator-從配置文件(GatewayProperties 例如，YML / Properties 等 ) 讀取RouteDefinition
• RouteDefinitionRepository-從存儲器( 例如，內存 / Redis / MySQL 等 )讀取RouteDefinition
• DiscoveryClientRouteDefinitionLocator-從注冊中心( 例如，Eureka / Consul / Zookeeper / Etcd 等

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接下來詳細看子類的源碼分析主要實現功能

• PropertiesRouteDefinitionLocator

/** * 從Properties（GatewayProperties）中加載RouteDefinition信息 * @author Spencer Gibb */ public class PropertiesRouteDefinitionLocator implements RouteDefinitionLocator { /** * 從appliccation.yml中解析前綴為spring.cloud.gateway的配置 */ private final GatewayProperties properties; public PropertiesRouteDefinitionLocator(GatewayProperties properties) { this.properties = properties; } @Override public Flux<RouteDefinition> getRouteDefinitions() { return Flux.fromIterable(this.properties.getRoutes()); } } 

PropertiesRouteDefinitionLocator很簡單從GatewayProperties實例獲取RouteDefinition信息

• GatewayProperties 在GatewayProperties初始化加載文中已詳細描述
• Flux 響應式編程

• CachingRouteDefinitionLocator

/** * RouteDefinitionLocator 包裝實現類，實現了路由定義的本地緩存功能 * @author Spencer Gibb */ public class CachingRouteDefinitionLocator implements RouteDefinitionLocator { /** * 實際路由定義定位器 */ private final RouteDefinitionLocator delegate; private final Flux<RouteDefinition> routeDefinitions; /** * 路由定義的本地緩存 */ private final Map<String, List> cache = new HashMap<>(); public CachingRouteDefinitionLocator(RouteDefinitionLocator delegate) { this.delegate = delegate; routeDefinitions = CacheFlux.lookup(cache, "routeDefs", RouteDefinition.class) .onCacheMissResume(() -> this.delegate.getRouteDefinitions()); } } 

RouteDefinitionLocator包裝類，緩存目標RouteDefinitionLocator 為routeDefinitions提供緩存功能

• DiscoveryClientRouteDefinitionLocator

public class DiscoveryClientRouteDefinitionLocator implements RouteDefinitionLocator { /** * 注冊中心客戶端 */ private final DiscoveryClient discoveryClient; /** * 本地配置信息 */ private final DiscoveryLocatorProperties properties; /** * 路由ID前綴 */ private final String routeIdPrefix; public DiscoveryClientRouteDefinitionLocator(DiscoveryClient discoveryClient, DiscoveryLocatorProperties properties) { this.discoveryClient = discoveryClient; this.properties = properties; if (StringUtils.hasText(properties.getRouteIdPrefix())) { this.routeIdPrefix = properties.getRouteIdPrefix(); } else { this.routeIdPrefix = this.discoveryClient.getClass().getSimpleName() + "_"; } } /** * 通過注冊中心查找服務組裝路由定義信息 * @return */ @Override public Flux<RouteDefinition> getRouteDefinitions() { ...代碼在根據注冊中心查找路由詳細解析 } } 

DiscoveryClientRouteDefinitionLocator通過調用 DiscoveryClient 獲取注冊在注冊中心的服務列表，生成對應的 RouteDefinition 數組

• CompositeRouteDefinitionLocator

/** * 組合多個 RouteDefinitionLocator 的實現，為 routeDefinitions提供統一入口 * @author Spencer Gibb */ public class CompositeRouteDefinitionLocator implements RouteDefinitionLocator { /** * 所有路由定義定位器實例集合 */ private final Flux<RouteDefinitionLocator> delegates; public CompositeRouteDefinitionLocator(Flux<RouteDefinitionLocator> delegates) { this.delegates = delegates; } @Override public Flux<RouteDefinition> getRouteDefinitions() { //將各個RouteDefinitionLocator的getRouteDefinitions合並返回統一的Flux<RouteDefinition> return this.delegates.flatMap(RouteDefinitionLocator::getRouteDefinitions); } } 

CompositeRouteDefinitionLocator 的主要作用就是將各個定位器合並提供統一的getRouteDefinitions方法入口

通過子類實現具體功能可以很清晰的看到定位器加載RouteDefinition整個流程

graph TD PropertiesRouteDefinitionLocator-->|配置文件加載初始化| CompositeRouteDefinitionLocator RouteDefinitionRepository-->|存儲器中加載初始化| CompositeRouteDefinitionLocator DiscoveryClientRouteDefinitionLocator-->|注冊中心加載初始化| CompositeRouteDefinitionLocator 

最終提供通過CompositeRouteDefinitionLocator提供統一的
getRouteDefinitions方法

RouteDefinitionLocator實例的初始化在GatewayAutoConfiguration中已經完成

GatewayDiscoveryClientAutoConfiguration

@Configuration @ConditionalOnProperty(name = "spring.cloud.gateway.enabled", matchIfMissing = true) @AutoConfigureBefore(GatewayAutoConfiguration.class) @ConditionalOnClass({DispatcherHandler.class, DiscoveryClient.class}) @EnableConfigurationProperties public class GatewayDiscoveryClientAutoConfiguration { //初始化注冊中心路由定義定位器 @Bean @ConditionalOnBean(DiscoveryClient.class) @ConditionalOnProperty(name = "spring.cloud.gateway.discovery.locator.enabled") public DiscoveryClientRouteDefinitionLocator discoveryClientRouteDefinitionLocator( DiscoveryClient discoveryClient, DiscoveryLocatorProperties properties) { return new DiscoveryClientRouteDefinitionLocator(discoveryClient, properties); } 

GatewayAutoConfiguration

   //初始化配置路由定義加載器 @Bean @ConditionalOnMissingBean public PropertiesRouteDefinitionLocator propertiesRouteDefinitionLocator(GatewayProperties properties) { return new PropertiesRouteDefinitionLocator(properties); } //初始化存儲路由定義加載器 @Bean @ConditionalOnMissingBean(RouteDefinitionRepository.class) public InMemoryRouteDefinitionRepository inMemoryRouteDefinitionRepository() { return new InMemoryRouteDefinitionRepository(); } //初始化聚合路由定義加載器 @Bean @Primary public RouteDefinitionLocator routeDefinitionLocator(List<RouteDefinitionLocator> routeDefinitionLocators) { return new CompositeRouteDefinitionLocator(Flux.fromIterable(routeDefinitionLocators)); } 

在Spring-Cloud-Gateway初始化完成后需要的路由定義加載器已全部實例化完成，這樣就為路由的加載創建完成了必要的條件。

 

作者：Mr_1214
鏈接：https://www.jianshu.com/p/b02c7495eb5e
來源：簡書
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