对于第1点来说,假设后端应用不能平滑无损上线,会有一定的几率出现网关路由请求到一些后端的“僵尸节点(请求路由过去的时候,应用更好在重启或者刚好停止)”,这个时候会路由会失败抛出异常,一般情况是Connection Refuse。
其实还有第3点隐藏的问题,网关如果不单单承担路由的功能,还包含了鉴权、限流等功能,如果这些功能开发的时候对异常捕获没有做完善的处理甚至是逻辑本身存在BUG,有可能导致异常没有被正常捕获处理,走了默认的异常处理器
DefaultErrorWebExceptionHandler
,默认的异常处理器的处理逻辑可能并不符合我们预期的结果。
目前最新的SpringBoot版本是2.3.8,SpringCloud版本是Hoxton.SR10
在springboot2.3之前是重写下面这个方法:
Map<String, Object> getErrorAttributes(ServerRequest request, boolean includeStackTrace)
在2.3版本之后,
Map<String, Object> getErrorAttributes(ServerRequest request, boolean includeStackTrace)
已经被标记为过时,使用
Map<String, Object> getErrorAttributes(ServerRequest request, ErrorAttributeOptions options)
取代,所以我们需要重写这个方法就可以了。
我们可以先看默认的异常处理器的配置类
ErrorWebFluxAutoConfiguration
:
@Configuration
@ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.REACTIVE)
@ConditionalOnClass(WebFluxConfigurer.class)
@AutoConfigureBefore(WebFluxAutoConfiguration.class)
@EnableConfigurationProperties({ ServerProperties.class, ResourceProperties.class })
public class ErrorWebFluxAutoConfiguration {
private final ServerProperties serverProperties;
private final ApplicationContext applicationContext;
private final ResourceProperties resourceProperties;
private final List<ViewResolver> viewResolvers;
private final ServerCodecConfigurer serverCodecConfigurer;
public ErrorWebFluxAutoConfiguration(ServerProperties serverProperties,
ResourceProperties resourceProperties,
ObjectProvider<ViewResolver> viewResolversProvider,
ServerCodecConfigurer serverCodecConfigurer,
ApplicationContext applicationContext) {
this.serverProperties = serverProperties;
this.applicationContext = applicationContext;
this.resourceProperties = resourceProperties;
this.viewResolvers = viewResolversProvider.orderedStream()
.collect(Collectors.toList());
this.serverCodecConfigurer = serverCodecConfigurer;
@Bean
@ConditionalOnMissingBean(value = ErrorWebExceptionHandler.class,
search = SearchStrategy.CURRENT)
@Order(-1)
public ErrorWebExceptionHandler errorWebExceptionHandler(
ErrorAttributes errorAttributes) {
DefaultErrorWebExceptionHandler exceptionHandler = new DefaultErrorWebExceptionHandler(
errorAttributes, this.resourceProperties,
this.serverProperties.getError(), this.applicationContext);
exceptionHandler.setViewResolvers(this.viewResolvers);
exceptionHandler.setMessageWriters(this.serverCodecConfigurer.getWriters());
exceptionHandler.setMessageReaders(this.serverCodecConfigurer.getReaders());
return exceptionHandler;
@Bean
@ConditionalOnMissingBean(value = ErrorAttributes.class,
search = SearchStrategy.CURRENT)
public DefaultErrorAttributes errorAttributes() {
return new DefaultErrorAttributes(
this.serverProperties.getError().isIncludeException());
注意到两个Bean实例ErrorWebExceptionHandler
和DefaultErrorAttributes
都使用了@ConditionalOnMissingBean
注解,也就是我们可以通过自定义实现去覆盖它们。先自定义一个CustomErrorWebFluxAutoConfiguration
(除了ErrorWebExceptionHandler
的自定义实现,其他直接拷贝ErrorWebFluxAutoConfiguration
):
@Configuration
@ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.REACTIVE)
@ConditionalOnClass(WebFluxConfigurer.class)
@AutoConfigureBefore(WebFluxAutoConfiguration.class)
@EnableConfigurationProperties({ServerProperties.class, ResourceProperties.class})
public class CustomErrorWebFluxAutoConfiguration {
private final ServerProperties serverProperties;
private final ApplicationContext applicationContext;
private final ResourceProperties resourceProperties;
private final List<ViewResolver> viewResolvers;
private final ServerCodecConfigurer serverCodecConfigurer;
public CustomErrorWebFluxAutoConfiguration(ServerProperties serverProperties,
ResourceProperties resourceProperties,
ObjectProvider<ViewResolver> viewResolversProvider,
ServerCodecConfigurer serverCodecConfigurer,
ApplicationContext applicationContext) {
this.serverProperties = serverProperties;
this.applicationContext = applicationContext;
this.resourceProperties = resourceProperties;
this.viewResolvers = viewResolversProvider.orderedStream()
.collect(Collectors.toList());
this.serverCodecConfigurer = serverCodecConfigurer;
@Bean
@ConditionalOnMissingBean(value = ErrorWebExceptionHandler.class,
search = SearchStrategy.CURRENT)
@Order(-1)
public ErrorWebExceptionHandler errorWebExceptionHandler(ErrorAttributes errorAttributes) {