Python – multiprocessing multiple folders

  multiprocessing, python, python-3.x

As a newbie to the programming, I’m still exploring the concepts of multiprocessing and multithreading.

I’ve written small script that reads a file and copies the files to multiple temporary folders and does the following actions on each folder.

  1. build a label.
  2. Generate an package
  3. Push it to the Nexus.

There are ~500 folders & are processed sequentially. How can I use multiprocessing here, thereby process 100 folders at a time parallel or increase the number still.
Also, is it possible to keep track of those process and fail the build even one sub process fails.

I read multiple articles on multiprocessing, but couldn’t wrap my head around it 🙁

Any guidance would be of great help to me, thanks.

   -- war file
   -- metadata

folder 2
   -- war file
   -- metadata

folder 500
   -- war file
   -- metadata

Code snippet

import re, shutil, os
from pathlib import Path

target = "/home/work"
file_path = target + "/file.txt"

dict = {}
count = 1

def commands_to_run_on_each_folder(filetype, tmp_folder):
    target_folder = tmp_folder+'/tmp'+str(count)

    os.system(<1st command to build the label>)
    os.system(<2nd command to build the package>)
    <multiple file manipulations, where `filetype` is used and get the required file with right extension>
    <curl command to upload it to the Nexus>

#Read the text file and assemble it in a dictionary.
with open(file_path, 'r') as f:
    lines =
    for i, line in enumerate(lines):
        match = re.match(r".*.war", line)
        if match:
            j = i-1 if i > 1 else 0
            for k in range(j, i):
                dict[match.string] = lines[k]
#Iterate the dictionary and copy the folder to the temporary folders.
for key, value in output.items():
    shutil.copy(key, target+'/tmp'+str(count))
    shutil.copy(value, target+'/tmp'+str(count))
    commands_to_run_on_each_folder("war", target)
    count += 1

OS : Ubuntu 18.04
Memory : 22 GB container

Source: Python Questions