如何解析构建SpringCloudGateway网关实战及原理
今天就跟大家聊聊有关如何解析构建Spring Cloud Gateway网关实战及原理,可能很多人都不太了解,为了让大家更加了解,小编给大家总结了以下内容,希望大家根据这篇文章可以有所收获。
常山ssl适用于网站、小程序/APP、API接口等需要进行数据传输应用场景,ssl证书未来市场广阔!成为创新互联公司的ssl证书销售渠道,可以享受市场价格4-6折优惠!如果有意向欢迎电话联系或者加微信:13518219792(备注:SSL证书合作)期待与您的合作!
API 网关
API 网关出现的原因是微服务架构的出现,不同的微服务一般会有不同的网络地址,而外部客户端可能需要调用多个服务的接口才能完成一个业务需求,如果让客户端直接与各个微服务通信,会有以下的问题:
客户端会多次请求不同的微服务,增加了客户端的复杂性。
存在跨域请求,在一定场景下处理相对复杂。
认证复杂,每个服务都需要独立认证。
难以重构,随着项目的迭代,可能需要重新划分微服务。例如,可能将多个服务合并成一个或者将一个服务拆分成多个。如果客户端直接与微服务通信,那么重构将会很难实施。
某些微服务可能使用了防火墙 / 浏览器不友好的协议,直接访问会有一定的困难。
以上这些问题可以借助 API 网关解决。API 网关是介于客户端和服务器端之间的中间层,所有的外部请求都会先经过 API 网关这一层。也就是说,API 的实现方面更多的考虑业务逻辑,而安全、性能、监控可以交由 API 网关来做,这样既提高业务灵活性又不缺安全性,典型的架构图如图所示:
使用 API 网关后的优点如下:
易于监控。可以在网关收集监控数据并将其推送到外部系统进行分析。
易于认证。可以在网关上进行认证,然后再将请求转发到后端的微服务,而无须在每个微服务中进行认证。
减少了客户端与各个微服务之间的交互次数。
API 网关选型
业界的情况:
此时生产了一个spring-cloud-gateway-example的空项目包,pom.xml文件如下
4.0.0 org.springframework.boot spring-boot-starter-parent 2.1.3.RELEASE com.example spring-cloud-gateway-example 0.0.1-SNAPSHOT spring-cloud-gateway-example Demo project for Spring Boot 1.8 Greenwich.RELEASE org.springframework.cloud spring-cloud-starter-gateway org.springframework.boot spring-boot-starter-test test org.springframework.cloud spring-cloud-dependencies ${spring-cloud.version} pom import org.springframework.boot spring-boot-maven-plugin spring-milestones Spring Milestones https://repo.spring.io/milestone
2.创建一个Route实例的配置类GatewayRoutes
package com.example.springcloudgatewayexample; import org.springframework.cloud.gateway.route.RouteLocator; import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; @Configuration public class GatewayRoutes { @Bean public RouteLocator routeLocator(RouteLocatorBuilder builder) { return builder.routes() .route(r -> r.path("/java/**") .filters( f -> f.stripPrefix(1) ) .uri("http://localhost:8090/helloWorld") ) .build(); } }
当然,也可以不适用配置类,使用配置文件,如下图所示
spring: cloud: gateway: routes: - predicates: - Path=/java/** filters: - StripPrefix=1 uri: "http://localhost:8090/helloWorld"
不过,为了调试方便,我们使用配置类方式。
此时项目已经完成,足够简单吧。
3.启动此项目
>>因api网关需要转发到一个服务上,本文为http://localhost:8090/helloWorld,那需要先启动我上文
. ____ _ __ _ _ /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ \\/ ___)| |_)| | | | | || (_| | ) ) ) ) ' |____| .__|_| |_|_| |_\__, | / / / / =========|_|==============|___/=/_/_/_/ :: Spring Boot :: (v2.1.3.RELEASE) 2019-02-21 09:29:07.450 INFO 11704 --- [ main] c.e.demo.Spring5WebfluxApplication : Starting Spring5WebfluxApplication on DESKTOP-405G2C8 with PID 11704 (E:\workspaceForCloud\spring5-webflux\target\classes started by dell in E:\workspaceForCloud\spring5-webflux) 2019-02-21 09:29:07.455 INFO 11704 --- [ main] c.e.demo.Spring5WebfluxApplication : No active profile set, falling back to default profiles: default 2019-02-21 09:29:09.409 INFO 11704 --- [ main] o.s.b.web.embedded.netty.NettyWebServer : Netty started on port(s): 8090 2019-02-21 09:29:09.413 INFO 11704 --- [ main] c.e.demo.Spring5WebfluxApplication : Started Spring5WebfluxApplication in 2.304 seconds (JVM running for 7.311)
>>以spring boot方式启动spring-cloud-gateway-example项目,日志如下
2019-02-21 10:34:33.435 INFO 8580 --- [ main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.cloud.autoconfigure.ConfigurationPropertiesRebinderAutoConfiguration' of type [org.springframework.cloud.autoconfigure.ConfigurationPropertiesRebinderAutoConfiguration$$EnhancerBySpringCGLIB$$1e059320] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying) . ____ _ __ _ _ /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ \\/ ___)| |_)| | | | | || (_| | ) ) ) ) ' |____| .__|_| |_|_| |_\__, | / / / / =========|_|==============|___/=/_/_/_/ :: Spring Boot :: (v2.1.3.RELEASE) 2019-02-21 10:34:33.767 INFO 8580 --- [ main] e.s.SpringCloudGatewayExampleApplication : No active profile set, falling back to default profiles: default 2019-02-21 10:34:34.219 INFO 8580 --- [ main] o.s.cloud.context.scope.GenericScope : BeanFactory id=d98183ec-3e46-38ba-ba4c-e976a1017dce 2019-02-21 10:34:34.243 INFO 8580 --- [ main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.cloud.autoconfigure.ConfigurationPropertiesRebinderAutoConfiguration' of type [org.springframework.cloud.autoconfigure.ConfigurationPropertiesRebinderAutoConfiguration$$EnhancerBySpringCGLIB$$1e059320] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying) 2019-02-21 