Check if a process is running or not on Windows?

Question

I am trying to create a python script which I will later run as a service. Now I want to run a particular part of the code only when iTunes is running. I understand from some research that polling the entire command list and then searching for the application for that list is expensive.

I found out that processes on UNIX-based operating systems create a lock file to notify that a program is currently running, at which point we can use os.stat(location_of_file) to check if the file exists to determine if a program is running or not.

Is there a similar lock file created on Windows?

If not what are the various ways in Python by which we can determine if a process is running or not?

I am using python 2.7 and iTunes COM interface.

Answer 1

You can not rely on lock files in Linux or Windows. I would just bite the bullet and iterate through all the running programs. I really do not believe it will be as "expensive" as you think. psutil is an excellent cross-platform python module cable of enumerating all the running programs on a system.

import psutil     "someProgram" in (p.name() for p in psutil.process_iter()) 

Answer 2

Although @zeller said it already here is an example how to use tasklist. As I was just looking for vanilla python alternatives...

import subprocess  def process_exists(process_name):     call = 'TASKLIST', '/FI', 'imagename eq %s' % process_name     # use buildin check_output right away     output = subprocess.check_output(call).decode()     # check in last line for process name     last_line = output.strip().split('\r\n')[-1]     # because Fail message could be translated     return last_line.lower().startswith(process_name.lower()) 

and now you can do:

>>> process_exists('eclipse.exe') True  >>> process_exists('AJKGVSJGSCSeclipse.exe') False 

To avoid calling this multiple times and have an overview of all the processes this way you could do something like:

# get info dict about all running processes import subprocess output = subprocess.check_output(('TASKLIST', '/FO', 'CSV')).decode() # get rid of extra " and split into lines output = output.replace('"', '').split('\r\n') keys = output[0].split(',') proc_list = [i.split(',') for i in output[1:] if i] # make dict with proc names as keys and dicts with the extra nfo as values proc_dict = dict((i[0], dict(zip(keys[1:], i[1:]))) for i in proc_list) for name, values in sorted(proc_dict.items(), key=lambda x: x[0].lower()):     print('%s: %s' % (name, values))