006-spring cloud gateway-GatewayAutoConfiguration核心配置-GatewayProperties初始化加载Route初始化加载

Posted 2021-01-12 木子旭

006-spring cloud gateway-GatewayAutoConfiguration核心配置-GatewayProperties初始化加载、Route初始化加载

一、GatewayProperties

1.1、在GatewayAutoConfiguration中加载

　　在Spring-Cloud-Gateway初始化时，同时GatewayAutoConfiguration核心配置类会被初始化加载如下 ：

NettyConfiguration 底层通信netty配置
GlobalFilter （AdaptCachedBodyGlobalFilter，RouteToRequestUrlFilter，ForwardRoutingFilter，ForwardPathFilter，WebsocketRoutingFilter，WeightCalculatorWebFilter等）
FilteringWebHandler
GatewayProperties
PrefixPathGatewayFilterFactory
RoutePredicateFactory
RouteDefinitionLocator
RouteLocator
RoutePredicateHandlerMapping 查找匹配到 Route并进行处理
GatewayWebfluxEndpoint 管理网关的 HTTP API

　　其中在GatewayAutoConfiguration配置加载中含初始化加载GatewayProperties实例的配置：

查看GatewayAutoConfiguration源码：

    @Bean
    public GatewayProperties gatewayProperties() {
        return new GatewayProperties();
    }

1.2、再次查看GatewayProperties源码：

@ConfigurationProperties("spring.cloud.gateway")
@Validated
public class GatewayProperties {
    @NotNull
    @Valid
    private List<RouteDefinition> routes = new ArrayList();
    private List<FilterDefinition> defaultFilters = new ArrayList();
    private List<MediaType> streamingMediaTypes;

    public GatewayProperties() {
        this.streamingMediaTypes = Arrays.asList(MediaType.TEXT_EVENT_STREAM, MediaType.APPLICATION_STREAM_JSON);
    }

    public List<RouteDefinition> getRoutes() {
        return this.routes;
    }

    public void setRoutes(List<RouteDefinition> routes) {
        this.routes = routes;
    }

    public List<FilterDefinition> getDefaultFilters() {
        return this.defaultFilters;
    }

    public void setDefaultFilters(List<FilterDefinition> defaultFilters) {
        this.defaultFilters = defaultFilters;
    }

    public List<MediaType> getStreamingMediaTypes() {
        return this.streamingMediaTypes;
    }

    public void setStreamingMediaTypes(List<MediaType> streamingMediaTypes) {
        this.streamingMediaTypes = streamingMediaTypes;
    }

    public String toString() {
        return "GatewayProperties{routes=" + this.routes + ", defaultFilters=" + this.defaultFilters + ", streamingMediaTypes=" + this.streamingMediaTypes + \'}\';
    }
}

以上会被默认加载并且读取配置信息，如下配置信息：

• spring.cloud.gateway.routes:网关路由定义配置，列表形式
• spring.cloud.gateway.default-filters: 网关默认过滤器定义配置，列表形式
• spring.cloud.gateway.streamingMediaTypes:网关网络媒体类型，列表形式

其中routes是RouteDefinition集合，defaultFilters是FilterDefinition集合，参看具体的配置字段。实际配置文件可如下：

spring:
  cloud:
    gateway:
      default-filters:
      - PrefixPath=/httpbin
      - AddResponseHeader=X-Response-Default-Foo, Default-Bar
      routes:
      - id: websocket_test
        uri: ws://localhost:9000
        order: 9000
        predicates:
        - Path=/echo
      - id: default_path_to_httpbin
        uri: ${test.uri}
        order: 10000
        predicates:
        - Path=/**

注意：default-filters的配置PrefixPath=/httpbin字符串，可以查看FilterDefinition的构造函数，它其中构造函数包含接收一个text字符串解析字符传并创建实例信息。predicates的配置也是如此。