10:34:44.367 INFO 8580 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [After] 2019-02-21 10:34:44.367 INFO 8580 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Before] 2019-02-21 10:34:44.367 INFO 8580 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Between] 2019-02-21 10:34:44.367 INFO 8580 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Cookie] 2019-02-21 10:34:44.367 INFO 8580 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Header] 2019-02-21 10:34:44.368 INFO 8580 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Host] 2019-02-21 10:34:44.368 INFO 8580 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Method] 2019-02-21 10:34:44.368 INFO 8580 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Path] 2019-02-21 10:34:44.368 INFO 8580 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Query] 2019-02-21 10:34:44.368 INFO 8580 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [ReadBodyPredicateFactory] 2019-02-21 10:34:44.368 INFO 8580 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [RemoteAddr] 2019-02-21 10:34:44.368 INFO 8580 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Weight] 2019-02-21 10:34:44.368 INFO 8580 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [CloudFoundryRouteService] 2019-02-21 10:34:44.920 INFO 8580 --- [ main] o.s.b.web.embedded.netty.NettyWebServer : Netty started on port(s): 8080 2019-02-21 10:34:44.923 INFO 8580 --- [ main] e.s.SpringCloudGatewayExampleApplication : Started SpringCloudGatewayExampleApplication in 12.329 seconds (JVM running for 13.126)
4.测试,浏览器访问http://localhost:8080/java/helloWorld
返回hello world !
5.从上面的代码和配置及实例中,我们可以看出spring cloud gateway处理request请求的流程如下所示:
即在最前端,启动一个netty server(默认端口为8080)接受请求,然后通过Routes(每个Route由Predicate(等同于HandlerMapping)和Filter(等同于HandlerAdapter))处理后通过Netty Client发给响应的微服务。
那么在gateway本身最重要的应该是Route(Netty Server和Client已经封装好了),它由RouteLocatorBuilder构建,内部包含Predicate和Filter,
private Route(String id, URI uri, int order, AsyncPredicatepredicate, List gatewayFilters) { this.id = id; this.uri = uri; this.order = order; this.predicate = predicate; this.gatewayFilters = gatewayFilters; }
那么我们就来探讨一下这两个组件吧
5.1.Predicate
Predicte由PredicateSpec来构建,主要实现有:
以path为例
/** * A predicate that checks if the path of the request matches the given pattern * @param patterns the pattern to check the path against. * The pattern is a {@link org.springframework.util.PathMatcher} pattern * @return a {@link BooleanSpec} to be used to add logical operators */ public BooleanSpec path(String... patterns) { return asyncPredicate(getBean(PathRoutePredicateFactory.class) .applyAsync(c -> c.setPatterns(Arrays.asList(patterns)))); }
PathRoutePredicateFactory中执行
@Override public Predicateapply(Config config) { final ArrayList pathPatterns = new ArrayList<>(); synchronized (this.pathPatternParser) { pathPatternParser.setMatchOptionalTrailingSeparator( config.isMatchOptionalTrailingSeparator()); config.getPatterns().forEach(pattern -> { PathPattern pathPattern = this.pathPatternParser.parse(pattern); pathPatterns.add(pathPattern); }); } return exchange -> { PathContainer path = parsePath(exchange.getRequest().getURI().getPath()); Optional optionalPathPattern = pathPatterns.stream() .filter(pattern -> pattern.matches(path)).findFirst(); if (optionalPathPattern.isPresent()) { PathPattern pathPattern = optionalPathPattern.get(); traceMatch("Pattern", pathPattern.getPatternString(), path, true); PathMatchInfo pathMatchInfo = pathPattern.matchAndExtract(path); putUriTemplateVariables(exchange, pathMatchInfo.getUriVariables()); return true; } else { traceMatch("Pattern", config.getPatterns(), path, false); return false; } }; }
5.2.Filter
Filter分两种,一种GatewayFilter,一种GlobalFilter
5.2.1 GatewayFilter
GatewayFilter由GatewayFilterSpec构建,GatewayFilter的构建器
5.3 GlobalFilter和GatewayFilter的联系
FilteringWebHandler.GatewayFilterAdapter代理了GlobalFilter
6.总结
本文从一个spring-cloud-gateway实例入手,深入浅出的介绍了spring-cloud-gateway的组件,并从源码角度给出了实现的原理。
spring-cloud-gateway在最前端,启动一个netty server(默认端口为8080)接受请求,然后通过Routes(每个Route由Predicate(等同于HandlerMapping)和Filter(等同于HandlerAdapter))处理后通过Netty Client发给响应的微服务。
Predicate和Filter的各个实现定义了spring-cloud-gateway拥有的功能。
看完上述内容,你们对如何解析构建Spring Cloud Gateway网关实战及原理有进一步的了解吗?如果还想了解更多知识或者相关内容,请关注创新互联行业资讯频道,感谢大家的支持。
网站名称:如何解析构建SpringCloudGateway网关实战及原理
本文URL:http://scyanting.com/article/gepise.html