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Spring 源码解析十五:SpringCloud 的根底组件
SpringCloud
并不是只有一个我的项目,而是很多我的项目形成的生态体系总称,如
- spring-cloud-netflix: 对 https://github.com/netflix 开源组件的集成
- spring-cloud-gateway: 网关
- spring-cloud-kubernetes: 对 kubernetes 的集成
- spring-cloud-config: 分布式配置
- spring-cloud-sleuth: 分布式链路跟踪
- spring-cloud-openfeign: 服务调用
但这些我的项目都依赖一个根底我的项目 spring-cloud-commons,
spring-cloud-commons
次要有 3 个模块
spring-cloud-context
:构建一个 Bootstrap 容器,并让其成为原有的 SpringBoot 程序构建的容器的父容器,所以应用 SpringCloud 的形式与 SpringBoot 是差不多的spring-cloud-commons
:对微服务中的服务注册与发现、负载平衡、熔断器等性能提供一个形象层代码,这个形象层与具体的实现无关,这些性能能够采纳不同的技术去实现spring-cloud-loadbalancer
:一个客户端负载均衡器,相似于 Ribbon,用于替换 Ribbon(Ribbon 曾经进入保护模式)
1. spring-cloud-context
组件的加载依然是通过 Spring Factories 扩大加载机制加载的,定在 spring.factories
# 属性主动拆卸
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.cloud.autoconfigure.ConfigurationPropertiesRebinderAutoConfiguration,\
org.springframework.cloud.autoconfigure.LifecycleMvcEndpointAutoConfiguration,\
org.springframework.cloud.autoconfigure.RefreshAutoConfiguration,\
org.springframework.cloud.autoconfigure.RefreshEndpointAutoConfiguration,\
org.springframework.cloud.autoconfigure.WritableEnvironmentEndpointAutoConfiguration
# 利用监听器
org.springframework.context.ApplicationListener=\
org.springframework.cloud.bootstrap.BootstrapApplicationListener,\
org.springframework.cloud.bootstrap.LoggingSystemShutdownListener,\
org.springframework.cloud.context.restart.RestartListener
# Spring Cloud 初始化组件
org.springframework.cloud.bootstrap.BootstrapConfiguration=\
org.springframework.cloud.bootstrap.config.PropertySourceBootstrapConfiguration,\
org.springframework.cloud.bootstrap.encrypt.EncryptionBootstrapConfiguration,\
org.springframework.cloud.autoconfigure.ConfigurationPropertiesRebinderAutoConfiguration,\
org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration
# Spring Boot 初始化注册
org.springframework.boot.BootstrapRegistryInitializer=\
org.springframework.cloud.bootstrap.RefreshBootstrapRegistryInitializer,\
org.springframework.cloud.bootstrap.TextEncryptorConfigBootstrapper
# 环境后置解决
org.springframework.boot.env.EnvironmentPostProcessor=\
org.springframework.cloud.bootstrap.encrypt.DecryptEnvironmentPostProcessor,\
org.springframework.cloud.util.random.CachedRandomPropertySourceEnvironmentPostProcessor
- ConfigurationPropertiesRebinderAutoConfiguration
ConfigurationPropertiesRebinder
的主动配置拆卸 - LifecycleMvcEndpointAutoConfiguration
一些 MVC 终端组件的主动配置拆卸 - RefreshAutoConfiguration
主动拆卸spring.cloud.refresh
配置 - RefreshEndpointAutoConfiguration
一些可刷新上下文数据终端组件的主动配置拆卸 - WritableEnvironmentEndpointAutoConfiguration
WritableEnvironmentEndpoint
的主动配置拆卸 - BootstrapApplicationListener
Cloud 利用初始化 - LoggingSystemShutdownListener
日志扩大解决 - RestartListener
利用重新启动的信息记录 - PropertySourceBootstrapConfiguration
Cloud 利用初始化时的配置属性解决 - EncryptionBootstrapConfiguration
对加密传输的初始化配置 - RefreshBootstrapRegistryInitializer
向利用上下文对象ApplicationContext
增加BootstrapContext
Cloud 初始化上下文对象 - TextEncryptorConfigBootstrapper
文本加密配置初始化 - DecryptEnvironmentPostProcessor
传输中加密信息的解密解决 - CachedRandomPropertySourceEnvironmentPostProcessor
对配置中随机值属性源random.xxx
的反对
上面次要解析一下 BootstrapApplicationListener
与 PropertySourceBootstrapConfiguration
1.1. BootstrapApplicationListener
BootstrapApplicationListener
的次要性能是扩大配置文件的加载地位、增加 spring.factories
的加载组件
public class BootstrapApplicationListener implements ApplicationListener<ApplicationEnvironmentPreparedEvent>, Ordered {
