Spring-Cloud-Gateway源码分析系列| Spring-Cloud-Gateway初始化

扫码关注公众号:Java 技术驿站

发送:vip
将链接复制到本浏览器,永久解锁本站全部文章

【公众号:Java 技术驿站】 【加作者微信交流技术,拉技术群】

推荐 Spring Boot/Cloud 视频:

Spring-Cloud项目使用EnableAutoConfiguration注解自动
初始化配置信息,Spring-Cloud-Gateway同样,Spring-Cloud-Gateway下的spring.factories(在包spring-cloud-gateway-core)如下:

    # Auto Configure
    org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
    //依赖包的校验配置
    org.springframework.cloud.gateway.config.GatewayClassPathWarningAutoConfiguration,\
    //网关的核心配置
    org.springframework.cloud.gateway.config.GatewayAutoConfiguration,\
    //负载均衡相关依赖配置信息
    org.springframework.cloud.gateway.config.GatewayLoadBalancerClientAutoConfiguration,\
    //流控的依赖配置信息
    org.springframework.cloud.gateway.config.GatewayRedisAutoConfiguration,\
    //注册中心相关的依赖配置
    org.springframework.cloud.gateway.discovery.GatewayDiscoveryClientAutoConfiguration

配置功能
分析配置功能前先了解下springboot常用的注解的含义

    执行顺序
    @AutoConfigureAfter:在指定的配置类初始化后再加载
    @AutoConfigureBefore:在指定的配置类初始化前加载
    @AutoConfigureOrder:数越小越先初始化
    条件配置
    @ConditionalOnClass : classpath中存在该类时起效
    @ConditionalOnMissingClass : classpath中不存在该类时起效
    @ConditionalOnBean : DI容器中存在该类型Bean时起效
    @ConditionalOnMissingBean : DI容器中不存在该类型Bean时起效
    @ConditionalOnSingleCandidate : DI容器中该类型Bean只有一个或@Primary的只有一个时起效
    @ConditionalOnExpression : SpEL表达式结果为true时
    @ConditionalOnProperty : 参数设置或者值一致时起效
    @ConditionalOnResource : 指定的文件存在时起效
    @ConditionalOnJndi : 指定的JNDI存在时起效
    @ConditionalOnJava : 指定的Java版本存在时起效
    @ConditionalOnWebApplication : Web应用环境下起效
    @ConditionalOnNotWebApplication : 非Web应用环境下起效

1.GatewayClassPathWarningAutoConfiguration配置

GatewayClassPathWarningAutoConfiguration配置用于检查项目是否正确导入 spring-boot-starter-webflux 依赖,而不是错误导入 spring-boot-starter-web 依赖,同时 GatewayClassPathWarningAutoConfiguration配置在EnableAutoConfiguration配置加载前加载
接下来我看代码如何实现

    @Configuration
    //执行顺序注解
    //当前注解标识需要在GatewayAutoConfiguration前加载此配置
    @AutoConfigureBefore(GatewayAutoConfiguration.class)
    public class GatewayClassPathWarningAutoConfiguration {
        @Configuration
        //条件判断注解
        //classpath中存在org.springframework.web.servlet.DispatcherServlet时起效,标识项目导入了spring-boot-starter-web包
        @ConditionalOnClass(name = "org.springframework.web.servlet.DispatcherServlet")
        protected static class SpringMvcFoundOnClasspathConfiguration {

            public SpringMvcFoundOnClasspathConfiguration() {
               //当前项目导入了spring-boot-starter-web依赖时,打印警告日志
                log.warn(BORDER+"Spring MVC found on classpath, which is incompatible with Spring Cloud Gateway at this time. "+
                        "Please remove spring-boot-starter-web dependency."+BORDER);
            }

        }
        @Configuration
        //条件判断注解
        //classpath中不存在org.springframework.web.reactive.DispatcherHandler时起效,标识项目未导入了spring-boot-starter-webflux包
        @ConditionalOnMissingClass("org.springframework.web.reactive.DispatcherHandler")
        protected static class WebfluxMissingFromClasspathConfiguration {
            public WebfluxMissingFromClasspathConfiguration() {
          //当前项目未导入了boot-starter-webflux依赖时,打印警告日志
                log.warn(BORDER+"Spring Webflux is missing from the classpath, which is required for Spring Cloud Gateway at this time. "+
                        "Please add spring-boot-starter-webflux dependency."+BORDER);
            }

        }
    }

2.GatewayLoadBalancerClientAutoConfiguration

GatewayLoadBalancerClientAutoConfiguration配置作用是初始化 LoadBalancerClientFilter 路由的负载均衡拦截器

    @Configuration
    //条件判断注解
    //classpath中存在LoadBalancerClient和RibbonAutoConfiguration和DispatcherHandler时此配置起效
    @ConditionalOnClass({LoadBalancerClient.class, RibbonAutoConfiguration.class, DispatcherHandler.class})
    //执行顺序注解
    @AutoConfigureAfter(RibbonAutoConfiguration.class)
    public class GatewayLoadBalancerClientAutoConfiguration {
        // GlobalFilter beans
        @Bean
        //条件判断注解
        //DI容器中存在LoadBalancerClient类型Bean时起效
        @ConditionalOnBean(LoadBalancerClient.class)
        public LoadBalancerClientFilter loadBalancerClientFilter(LoadBalancerClient client) {
            return new LoadBalancerClientFilter(client);
        }
    }

