The Hystrix timeout of 60000 ms for the command “foo” is set lower than the combination of the Ribbon read and connect timeout, 200000ms.

hytrix超时时间

log出自AbstractRibbonCommand.java，昆山软件公司，那么索性研究一下源码。

假设：

protected static int getHystrixTimeout(IClientConfig config, String commandKey) {
	int ribbonTimeout = getRibbonTimeout(config, commandKey);
	DynamicPropertyFactory dynamicPropertyFactory = DynamicPropertyFactory.getInstance();
	
	// 获取默认的hytrix超时时间
	int defaultHystrixTimeout = dynamicPropertyFactory.getIntProperty("hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds",
		0).get();
	// 获取详细处事的hytrix超时时间，这里应该是hystrix.command.foo.execution.isolation.thread.timeoutInMilliseconds
	int commandHystrixTimeout = dynamicPropertyFactory.getIntProperty("hystrix.command." + commandKey + ".execution.isolation.thread.timeoutInMilliseconds",
		0).get();
	int hystrixTimeout;
	// hystrixTimeout的优先级是 详细处事的hytrix超时时间 > 默认的hytrix超时时间 > ribbon超时时间
	if(commandHystrixTimeout > 0) {
		hystrixTimeout = commandHystrixTimeout;
	}
	else if(defaultHystrixTimeout > 0) {
		hystrixTimeout = defaultHystrixTimeout;
	} else {
		hystrixTimeout = ribbonTimeout;
	}
	// 假如默认的可能详细处事的hytrix超时时间小于ribbon超时时间就会告诫
	if(hystrixTimeout < ribbonTimeout) {
		LOGGER.warn("The Hystrix timeout of " + hystrixTimeout + "ms for the command " + commandKey +
			" is set lower than the combination of the Ribbon read and connect timeout, " + ribbonTimeout + "ms.");
	}
	return hystrixTimeout;
}

紧接着，看一下我们的设置是什么

hystrix:
  command:
    default:
      execution:
        isolation:
          thread:
            timeoutInMilliseconds: 60000
            
ribbon:
  ReadTimeout: 50000
  ConnectTimeout: 50000
  MaxAutoRetries: 0
  MaxAutoRetriesNextServer: 1

ribbon超时时间

这里ribbon的超时时间是50000ms，那么为什么log中写的ribbon时间是200000ms?

继承阐明源码：

protected static int getRibbonTimeout(IClientConfig config, String commandKey) {
	int ribbonTimeout;
	// 这是较量异常的环境，不说
	if (config == null) {
		ribbonTimeout = RibbonClientConfiguration.DEFAULT_READ_TIMEOUT + RibbonClientConfiguration.DEFAULT_CONNECT_TIMEOUT;
	} else {
	   // 这里获取了四个参数，劳务派遣管理系统，ReadTimeout，ConnectTimeout，MaxAutoRetries， MaxAutoRetriesNextServer
		int ribbonReadTimeout = getTimeout(config, commandKey, "ReadTimeout",
			IClientConfigKey.Keys.ReadTimeout, RibbonClientConfiguration.DEFAULT_READ_TIMEOUT);
		int ribbonConnectTimeout = getTimeout(config, commandKey, "ConnectTimeout",
			IClientConfigKey.Keys.ConnectTimeout, RibbonClientConfiguration.DEFAULT_CONNECT_TIMEOUT);
		int maxAutoRetries = getTimeout(config, commandKey, "MaxAutoRetries",
			IClientConfigKey.Keys.MaxAutoRetries, DefaultClientConfigImpl.DEFAULT_MAX_AUTO_RETRIES);
		int maxAutoRetriesNextServer = getTimeout(config, commandKey, "MaxAutoRetriesNextServer",
			IClientConfigKey.Keys.MaxAutoRetriesNextServer, DefaultClientConfigImpl.DEFAULT_MAX_AUTO_RETRIES_NEXT_SERVER);
		// 本来ribbonTimeout的计较要领在这里，昆山软件开发，以上文的配置为例
		// ribbonTimeout = (50000 + 50000) * (0 + 1) * (1 + 1) = 200000
		ribbonTimeout = (ribbonReadTimeout + ribbonConnectTimeout) * (maxAutoRetries + 1) * (maxAutoRetriesNextServer + 1);
	}
	return ribbonTimeout;
}

可以看到ribbonTimeout是一个总时间，所以从逻辑上来讲，作者但愿hystrixTimeout要大于ribbonTimeout，不然hystrix熔断了今后，ribbon的重试就都没有意义了。

ribbon单处事配置

到这里最前面的疑问已经解开了，可是hytrix可以分处事配置timeout，ribbon可不行以? 源码走起，这里看的文件是DefaultClientConfigImpl.java

// 这是获取设置的进口要领，假如是null，那么用默认值
// 所有ribbon的默认值的都在该类中配置了，可以本身看一下
public <T> T get(IClientConfigKey<T> key, T defaultValue) {
    T value = get(key);
    if (value == null) {
        value = defaultValue;
    }
    return value;
}
// 这是焦点要领   
protected Object getProperty(String key) {
    if (enableDynamicProperties) {
        String dynamicValue = null;
        DynamicStringProperty dynamicProperty = dynamicProperties.get(key);
        // dynamicProperties其实是一个缓存，首次会见foo处事的时候会加载
        if (dynamicProperty != null) {
            dynamicValue = dynamicProperty.get();
        }
        // 假如缓存没有，那么就再获取一次，留意这里的getConfigKey(key)是生成key的要领
        if (dynamicValue == null) {
            dynamicValue = DynamicProperty.getInstance(getConfigKey(key)).getString();
            // 假如照旧没有取默认值，getDefaultPropName(key)生成key的要领
            if (dynamicValue == null) {
                dynamicValue = DynamicProperty.getInstance(getDefaultPropName(key)).getString();
            }
        }
        if (dynamicValue != null) {
            return dynamicValue;
        }
    }
    return properties.get(key);
}

以我们的处事为例：

getConfigKey(key) returns foo.ribbon.ReadTimeout
getDefaultPropName(key) returns ribbon.ReadTimeout

一目了然，{serviceName}.ribbon.{propertyName}就可以了。

小结