字符传格式：name=param1,param2,param3

    public FilterDefinition(String text) {
        int eqIdx = text.indexOf("=");
        if (eqIdx <= 0) {
            this.setName(text);
        } else {
            this.setName(text.substring(0, eqIdx));
            String[] args = StringUtils.tokenizeToStringArray(text.substring(eqIdx + 1), ",");

            for(int i = 0; i < args.length; ++i) {
                this.args.put(NameUtils.generateName(i), args[i]);
            }

        }
    }

二、Route初始化加载

2.1、GatewayAutoConfiguration加载RouteLocator

　　Spring-Cloud-Gateway路由信息是通过路由定位器RouteLocator加载以及初始化。

　　在Spring-Cloud-Gateway初始化时，同时GatewayAutoConfiguration核心配置类会被初始化加载如下 ：

    /**
     * 创建一个根据RouteDefinition转换的路由定位器
     */
    @Bean
    public RouteLocator routeDefinitionRouteLocator(GatewayProperties properties,
                                                   List<GatewayFilterFactory> GatewayFilters,
                                                   List<RoutePredicateFactory> predicates,
                                                   RouteDefinitionLocator routeDefinitionLocator) {
        return new RouteDefinitionRouteLocator(routeDefinitionLocator, predicates, GatewayFilters, properties);
    }

    /**
     * 创建一个缓存路由的路由定位器
     * @param routeLocators
     * @return
     */
    @Bean
    @Primary//在相同的bean中，优先使用用@Primary注解的bean.
    public RouteLocator cachedCompositeRouteLocator(List<RouteLocator> routeLocators) {
        
        //1.创建组合路由定位器，根据(容器)已有的路由定位器集合
        //2.创建缓存功能的路由定位器
        return new CachingRouteLocator(new CompositeRouteLocator(Flux.fromIterable(routeLocators)));
    }

路由定位器的创建流程：

1、RouteDefinitionRouteLocator
2、CompositeRouteLocator
3、CachingRouteLocator
其中 RouteDefinitionRouteLocator 是获取路由的主要地方，CompositeRouteLocator，CachingRouteLocator对路由定位器做了附加功能的包装，最终使用的是CachingRouteLocator对外提供服务

2.2、查看RouteLocator源码：

/**
 * 路由定位器，服务获取路由信息
 * 可以通过 RouteDefinitionRouteLocator 获取 RouteDefinition ，并转换成 Route
 */
public interface RouteLocator {

    /**
     * 获取路由
     */
    Flux<Route> getRoutes();
}

查看RouteLocator实现类

缓存功能实现→CachingRouteLocator

组合功能实现→CompositeRouteLocator

通过路由定义转换路由实现→RouteDefinitionRouteLocator

2.3、缓存功能实现→CachingRouteLocator

// 路由定位器的包装类，实现了路由的本地缓存功能
public class CachingRouteLocator implements RouteLocator {
    //目标路由定位器
    private final RouteLocator delegate;

    /**
     * 路由信息
     * Flux 相当于一个 RxJava Observable，
     * 能够发出 0~N 个数据项，然后（可选地）completing 或 erroring。处理多个数据项作为stream
     */
    private final Flux<Route> routes;

    // 本地缓存，用于缓存路由定位器获取的路由集合
    private final Map<String, List> cache = new HashMap<>();
    public CachingRouteLocator(RouteLocator delegate) {
        this.delegate = delegate;
        routes = CacheFlux.lookup(cache, "routes", Route.class)
                .onCacheMissResume(() -> this.delegate.getRoutes().sort(AnnotationAwareOrderComparator.INSTANCE));
    }
    @Override
    public Flux<Route> getRoutes() {
        return this.routes;
    }

    // 刷新缓存
    public Flux<Route> refresh() {
        this.cache.clear();
        return this.routes;
    }

    @EventListener(RefreshRoutesEvent.class)
    void handleRefresh() {
        refresh();
    }
}

1、路由信息的本地缓存，通过Map<String, List> cache 缓存路由到内存中；
2、此类通过@EventListener(RefreshRoutesEvent.class)监听RefreshRoutesEvent事件实现了对缓存的动态刷新；

