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本文主要研究一下spring cloud netflix ribbon的eager load
RibbonAutoConfiguration
spring-cloud-netflix-ribbon-2.1.1.RELEASE-sources.jar!/org/springframework/cloud/netflix/ribbon/RibbonAutoConfiguration.java
@Configuration@Conditional(RibbonAutoConfiguration.RibbonClassesConditions.class)@RibbonClients@AutoConfigureAfter(name = "org.springframework.cloud.netflix.eureka.EurekaClientAutoConfiguration")@AutoConfigureBefore({ LoadBalancerAutoConfiguration.class, AsyncLoadBalancerAutoConfiguration.class })@EnableConfigurationProperties({ RibbonEagerLoadProperties.class, ServerIntrospectorProperties.class })public class RibbonAutoConfiguration { @Autowired(required = false) private List<RibbonClientSpecification> configurations = new ArrayList<>(); @Autowired private RibbonEagerLoadProperties ribbonEagerLoadProperties; @Bean public HasFeatures ribbonFeature() { return HasFeatures.namedFeature("Ribbon", Ribbon.class); } @Bean public SpringClientFactory springClientFactory() { SpringClientFactory factory = new SpringClientFactory(); factory.setConfigurations(this.configurations); return factory; } @Bean @ConditionalOnMissingBean(LoadBalancerClient.class) public LoadBalancerClient loadBalancerClient() { return new RibbonLoadBalancerClient(springClientFactory()); } @Bean @ConditionalOnClass(name = "org.springframework.retry.support.RetryTemplate") @ConditionalOnMissingBean public LoadBalancedRetryFactory loadBalancedRetryPolicyFactory( final SpringClientFactory clientFactory) { return new RibbonLoadBalancedRetryFactory(clientFactory); } @Bean @ConditionalOnMissingBean public PropertiesFactory propertiesFactory() { return new PropertiesFactory(); } @Bean @ConditionalOnProperty("ribbon.eager-load.enabled") public RibbonApplicationContextInitializer ribbonApplicationContextInitializer() { return new RibbonApplicationContextInitializer(springClientFactory(), ribbonEagerLoadProperties.getClients()); } @Configuration @ConditionalOnClass(HttpRequest.class) @ConditionalOnRibbonRestClient protected static class RibbonClientHttpRequestFactoryConfiguration { @Autowired private SpringClientFactory springClientFactory; @Bean public RestTemplateCustomizer restTemplateCustomizer( final RibbonClientHttpRequestFactory ribbonClientHttpRequestFactory) { return restTemplate -> restTemplate .setRequestFactory(ribbonClientHttpRequestFactory); } @Bean public RibbonClientHttpRequestFactory ribbonClientHttpRequestFactory() { return new RibbonClientHttpRequestFactory(this.springClientFactory); } } // TODO: support for autoconfiguring restemplate to use apache http client or okhttp @Target({ ElementType.TYPE, ElementType.METHOD }) @Retention(RetentionPolicy.RUNTIME) @Documented @Conditional(OnRibbonRestClientCondition.class) @interface ConditionalOnRibbonRestClient { } private static class OnRibbonRestClientCondition extends AnyNestedCondition { OnRibbonRestClientCondition() { super(ConfigurationPhase.REGISTER_BEAN); } @Deprecated // remove in Edgware" @ConditionalOnProperty("ribbon.http.client.enabled") static class ZuulProperty { } @ConditionalOnProperty("ribbon.restclient.enabled") static class RibbonProperty { } } /** * {@link AllNestedConditions} that checks that either multiple classes are present. */ static class RibbonClassesConditions extends AllNestedConditions { RibbonClassesConditions() { super(ConfigurationPhase.PARSE_CONFIGURATION); } @ConditionalOnClass(IClient.class) static class IClientPresent { } @ConditionalOnClass(RestTemplate.class) static class RestTemplatePresent { } @ConditionalOnClass(AsyncRestTemplate.class) static class AsyncRestTemplatePresent { } @ConditionalOnClass(Ribbon.class) static class RibbonPresent { } }}- RibbonAutoConfiguration启用了RibbonEagerLoadProperties、ServerIntrospectorProperties两个配置，这里主要是注册了SpringClientFactory，创建LoadBalancerClient、LoadBalancedRetryFactory、RibbonApplicationContextInitializer、RestTemplateCustomizer及RibbonClientHttpRequestFactory
