先开个头吧
作为偶尔点进源码的时候看到东西，或是学到，或是不解，或是惊讶，之后的一些记录。从springcloud各个组件开始吧，计划文段保持间断，只道出核心点，不过各个文段保持连续。
zuul作为spring cloud 推荐网关，搭建起来很方便。
Spring Cloud 1.4.4 core jar包里面的package基本描述了整个微服务架构的核心部分，其中zuul也囊括其中。
在使用zuul时我们会使用EnableZuulProxy注解，配合使用spring cloud。
@EnableCircuitBreaker
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Import(ZuulProxyMarkerConfiguration.class)
public @interface EnableZuulProxy {
}
@EnableCircuitBreaker 默认使用断路器 参考文档：https://martinfowler.com/bliki/CircuitBreaker.html
@Import(ZuulProxyMarkerConfiguration.class)就技巧了。
@Configuration
public class ZuulProxyMarkerConfiguration {
@Bean
public Marker zuulProxyMarkerBean() {
return new Marker();
}
class Marker {
}
}
啥都没干，就是配置了个zuulProxyMarkerBean。看字面意思就猜差不多了，这个东西可以用于标记，标记都是用来判断什么用的。
用于ZuulProxyAutoConfiguration的ConditionalOnBean，也就是使用EnableZuulProxy注解连带的开启了ZuulProxyAutoConfiguration的配置。
还有个注解 EnableZuulServer 一样有个ZuulServerMarkerConfiguration 一样的道理。
事实上EnableZuulProxy是EnableZuulServer的增强版，为什么，因为ZuulProxyAutoConfiguration继承ZuulServerAutoConfiguration。
那么zuul的配置文件里有什么呢？我觉得最重要的一个spring cloud网关要组合两个组件：一个是Ribbon，一个是hystrix，后者签名通过EnableCircuitBreaker搞进来了，后续在写。
核心关注两个类：ZuulProxyAutoConfiguration 和 ZuulServerAutoConfiguration
@Configuration
@Import({ RibbonCommandFactoryConfiguration.RestClientRibbonConfiguration.class,
RibbonCommandFactoryConfiguration.OkHttpRibbonConfiguration.class,
RibbonCommandFactoryConfiguration.HttpClientRibbonConfiguration.class,
HttpClientConfiguration.class })
@ConditionalOnBean(ZuulProxyMarkerConfiguration.Marker.class)
public class ZuulProxyAutoConfiguration extends ZuulServerAutoConfiguration {
@SuppressWarnings("rawtypes")
@Autowired(required = false)
private List<RibbonRequestCustomizer> requestCustomizers = Collections.emptyList();
@Autowired(required = false)
private Registration registration;
@Autowired
private DiscoveryClient discovery;
@Autowired
private ServiceRouteMapper serviceRouteMapper;
@Override
public HasFeatures zuulFeature() {
return HasFeatures.namedFeature("Zuul (Discovery)",
ZuulProxyAutoConfiguration.class);
}
@Bean
@ConditionalOnMissingBean(DiscoveryClientRouteLocator.class)
public DiscoveryClientRouteLocator discoveryRouteLocator() {
return new DiscoveryClientRouteLocator(this.server.getServletPrefix(),
this.discovery, this.zuulProperties, this.serviceRouteMapper, this.registration);
}
// pre filters
@Bean
public PreDecorationFilter preDecorationFilter(RouteLocator routeLocator,
ProxyRequestHelper proxyRequestHelper) {
return new PreDecorationFilter(routeLocator, this.server.getServletPrefix(),
this.zuulProperties, proxyRequestHelper);
}
// route filters
@Bean
public RibbonRoutingFilter ribbonRoutingFilter(ProxyRequestHelper helper,
RibbonCommandFactory<?> ribbonCommandFactory) {
RibbonRoutingFilter filter = new RibbonRoutingFilter(helper, ribbonCommandFactory,
this.requestCustomizers);
return filter;
}
@Bean
@ConditionalOnMissingBean({SimpleHostRoutingFilter.class, CloseableHttpClient.class})
public SimpleHostRoutingFilter simpleHostRoutingFilter(ProxyRequestHelper helper,
ZuulProperties zuulProperties,
ApacheHttpClientConnectionManagerFactory connectionManagerFactory,
ApacheHttpClientFactory httpClientFactory) {
return new SimpleHostRoutingFilter(helper, zuulProperties,
connectionManagerFactory, httpClientFactory);
}
@Bean
@ConditionalOnMissingBean({SimpleHostRoutingFilter.class})
public SimpleHostRoutingFilter simpleHostRoutingFilter2(ProxyRequestHelper helper,
ZuulProperties zuulProperties,
CloseableHttpClient httpClient) {
return new SimpleHostRoutingFilter(helper, zuulProperties,
httpClient);
}
@Bean
public ApplicationListener<ApplicationEvent> zuulDiscoveryRefreshRoutesListener() {
return new ZuulDiscoveryRefreshListener();
}
@Bean
@ConditionalOnMissingBean(ServiceRouteMapper.class)
public ServiceRouteMapper serviceRouteMapper() {
return new SimpleServiceRouteMapper();
}
@Configuration
@ConditionalOnMissingClass("org.springframework.boot.actuate.endpoint.Endpoint")