注：路由动态刷新，使用GatewayControllerEndpoint发布刷新事件

@RestControllerEndpoint(id = "gateway")
public class GatewayControllerEndpoint implements ApplicationEventPublisherAware{
    // 调用url= /gateway/refresh 刷新缓存中的路由信息
        @PostMapping("/refresh")
    public Mono<Void> refresh() {
        this.publisher.publishEvent(new RefreshRoutesEvent(this));
        return Mono.empty();
    }
}

2.4、组合功能实现→CompositeRouteLocator

//组合多个 RRouteLocator 的实现，为Route提供统一获取入口
public class CompositeRouteLocator implements RouteLocator {

    /**
     * 能够发出 0~N 个数据项(RouteLocator)，然后（可选地）completing 或 erroring。处理多个数据项作为stream
     */
    private final Flux<RouteLocator> delegates;

    public CompositeRouteLocator(Flux<RouteLocator> delegates) {
        this.delegates = delegates;
    }

    @Override
    public Flux<Route> getRoutes() {
        //this.delegates.flatMap((routeLocator)-> routeLocator.getRoutes());
        return this.delegates.flatMap(RouteLocator::getRoutes);
    }
}

此类将遍历传入的目录路由定位器集合，组合每个路由定位器获取到的路由信息

2.5、通过路由定义转换路由实现→RouteDefinitionRouteLocator

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.springframework.cloud.gateway.route;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.stream.Collectors;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.gateway.config.GatewayProperties;
import org.springframework.cloud.gateway.event.FilterArgsEvent;
import org.springframework.cloud.gateway.event.PredicateArgsEvent;
import org.springframework.cloud.gateway.filter.FilterDefinition;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.OrderedGatewayFilter;
import org.springframework.cloud.gateway.filter.factory.GatewayFilterFactory;
import org.springframework.cloud.gateway.handler.AsyncPredicate;
import org.springframework.cloud.gateway.handler.predicate.PredicateDefinition;
import org.springframework.cloud.gateway.handler.predicate.RoutePredicateFactory;
import org.springframework.cloud.gateway.route.Route.AsyncBuilder;
import org.springframework.cloud.gateway.support.ConfigurationUtils;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.AnnotationAwareOrderComparator;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.validation.Validator;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Flux;

public class RouteDefinitionRouteLocator implements RouteLocator, BeanFactoryAware, ApplicationEventPublisherAware {
    protected final Log logger = LogFactory.getLog(this.getClass());
    private final RouteDefinitionLocator routeDefinitionLocator;
    private final Map<String, RoutePredicateFactory> predicates = new LinkedHashMap();
    private final Map<String, GatewayFilterFactory> gatewayFilterFactories = new HashMap();
    private final GatewayProperties gatewayProperties;
    private final SpelExpressionParser parser = new SpelExpressionParser();
    private BeanFactory beanFactory;
    private ApplicationEventPublisher publisher;
    @Autowired
    private Validator validator;

    public RouteDefinitionRouteLocator(RouteDefinitionLocator routeDefinitionLocator, List<RoutePredicateFactory> predicates, List<GatewayFilterFactory> gatewayFilterFactories, GatewayProperties gatewayProperties) {
        this.routeDefinitionLocator = routeDefinitionLocator;
        this.initFactories(predicates);
        gatewayFilterFactories.forEach((factory) -> {
            GatewayFilterFactory var10000 = (GatewayFilterFactory)this.gatewayFilterFactories.put(factory.name(), factory);
        });
        this.gatewayProperties = gatewayProperties;
    }

    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        this.beanFactory = beanFactory;
    }

    public void setApplicationEventPublisher(ApplicationEventPublisher publisher) {
        this.publisher = publisher;
    }

    private void initFactories(List<RoutePredicateFactory> predicates) {
        predicates.forEach((factory) -> {
            String key = factory.name();
            if (this.predicates.containsKey(key)) {
                this.logger.warn("A RoutePredicateFactory named " + key + " already exists, class: " + this.predicates.get(key) + ". It will be overwritten.");
            }

            this.predicates.put(key, factory);
            if (this.logger.isInfoEnabled()) {
                this.logger.info("Loaded RoutePredicateFactory [" + key + "]");
            }

