feignclient设置hystrix参数

序

feign默认集成了hystrix，那么问题来了，如何像hystrix command那样设置每个方法的hystrix属性呢。

实例

@FeignClient("product") public interface RemoteProductService { @RequestMapping(method = RequestMethod.GET,value = "/product/{productId}") public Product getProduct(@PathVariable(value = "productId") int productId); } 

FeignClientsConfiguration

spring-cloud-netflix-core-1.2.6.RELEASE-sources.jar!/org/springframework/cloud/netflix/feign/FeignClientsConfiguration.java

    @Configuration @ConditionalOnClass({ HystrixCommand.class, HystrixFeign.class }) protected static class HystrixFeignConfiguration { @Bean @Scope("prototype") @ConditionalOnMissingBean @ConditionalOnProperty(name = "feign.hystrix.enabled", matchIfMissing = true) public Feign.Builder feignHystrixBuilder() { return HystrixFeign.builder(); } }

HystrixFeign

feign-hystrix-9.3.1-sources.jar!/feign/hystrix/HystrixFeign.java

private SetterFactory setterFactory = new SetterFactory.Default();

SetterFactory

feign-hystrix-9.3.1-sources.jar!/feign/hystrix/SetterFactory.java

public interface SetterFactory { /** * Returns a hystrix setter appropriate for the given target and method */ HystrixCommand.Setter create(Target<?> target, Method method); /** * Default behavior is to derive the group key from {@link Target#name()} and the command key from * {@link Feign#configKey(Class, Method)}. */ final class Default implements SetterFactory { @Override public HystrixCommand.Setter create(Target<?> target, Method method) { String groupKey = target.name(); String commandKey = Feign.configKey(target.type(), method); return HystrixCommand.Setter .withGroupKey(HystrixCommandGroupKey.Factory.asKey(groupKey)) .andCommandKey(HystrixCommandKey.Factory.asKey(commandKey)); } } }

groupKey，这里为product，即@FeignClient("product")中的值。

Feign.configKey

feign-core-9.3.1-sources.jar!/feign/Feign.java

public static String configKey(Class targetType, Method method) { StringBuilder builder = new StringBuilder(); builder.append(targetType.getSimpleName()); builder.append('#').append(method.getName()).append('('); for (Type param : method.getGenericParameterTypes()) { param = Types.resolve(targetType, targetType, param); builder.append(Types.getRawType(param).getSimpleName()).append(','); } if (method.getParameterTypes().length > 0) { builder.deleteCharAt(builder.length() - 1); } return builder.append(')').toString(); }

commandKey的构造，这里组装了类、方法名、参数，比如本文的实例，commandKey=RemoteProductService#getProduct(int)

配置文件指定

hystrix:  command: "RemoteProductService#getProduct(int)":  execution:  isolation:  thread:  timeoutInMilliseconds: 500

Java中指定

@Bean public Feign.Builder feignHystrixBuilder() { return HystrixFeign.builder().setterFactory(new SetterFactory() { @Override public HystrixCommand.Setter create(Target<?> target, Method method) { return HystrixCommand.Setter .withGroupKey(HystrixCommandGroupKey.Factory.asKey(RemoteProductService.class.getSimpleName()))// 控制 RemoteProductService 下,所有方法的Hystrix Configuration .andCommandPropertiesDefaults( HystrixCommandProperties.Setter().withExecutionTimeoutInMilliseconds(10000) // 超时配置 ); } }); }

小结

论灵活程度，还是配置文件灵活一点，唯一的工作量就是根据规则构造commandKey，然后就可以进行相关配置了。

 

import com.netflix.hystrix.HystrixCommand; 

 HystrixCommand.Setter