Is it possible to selectively ignore service exception in Hystrix?

问题

I have client API jar which internally makes external calls and throws single generic Service exception in case of issues. I have written hystrix wrapper over the API calls. There are cases like "user not found" returning exception. Though the call was successful and service responded with valid response, the hystrix is treating it as a failure. I know that we can ignore the exception in Hystrix; but it will whitelist the only exception thrown by service calls. Is there a way to selectively ignore exception thrown by the service calls based on message in exception or http status code or something?

回答1:

If the external service throw different exceptions in different cases, then you can probably ignore those exceptions like this

 @HystrixCommand(ignoreExceptions = {SomeException.class})

But if you have to ignore exceptions bases on error message then the best way to tackle this is put a try catch around your external call. And in the catch block check if it is one of those exceptions which needs to be ignored. If so don't do anything. If not rethrow this exception. Something like this will do. More info about HystrixBadRequestException

@HystrixCommand(fallbackMethod = "fallBackMethod", groupKey = "CircuitBreaker", commandKey = "somekey", threadPoolKey = "somekey",
        commandProperties = {
            @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "10000"),
            @HystrixProperty(name = "execution.timeout.enabled", value = "false"),
            @HystrixProperty(name = "circuitBreaker.requestVolumeThreshold", value = "20"),
            @HystrixProperty(name = "circuitBreaker.sleepWindowInMilliseconds", value = "1200000"),
        },
        threadPoolProperties = {
            @HystrixProperty(name = "coreSize", value = "30"),
            @HystrixProperty(name = "metrics.rollingStats.timeInMilliseconds", value = "180000")
        })
    public void someMethod(....){
             try {
               // Call external service
             } catch(Exception e) {
               if(exception to be ignored)
                 throw new HystrixBadRequestException("Some message", e);
               else
                  throw e
             } 
    }

来源：https://stackoverflow.com/questions/47708195/is-it-possible-to-selectively-ignore-service-exception-in-hystrix

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hystrix