        });
    }

    public Flux<Route> getRoutes() {
        return this.routeDefinitionLocator.getRouteDefinitions().map(this::convertToRoute).map((route) -> {
            if (this.logger.isDebugEnabled()) {
                this.logger.debug("RouteDefinition matched: " + route.getId());
            }

            return route;
        });
    }

    private Route convertToRoute(RouteDefinition routeDefinition) {
        AsyncPredicate<ServerWebExchange> predicate = this.combinePredicates(routeDefinition);
        List<GatewayFilter> gatewayFilters = this.getFilters(routeDefinition);
        return ((AsyncBuilder)Route.async(routeDefinition).asyncPredicate(predicate).replaceFilters(gatewayFilters)).build();
    }

    private List<GatewayFilter> loadGatewayFilters(String id, List<FilterDefinition> filterDefinitions) {
        List<GatewayFilter> filters = (List)filterDefinitions.stream().map((definition) -> {
            GatewayFilterFactory factory = (GatewayFilterFactory)this.gatewayFilterFactories.get(definition.getName());
            if (factory == null) {
                throw new IllegalArgumentException("Unable to find GatewayFilterFactory with name " + definition.getName());
            } else {
                Map<String, String> args = definition.getArgs();
                if (this.logger.isDebugEnabled()) {
                    this.logger.debug("RouteDefinition " + id + " applying filter " + args + " to " + definition.getName());
                }

                Map<String, Object> properties = factory.shortcutType().normalize(args, factory, this.parser, this.beanFactory);
                Object configuration = factory.newConfig();
                ConfigurationUtils.bind(configuration, properties, factory.shortcutFieldPrefix(), definition.getName(), this.validator);
                GatewayFilter gatewayFilter = factory.apply(configuration);
                if (this.publisher != null) {
                    this.publisher.publishEvent(new FilterArgsEvent(this, id, properties));
                }

                return gatewayFilter;
            }
        }).collect(Collectors.toList());
        ArrayList<GatewayFilter> ordered = new ArrayList(filters.size());

        for(int i = 0; i < filters.size(); ++i) {
            GatewayFilter gatewayFilter = (GatewayFilter)filters.get(i);
            if (gatewayFilter instanceof Ordered) {
                ordered.add(gatewayFilter);
            } else {
                ordered.add(new OrderedGatewayFilter(gatewayFilter, i + 1));
            }
        }

        return ordered;
    }

    private List<GatewayFilter> getFilters(RouteDefinition routeDefinition) {
        List<GatewayFilter> filters = new ArrayList();
        if (!this.gatewayProperties.getDefaultFilters().isEmpty()) {
            filters.addAll(this.loadGatewayFilters("defaultFilters", this.gatewayProperties.getDefaultFilters()));
        }

        if (!routeDefinition.getFilters().isEmpty()) {
            filters.addAll(this.loadGatewayFilters(routeDefinition.getId(), routeDefinition.getFilters()));
        }

        AnnotationAwareOrderComparator.sort(filters);
        return filters;
    }

    private AsyncPredicate<ServerWebExchange> combinePredicates(RouteDefinition routeDefinition) {
        List<PredicateDefinition> predicates = routeDefinition.getPredicates();
        AsyncPredicate<ServerWebExchange> predicate = this.lookup(routeDefinition, (PredicateDefinition)predicates.get(0));