@Override
public void onApplicationEvent(ApplicationEnvironmentPreparedEvent event) {
// ... 代码省略
// 初始化上下文环境
context = bootstrapServiceContext(environment, event.getSpringApplication(), configName);
// ... 代码省略
}
// 初始化上下文环境
private ConfigurableApplicationContext bootstrapServiceContext(ConfigurableEnvironment environment,
final SpringApplication application, String configName) {
// ... 代码省略
String configLocation = environment.resolvePlaceholders("${spring.cloud.bootstrap.location:}");
String configAdditionalLocation = environment
.resolvePlaceholders("${spring.cloud.bootstrap.additional-location:}");
Map<String, Object> bootstrapMap = new HashMap<>();
// 扩大 spring.cloud.bootstrap.location 配置到 spring.config.location 中
if (StringUtils.hasText(configLocation)) {bootstrapMap.put("spring.config.location", configLocation);
}
// 扩大 spring.cloud.bootstrap.additional-location 配置到 spring.config.additional-location 中
if (StringUtils.hasText(configAdditionalLocation)) {bootstrapMap.put("spring.config.additional-location", configAdditionalLocation);
}
// ... 代码省略
// 通过 BootstrapImportSelector 增加 `spring.factories` 的加载组件 `org.springframework.cloud.bootstrap.BootstrapConfiguration`
builder.sources(BootstrapImportSelectorConfiguration.class);
}
}
public class BootstrapImportSelector implements EnvironmentAware, DeferredImportSelector {
@Override
public String[] selectImports(AnnotationMetadata annotationMetadata) {
// ... 代码省略
// 通过 SpringFactoriesLoader 加载 `org.springframework.cloud.bootstrap.BootstrapConfiguration` 指定的组件
List<String> names = new ArrayList<>(SpringFactoriesLoader.loadFactoryNames(BootstrapConfiguration.class, classLoader));
// 配置中的 spring.cloud.bootstrap.sources 也当做 BootstrapConfiguration 组件加载
names.addAll(Arrays.asList(StringUtils
.commaDelimitedListToStringArray(this.environment.getProperty("spring.cloud.bootstrap.sources", ""))));
// ... 代码省略
}
}
1.2. PropertySourceBootstrapConfiguration
PropertySourceBootstrapConfiguration
的次要性能是针对 SpringCloud 的日志、Profile、配置解决
public class PropertySourceBootstrapConfiguration
implements ApplicationContextInitializer<ConfigurableApplicationContext>, Ordered {
@Override
public void initialize(ConfigurableApplicationContext applicationContext) {
// ... 代码省略
MutablePropertySources propertySources = environment.getPropertySources();
// ... 代码省略
// 加载自定义的配置加载解决,spring-cloud-config 的分布式配置性能就有赖于此
insertPropertySources(propertySources, composite);
// 解决 logging.config 指定的日志配置
String logConfig = environment.resolvePlaceholders("${logging.config:}");
LogFile logFile = LogFile.get(environment);
reinitializeLoggingSystem(environment, logConfig, logFile);
// 设置日志记录等级
setLogLevels(applicationContext, environment);
// 解决 spring.profiles.active 激活的环境
handleIncludedProfiles(environment);
}
}
1.3. @BootstrapConfiguration
这个注解是 spring-cloud-context
次要的注解,用于初始化 Spring Cloud 组件
BootstrapConfiguration
// 通过后面介绍的 `BootstrapImportSelector` 来实现主动加载在 `spring.factories` 中应用
// `org.springframework.cloud.bootstrap.BootstrapConfiguration` 配置的类
public @interface BootstrapConfiguration {}
2. spring-cloud-commons
组件的加载依然是通过 Spring Factories 扩大加载机制加载的,定在 spring.factories
# 属性主动拆卸
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.cloud.client.CommonsClientAutoConfiguration,\
org.springframework.cloud.client.ReactiveCommonsClientAutoConfiguration,\
org.springframework.cloud.client.discovery.composite.CompositeDiscoveryClientAutoConfiguration,\
