python看门狗运行不止一次

时间:2014-12-24 18:03:07

标签: python python-watchdog

我正在尝试学习python-watchdog,但我有点困惑为什么我设置的工作运行不止一次。所以,这是我的设置:

#handler.py
import os
from watchdog.events import FileSystemEventHandler
from actions import run_something

def getext(filename):
    return os.path.splitext(filename)[-1].lower()

class ChangeHandler(FileSystemEventHandler):

    def on_any_event(self, event):

        if event.is_directory:
            return
        if getext(event.src_path) == '.done':
            run_something()
        else: 
            print "event not directory.. exiting..."
            pass

观察者的设置如下:

#observer.py
import os
import time
from watchdog.observers import Observer
from handler import ChangeHandler

BASEDIR = "/path/to/some/directory/bin"

def main():

    while 1:

        event_handler = ChangeHandler()
        observer = Observer()
        observer.schedule(event_handler, BASEDIR, recursive=True)
        observer.start()
        try:
            while True:
                time.sleep(1)
        except KeyboardInterrupt:
            observer.stop()
        observer.join()

 if __name__ == '__main__':
    main()

最后,这样的行为:

#actions.py
import os
import subprocess

def run_something():
    output = subprocess.check_output(['./run.sh'])
    print output
    return None

.. ./run.sh只是一个shell脚本我希望在.done

上找到扩展名为/path/to/some/directory/bin的文件时运行
#run.sh
#!/bin/bash
echo "Job Start: $(date)"
rm -rf /path/to/some/directory/bin/job.done # remove the .done file
echo "Job Done: $(date)"

但是,当我发出python observer.py然后在touch job.done上执行/path/to/some/directory/bin时,我发现我的shell脚本./run.sh运行了三次而不是一次.. < / p>

我很困惑为什么这会运行三次而不只是一次(我确实删除了我的bash脚本上的job.done文件)

1 个答案:

答案 0 :(得分:3)

要调试监视程序脚本,打印看门狗所看到的事件非常有用。一个文件编辑或CLI命令(例如touch)可能导致多个监视程序事件。例如,如果插入print语句:

class ChangeHandler(FileSystemEventHandler):

    def on_any_event(self, event):
        print(event)

记录每个事件,运行

% touch job.done

产生

2014-12-24 13:11:02 - <FileCreatedEvent: src_path='/home/unutbu/tmp/job.done'>
2014-12-24 13:11:02 - <DirModifiedEvent: src_path='/home/unutbu/tmp'>
2014-12-24 13:11:02 - <FileModifiedEvent: src_path='/home/unutbu/tmp/job.done'>

上面有两个src_pathjob.done结尾的事件。因此,

    if getext(event.src_path) == '.done':
        run_something()

运行两次,因为有FileCreatedEventFileModifiedEvent。 您可能最好只监控FileModifiedEvent s。