protected static class NoActuatorConfiguration {
@Bean
public ProxyRequestHelper proxyRequestHelper(ZuulProperties zuulProperties) {
ProxyRequestHelper helper = new ProxyRequestHelper();
helper.setIgnoredHeaders(zuulProperties.getIgnoredHeaders());
helper.setTraceRequestBody(zuulProperties.isTraceRequestBody());
return helper;
}
}
@Configuration
@ConditionalOnClass(Endpoint.class)
protected static class EndpointConfiguration {
@Autowired(required = false)
private TraceRepository traces;
@ConditionalOnEnabledEndpoint("routes")
@Bean
public RoutesEndpoint routesEndpoint(RouteLocator routeLocator) {
return new RoutesEndpoint(routeLocator);
}
@ConditionalOnEnabledEndpoint("routes")
@Bean
public RoutesMvcEndpoint routesMvcEndpoint(RouteLocator routeLocator,
RoutesEndpoint endpoint) {
return new RoutesMvcEndpoint(endpoint, routeLocator);
}
@ConditionalOnEnabledEndpoint("filters")
@Bean
public FiltersEndpoint filtersEndpoint() {
FilterRegistry filterRegistry = FilterRegistry.instance();
return new FiltersEndpoint(filterRegistry);
}
@Bean
public ProxyRequestHelper proxyRequestHelper(ZuulProperties zuulProperties) {
TraceProxyRequestHelper helper = new TraceProxyRequestHelper();
if (this.traces != null) {
helper.setTraces(this.traces);
}
helper.setIgnoredHeaders(zuulProperties.getIgnoredHeaders());
helper.setTraceRequestBody(zuulProperties.isTraceRequestBody());
return helper;
}
}
private static class ZuulDiscoveryRefreshListener
implements ApplicationListener<ApplicationEvent> {
private HeartbeatMonitor monitor = new HeartbeatMonitor();
@Autowired
private ZuulHandlerMapping zuulHandlerMapping;
@Override
public void onApplicationEvent(ApplicationEvent event) {
if (event instanceof InstanceRegisteredEvent) {
reset();
}
else if (event instanceof ParentHeartbeatEvent) {
ParentHeartbeatEvent e = (ParentHeartbeatEvent) event;
resetIfNeeded(e.getValue());
}
else if (event instanceof HeartbeatEvent) {
HeartbeatEvent e = (HeartbeatEvent) event;
resetIfNeeded(e.getValue());
}
}
private void resetIfNeeded(Object value) {
if (this.monitor.update(value)) {
reset();
}
}
private void reset() {
this.zuulHandlerMapping.setDirty(true);
}
}
}
@Configuration
@EnableConfigurationProperties({ ZuulProperties.class })
@ConditionalOnClass(ZuulServlet.class)
@ConditionalOnBean(ZuulServerMarkerConfiguration.Marker.class)
// Make sure to get the ServerProperties from the same place as a normal web app would
@Import(ServerPropertiesAutoConfiguration.class)
public class ZuulServerAutoConfiguration {
@Autowired
protected ZuulProperties zuulProperties;
@Autowired
protected ServerProperties server;
@Autowired(required = false)
private ErrorController errorController;
@Bean
public HasFeatures zuulFeature() {
return HasFeatures.namedFeature("Zuul (Simple)", ZuulServerAutoConfiguration.class);
}
@Bean
@Primary
public CompositeRouteLocator primaryRouteLocator(
Collection<RouteLocator> routeLocators) {
return new CompositeRouteLocator(routeLocators);
}
@Bean
@ConditionalOnMissingBean(SimpleRouteLocator.class)
public SimpleRouteLocator simpleRouteLocator() {
return new SimpleRouteLocator(this.server.getServletPrefix(),
this.zuulProperties);
}
@Bean
public ZuulController zuulController() {
return new ZuulController();
}
@Bean
public ZuulHandlerMapping zuulHandlerMapping(RouteLocator routes) {
ZuulHandlerMapping mapping = new ZuulHandlerMapping(routes, zuulController());
mapping.setErrorController(this.errorController);
return mapping;
}
@Bean
public ApplicationListener<ApplicationEvent> zuulRefreshRoutesListener() {
return new ZuulRefreshListener();
}
@Bean
@ConditionalOnMissingBean(name = "zuulServlet")
public ServletRegistrationBean zuulServlet() {
ServletRegistrationBean servlet = new ServletRegistrationBean(new ZuulServlet(),
this.zuulProperties.getServletPattern());
// The whole point of exposing this servlet is to provide a route that doesn't
// buffer requests.