        AsyncPredicate found;
        for(Iterator var4 = predicates.subList(1, predicates.size()).iterator(); var4.hasNext(); predicate = predicate.and(found)) {
            PredicateDefinition andPredicate = (PredicateDefinition)var4.next();
            found = this.lookup(routeDefinition, andPredicate);
        }

        return predicate;
    }

    private AsyncPredicate<ServerWebExchange> lookup(RouteDefinition route, PredicateDefinition predicate) {
        RoutePredicateFactory<Object> factory = (RoutePredicateFactory)this.predicates.get(predicate.getName());
        if (factory == null) {
            throw new IllegalArgumentException("Unable to find RoutePredicateFactory with name " + predicate.getName());
        } else {
            Map<String, String> args = predicate.getArgs();
            if (this.logger.isDebugEnabled()) {
                this.logger.debug("RouteDefinition " + route.getId() + " applying " + args + " to " + predicate.getName());
            }

            Map<String, Object> properties = factory.shortcutType().normalize(args, factory, this.parser, this.beanFactory);
            Object config = factory.newConfig();
            ConfigurationUtils.bind(config, properties, factory.shortcutFieldPrefix(), predicate.getName(), this.validator);
            if (this.publisher != null) {
                this.publisher.publishEvent(new PredicateArgsEvent(this, route.getId(), properties));
            }

            return factory.applyAsync(config);
        }
    }
}

View Code

此类的核心方法getRoutes通过传入的routeDefinitionLocator获取路由定位，并循环遍历路由定位依次转换成路由返回，
代码中可以看到getRoutes通过convertToRoute方法将路由定位转换成路由的

2.5.1、RouteDefinition转换:convertToRoute

    // RouteDefinition 转换为对应的Route
    private Route convertToRoute(RouteDefinition routeDefinition) {
        //获取routeDefinition中的Predicate信息
        Predicate<ServerWebExchange> predicate = combinePredicates(routeDefinition);
        //获取routeDefinition中的GatewayFilter信息
        List<GatewayFilter> gatewayFilters = getFilters(routeDefinition);
        //构建路由信息
        return Route.builder(routeDefinition)
                .predicate(predicate)
                .replaceFilters(gatewayFilters)
                .build();
    }

convertToRoute方法功能作用
　　获取routeDefinition中的Predicate信息 （通过combinePredicates方法）
　　获取routeDefinition中的GatewayFilter信息（通过gatewayFilters方法）
　　构建路由信息

1、convertToRoute中combinePredicates获取routeDefinition中的Predicate信息如下：

    // 返回组合的谓词
    private Predicate<ServerWebExchange> combinePredicates(RouteDefinition routeDefinition) {
        //获取RouteDefinition中的PredicateDefinition集合
        List<PredicateDefinition> predicates = routeDefinition.getPredicates();

        Predicate<ServerWebExchange> predicate = lookup(routeDefinition, predicates.get(0));

        for (PredicateDefinition andPredicate : predicates.subList(1, predicates.size())) {
            Predicate<ServerWebExchange> found = lookup(routeDefinition, andPredicate);
             //流程4
            //返回一个组合的谓词，表示该谓词与另一个谓词的短路逻辑AND
            predicate = predicate.and(found);
        }

        return predicate;
    }

    /**
     * 获取一个谓语定义（PredicateDefinition）转换的谓语
     * @param route
     * @param predicate
     * @return
     */
    @SuppressWarnings("unchecked")
    private Predicate<ServerWebExchange> lookup(RouteDefinition route, PredicateDefinition predicate) {
        //流程1
        //流程1==获取谓语创建工厂
        RoutePredicateFactory<Object> factory = this.predicates.get(predicate.getName());
        if (factory == null) {
            throw new IllegalArgumentException("Unable to find RoutePredicateFactory with name " + predicate.getName());
        }
        //流程2
        //获取参数
        Map<String, String> args = predicate.getArgs();
        if (logger.isDebugEnabled()) {
            logger.debug("RouteDefinition " + route.getId() + " applying "
                    + args + " to " + predicate.getName());
        }

        //组装参数
        Map<String, Object> properties = factory.shortcutType().normalize(args, factory, this.parser, this.beanFactory);
        //构建创建谓语的配置信息
        Object config = factory.newConfig();
        ConfigurationUtils.bind(config, properties,
                factory.shortcutFieldPrefix(), predicate.getName(), validator);
        if (this.publisher != null) {
            this.publisher.publishEvent(new PredicateArgsEvent(this, route.getId(), properties));
        }
        //流程3
        //通过谓语工厂构建谓语
        return factory.apply(config);
    }

