pythonwindows-task-scheduler

Why do seemingly valid Python scripts fail to run when initiated via the Windows Task Scheduler?

I have been writing scripts in Python which I want to automatically run on a Windows server on a scheduled basis. I tried working with batch files very briefly, but have enthusiastically moved on to Python scripts instead and am doing fine with them. The scripts I write are easy to write and they do exactly what I want them to do when I manually execute them. I have written many different scripts now, mostly dealing with copying, deleting, and renaming files or moving directories around.

The problem is when I try to schedule Python scripts using Windows Task Scheduler, many of them fail to run (Task Scheduler says "Last Run Result = 0x1"). This happens all the time. I have had similar experiences with batch files as well (batch files which can be run manually fail to run when scheduled). Given my limited experience thus far, I would have to say this is certainly a Windows Task Scheduler problem and not a Python problem.

Here is an example Python script:

#import modules
import os, shutil, datetime, subprocess

#global variables
zip_dir = 'Y:\7z'
zip_dir_misc = 'X:\7z'
zip_extension = '.7z'

def newest_zip_file(directory, extension = zip_extension): 
  return max(
    (os.path.join(dir_name, file_name)
    for dir_name, dir_names, file_names in os.walk(directory)
    for file_name in file_names
    if file_name.endswith(extension)),
    key=lambda fn: os.stat(fn).st_mtime)  

def copy_zip_file(src_dir_p, temp_dir_p):
  src_file = newest_zip_file(src_dir_p)
  new_file = temp_dir_p + '\\' + os.path.basename(src_file)
  shutil.copyfile(src_file, new_file)

copy_zip_file(zip_dir, zip_dir_misc)

This script copies a .7z file from one server to another via a networked folder (represented as the X: partition). This script works when run manually, but not when scheduled. However, when the script is changed to copy the same .7z file to another directory on the same server (not a networked folder), the script will work flawlessly, either when executed manually or scheduled.

If I am doing something programmatically incorrect in the script above (perhaps I am referring to a networked folder improperly) then I can fix this script this one time (although I have already tried every combination I could imagine for defining the networked folder using things like the full server name). But I keep running into the same problem with totally different Python scripts which behave the same way, which brings me to the real question:

Why do seemingly valid Python scripts fail to run when initiated via the Windows Task Scheduler?

My Windows Task Scheduler configuration:

I am looking mostly for suggestions and best practices for solving this general problem, and not so much specific fixes to the example script posted above.

Solution

  • You mention networked folders, this is a known issue with the task scheduler. For tips on dealing with it in Python, see this post.

    Generally: