前言

熟悉 Spring Cloud Gateway 的人都知道 Gateway 提供了鉴权、路由等功能,本篇我们重点分析的是 Gateway 的动态路由功能。

Gateway Actuator API 方法源码解析

Spring Cloud Gateway 的 Actuator 端点允许监视 Spring Cloud Gateway 应用程序并与之交互,Gateway 依赖中默认包含了路由端点操作,我们引入 spring-boot-starter-actuator。

Gateway 端点开启方式如下:

management.endpoint.gateway.enabled=true
management.endpoints.web.exposure.include=gateway

我们在 IDEA 中按住 Ctrl,用鼠标点击 enable 就可以看 Gateway 端点的源码,如下:

在这里插入图片描述

GatewayControllerEndpoint 源码解析

GatewayControllerEndpoint 主要提供了三个方法,作用如下:

  • routesdef():获取路由定义信息。
  • routes():获取网关已经加载的所有路由信息。
  • route(@PathVariable String id):根据路由 id 获取路由信息。
@RestControllerEndpoint(
    id = "gateway"
)
public class GatewayControllerEndpoint extends AbstractGatewayControllerEndpoint {
    public GatewayControllerEndpoint(List<GlobalFilter> globalFilters, List<GatewayFilterFactory> gatewayFilters, List<RoutePredicateFactory> routePredicates, RouteDefinitionWriter routeDefinitionWriter, RouteLocator routeLocator, RouteDefinitionLocator routeDefinitionLocator) {
        super(routeDefinitionLocator, globalFilters, gatewayFilters, routePredicates, routeDefinitionWriter, routeLocator);
    }
	
	//获取路由定义信息
    @GetMapping({"/routedefinitions"})
    public Flux<RouteDefinition> routesdef() {
        return this.routeDefinitionLocator.getRouteDefinitions();
    }
	
	//获取网关已经加载的所有路由信息
    @GetMapping({"/routes"})
    public Flux<Map<String, Object>> routes() {
        return this.routeLocator.getRoutes().map(this::serialize);
    }

    Map<String, Object> serialize(Route route) {
        HashMap<String, Object> r = new HashMap();
        r.put("route_id", route.getId());
        r.put("uri", route.getUri().toString());
        r.put("order", route.getOrder());
        r.put("predicate", route.getPredicate().toString());
        if (!CollectionUtils.isEmpty(route.getMetadata())) {
            r.put("metadata", route.getMetadata());
        }

        ArrayList<String> filters = new ArrayList();

        for(int i = 0; i < route.getFilters().size(); ++i) {
            GatewayFilter gatewayFilter = (GatewayFilter)route.getFilters().get(i);
            filters.add(gatewayFilter.toString());
        }

        r.put("filters", filters);
        return r;
    }

	//根据路由id 获取路由信息
    @GetMapping({"/routes/{id}"})
    public Mono<ResponseEntity<Map<String, Object>>> route(@PathVariable String id) {
        return this.routeLocator.getRoutes().filter((route) -> {
            return route.getId().equals(id);
        }).singleOrEmpty().map(this::serialize).map(ResponseEntity::ok).switchIfEmpty(Mono.just(ResponseEntity.notFound().build()));
    }
}

获取路由信息接口演示如下:

在这里插入图片描述

AbstractGatewayControllerEndpoint 源码解析

AbstractGatewayControllerEndpoint 主要提供了一下功能:

  • refresh():刷新路由。
  • refresh():获取全局过滤器。
  • refresh():获取路由过滤器。
  • refresh():获取断言工厂。
  • refresh():保存路由信息。
  • refresh():删除路由信息。
  • refresh():根据路由id 获取组合过滤器。
public class AbstractGatewayControllerEndpoint implements ApplicationEventPublisherAware {
    private static final Log log = LogFactory.getLog(GatewayControllerEndpoint.class);
    protected RouteDefinitionLocator routeDefinitionLocator;
    protected List<GlobalFilter> globalFilters;
    protected List<GatewayFilterFactory> GatewayFilters;
    protected List<RoutePredicateFactory> routePredicates;
    protected RouteDefinitionWriter routeDefinitionWriter;
    protected RouteLocator routeLocator;
    protected ApplicationEventPublisher publisher;

