srping cloud gateway 版本: 2.0.2

自动配置类列表spring.factories

# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.cloud.gateway.config.GatewayClassPathWarningAutoConfiguration,\
org.springframework.cloud.gateway.config.GatewayAutoConfiguration,\
org.springframework.cloud.gateway.config.GatewayLoadBalancerClientAutoConfiguration,\
org.springframework.cloud.gateway.config.GatewayMetricsAutoConfiguration,\
org.springframework.cloud.gateway.config.GatewayRedisAutoConfiguration,\
org.springframework.cloud.gateway.discovery.GatewayDiscoveryClientAutoConfiguration

• GatewayClassPathWarningAutoConfiguration
  依赖检查类
• GatewayAutoConfiguration
  主配置类
• GatewayLoadBalancerClientAutoConfiguration
  负载均衡客户端配置
• GatewayMetricsAutoConfiguration
  度量配置
• GatewayRedisAutoConfiguration
  redis配置
• GatewayDiscoveryClientAutoConfiguration
  自动发现客户端配置

GatewayClassPathWarningAutoConfiguration

这个主要是检查:

1. 如果有spring-boot-starter-web, 提示移除
2. 如果没有spring-boot-starter-webflux 提示添加

GatewayLoadBalancerClientAutoConfiguration

依赖RibbonAutoConfiguration创建的LoadBalancerClient
使用LoadBalancerClient创建了LoadBalancerClientFilter

GatewayDiscoveryClientAutoConfiguration

创建List<PredicateDefinition>: lb://+serviceId
创建List<FilterDefinition> : RewritePath '/' + serviceId + '/(?<remaining>.*)' => '/${remaining}'
创建DiscoveryLocatorProperties
创建DiscoveryClientRouteDefinitionLocator

GatewayMetricsAutoConfiguration

创建GatewayMetricsFilter过滤器

RedisAutoConfiguration

创建redisTemplate

GatewayAutoConfiguration

@Configuration
//spring.cloud.gateway.enabled 决定是否打开网关, 默认打开
@ConditionalOnProperty(name = "spring.cloud.gateway.enabled", matchIfMissing = true)
@EnableConfigurationProperties
@AutoConfigureBefore(HttpHandlerAutoConfiguration.class)
@AutoConfigureAfter({ GatewayLoadBalancerClientAutoConfiguration.class,
        GatewayClassPathWarningAutoConfiguration.class })
@ConditionalOnClass(DispatcherHandler.class)

创建NettyConfiguration

• 创建HttpClientProperties
• 创建nettyClientOptions: connectTimeout, ssl, pool, proxy
• 创建HttpClient
• 创建NettyRoutingFilter
• 创建NettyWriteResponseFilter
• 创建ReactorNettyWebSocketClient

创建HiddenHttpMethodFilter

创建RouteLocatorBuilder

创建GatewayProperties

这里从属性文件中创建路由器配置和默认过滤器配置:
List<RouteDefinition> routes ;
List<FilterDefinition> defaultFilters ;
List<MediaType> streamingMediaTypes ;

创建 PropertiesRouteDefinitionLocator

PropertiesRouteDefinitionLocator实现了RouteDefinitionLocator, 保存了从GatewayProperties获取的RouteDefinition

创建 InMemoryRouteDefinitionRepository

InMemoryRouteDefinitionRepository 实现了RouteDefinitionLocator, 保存了运行时创建的RouteDefinition

创建CompositeRouteDefinitionLocator(Primary RouteDefinitionLocator)

合并InMemoryRouteDefinitionRepository,PropertiesRouteDefinitionLocator,
DiscoveryClientRouteDefinitionLocator 及任何自定义的RouteDefinitionLocator

创建RouteLocator

    @Bean
    public RouteLocator routeDefinitionRouteLocator(GatewayProperties properties,
                                                   List<GatewayFilterFactory> GatewayFilters,
                                                   List<RoutePredicateFactory> predicates,
                                                   RouteDefinitionLocator routeDefinitionLocator) {
        return new RouteDefinitionRouteLocator(routeDefinitionLocator, predicates, GatewayFilters, properties);
    }

