Spring-Cloud-Gateway源码分析系列 | Spring-Cloud-Gateway之RouteDefinition初始化加载
推荐 Spring Boot/Cloud 视频：
- Java 微服务实践 - Spring Boot
- Java 微服务实践 - Spring Cloud
RouteDefinition路由定义，Spring-Cloud-Gateway通过RouteDefinition来转换生成具体的路由信息。RouteDefinition的信息是怎么加载初始化到网关系统中的，接下来阅读Spring-Cloud-Gateway的RouteDefinitionLocator（路由定义信息加载器）接口，学习RouteDefinition初始化加载
首先查看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
* @author Spencer Gibb
*/
public interface RouteDefinitionLocator {
/**
* 获取RouteDefinition
* @return
*/
Flux getRouteDefinitions();
}
RouteDefinitionLocator接口有且仅有一个方法getRouteDefinitions，此方法获取RouteDefinition的核心方法，返回Flux
RouteDefinitionLocator 类图如下：
graph TD
RouteDefinitionLocator-->CachingRouteDefinitionLocator
RouteDefinitionLocator-->CompositeRouteDefinitionLocator
RouteDefinitionLocator-->PropertiesRouteDefinitionLocator
RouteDefinitionLocator-->DiscoveryClientRouteDefinitionLocator
RouteDefinitionLocator-->RouteDefinitionRepository
子类功能描述：
-
CachingRouteDefinitionLocator：RouteDefinitionLocator包装类， 缓存目标RouteDefinitionLocator 为routeDefinitions提供缓存功能
-
CompositeRouteDefinitionLocator -RouteDefinitionLocator包装类，组合多种 RouteDefinitionLocator 的实现，为 routeDefinitions提供统一入口
-
PropertiesRouteDefinitionLocator-从配置文件(GatewayProperties 例如，YML / Properties 等 ) 读取RouteDefinition
-
RouteDefinitionRepository-从存储器( 例如，内存 / Redis / MySQL 等 )读取RouteDefinition
-
DiscoveryClientRouteDefinitionLocator-从注册中心( 例如，Eureka / Consul / Zookeeper / Etcd 等
接下来详细看子类的源码分析主要实现功能 -
PropertiesRouteDefinitionLocator
/**
* 从Properties（GatewayProperties）中加载RouteDefinition信息
* @author Spencer Gibb
*/
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 getRouteDefinitions() {
return Flux.fromIterable(this.properties.getRoutes());
}
}
PropertiesRouteDefinitionLocator很简单从GatewayProperties实例获取RouteDefinition信息
- GatewayProperties 在GatewayProperties初始化加载文中已详细描述
- Flux 响应式编程
- CachingRouteDefinitionLocator
/**
* RouteDefinitionLocator 包装实现类，实现了路由定义的本地缓存功能
* @author Spencer Gibb
*/
public class CachingRouteDefinitionLocator implements RouteDefinitionLocator {
/**
* 实际路由定义定位器
*/
private final RouteDefinitionLocator delegate;
private final Flux routeDefinitions;
/**
* 路由定义的本地缓存
*/
private final Map cache = new HashMap<>();
public CachingRouteDefinitionLocator(RouteDefinitionLocator delegate) {
this.delegate = delegate;
routeDefinitions = CacheFlux.lookup(cache, "routeDefs", RouteDefinition.class)
.onCacheMissResume(() -> this.delegate.getRouteDefinitions());
}
}
RouteDefinitionLocator包装类，缓存目标RouteDefinitionLocator 为routeDefinitions提供缓存功能
- DiscoveryClientRouteDefinitionLocator
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
* @return
*/
@Override
public Flux getRouteDefinitions() {
...代码在根据注册中心查找路由详细解析
}
}
DiscoveryClientRouteDefinitionLocator通过调用 DiscoveryClient 获取注册在注册中心的服务列表，生成对应的 RouteDefinition 数组
- CompositeRouteDefinitionLocator
/**
* 组合多个 RouteDefinitionLocator 的实现，为 routeDefinitions提供统一入口
* @author Spencer Gibb
*/
public class CompositeRouteDefinitionLocator implements RouteDefinitionLocator {
/**
* 所有路由定义定位器实例集合
*/
private final Flux delegates;
public CompositeRouteDefinitionLocator(Flux delegates) {
this.delegates = delegates;
}
@Override
public Flux getRouteDefinitions() {
//将各个RouteDefinitionLocator的getRouteDefinitions合并返回统一的Flux
return this.delegates.flatMap(RouteDefinitionLocator::getRouteDefinitions);
}
}
CompositeRouteDefinitionLocator 的主要作用就是将各个定位器合并提供统一的getRouteDefinitions方法入口
通过子类实现具体功能可以很清晰的看到定位器加载RouteDefinition整个流程
graph TD
PropertiesRouteDefinitionLocator-->|配置文件加载初始化| CompositeRouteDefinitionLocator
RouteDefinitionRepository-->|存储器中加载初始化| CompositeRouteDefinitionLocator
DiscoveryClientRouteDefinitionLocator-->|注册中心加载初始化| CompositeRouteDefinitionLocator
最终提供通过CompositeRouteDefinitionLocator提供统一的
getRouteDefinitions方法
RouteDefinitionLocator实例的初始化在GatewayAutoConfiguration中已经完成
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);
}
GatewayAutoConfiguration
//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 routeDefinitionLocators) {
return new CompositeRouteDefinitionLocator(Flux.fromIterable(routeDefinitionLocators));
}
在Spring-Cloud-Gateway初始化完成后需要的路由定义加载器已全部实例化完成，这样就为路由的加载创建完成了必要的条件。
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