    public AbstractGatewayControllerEndpoint(RouteDefinitionLocator routeDefinitionLocator, List<GlobalFilter> globalFilters, List<GatewayFilterFactory> gatewayFilters, List<RoutePredicateFactory> routePredicates, RouteDefinitionWriter routeDefinitionWriter, RouteLocator routeLocator) {
        this.routeDefinitionLocator = routeDefinitionLocator;
        this.globalFilters = globalFilters;
        this.GatewayFilters = gatewayFilters;
        this.routePredicates = routePredicates;
        this.routeDefinitionWriter = routeDefinitionWriter;
        this.routeLocator = routeLocator;
    }

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

	//刷新路由
    @PostMapping({"/refresh"})
    public Mono<Void> refresh() {
        this.publisher.publishEvent(new RefreshRoutesEvent(this));
        return Mono.empty();
    }

	//获取全局过滤器
    @GetMapping({"/globalfilters"})
    public Mono<HashMap<String, Object>> globalfilters() {
        return this.getNamesToOrders(this.globalFilters);
    }

	//获取路由过滤器
    @GetMapping({"/routefilters"})
    public Mono<HashMap<String, Object>> routefilers() {
        return this.getNamesToOrders(this.GatewayFilters);
    }

	//获取断言工厂
    @GetMapping({"/routepredicates"})
    public Mono<HashMap<String, Object>> routepredicates() {
        return this.getNamesToOrders(this.routePredicates);
    }

    private <T> Mono<HashMap<String, Object>> getNamesToOrders(List<T> list) {
        return Flux.fromIterable(list).reduce(new HashMap(), this::putItem);
    }

    private HashMap<String, Object> putItem(HashMap<String, Object> map, Object o) {
        Integer order = null;
        if (o instanceof Ordered) {
            order = ((Ordered)o).getOrder();
        }

        map.put(o.toString(), order);
        return map;
    }
	
	//保存路由信息
    @PostMapping({"/routes/{id}"})
    public Mono<ResponseEntity<Object>> save(@PathVariable String id, @RequestBody RouteDefinition route) {
        return Mono.just(route).filter(this::validateRouteDefinition).flatMap((routeDefinition) -> {
            return this.routeDefinitionWriter.save(Mono.just(routeDefinition).map((r) -> {
                r.setId(id);
                log.debug("Saving route: " + route);
                return r;
            })).then(Mono.defer(() -> {
                return Mono.just(ResponseEntity.created(URI.create("/routes/" + id)).build());
            }));
        }).switchIfEmpty(Mono.defer(() -> {
            return Mono.just(ResponseEntity.badRequest().build());
        }));
    }

    private boolean validateRouteDefinition(RouteDefinition routeDefinition) {
        boolean hasValidFilterDefinitions = routeDefinition.getFilters().stream().allMatch((filterDefinition) -> {
            return this.GatewayFilters.stream().anyMatch((gatewayFilterFactory) -> {
                return filterDefinition.getName().equals(gatewayFilterFactory.name());
            });
        });
        boolean hasValidPredicateDefinitions = routeDefinition.getPredicates().stream().allMatch((predicateDefinition) -> {
            return this.routePredicates.stream().anyMatch((routePredicate) -> {
                return predicateDefinition.getName().equals(routePredicate.name());
            });
        });
        log.debug("FilterDefinitions valid: " + hasValidFilterDefinitions);
        log.debug("PredicateDefinitions valid: " + hasValidPredicateDefinitions);
        return hasValidFilterDefinitions && hasValidPredicateDefinitions;
    }
	
