007-spring cloud gateway-GatewayAutoConfiguration核心配置-RouteDefinition初始化加载

一、RouteDefinitionLocator

　　在Spring-Cloud-Gateway的GatewayAutoConfiguration初始化加载中会加载RouteDefinitionLocator（路由定义信息加载器）信息。

//初始化配置路由定义加载器

    @Bean

    @ConditionalOnMissingBean

    public PropertiesRouteDefinitionLocator propertiesRouteDefinitionLocator(GatewayProperties properties) {

        return new PropertiesRouteDefinitionLocator(properties);

    }

    //初始化存储路由定义加载器

    @Bean

    @ConditionalOnMissingBean(RouteDefinitionRepository.class)

    public InMemoryRouteDefinitionRepository inMemoryRouteDefinitionRepository() {

        return new InMemoryRouteDefinitionRepository();

    }

     //初始化聚合路由定义加载器

    @Bean

    @Primary

    public RouteDefinitionLocator routeDefinitionLocator(List<RouteDefinitionLocator> routeDefinitionLocators) {

        return new CompositeRouteDefinitionLocator(Flux.fromIterable(routeDefinitionLocators));

    }

查看RouteDefinitionLocator源码

/**

 * 路由定义信息的定位器，

 * 负责读取路由配置( org.springframework.cloud.gateway.route.RouteDefinition

 * 子类实现类

 *  1.CachingRouteDefinitionLocator -RouteDefinitionLocator包装类， 缓存目标RouteDefinitionLocator 为routeDefinitions提供缓存功能

 *  2.CompositeRouteDefinitionLocator -RouteDefinitionLocator包装类，组合多种 RouteDefinitionLocator 的实现，为 routeDefinitions提供统一入口

 *  3.PropertiesRouteDefinitionLocator-从配置文件(GatewayProperties 例如，YML / Properties 等 ) 读取RouteDefinition

 *  4.DiscoveryClientRouteDefinitionLocator-从注册中心( 例如，Eureka / Consul / Zookeeper / Etcd 等 )读取RouteDefinition

 *  5.RouteDefinitionRepository-从存储器( 例如，内存 / Redis / MySQL 等 )读取RouteDefinition
*/ public interface RouteDefinitionLocator { /** * 获取RouteDefinition */ Flux<RouteDefinition> getRouteDefinitions(); }

RouteDefinitionLocator接口只有一个方法getRouteDefinitions，此方法获取RouteDefinition的核心方法，返回Flux<RouteDefinition>

1.1、PropertiesRouteDefinitionLocator--从配置文件读取定义定位器

// 从Properties（GatewayProperties）中加载RouteDefinition信息

public class PropertiesRouteDefinitionLocator implements RouteDefinitionLocator {

    // 从appliccation.yml中解析前缀为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());

    }

}

GatewayProperties 在GatewayProperties初始化加载，参看：
Flux 响应式编程

1.2、CachingRouteDefinitionLocator--缓存路由定义定位器

// RouteDefinitionLocator 包装实现类，实现了路由定义的本地缓存功能

public class CachingRouteDefinitionLocator implements RouteDefinitionLocator {

    //  实际路由定义定位器

    private final RouteDefinitionLocator delegate;

    private final Flux<RouteDefinition> routeDefinitions;

    // 路由定义的本地缓存

    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());

    }

}

1.3、DiscoveryClientRouteDefinitionLocator--配置中心路由定义定位器

public class DiscoveryClientRouteDefinitionLocator implements RouteDefinitionLocator {

     //* 注册中心客户端

    private final DiscoveryClient discoveryClient;

     //* 本地配置信息

    private final DiscoveryLocatorProperties properties;

     //* 路由ID前缀

    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() + "_";

        }

    }

     //* 通过注册中心查找服务组装路由定义信息

    @Override

    public Flux<RouteDefinition> getRouteDefinitions() {

     //...

    }

}

1.4、CompositeRouteDefinitionLocator--各个定位器合并提供统一的getRouteDefinitions方法入口

// 组合多个 RouteDefinitionLocator 的实现，为 routeDefinitions提供统一入口

public class CompositeRouteDefinitionLocator implements RouteDefinitionLocator {

    /**

     * 所有路由定义定位器实例集合

     */

    private final Flux<RouteDefinitionLocator> delegates;

    public CompositeRouteDefinitionLocator(Flux<RouteDefinitionLocator> delegates) {

        this.delegates = delegates;

    }

    @Override

    public Flux<RouteDefinition> getRouteDefinitions() {

        //将各个RouteDefinitionLocator的getRouteDefinitions合并返回统一的Flux<RouteDefinition>

        return this.delegates.flatMap(RouteDefinitionLocator::getRouteDefinitions);

    }

}

综合上述

最终提供通过CompositeRouteDefinitionLocator提供统一的getRouteDefinitions方法

其中GatewayDiscoveryClientAutoConfiguration如下

@Configuration

@ConditionalOnProperty(name = "spring.cloud.gateway.enabled", matchIfMissing = true)

@AutoConfigureBefore(GatewayAutoConfiguration.class)

@ConditionalOnClass({DispatcherHandler.class, DiscoveryClient.class})

@EnableConfigurationProperties

public class GatewayDiscoveryClientAutoConfiguration {

    //初始化注册中心路由定义定位器

    @Bean

    @ConditionalOnBean(DiscoveryClient.class)

    @ConditionalOnProperty(name = "spring.cloud.gateway.discovery.locator.enabled")

    public DiscoveryClientRouteDefinitionLocator discoveryClientRouteDefinitionLocator(

            DiscoveryClient discoveryClient, DiscoveryLocatorProperties properties) {

        return new DiscoveryClientRouteDefinitionLocator(discoveryClient, properties);

    }

}

巴特西