servlet.addInitParameter("buffer-requests", "false");
return servlet;
}
// pre filters
@Bean
public ServletDetectionFilter servletDetectionFilter() {
return new ServletDetectionFilter();
}
@Bean
public FormBodyWrapperFilter formBodyWrapperFilter() {
return new FormBodyWrapperFilter();
}
@Bean
public DebugFilter debugFilter() {
return new DebugFilter();
}
@Bean
public Servlet30WrapperFilter servlet30WrapperFilter() {
return new Servlet30WrapperFilter();
}
// post filters
@Bean
public SendResponseFilter sendResponseFilter() {
return new SendResponseFilter();
}
@Bean
public SendErrorFilter sendErrorFilter() {
return new SendErrorFilter();
}
@Bean
public SendForwardFilter sendForwardFilter() {
return new SendForwardFilter();
}
@Bean
@ConditionalOnProperty(value = "zuul.ribbon.eager-load.enabled", matchIfMissing = false)
public ZuulRouteApplicationContextInitializer zuulRoutesApplicationContextInitiazer(
SpringClientFactory springClientFactory) {
return new ZuulRouteApplicationContextInitializer(springClientFactory,
zuulProperties);
}
@Configuration
protected static class ZuulFilterConfiguration {
@Autowired
private Map<String, ZuulFilter> filters;
@Bean
public ZuulFilterInitializer zuulFilterInitializer(
CounterFactory counterFactory, TracerFactory tracerFactory) {
FilterLoader filterLoader = FilterLoader.getInstance();
FilterRegistry filterRegistry = FilterRegistry.instance();
return new ZuulFilterInitializer(this.filters, counterFactory, tracerFactory, filterLoader, filterRegistry);
}
}
@Configuration
@ConditionalOnClass(CounterService.class)
protected static class ZuulCounterFactoryConfiguration {
@Bean
@ConditionalOnBean(CounterService.class)
public CounterFactory counterFactory(CounterService counterService) {
return new DefaultCounterFactory(counterService);
}
}
@Configuration
protected static class ZuulMetricsConfiguration {
@Bean
@ConditionalOnMissingBean(CounterFactory.class)
public CounterFactory counterFactory() {
return new EmptyCounterFactory();
}
@ConditionalOnMissingBean(TracerFactory.class)
@Bean
public TracerFactory tracerFactory() {
return new EmptyTracerFactory();
}
}
private static class ZuulRefreshListener
implements ApplicationListener<ApplicationEvent> {
@Autowired
private ZuulHandlerMapping zuulHandlerMapping;
private HeartbeatMonitor heartbeatMonitor = new HeartbeatMonitor();
@Override
public void onApplicationEvent(ApplicationEvent event) {
if (event instanceof ContextRefreshedEvent
|| event instanceof RefreshScopeRefreshedEvent
|| event instanceof RoutesRefreshedEvent) {
this.zuulHandlerMapping.setDirty(true);
}
else if (event instanceof HeartbeatEvent) {
if (this.heartbeatMonitor.update(((HeartbeatEvent) event).getValue())) {
this.zuulHandlerMapping.setDirty(true);
}
}
}
}
}