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本文主要研究一下spring cloud gateway的RouteLocator
RouteLocator
spring-cloud-gateway-core-2.0.0.RC2-sources.jar!/org/springframework/cloud/gateway/route/RouteLocator.java
public interface RouteLocator {
Flux<Route> getRoutes();
}
其有三个实现类:
- RouteDefinitionRouteLocator
- CompositeRouteLocator
- CachingRouteLocator
GatewayAutoConfiguration
spring-cloud-gateway-core-2.0.0.RC2-sources.jar!/org/springframework/cloud/gateway/config/GatewayAutoConfiguration.java
@Configuration
@ConditionalOnProperty(name = "spring.cloud.gateway.enabled", matchIfMissing = true)
@EnableConfigurationProperties
@AutoConfigureBefore(HttpHandlerAutoConfiguration.class)
@AutoConfigureAfter({GatewayLoadBalancerClientAutoConfiguration.class, GatewayClassPathWarningAutoConfiguration.class})
@ConditionalOnClass(DispatcherHandler.class)
public class GatewayAutoConfiguration {
//......
@Bean
public RouteLocatorBuilder routeLocatorBuilder(ConfigurableApplicationContext context) {
return new RouteLocatorBuilder(context);
}
@Bean
public RouteLocator routeDefinitionRouteLocator(GatewayProperties properties,
List<GatewayFilterFactory> GatewayFilters,
List<RoutePredicateFactory> predicates,
RouteDefinitionLocator routeDefinitionLocator) {
return new RouteDefinitionRouteLocator(routeDefinitionLocator, predicates, GatewayFilters, properties);
}
@Bean
@Primary
//TODO: property to disable composite?
public RouteLocator cachedCompositeRouteLocator(List<RouteLocator> routeLocators) {
return new CachingRouteLocator(new CompositeRouteLocator(Flux.fromIterable(routeLocators)));
}
@Bean
public RoutePredicateHandlerMapping routePredicateHandlerMapping(FilteringWebHandler webHandler,
RouteLocator routeLocator) {
return new RoutePredicateHandlerMapping(webHandler, routeLocator);
}
@Configuration
@ConditionalOnClass(Health.class)
protected static class GatewayActuatorConfiguration {
@Bean
@ConditionalOnEnabledEndpoint
public GatewayControllerEndpoint gatewayControllerEndpoint(RouteDefinitionLocator routeDefinitionLocator, List<GlobalFilter> globalFilters,
List<GatewayFilterFactory> GatewayFilters, RouteDefinitionWriter routeDefinitionWriter,
RouteLocator routeLocator) {
return new GatewayControllerEndpoint(routeDefinitionLocator, globalFilters, GatewayFilters, routeDefinitionWriter, routeLocator);
}
}
//......
}
可以看到默认创建了RouteDefinitionRouteLocator,然后又基于它创建了CompositeRouteLocator,最后由CachingRouteLocator再包装一层
RouteDefinitionRouteLocator
spring-cloud-gateway-core-2.0.0.RC2-sources.jar!/org/springframework/cloud/gateway/route/RouteDefinitionRouteLocator.java
/**
* {@link RouteLocator} that loads routes from a {@link RouteDefinitionLocator}
* @author Spencer Gibb
*/
public class RouteDefinitionRouteLocator implements RouteLocator, BeanFactoryAware, ApplicationEventPublisherAware {
protected final Log logger = LogFactory.getLog(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;
public RouteDefinitionRouteLocator(RouteDefinitionLocator routeDefinitionLocator,
List<RoutePredicateFactory> predicates,
List<GatewayFilterFactory> gatewayFilterFactories,
GatewayProperties gatewayProperties) {
this.routeDefinitionLocator = routeDefinitionLocator;
initFactories(predicates);
gatewayFilterFactories.forEach(factory -> this.gatewayFilterFactories.put(factory.name(), factory));
this.gatewayProperties = gatewayProperties;
}
@Autowired
private Validator validator;
@Override
public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
this.beanFactory = beanFactory;
}
@Override
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 (logger.isInfoEnabled()) {
logger.info("Loaded RoutePredicateFactory [" + key + "]");
}
});
}
@Override
public Flux<Route> getRoutes() {
return this.routeDefinitionLocator.getRouteDefinitions()
.map(this::convertToRoute)
//TODO: error handling
.map(route -> {
if (logger.isDebugEnabled()) {
logger.debug("RouteDefinition matched: " + route.getId());
}
return route;
});
/* TODO: trace logging
if (logger.isTraceEnabled()) {
logger.trace("RouteDefinition did not match: " + routeDefinition.getId());
}*/
}
//......
