检查一个concurrent.futures.ThreadPoolExecutor [英] Checking up on a `concurrent.futures.ThreadPoolExecutor`

问题描述

我有一个实时的 concurrent.futures.ThreadPoolExecutor 。我要检查其状态。我想知道有多少个线程，有多少个正在处理任务，哪些任务，有多少空闲，以及队列中有哪些任务。我怎么能找到这些东西？

I've got a live concurrent.futures.ThreadPoolExecutor. I want to check its status. I want to know how many threads there are, how many are handling tasks and which tasks, how many are free, and which tasks are in the queue. How can I find out these things?

推荐答案

对Pool和挂起的工作项队列有一些可见性。要找出可用的内容，请打印 poolx .__ dict __ 来查看结构。阅读ThreadPool代码，它非常好：并发。 futures.thread

There is some visibility into the Pool, and the pending workitem queue. To find out what's available, print poolx.__dict__ to see the structure. Read the ThreadPool code, it's pretty good: concurrent.futures.thread

以下内容创建了一个线程池。然后，它创建了两个作业：一个睡眠3秒，另一个立即返回。然后打印该池中待处理的工作项数。

The following creates a pool with one thread. It then creates two jobs: one sleeps for 3 seconds, the other immediately returns. The pool's number of pending work items is then printed.

然后，我们从工作队列中打印出工作项。在这种情况下，线程已经在执行 time.sleep（3）函数，因此不在队列中。函数 sleep ，带有args [0] 和kwargs {} ，因为这是要运行的池的下一个工作项。

Following that, we print out items from the work queue. In this case, a thread is already executing the time.sleep(3) function, so that's not in the queue. The function sleep with args [0] and kwargs {} is printed, because that's the next work item for the pool to run.

对于无破坏性队列见解，@ dano和@abarnert表示敬意。

Kudos to @dano for the nondestructive queue insight, and @abarnert.

import concurrent.futures, time

poolx = concurrent.futures.ThreadPoolExecutor(max_workers=1)
poolx.submit(time.sleep, 3)
poolx.submit(time.sleep, 0)   # very fast

print('pending:', poolx._work_queue.qsize(), 'jobs')
print('threads:', len(poolx._threads))
print()

# TODO: make thread safe; work on copy of queue?
print('Estimated Pending Work Queue:')
for num,item in enumerate(poolx._work_queue.queue):
    print('{}\t{}\t{}\t{}'.format(
        num+1, item.fn, item.args, item.kwargs,
        ))

poolx.shutdown(wait=False)

输出

output

pending: 1 jobs
threads: 1

Pending Work Queue:
1   <built-in function sleep>   (0,)    {}

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