	//删除路由信息
    @DeleteMapping({"/routes/{id}"})
    public Mono<ResponseEntity<Object>> delete(@PathVariable String id) {
        return this.routeDefinitionWriter.delete(Mono.just(id)).then(Mono.defer(() -> {
            return Mono.just(ResponseEntity.ok().build());
        })).onErrorResume((t) -> {
            return t instanceof NotFoundException;
        }, (t) -> {
            return Mono.just(ResponseEntity.notFound().build());
        });
    }
	
	//根据路由id 获取组合过滤器
    @GetMapping({"/routes/{id}/combinedfilters"})
    public Mono<HashMap<String, Object>> combinedfilters(@PathVariable String id) {
        return this.routeLocator.getRoutes().filter((route) -> {
            return route.getId().equals(id);
        }).reduce(new HashMap(), this::putItem);
    }
}

获取全局过滤器演示如下:

在这里插入图片描述
其他接口不在一一演示。

通过 GatewayControllerEndpoint 和 AbstractGatewayControllerEndpoint 类的源码,我们可以知道 Gateway 提供获取路由信息、过滤器、断言等接口,这里面我们重点关注了的关于路由部分的,也是源码中涉及较多的,这两个类的源码提供了路由的增删改查及刷新的接口。

AbstractGatewayControllerEndpoint#save 方法源码分析

上面我们分析到 Gateway 源码提供了完整的增删改查及刷新的接口,我们重点来分析一下 Gateway 的新增路由的接口,也就是 AbstractGatewayControllerEndpoint#save 方法,该方法主要逻辑如下:

  • 校验新增路由的入参,入参不合法直接返回失败。
  • 调用 RouteDefinitionWriter 保存路由(实际调用的是 InMemoryRouteDefinitionRepository#save 方法)。
//org.springframework.cloud.gateway.actuate.AbstractGatewayControllerEndpoint#save
@PostMapping({"/routes/{id}"})
public Mono<ResponseEntity<Object>> save(@PathVariable String id, @RequestBody RouteDefinition route) {
	//this::validateRouteDefinition 路由参数校验
	return Mono.just(route).filter(this::validateRouteDefinition).flatMap((routeDefinition) -> {
		//this.routeDefinitionWriter.save 调用routeDefinitionWriter 进行保存
		return this.routeDefinitionWriter.save(Mono.just(routeDefinition).map((r) -> {
			r.setId(id);
			log.debug("Saving route: " + route);
			return r;
		})).then(Mono.defer(() -> {
			return Mono.just(ResponseEntity.created(URI.create("/routes/" + id)).build());
		}));
	}).switchIfEmpty(Mono.defer(() -> {
		return Mono.just(ResponseEntity.badRequest().build());
	}));
}

private boolean validateRouteDefinition(RouteDefinition routeDefinition) {
	//是否有重复的过滤器
	boolean hasValidFilterDefinitions = routeDefinition.getFilters().stream().allMatch((filterDefinition) -> {
		return this.GatewayFilters.stream().anyMatch((gatewayFilterFactory) -> {
			return filterDefinition.getName().equals(gatewayFilterFactory.name());
		});
	});
	//是否有重复的断言
	boolean hasValidPredicateDefinitions = routeDefinition.getPredicates().stream().allMatch((predicateDefinition) -> {
		return this.routePredicates.stream().anyMatch((routePredicate) -> {
			return predicateDefinition.getName().equals(routePredicate.name());
		});
	});
	log.debug("FilterDefinitions valid: " + hasValidFilterDefinitions);
	log.debug("PredicateDefinitions valid: " + hasValidPredicateDefinitions);
	return hasValidFilterDefinitions && hasValidPredicateDefinitions;
}


RouteDefinitionWriter 接口源码分析

我们上面分析到保存路由调用了的 RouteDefinitionWriter 接口的方法,RouteDefinitionWriter 中定义了保存路由和删除路由的方法,上面提到的 InMemoryRouteDefinitionRepository 间接实现了 RouteDefinitionWriter 接口。


public interface RouteDefinitionWriter {
	
	//保存路由
    Mono<Void> save(Mono<RouteDefinition> route);
	
