com.netflix.hystrix.metric

Class HystrixThreadEventStream

java.lang.Object

com.netflix.hystrix.metric.HystrixThreadEventStream

public class HystrixThreadEventStream
extends java.lang.Object

Per-thread event stream. No synchronization required when writing to it since it's single-threaded. Some threads will be dedicated to a single HystrixCommandKey (a member of a thread-isolated HystrixThreadPool. However, many situations arise where a single thread may serve many different commands. Examples include: * Application caller threads (semaphore-isolated commands, or thread-pool-rejections) * Timer threads (timeouts or collapsers)

I don't think that a thread-level view is an interesting one to consume (I could be wrong), so at the moment there is no public way to consume it. I can always add it later, if desired.

Instead, this stream writes to the following streams, which have more meaning to metrics consumers:

• HystrixCommandCompletionStream
• HystrixCommandStartStream
• HystrixThreadPoolCompletionStream
• HystrixThreadPoolStartStream
• HystrixCollapserEventStream

Also note that any observers of this stream do so on the thread that writes the metric. This is the command caller thread in the SEMAPHORE-isolated case, and the Hystrix thread in the THREAD-isolated case. I determined this to be more efficient CPU-wise than immediately hopping off-thread and doing all the metric calculations in the RxComputationThreadPool.

Method Summary

Methods

Modifier and Type	Method and Description
void	collapserBatchExecuted(HystrixCollapserKey collapserKey, int batchSize)
void	collapserResponseFromCache(HystrixCollapserKey collapserKey)
void	commandExecutionStarted(HystrixCommandKey commandKey, HystrixThreadPoolKey threadPoolKey, HystrixCommandProperties.ExecutionIsolationStrategy isolationStrategy, int currentConcurrency)
void	executionDone(ExecutionResult executionResult, HystrixCommandKey commandKey, HystrixThreadPoolKey threadPoolKey)
static HystrixThreadEventStream	getInstance()
void	shutdown()
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

getInstance

public static HystrixThreadEventStream getInstance()

shutdown

public void shutdown()

commandExecutionStarted

public void commandExecutionStarted(HystrixCommandKey commandKey,
                           HystrixThreadPoolKey threadPoolKey,
                           HystrixCommandProperties.ExecutionIsolationStrategy isolationStrategy,
                           int currentConcurrency)

executionDone

public void executionDone(ExecutionResult executionResult,
                 HystrixCommandKey commandKey,
                 HystrixThreadPoolKey threadPoolKey)

collapserResponseFromCache

public void collapserResponseFromCache(HystrixCollapserKey collapserKey)

collapserBatchExecuted

public void collapserBatchExecuted(HystrixCollapserKey collapserKey,
                          int batchSize)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object