}
- 这个类名有点绕,如同注释里头说的,它是一个routeLocator,从routeDefinitionLocator获取Route信息
- 这里注入的routeDefinitionLocator是CompositeRouteDefinitionLocator,它组合了InMemoryRouteDefinitionRepository、PropertiesRouteDefinitionLocator、DiscoveryClientRouteDefinitionLocator三个RouteDefinitionLocator。
- PropertiesRouteDefinitionLocator是直接使用GatewayProperties的getRoutes()获取,其是通过spring.cloud.gateway.routes配置得来。
convertToRoute
private Route convertToRoute(RouteDefinition routeDefinition) {
Predicate<ServerWebExchange> predicate = combinePredicates(routeDefinition);
List<GatewayFilter> gatewayFilters = getFilters(routeDefinition);
return Route.builder(routeDefinition)
.predicate(predicate)
.replaceFilters(gatewayFilters)
.build();
}
RouteDefinitionRouteLocator的getRoutes方法,从routeDefinitionLocator.getRouteDefinitions(),然后使用convertToRoute方法进行转换,该方法主要用到了combinePredicates、getFilters两个方法
combinePredicates
private Predicate<ServerWebExchange> combinePredicates(RouteDefinition routeDefinition) {
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);
predicate = predicate.and(found);
}
return predicate;
}
private Predicate<ServerWebExchange> lookup(RouteDefinition route, PredicateDefinition predicate) {
RoutePredicateFactory<Object> factory = this.predicates.get(predicate.getName());
if (factory == null) {
throw new IllegalArgumentException("Unable to find RoutePredicateFactory with name " + predicate.getName());
}
Map<String, String> args = predicate.getArgs();
if (logger.isDebugEnabled()) {
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(), validator);
if (this.publisher != null) {
this.publisher.publishEvent(new PredicateArgsEvent(this, route.getId(), properties));
}
return factory.apply(config);
}
这里利用工厂方法,根据config去apply出来Predicate<ServerWebExchange>
而combinePredicates主要是对找出来的predicate进行and操作
getFilters
private List<GatewayFilter> getFilters(RouteDefinition routeDefinition) {
List<GatewayFilter> filters = new ArrayList<>();
//TODO: support option to apply defaults after route specific filters?
if (!this.gatewayProperties.getDefaultFilters().isEmpty()) {
filters.addAll(loadGatewayFilters("defaultFilters",
this.gatewayProperties.getDefaultFilters()));
}
if (!routeDefinition.getFilters().isEmpty()) {
filters.addAll(loadGatewayFilters(routeDefinition.getId(), routeDefinition.getFilters()));
}
AnnotationAwareOrderComparator.sort(filters);
return filters;
}
private List<GatewayFilter> loadGatewayFilters(String id, List<FilterDefinition> filterDefinitions) {
List<GatewayFilter> filters = filterDefinitions.stream()
.map(definition -> {
GatewayFilterFactory factory = this.gatewayFilterFactories.get(definition.getName());
if (factory == null) {
throw new IllegalArgumentException("Unable to find GatewayFilterFactory with name " + definition.getName());
}
Map<String, String> args = definition.getArgs();
if (logger.isDebugEnabled()) {
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(), 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 = filters.get(i);
if (gatewayFilter instanceof Ordered) {
ordered.add(gatewayFilter);
}
else {
ordered.add(new OrderedGatewayFilter(gatewayFilter, i + 1));
}
}
return ordered;
}
getFilters主要是利用loadGatewayFilters获取filter,返回使用AnnotationAwareOrderComparator进行排序
loadGatewayFilters也是利用工厂方法,使用GatewayFilterFactory根据config去apply出来具体的GatewayFilter实例
小结
RouteLocator接口用于获取路由信息,其有三个实现类
- RouteDefinitionRouteLocator
- CompositeRouteLocator
- CachingRouteLocator
最终使用的是CachingRouteLocator,它包装了CompositeRouteLocator,而CompositeRouteLocator则组合了RouteDefinitionRouteLocator。
RouteDefinitionRouteLocator与RouteDefinitionLocator比较容易混淆,前者是一个RouteLocator,后者是一个RouteDefinitionLocator,前者的RouteDefinitionRouteLocator主要从后者获取路由定义信息。
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