RibbonApplicationContextInitializer
spring-cloud-netflix-ribbon-2.1.1.RELEASE-sources.jar!/org/springframework/cloud/netflix/ribbon/RibbonApplicationContextInitializer.java
public class RibbonApplicationContextInitializer implements ApplicationListener<ApplicationReadyEvent> { private final SpringClientFactory springClientFactory; // List of Ribbon client names private final List<String> clientNames; public RibbonApplicationContextInitializer(SpringClientFactory springClientFactory, List<String> clientNames) { this.springClientFactory = springClientFactory; this.clientNames = clientNames; } protected void initialize() { if (clientNames != null) { for (String clientName : clientNames) { this.springClientFactory.getContext(clientName); } } } @Override public void onApplicationEvent(ApplicationReadyEvent event) { initialize(); }}- RibbonApplicationContextInitializer实现了ApplicationListener接口，其响应ApplicationReadyEvent事件执行initialize操作，这里主要是挨个对配置的clientNames执行springClientFactory.getContext(clientName)操作
SpringClientFactory
spring-cloud-netflix-ribbon-2.1.1.RELEASE-sources.jar!/org/springframework/cloud/netflix/ribbon/SpringClientFactory.java
public class SpringClientFactory extends NamedContextFactory<RibbonClientSpecification> { //...... protected AnnotationConfigApplicationContext getContext(String name) { return super.getContext(name); } //......}- SpringClientFactory的getContext方法调用了父类NamedContextFactory的getContext
NamedContextFactory
spring-cloud-context-2.2.0.M1-sources.jar!/org/springframework/cloud/context/named/NamedContextFactory.java
public abstract class NamedContextFactory<C extends NamedContextFactory.Specification> implements DisposableBean, ApplicationContextAware { //...... protected AnnotationConfigApplicationContext getContext(String name) { if (!this.contexts.containsKey(name)) { synchronized (this.contexts) { if (!this.contexts.containsKey(name)) { this.contexts.put(name, createContext(name)); } } } return this.contexts.get(name); } protected AnnotationConfigApplicationContext createContext(String name) { AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(); if (this.configurations.containsKey(name)) { for (Class<?> configuration : this.configurations.get(name) .getConfiguration()) { context.register(configuration); } } for (Map.Entry<String, C> entry : this.configurations.entrySet()) { if (entry.getKey().startsWith("default.")) { for (Class<?> configuration : entry.getValue().getConfiguration()) { context.register(configuration); } } } context.register(PropertyPlaceholderAutoConfiguration.class, this.defaultConfigType); context.getEnvironment().getPropertySources().addFirst(new MapPropertySource( this.propertySourceName, Collections.<String, Object>singletonMap(this.propertyName, name))); if (this.parent != null) { // Uses Environment from parent as well as beans context.setParent(this.parent); // jdk11 issue // https://github.com/spring-cloud/spring-cloud-netflix/issues/3101 context.setClassLoader(this.parent.getClassLoader()); } context.setDisplayName(generateDisplayName(name)); context.refresh(); return context; } //......} - NamedContextFactory的getContext主要是返回或者创建AnnotationConfigApplicationContext
小结
- RibbonAutoConfiguration启用了RibbonEagerLoadProperties、ServerIntrospectorProperties两个配置，这里主要是注册了SpringClientFactory，创建LoadBalancerClient、LoadBalancedRetryFactory、RibbonApplicationContextInitializer、RestTemplateCustomizer及RibbonClientHttpRequestFactory
- RibbonApplicationContextInitializer实现了ApplicationListener接口，其响应ApplicationReadyEvent事件执行initialize操作，这里主要是挨个对配置的clientNames执行springClientFactory.getContext(clientName)操作
- SpringClientFactory的getContext方法调用了父类NamedContextFactory的getContext；NamedContextFactory的getContext主要是返回或者创建AnnotationConfigApplicationContext
doc
- RibbonClientConfiguration