	//删除路由
    Mono<Void> delete(Mono<String> routeId);
}

InMemoryRouteDefinitionRepository#save 方法源码分析

InMemoryRouteDefinitionRepository#save 方法的逻辑很简单,就只是把路由信息存入到 Map 对象 routes 中,基于内存的操作,因此 Gateway 重启之后就会丢失。

//org.springframework.cloud.gateway.route.InMemoryRouteDefinitionRepository#save
public Mono<Void> save(Mono<RouteDefinition> route) {
	//private final Map<String, RouteDefinition> routes = Collections.synchronizedMap(new LinkedHashMap());
	return route.flatMap((r) -> {
		if (StringUtils.isEmpty(r.getId())) {
			return Mono.error(new IllegalArgumentException("id may not be empty"));
		} else {
			//存入 routes 中  本质是一个 map
			this.routes.put(r.getId(), r);
			return Mono.empty();
		}
	});
}



AbstractGatewayControllerEndpoint#refresh 方法源码分析

AbstractGatewayControllerEndpoint#refresh 路由刷新功能,逻辑很简单,使用了事件监听的机制,发布了一个路由刷新事件。


//org.springframework.cloud.gateway.actuate.AbstractGatewayControllerEndpoint#refresh
@PostMapping({"/refresh"})
public Mono<Void> refresh() {
	//发布路由刷新事件
	this.publisher.publishEvent(new RefreshRoutesEvent(this));
	return Mono.empty();
}


CachingRouteLocator#onApplicationEvent 方法源码分析

CachingRouteLocator#onApplicationEvent 方法订阅 RefreshRoutesEvent 事件,主要做了以下两件事:

  • 调用 CachingRouteLocator#fetch 方法。
  • 发布路由刷新完成事件。

//org.springframework.cloud.gateway.route.CachingRouteLocator#onApplicationEvent
public void onApplicationEvent(RefreshRoutesEvent event) {
	try {
		//调用 CachingRouteLocator#fetch 方法
		this.fetch().collect(Collectors.toList()).subscribe((list) -> {
			Flux.fromIterable(list).materialize().collect(Collectors.toList()).subscribe((signals) -> {
				//发布路由刷新完成事件
				this.applicationEventPublisher.publishEvent(new RefreshRoutesResultEvent(this));
				this.cache.put("routes", signals);
			}, (throwable) -> {
				this.handleRefreshError(throwable);
			});
		});
	} catch (Throwable var3) {
		this.handleRefreshError(var3);
	}

}

CachingRouteLocator#fetch 方法源码分析

CachingRouteLocator#fetch 方法调用了


//org.springframework.cloud.gateway.route.CachingRouteLocator#fetch
private Flux<Route> fetch() {
	return this.delegate.getRoutes().sort(AnnotationAwareOrderComparator.INSTANCE);
}

RouteDefinitionRouteLocator#getRoutes 方法源码分析

RouteDefinitionRouteLocator#getRoutes 方法主要逻辑如下:

  • 获取路由定义信息,调用 convertToRoute 方法将路由定义信息转换为路由信息 。
  • 将路由信息存入到 routes 中。
//org.springframework.cloud.gateway.route.RouteDefinitionRouteLocator#getRoutes
public Flux<Route> getRoutes() {
	//调用 convertToRoute 方法将路由定义信息转化为路由
	Flux<Route> routes = this.routeDefinitionLocator.getRouteDefinitions().map(this::convertToRoute);
	if (!this.gatewayProperties.isFailOnRouteDefinitionError()) {
		routes = routes.onErrorContinue((error, obj) -> {
			if (this.logger.isWarnEnabled()) {
				this.logger.warn("RouteDefinition id " + ((RouteDefinition)obj).getId() + " will be ignored. Definition has invalid configs, " + error.getMessage());
			}

		});
	}
	
	//路由存储 routes 中
	return routes.map((route) -> {
		if (this.logger.isDebugEnabled()) {
			this.logger.debug("RouteDefinition matched: " + route.getId());
		}

		return route;
	});
}


如有不正确的地方请各位指出纠正。

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