许多线程在Python中同时写入日志文件 [英] Many threads to write log file at same time in Python

问题描述

我正在编写一个脚本，以便同时从多台计算机检索WMI信息，然后将此信息写入文本文件:

I am writing a script to retrieve WMI info from many computers at the same time then write this info in a text file:

f = open("results.txt", 'w+') ## to clean the results file before the start


def filesize(asset):  
    f = open("results.txt", 'a+')  
    c = wmi.WMI(asset)  
    wql = 'SELECT FileSize,Name FROM CIM_DataFile where (Drive="D:" OR Drive="E:") and Caption like "%file%"'  
    for item in c.query(wql):  
        print >> f, item.Name.split("\\")[2].strip().upper(), str(item.FileSize)  




class myThread (threading.Thread):  
    def __init__(self,name):  
        threading.Thread.__init__(self)  
        self.name = name  
    def run(self):  
        pythoncom.CoInitialize ()  
        print "Starting " + self.name       
        filesize(self.name)  
        print "Exiting " + self.name  



thread1 = myThread('10.24.2.31')  
thread2 = myThread('10.24.2.32')  
thread3 = myThread('10.24.2.33')  
thread4 = myThread('10.24.2.34')  
thread1.start()  
thread2.start()  
thread3.start()  
thread4.start()

问题是所有线程都在同一时间写.

The problem is that all threads writing at the same time.

推荐答案

您可以简单地创建自己的锁定机制，以确保只有一个线程正在写入文件.

You can simply create your own locking mechanism to ensure that only one thread is ever writing to a file.

import threading
lock = threading.Lock()

def write_to_file(f, text, file_size):
    lock.acquire() # thread blocks at this line until it can obtain lock

    # in this section, only one thread can be present at a time.
    print >> f, text, file_size

    lock.release()

def filesize(asset):  
    f = open("results.txt", 'a+')  
    c = wmi.WMI(asset)  
    wql = 'SELECT FileSize,Name FROM CIM_DataFile where (Drive="D:" OR Drive="E:") and Caption like "%file%"'  
    for item in c.query(wql):  
        write_to_file(f, item.Name.split("\\")[2].strip().upper(), str(item.FileSize))

您可能要考虑在整个for循环for item in c.query(wql):上放置锁，以允许每个线程在释放锁之前做较大的工作.

You may want to consider placing the lock around the entire for loop for item in c.query(wql): to allow each thread to do a larger chunk of work before releasing the lock.

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