获取Predicate流程:

• 根据PredicateDefinition name 获取 RoutePredicateFactory
• 根据PredicateDefinition args 组装 config信息
• 通过RoutePredicateFactory 根据config信息创建Predicate信息
• 多个Predicate 以短路逻辑AND组合

2、convertToRoute中 getFilters获取routeDefinition中的GatewayFilter信息

private List<GatewayFilter> getFilters(RouteDefinition routeDefinition) {
        List<GatewayFilter> filters = new ArrayList<>();

        //校验gatewayProperties是否含义默认的过滤器集合
        if (!this.gatewayProperties.getDefaultFilters().isEmpty()) {
            //加载全局配置的默认过滤器集合
            filters.addAll(loadGatewayFilters("defaultFilters",
                    this.gatewayProperties.getDefaultFilters()));
        }

        if (!routeDefinition.getFilters().isEmpty()) {
            //加载路由定义中的过滤器集合
            filters.addAll(loadGatewayFilters(routeDefinition.getId(), routeDefinition.getFilters()));
        }

        //排序
        AnnotationAwareOrderComparator.sort(filters);
        return filters;
    }
     /**
     * 加载过滤器，根据过滤器的定义加载
     * @param id
     * @param filterDefinitions
     * @return
     */
    @SuppressWarnings("unchecked")
    private List<GatewayFilter> loadGatewayFilters(String id, List<FilterDefinition> filterDefinitions) {
        //遍历过滤器定义，将过滤器定义转换成对应的过滤器
        List<GatewayFilter> filters = filterDefinitions.stream()
                .map(definition -> {
                
                   //流程1    //通过过滤器定义名称获取过滤器创建工厂
                    GatewayFilterFactory factory = this.gatewayFilterFactories.get(definition.getName());
                    if (factory == null) {
                        throw new IllegalArgumentException("Unable to find GatewayFilterFactory with name " + definition.getName());
                    }
                    //流程2
                    //获取参数
                    Map<String, String> args = definition.getArgs();
                    if (logger.isDebugEnabled()) {
                        logger.debug("RouteDefinition " + id + " applying filter " + args + " to " + definition.getName());
                    }

                    //根据args组装配置信息
                    Map<String, Object> properties = factory.shortcutType().normalize(args, factory, this.parser, this.beanFactory);
                    //构建过滤器创建配置信息
                    Object configuration = factory.newConfig();
                    ConfigurationUtils.bind(configuration, properties,
                            factory.shortcutFieldPrefix(), definition.getName(), validator);

//流程3
                    //通过过滤器工厂创建GatewayFilter
                    GatewayFilter gatewayFilter = factory.apply(configuration);
                    if (this.publisher != null) {
                        //发布事件
                        this.publisher.publishEvent(new FilterArgsEvent(this, id, properties));
                    }
                    return gatewayFilter;
                })
                .collect(Collectors.toList());

        ArrayList<GatewayFilter> ordered = new ArrayList<>(filters.size());
        //包装过滤器使其所有过滤器继承Ordered属性，可进行排序
        for (int i = 0; i < filters.size(); i++) {
            GatewayFilter gatewayFilter = filters.get(i);
            if (gatewayFilter instanceof Ordered) {
                ordered.add(gatewayFilter);
            }
            else {
                ordered.add(new OrderedGatewayFilter(gatewayFilter, i + 1));
            }
        }

        return ordered;
    }

• getFilters 方法 同时加载 全局配置 gatewayProperties与routeDefinition配置下的所有过滤器定义filterDefinitions
• loadGatewayFilters 负责将filterDefinition转化成对应的GatewayFilter
  转化流程如下

1. 根据filterDefinition name 获取 GatewayFilterFactory
2. 根据filterDefinition args 组装 config信息
3. 通过GatewayFilterFactory 根据config信息创建PGatewayFilter信息