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本文主要研究一下ExecutorService的监控

InstrumentedExecutorService

metrics-core-4.0.2-sources.jar!/com/codahale/metrics/InstrumentedExecutorService.java

/*** An {@link ExecutorService} that monitors the number of tasks submitted, running,* completed and also keeps a {@link Timer} for the task duration.* <p/>* It will register the metrics using the given (or auto-generated) name as classifier, e.g:* "your-executor-service.submitted", "your-executor-service.running", etc.*/
public class InstrumentedExecutorService implements ExecutorService {private static final AtomicLong NAME_COUNTER = new AtomicLong();private final ExecutorService delegate;private final Meter submitted;private final Counter running;private final Meter completed;private final Timer idle;private final Timer duration;/*** Wraps an {@link ExecutorService} uses an auto-generated default name.** @param delegate {@link ExecutorService} to wrap.* @param registry {@link MetricRegistry} that will contain the metrics.*/public InstrumentedExecutorService(ExecutorService delegate, MetricRegistry registry) {this(delegate, registry, "instrumented-delegate-" + NAME_COUNTER.incrementAndGet());}/*** Wraps an {@link ExecutorService} with an explicit name.** @param delegate {@link ExecutorService} to wrap.* @param registry {@link MetricRegistry} that will contain the metrics.* @param name     name for this executor service.*/public InstrumentedExecutorService(ExecutorService delegate, MetricRegistry registry, String name) {this.delegate = delegate;this.submitted = registry.meter(MetricRegistry.name(name, "submitted"));this.running = registry.counter(MetricRegistry.name(name, "running"));this.completed = registry.meter(MetricRegistry.name(name, "completed"));this.idle = registry.timer(MetricRegistry.name(name, "idle"));this.duration = registry.timer(MetricRegistry.name(name, "duration"));}@Overridepublic void execute(Runnable runnable) {submitted.mark();delegate.execute(new InstrumentedRunnable(runnable));}@Overridepublic Future<?> submit(Runnable runnable) {submitted.mark();return delegate.submit(new InstrumentedRunnable(runnable));}@Overridepublic <T> Future<T> submit(Runnable runnable, T result) {submitted.mark();return delegate.submit(new InstrumentedRunnable(runnable), result);}@Overridepublic <T> Future<T> submit(Callable<T> task) {submitted.mark();return delegate.submit(new InstrumentedCallable<>(task));}@Overridepublic <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) throws InterruptedException {submitted.mark(tasks.size());Collection<? extends Callable<T>> instrumented = instrument(tasks);return delegate.invokeAll(instrumented);}@Overridepublic <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit) throws InterruptedException {submitted.mark(tasks.size());Collection<? extends Callable<T>> instrumented = instrument(tasks);return delegate.invokeAll(instrumented, timeout, unit);}@Overridepublic <T> T invokeAny(Collection<? extends Callable<T>> tasks) throws ExecutionException, InterruptedException {submitted.mark(tasks.size());Collection<? extends Callable<T>> instrumented = instrument(tasks);return delegate.invokeAny(instrumented);}@Overridepublic <T> T invokeAny(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit) throws ExecutionException, InterruptedException, TimeoutException {submitted.mark(tasks.size());Collection<? extends Callable<T>> instrumented = instrument(tasks);return delegate.invokeAny(instrumented, timeout, unit);}private <T> Collection<? extends Callable<T>> instrument(Collection<? extends Callable<T>> tasks) {final List<InstrumentedCallable<T>> instrumented = new ArrayList<>(tasks.size());for (Callable<T> task : tasks) {instrumented.add(new InstrumentedCallable<>(task));}return instrumented;}@Overridepublic void shutdown() {delegate.shutdown();}@Overridepublic List<Runnable> shutdownNow() {return delegate.shutdownNow();}@Overridepublic boolean isShutdown() {return delegate.isShutdown();}@Overridepublic boolean isTerminated() {return delegate.isTerminated();}@Overridepublic boolean awaitTermination(long l, TimeUnit timeUnit) throws InterruptedException {return delegate.awaitTermination(l, timeUnit);}//......
}

• InstrumentedExecutorService实现了ExecutorService，对jdk原始的ExecutorService进行了包装，对相应的方法织入指标统计
• 主要统计了已提交的任务submitted(Meter)，运行中的任务running(Counter)，完成的任务completed(Meter)，空闲时长idle(Timer)，运行时长duration(Timer)
• 为了统计后面几个指标，需要对Runnable以及Callable进行织入，因而引入了InstrumentedRunnable、InstrumentedCallable