org.springframework.cloud.client.discovery.composite.reactive.ReactiveCompositeDiscoveryClientAutoConfiguration,\
org.springframework.cloud.client.discovery.simple.SimpleDiscoveryClientAutoConfiguration,\
org.springframework.cloud.client.discovery.simple.reactive.SimpleReactiveDiscoveryClientAutoConfiguration,\
org.springframework.cloud.client.hypermedia.CloudHypermediaAutoConfiguration,\
org.springframework.cloud.client.loadbalancer.AsyncLoadBalancerAutoConfiguration,\
org.springframework.cloud.client.loadbalancer.LoadBalancerAutoConfiguration,\
org.springframework.cloud.client.loadbalancer.reactive.LoadBalancerBeanPostProcessorAutoConfiguration,\
org.springframework.cloud.client.loadbalancer.reactive.ReactorLoadBalancerClientAutoConfiguration,\
org.springframework.cloud.client.serviceregistry.ServiceRegistryAutoConfiguration,\
org.springframework.cloud.commons.httpclient.HttpClientConfiguration,\
org.springframework.cloud.commons.util.UtilAutoConfiguration,\
org.springframework.cloud.configuration.CompatibilityVerifierAutoConfiguration,\
org.springframework.cloud.client.serviceregistry.AutoServiceRegistrationAutoConfiguration,\
org.springframework.cloud.commons.security.ResourceServerTokenRelayAutoConfiguration
# 环境后置解决
org.springframework.boot.env.EnvironmentPostProcessor=\
org.springframework.cloud.client.HostInfoEnvironmentPostProcessor
# 谬误剖析
org.springframework.boot.diagnostics.FailureAnalyzer=\
org.springframework.cloud.configuration.CompatibilityNotMetFailureAnalyzer
- CommonsClientAutoConfiguration
DiscoveryClient
与LoadBalancerClient
的主动配置拆卸 - ReactiveCommonsClientAutoConfiguration
ReactiveDiscoveryClient
与ReactiveLoadBalancer
的主动配置拆卸 - CompositeDiscoveryClientAutoConfiguration
CompositeDiscoveryClient
的主动配置拆卸 - ReactiveCompositeDiscoveryClientAutoConfiguration
ReactiveCompositeDiscoveryClient
的主动配置拆卸 - SimpleDiscoveryClientAutoConfiguration
SimpleDiscoveryClient
的主动配置拆卸 - SimpleReactiveDiscoveryClientAutoConfiguration
SimpleReactiveDiscoveryClient
的主动配置拆卸 - CloudHypermediaAutoConfiguration
spring.cloud.hypermedia
的主动配置拆卸 - AsyncLoadBalancerAutoConfiguration
异步负载平衡的主动配置拆卸 - LoadBalancerAutoConfiguration
阻塞负载平衡的主动配置拆卸 - LoadBalancerBeanPostProcessorAutoConfiguration
负载平衡后置解决的主动配置拆卸 - ReactorLoadBalancerClientAutoConfiguration
Reactive 负载平衡的主动配置拆卸 - ServiceRegistryAutoConfiguration
注册ServiceRegistryEndpoint
- HttpClientConfiguration
Http 客户端配置 - UtilAutoConfiguration
spring.cloud.util
的主动配置拆卸 - CompatibilityVerifierAutoConfiguration
spring.cloud.compatibility-verifier
的主动配置拆卸 - AutoServiceRegistrationAutoConfiguration
spring.cloud.service-registry.auto-registration
的主动配置拆卸 - ResourceServerTokenRelayAutoConfiguration
spring.cloud.mvc.token-relay
的主动配置拆卸 - HostInfoEnvironmentPostProcessor
主动加上spring.cloud.client.hostname
与spring.cloud.client.ip-address
配置属性 - CompatibilityNotMetFailureAnalyzer
Cloud 谬误剖析解决
2.1. @EnableDiscoveryClient & @LoadBalanced
这两个注解是 spring-cloud-commons
次要的注解,@EnableDiscoveryClient
用于增加服务发现客户端,@LoadBalanced
用于标记申请是负载平衡的
EnableDiscoveryClient
// 主动实例化 `EnableDiscoveryClientImportSelector`,并载入 Spring IOC 容器
// 实例化 `@EnableDiscoveryClient` 注解的类,但不做理论注册、发现解决
@Import(EnableDiscoveryClientImportSelector.class)
public @interface EnableDiscoveryClient {}
LoadBalanced
// 没有任何解决,只是定义注解
public @interface LoadBalanced {}
@EnableDiscoveryClient
与 @LoadBalanced
都没有本质上的解决,只是定义好注解标准,留待其余组件实现
3. spring-cloud-loadbalancer
