Spring-Cloud-Gateway原始碼分析系列| Spring-Cloud-Gateway初始化
阿新 • • 發佈：2018-12-17
推薦 Spring Boot/Cloud 視訊：
Spring-Cloud專案使用EnableAutoConfiguration註解自動 初始化配置資訊，Spring-Cloud-Gateway同樣，Spring-Cloud-Gateway下的spring.factories（在包spring-cloud-gateway-core）如下:
# Auto Configure org.springframework.boot.autoconfigure.EnableAutoConfiguration=\ //依賴包的校驗配置 org.springframework.cloud.gateway.config.GatewayClassPathWarningAutoConfiguration,\ //閘道器的核心配置 org.springframework.cloud.gateway.config.GatewayAutoConfiguration,\ //負載均衡相關依賴配置資訊 org.springframework.cloud.gateway.config.GatewayLoadBalancerClientAutoConfiguration,\ //流控的依賴配置資訊 org.springframework.cloud.gateway.config.GatewayRedisAutoConfiguration,\ //註冊中心相關的依賴配置 org.springframework.cloud.gateway.discovery.GatewayDiscoveryClientAutoConfiguration
配置功能 分析配置功能前先了解下springboot常用的註解的含義
執行順序
@AutoConfigureAfter：在指定的配置類初始化後再載入
@AutoConfigureBefore：在指定的配置類初始化前載入
@AutoConfigureOrder：數越小越先初始化
條件配置 @ConditionalOnClass ： classpath中存在該類時起效 @ConditionalOnMissingClass ： classpath中不存在該類時起效 @ConditionalOnBean ： DI容器中存在該型別Bean時起效 @ConditionalOnMissingBean ： DI容器中不存在該型別Bean時起效 @ConditionalOnSingleCandidate ： DI容器中該型別Bean只有一個或@Primary的只有一個時起效 @ConditionalOnExpression ： SpEL表示式結果為true時 @ConditionalOnProperty ： 引數設定或者值一致時起效 @ConditionalOnResource ： 指定的檔案存在時起效 @ConditionalOnJndi ： 指定的JNDI存在時起效 @ConditionalOnJava ： 指定的Java版本存在時起效 @ConditionalOnWebApplication ： Web應用環境下起效 @ConditionalOnNotWebApplication ： 非Web應用環境下起效
1.GatewayClassPathWarningAutoConfiguration配置
GatewayClassPathWarningAutoConfiguration配置用於檢查專案是否正確匯入 spring-boot-starter-webflux 依賴，而不是錯誤匯入 spring-boot-starter-web 依賴，同時 GatewayClassPathWarningAutoConfiguration配置在EnableAutoConfiguration配置載入前載入 接下來我看程式碼如何實現
@Configuration //執行順序註解 //當前註解標識需要在GatewayAutoConfiguration前載入此配置 @AutoConfigureBefore(GatewayAutoConfiguration.class) public class GatewayClassPathWarningAutoConfiguration { @Configuration //條件判斷註解 //classpath中存在org.springframework.web.servlet.DispatcherServlet時起效，標識專案匯入了spring-boot-starter-web包 @ConditionalOnClass(name = "org.springframework.web.servlet.DispatcherServlet") protected static class SpringMvcFoundOnClasspathConfiguration { public SpringMvcFoundOnClasspathConfiguration() { //當前專案匯入了spring-boot-starter-web依賴時，列印警告日誌 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 //條件判斷註解 //classpath中不存在org.springframework.web.reactive.DispatcherHandler時起效，標識專案未匯入了spring-boot-starter-webflux包 @ConditionalOnMissingClass("org.springframework.web.reactive.DispatcherHandler") protected static class WebfluxMissingFromClasspathConfiguration { public WebfluxMissingFromClasspathConfiguration() { //當前專案未匯入了boot-starter-webflux依賴時，列印警告日誌 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 路由的負載均衡攔截器
@Configuration
//條件判斷註解
//classpath中存在LoadBalancerClient和RibbonAutoConfiguration和DispatcherHandler時此配置起效
@ConditionalOnClass({LoadBalancerClient.class, RibbonAutoConfiguration.class, DispatcherHandler.class})
//執行順序註解
@AutoConfigureAfter(RibbonAutoConfiguration.class)
public class GatewayLoadBalancerClientAutoConfiguration {
// GlobalFilter beans
@Bean
//條件判斷註解
//DI容器中存在LoadBalancerClient型別Bean時起效
@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 基於 RedisRateLimiter 實現閘道器的限流功能，程式碼略
4.GatewayAutoConfiguration
GatewayAutoConfiguration配置是Spring Cloud Gateway 核心配置類，初始化如下 ：
- NettyConfiguration 底層通訊netty配置
- GlobalFilter （AdaptCachedBodyGlobalFilter，RouteToRequestUrlFilter，ForwardRoutingFilter，ForwardPathFilter，WebsocketRoutingFilter，WeightCalculatorWebFilter等）
- FilteringWebHandler
- GatewayProperties
- PrefixPathGatewayFilterFactory
- RoutePredicateFactory
- RouteDefinitionLocator
- RouteLocator
- RoutePredicateHandlerMapping 查詢匹配到 Route並進行處理
- GatewayWebfluxEndpoint 管理閘道器的 HTTP API
@Configuration
//條件註解
//通過 spring.cloud.gateway.enabled配置閘道器的開啟與關閉
//matchIfMissing = true => 閘道器預設開啟。
@ConditionalOnProperty(name = "spring.cloud.gateway.enabled", matchIfMissing = true)
@EnableConfigurationProperties
@AutoConfigureBefore(HttpHandlerAutoConfiguration.class)
@AutoConfigureAfter({GatewayLoadBalancerClientAutoConfiguration.class, GatewayClassPathWarningAutoConfiguration.class})
@ConditionalOnClass(DispatcherHandler.class)
public class GatewayAutoConfiguration {
@Configuration
//當classpath中存在HttpClient起效
@ConditionalOnClass(HttpClient.class)
protected static class NettyConfiguration {
.....略
}
//載入配置beans
// ConfigurationProperty beans
@Bean
public GatewayProperties gatewayProperties() {
return new GatewayProperties();
}
@Bean
public SecureHeadersProperties secureHeadersProperties() {
return new SecureHeadersProperties();
}
// GlobalFilter beans
//載入全域性的攔截器
@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註冊發現服務資訊
@Configuration
//同4
@ConditionalOnProperty(name = "spring.cloud.gateway.enabled", matchIfMissing = true)
@AutoConfigureBefore(GatewayAutoConfiguration.class)
@ConditionalOnClass({DispatcherHandler.class, DiscoveryClient.class})
@EnableConfigurationProperties
public class GatewayDiscoveryClientAutoConfiguration {
@Bean
//當classpath中存在DiscoveryClient起效
@ConditionalOnBean(DiscoveryClient.class)
//通過spring.cloud.gateway.discovery.locator.enabled配置註冊中心查詢的開啟與關閉
@ConditionalOnProperty(name = "spring.cloud.gateway.discovery.locator.enabled")
public DiscoveryClientRouteDefinitionLocator discoveryClientRouteDefinitionLocator(
DiscoveryClient discoveryClient, DiscoveryLocatorProperties properties) {
return new DiscoveryClientRouteDefinitionLocator(discoveryClient, properties);
}
}
通過自動載入初始化上述五個配置例項Spring-Cloud-Gateway就完成自身的資訊載入和初始化工作
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