在python中运行计时器几分钟 [英] Running a timer for few minutes in python

问题描述

我试图每秒运行某个函数"foo".我必须这样做几分钟(比如说5).

I am trying to run a certain function "foo" every second. I have to do this for a few minutes (say 5).

函数foo()向服务器发出100个HTTP请求(其中包含JSON对象)，并打印JSON响应.

The function foo() makes 100 HTTP Requests (which contains a JSON object) to the server and prints the JSON response.

简而言之，我必须在5分钟内每秒发出100个HTTP请求.

In short, I have to make 100 HTTP requests per second for 5 minutes.

我刚刚开始学习python，因此没有广泛的知识.这是我尝试过的:

I have just started learning python, thus don't have extensive knowledge. This is what I have tried:

import threading
noOfSecondsPassed = 0
def foo():
   global noOfSecondsPassed
   # piece of code which makes 100 HTTP requests (I use while loop)
   noOfSecondsPassed += 1

while True:
   if noOfSecondsPassed < (300)  # 5 minutes
       t = threading.Timer(1.0, foo)
       t.start()

由于有多个线程，因此函数foo没有被调用300次，但远远不止于此. 我也尝试过设置锁:

Due to multiple threads, the function foo isn't called 300 times but much much more than that. I have tried setting a lock too:

def foo():
  l = threading.Lock()
  l.acquire()
  global noOfSecondsPassed
  # piece of code which makes 100 HTTP requests (I use while loop)
  noOfSecondsPassed += 1
  l.release()

其他代码段与先前的代码段相同.但这也行不通.

Rest of code is same as the previous code snippet. But this also does not work.

我该怎么做?

不同的方法

我尝试了这种对我有用的方法:

I have tried this approach which worked for me:

def foo():
    noOfSecondsPassed = 0
    while noOfSecondsPassed < 300:
       #Code to make 100 HTTP requests
       noOfSecondsPassed +=1
       time.sleep(1.0)
foo()

这样做有什么缺点吗?

推荐答案

我会使用另一种更容易的方法.

I would use another approach which is easier I think.

创建300个计时器线程，每个计时器线程在前一个之后运行1秒.主循环几乎在瞬间执行，因此错误系数非常低. 这是一个示例演示:

Create 300 timer thread, each running 1 sec after the previous. The main loop is executed in almost an instant so the error factor is very low. Here's a sample Demo:

import datetime
import thread
import threading

def foo():
     print datetime.datetime.now()
     print threading.active_count()

for x in range(0,300): 
     t = threading.Timer(x + 1, foo)
     t.start()

此代码输出应如下所示:

This code output should look like this:

2012-10-01 13:21:07.328029
301
2012-10-01 13:21:08.328281
300
2012-10-01 13:21:09.328449
299
2012-10-01 13:21:10.328615
298
2012-10-01 13:21:11.328768
297
2012-10-01 13:21:12.329006
296
2012-10-01 13:21:13.329289
295
2012-10-01 13:21:14.329369
294
2012-10-01 13:21:15.329580
293
2012-10-01 13:21:16.329793
292
2012-10-01 13:21:17.329958
291
2012-10-01 13:21:18.330138
290
2012-10-01 13:21:19.330300                                                                                                                                                                                                                         
289                         
...

如您所见，每个线程在前一个线程之后大约1秒钟启动，您正好启动了300个线程.

As you can see, each thread is launched about 1 sec after the previous and you are starting exactly 300 threads.

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