组件的加载依然是通过 Spring Factories 扩大加载机制加载的,定在 spring.factories
# 属性主动拆卸
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.cloud.loadbalancer.config.LoadBalancerAutoConfiguration,\
org.springframework.cloud.loadbalancer.config.BlockingLoadBalancerClientAutoConfiguration,\
org.springframework.cloud.loadbalancer.config.LoadBalancerCacheAutoConfiguration,\
org.springframework.cloud.loadbalancer.security.OAuth2LoadBalancerClientAutoConfiguration,\
org.springframework.cloud.loadbalancer.config.LoadBalancerStatsAutoConfiguration
- LoadBalancerAutoConfiguration
spring.cloud.loadbalancer
的主动配置拆卸 - BlockingLoadBalancerClientAutoConfiguration
阻塞负载平衡客户端的主动配置拆卸 - LoadBalancerCacheAutoConfiguration
spring.cloud.loadbalancer.cache
的主动配置拆卸 - OAuth2LoadBalancerClientAutoConfiguration
spring.cloud.oauth2.load-balanced
的主动配置拆卸 - LoadBalancerStatsAutoConfiguration
spring.cloud.loadbalancer.stats
的主动配置拆卸
这里次要解析一下 LoadBalancerAutoConfiguration
3.1. LoadBalancerAutoConfiguration
LoadBalancerAutoConfiguration
的次要性能是实现 spring.cloud.loadbalancer
的主动配置拆卸,并实例化负载平衡组件
// 继承 `LoadBalancerClients` 的注解
@LoadBalancerClients
// 主动拆卸 `spring.cloud.loadbalancer` 配置
@EnableConfigurationProperties(LoadBalancerProperties.class)
// 应用 `spring.cloud.loadbalancer.enabled` 来启动此组件
@ConditionalOnProperty(value = "spring.cloud.loadbalancer.enabled", havingValue = "true", matchIfMissing = true)
public class LoadBalancerAutoConfiguration {// ... 代码省略}
因为 LoadBalancerAutoConfiguration
继承了 LoadBalancerClients
的注解,所以来看看 LoadBalancerClients
// 主动实例化 `LoadBalancerClientConfigurationRegistrar`,并载入 Spring IOC 容器
@Import(LoadBalancerClientConfigurationRegistrar.class)
public @interface LoadBalancerClients {// ... 代码省略}
再来看看 LoadBalancerClientConfigurationRegistrar
public class LoadBalancerClientConfigurationRegistrar implements ImportBeanDefinitionRegistrar {
@Override
public void registerBeanDefinitions(AnnotationMetadata metadata, BeanDefinitionRegistry registry) {
// 获取 @LoadBalancerClients 注解
Map<String, Object> attrs = metadata.getAnnotationAttributes(LoadBalancerClients.class.getName(), true);
if (attrs != null && attrs.containsKey("value")) {
// 获取注解中 value 指定的值,并注册 bean 组件定义
AnnotationAttributes[] clients = (AnnotationAttributes[]) attrs.get("value");
for (AnnotationAttributes client : clients) {registerClientConfiguration(registry, getClientName(client), client.get("configuration"));
}
}
// ... 代码省略
// 获取 @LoadBalancerClient 注解
Map<String, Object> client = metadata.getAnnotationAttributes(LoadBalancerClient.class.getName(), true);
// 获取注解中 name/value 指定的值,并注册 bean 组件定义
String name = getClientName(client);
if (name != null) {registerClientConfiguration(registry, name, client.get("configuration"));
}
}
}
3.2. @LoadBalancerClients & @LoadBalancerClient
这两个注解是 spring-cloud-loadbalancer
次要的注解,用于增加负载平衡客户端
LoadBalancerClients
// 主动实例化 `LoadBalancerClientConfigurationRegistrar`,并载入 Spring IOC 容器
// 主动解决标记有 `@LoadBalancerClients` & `@LoadBalancerClient` 注解的类
@Import(LoadBalancerClientConfigurationRegistrar.class)
public @interface LoadBalancerClients {// ... 代码省略}
LoadBalancerClient
// 主动实例化 `LoadBalancerClientConfigurationRegistrar`,并载入 Spring IOC 容器
// 主动解决标记有 `@LoadBalancerClients` & `@LoadBalancerClient` 注解的类
@Import(LoadBalancerClientConfigurationRegistrar.class)
public @interface LoadBalancerClient {// ... 代码省略}
后续
更多博客,查看 https://github.com/senntyou/blogs
作者:深予之 (@senntyou)
版权申明:自在转载 - 非商用 - 非衍生 - 放弃署名(创意共享 3.0 许可证)