InstrumentedRunnable

    private class InstrumentedRunnable implements Runnable {private final Runnable task;private final Timer.Context idleContext;InstrumentedRunnable(Runnable task) {this.task = task;this.idleContext = idle.time();}@Overridepublic void run() {idleContext.stop();running.inc();final Timer.Context durationContext = duration.time();try {task.run();} finally {durationContext.stop();running.dec();completed.mark();}}}

• 织入了对idle、duration、running、completed的统计

InstrumentedCallable

    private class InstrumentedCallable<T> implements Callable<T> {private final Callable<T> callable;InstrumentedCallable(Callable<T> callable) {this.callable = callable;}@Overridepublic T call() throws Exception {running.inc();final Timer.Context context = duration.time();try {return callable.call();} finally {context.stop();running.dec();completed.mark();}}}

• 织入了对duration、running、completed的统计

ExecutorServiceMetrics

micrometer-core-1.0.3-sources.jar!/io/micrometer/core/instrument/binder/jvm/ExecutorServiceMetrics.java

/*** Monitors the status of executor service pools. Does not record timings on operations executed in the {@link ExecutorService},* as this requires the instance to be wrapped. Timings are provided separately by wrapping the executor service* with {@link TimedExecutorService}.** @author Jon Schneider* @author Clint Checketts*/
@NonNullApi
@NonNullFields
public class ExecutorServiceMetrics implements MeterBinder {@Nullableprivate final ExecutorService executorService;private final Iterable<Tag> tags;public ExecutorServiceMetrics(@Nullable ExecutorService executorService, String executorServiceName, Iterable<Tag> tags) {this.executorService = executorService;this.tags = Tags.concat(tags, "name", executorServiceName);}//....../*** Record metrics on the use of an {@link Executor}.** @param registry     The registry to bind metrics to.* @param executor     The executor to instrument.* @param executorName Will be used to tag metrics with "name".* @param tags         Tags to apply to all recorded metrics.* @return The instrumented executor, proxied.*/public static Executor monitor(MeterRegistry registry, Executor executor, String executorName, Iterable<Tag> tags) {if (executor instanceof ExecutorService) {return monitor(registry, (ExecutorService) executor, executorName, tags);}return new TimedExecutor(registry, executor, executorName, tags);}/*** Record metrics on the use of an {@link ExecutorService}.** @param registry            The registry to bind metrics to.* @param executor            The executor to instrument.* @param executorServiceName Will be used to tag metrics with "name".* @param tags                Tags to apply to all recorded metrics.* @return The instrumented executor, proxied.*/public static ExecutorService monitor(MeterRegistry registry, ExecutorService executor, String executorServiceName, Iterable<Tag> tags) {new ExecutorServiceMetrics(executor, executorServiceName, tags).bindTo(registry);return new TimedExecutorService(registry, executor, executorServiceName, tags);}@Overridepublic void bindTo(MeterRegistry registry) {if (executorService == null) {return;}String className = executorService.getClass().getName();if (executorService instanceof ThreadPoolExecutor) {monitor(registry, (ThreadPoolExecutor) executorService);} else if (className.equals("java.util.concurrent.Executors$DelegatedScheduledExecutorService")) {monitor(registry, unwrapThreadPoolExecutor(executorService, executorService.getClass()));} else if (className.equals("java.util.concurrent.Executors$FinalizableDelegatedExecutorService")) {monitor(registry, unwrapThreadPoolExecutor(executorService, executorService.getClass().getSuperclass()));} else if (executorService instanceof ForkJoinPool) {monitor(registry, (ForkJoinPool) executorService);}}private void monitor(MeterRegistry registry, @Nullable ThreadPoolExecutor tp) {if (tp == null) {return;}FunctionCounter.builder("executor.completed", tp, ThreadPoolExecutor::getCompletedTaskCount).tags(tags).description("The approximate total number of tasks that have completed execution").baseUnit("tasks").register(registry);Gauge.builder("executor.active", tp, ThreadPoolExecutor::getActiveCount).tags(tags).description("The approximate number of threads that are actively executing tasks").baseUnit("threads").register(registry);Gauge.builder("executor.queued", tp, tpRef -> tpRef.getQueue().size()).tags(tags).description("The approximate number of threads that are queued for execution").baseUnit("threads").register(registry);Gauge.builder("executor.pool.size", tp, ThreadPoolExecutor::getPoolSize).tags(tags).description("The current number of threads in the pool").baseUnit("threads").register(registry);}//......
}