3.GatewayRedisAutoConfiguration

GatewayRedisAutoConfiguration 配置作用是初始化初始化 RedisRateLimiter 限流功能的RequestRateLimiterGatewayFilterFactory 基于 RedisRateLimiter 实现网关的限流功能,代码略

4.GatewayAutoConfiguration

GatewayAutoConfiguration配置是Spring Cloud Gateway 核心配置类,初始化如下 :

  • 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
    @Configuration
    //条件注解
    //通过 spring.cloud.gateway.enabled配置网关的开启与关闭
    //matchIfMissing = true => 网关默认开启。
    @ConditionalOnProperty(name = "spring.cloud.gateway.enabled", matchIfMissing = true)
    @EnableConfigurationProperties
    @AutoConfigureBefore(HttpHandlerAutoConfiguration.class)
    @AutoConfigureAfter({GatewayLoadBalancerClientAutoConfiguration.class, GatewayClassPathWarningAutoConfiguration.class})
    @ConditionalOnClass(DispatcherHandler.class)
    public class GatewayAutoConfiguration {
        @Configuration
        //当classpath中存在HttpClient起效
        @ConditionalOnClass(HttpClient.class)
        protected static class NettyConfiguration {
            .....略
        }

        //加载配置beans
        // ConfigurationProperty beans
        @Bean
        public GatewayProperties gatewayProperties() {
            return new GatewayProperties();
        }
        @Bean
        public SecureHeadersProperties secureHeadersProperties() {
            return new SecureHeadersProperties();
        }

        // GlobalFilter beans
        //加载全局的拦截器
        @Bean
        public AdaptCachedBodyGlobalFilter adaptCachedBodyGlobalFilter() {
            return new AdaptCachedBodyGlobalFilter();
        }

        @Bean
        public RouteToRequestUrlFilter routeToRequestUrlFilter() {
            return new RouteToRequestUrlFilter();
        }

        @Bean
        @ConditionalOnBean(DispatcherHandler.class)
        public ForwardRoutingFilter forwardRoutingFilter(DispatcherHandler dispatcherHandler) {
            return new ForwardRoutingFilter(dispatcherHandler);
        }

        @Bean
        public ForwardPathFilter forwardPathFilter() {
            return new ForwardPathFilter();
        }

        @Bean
        public WebSocketService webSocketService() {
            return new HandshakeWebSocketService();
        }
        @Bean
        public WebsocketRoutingFilter websocketRoutingFilter(WebSocketClient webSocketClient,
            return new WebsocketRoutingFilter(webSocketClient, webSocketService, headersFilters);
        }
        @Bean
        public WeightCalculatorWebFilter weightCalculatorWebFilter(Validator validator) {
            return new WeightCalculatorWebFilter(validator);
        }
    }

5.GatewayDiscoveryClientAutoConfiguration

GatewayDiscoveryClientAutoConfiguration配置的作用是初始化配置路由中的注册发现服务信息

    @Configuration
    //同4
    @ConditionalOnProperty(name = "spring.cloud.gateway.enabled", matchIfMissing = true)
    @AutoConfigureBefore(GatewayAutoConfiguration.class)
    @ConditionalOnClass({DispatcherHandler.class, DiscoveryClient.class})
    @EnableConfigurationProperties
    public class GatewayDiscoveryClientAutoConfiguration {

        @Bean
        //当classpath中存在DiscoveryClient起效
        @ConditionalOnBean(DiscoveryClient.class)
        //通过spring.cloud.gateway.discovery.locator.enabled配置注册中心查找的开启与关闭
        @ConditionalOnProperty(name = "spring.cloud.gateway.discovery.locator.enabled")
        public DiscoveryClientRouteDefinitionLocator discoveryClientRouteDefinitionLocator(
                DiscoveryClient discoveryClient, DiscoveryLocatorProperties properties) {
            return new DiscoveryClientRouteDefinitionLocator(discoveryClient, properties);
        }
    }

通过自动加载初始化上述五个配置实例Spring-Cloud-Gateway就完成自身的信息加载和初始化工作

专家推荐

“随着微服务架构的发展,Spring Cloud 使用得越来越广泛。驰狼课堂 Spring Boot 快速入门,Spring Boot 与Spring Cloud 整合,docker+k8s,大型电商商城等多套免费实战教程可以帮您真正做到快速上手,将技术点切实运用到微服务项目中。” 
关注公众号,每天精彩内容,第一时间送达!

20191017100369\_1.png


来源:[]()

赞(0) 打赏
版权归原创作者所有,任何形式的转载请联系博主:daming_90:Java 技术驿站 » Spring-Cloud-Gateway源码分析系列| Spring-Cloud-Gateway初始化

评论 抢沙发

  • 昵称 (必填)
  • 邮箱 (必填)
  • 网址

觉得文章有用就打赏一下文章作者

支付宝扫一扫打赏

微信扫一扫打赏