使用GatewayProperties+所有的GatewayFilterFactory+所有的RoutePredicateFactory + 上面创建的CompositeRouteDefinitionLocator
创建路由器列表RouteDefinitionRouteLocator

创建CachingRouteLocator (Primary RouteLocator)

使用CachingRouteLocator包装RouteDefinitionRouteLocator

创建RouteRefreshListener

监听上下文事件, 必要时刷新CachingRouteLocator的缓存

创建GlobalCorsProperties

全局跨域访问配置

创建FilteringWebHandler

过滤器处理核心类, 在这里组装过滤器链.

创建RoutePredicateHandlerMapping

请求处理核心类, 使用FilteringWebHandler+RouteLocator+GlobalCorsProperties+Environment 创建, 所有的请求处理都在这里组装.

创建SecureHeadersProperties

http头部和安全相关的配置

创建ForwardedHeadersFilter 过滤器

创建RemoveHopByHopHeadersFilter过滤器

创建XForwardedHeadersFilter过滤器

创建全局过滤器

• AdaptCachedBodyGlobalFilter
• RouteToRequestUrlFilter
• ForwardRoutingFilter
• ForwardPathFilter
• WebsocketRoutingFilter
• WeightCalculatorWebFilter

创建predicate factory

• AfterRoutePredicateFactory
• BeforeRoutePredicateFactory
• BetweenRoutePredicateFactory
• CookieRoutePredicateFactory
• HeaderRoutePredicateFactory
• HostRoutePredicateFactory
• MethodRoutePredicateFactory
• PathRoutePredicateFactory
• QueryRoutePredicateFactory
• ReadBodyPredicateFactory
• RemoteAddrRoutePredicateFactory
• WeightRoutePredicateFactory
• CloudFoundryRouteServiceRoutePredicateFactory

创建内置过滤器

• AddRequestHeaderGatewayFilterFactory
• AddRequestParameterGatewayFilterFactory
• AddResponseHeaderGatewayFilterFactory
• HystrixGatewayFilterFactory
• ModifyRequestBodyGatewayFilterFactory
• ModifyResponseBodyGatewayFilterFactory
• PrefixPathGatewayFilterFactory
• PreserveHostHeaderGatewayFilterFactory
• RedirectToGatewayFilterFactory
• RemoveRequestHeaderGatewayFilterFactory
• RemoveResponseHeaderGatewayFilterFactory
• RequestRateLimiterGatewayFilterFactory
• RewritePathGatewayFilterFactory
• RetryGatewayFilterFactory
• SetPathGatewayFilterFactory
• SecureHeadersGatewayFilterFactory
• SetRequestHeaderGatewayFilterFactory
• SetResponseHeaderGatewayFilterFactory
• SetStatusGatewayFilterFactory
• SaveSessionGatewayFilterFactory
• StripPrefixGatewayFilterFactory
• RequestHeaderToRequestUriGatewayFilterFactory

创建gatewayControllerEndpoint

总结

spring cloud gateway的创建是比较复杂的, 核心类是GatewayAutoConfiguration, 它做了以下几件事:

• 配置了Netty
• 创建GatewayProperties, 这里从属性文件中获取了路由器定义和默认过滤器定义
• 创建了属性RouteDefinitionLocator, 内存RouteDefinitionLocator和自动发现服务RouteDefinitionLocator, 并且将这三者合并为CompositeRouteDefinitionLocator
• 使用GatewayProperties+所有的GatewayFilterFactory,RoutePredicateFactory+CompositeRouteDefinitionLocator创建路由器列表RouteLocator, 这个东西包含所有.
• 创建了一批全局过滤器
• 创建过滤器处理类 FilteringWebHandler
• 创建请求处理类 RoutePredicateHandlerMapping