• ExecutorServiceMetrics实现了MeterBinder接口，另外提供了静态方法来创建带有监控指标的ExecutorService，该静态方法命名为monitor，非常形象
• monitor方法首先创建ExecutorServiceMetrics，并bindTo了MeterRegistry，然后返回TimedExecutorService
• bindTo方法上报了executor.completed(FunctionCounter)，executor.active(Gauge)，executor.queued(Gauge)，executor.pool.size(Gauge)这几个指标

TimedExecutorService

micrometer-core-1.0.3-sources.jar!/io/micrometer/core/instrument/internal/TimedExecutorService.java

/*** An {@link java.util.concurrent.ExecutorService} that is timed** @author Jon Schneider*/
public class TimedExecutorService implements ExecutorService {private final ExecutorService delegate;private final Timer timer;public TimedExecutorService(MeterRegistry registry, ExecutorService delegate, String executorServiceName, Iterable<Tag> tags) {this.delegate = delegate;this.timer = registry.timer("executor", Tags.concat(tags ,"name", executorServiceName));}@Overridepublic void shutdown() {delegate.shutdown();}@Overridepublic List<Runnable> shutdownNow() {return delegate.shutdownNow();}@Overridepublic boolean isShutdown() {return delegate.isShutdown();}@Overridepublic boolean isTerminated() {return delegate.isTerminated();}@Overridepublic boolean awaitTermination(long timeout, TimeUnit unit) throws InterruptedException {return delegate.awaitTermination(timeout, unit);}@Overridepublic <T> Future<T> submit(Callable<T> task) {return delegate.submit(timer.wrap(task));}@Overridepublic <T> Future<T> submit(Runnable task, T result) {return delegate.submit(() -> timer.record(task), result);}@Overridepublic Future<?> submit(Runnable task) {return delegate.submit(() -> timer.record(task));}@Overridepublic <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) throws InterruptedException {return delegate.invokeAll(wrapAll(tasks));}@Overridepublic <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit) throws InterruptedException {return delegate.invokeAll(wrapAll(tasks), timeout, unit);}@Overridepublic <T> T invokeAny(Collection<? extends Callable<T>> tasks) throws InterruptedException, ExecutionException {return delegate.invokeAny(wrapAll(tasks));}@Overridepublic <T> T invokeAny(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {return delegate.invokeAny(wrapAll(tasks), timeout, unit);}@Overridepublic void execute(Runnable command) {delegate.execute(timer.wrap(command));}private <T> Collection<? extends Callable<T>> wrapAll(Collection<? extends Callable<T>> tasks) {return tasks.stream().map(timer::wrap).collect(toList());}
}

• 对ExecutorService进行包装，增加了

Timer.record

micrometer-core-1.0.3-sources.jar!/io/micrometer/core/instrument/Timer.java

    /*** Executes the runnable `f` and records the time taken.** @param f Function to execute and measure the execution time.*/void record(Runnable f);/*** Wrap a {@link Runnable} so that it is timed when invoked.** @param f The Runnable to time when it is invoked.* @return The wrapped Runnable.*/default Runnable wrap(Runnable f) {return () -> record(f);}/*** Wrap a {@link Callable} so that it is timed when invoked.** @param f   The Callable to time when it is invoked.* @param <T> The return type of the callable.* @return The wrapped callable.*/default <T> Callable<T> wrap(Callable<T> f) {return () -> recordCallable(f);}

• warp方法主要是包装调用record方法，而record由实现类去实现

AbstractTimer

micrometer-core-1.0.3-sources.jar!/io/micrometer/core/instrument/AbstractTimer.java

    @Overridepublic void record(Runnable f) {final long s = clock.monotonicTime();try {f.run();} finally {final long e = clock.monotonicTime();record(e - s, TimeUnit.NANOSECONDS);}}@Overridepublic final void record(long amount, TimeUnit unit) {if (amount >= 0) {histogram.recordLong(TimeUnit.NANOSECONDS.convert(amount, unit));recordNonNegative(amount, unit);if (intervalEstimator != null) {intervalEstimator.recordInterval(clock.monotonicTime());}}}

• record采用histogram进行统计

小结

dropwizard及micrometer均提供了对ExecutorService的指标统计的包装，micrometer则更近一步提供了静态方法来直接创建，非常方便。

doc

• InstrumentedExecutorService
• ExecutorServiceMetrics