a usefull little class for running long running shell commands in the background and manging them in a python program or service

session_pool.py

import os
import subprocess as sp
from multiprocessing import Process

class session_pool():
    """
    Session_pool is used to run long running processes in the background
    Usage:
        sess_pool=session_pool()
    
        sess_pool.run_session_process("command")
        sess_pool.kill_session_process("command")
    NOTICE: supply command without the & argument run_session_process() handles pushing to the background for
    """
    def __init__(self):
        self.process_dict={}
        
    def session_process_thread(self,cmd):
        "Internal Method where the actual thread runs"
        exit_code=sp.call('({0})'.format(cmd),stdout=open('/dev/stdout', 'wb'),shell=True,executable='/bin/bash')
        return self.on_exit(cmd,exit_code)

    def run_session_process(self,cmd):   
        """run Session Process (nonblocking)"""
        proc_thread=Process(target=self.session_process_thread,args=(cmd,))
        proc_thread.start()
        self.process_dict.update({cmd:proc_thread})
        return proc_thread

    def kill_session_process(self,cmd):
        proc_thread=self.process_dict[cmd]
        proc_thread.terminate()
        del self.process_dict[cmd]
        PROC_LIST = os.popen("ps aux").read() # bash doesn't do signal forwarding; so we need to find it AND KILL IT
        for sys_proc in PROC_LIST.split("\n"):
            if cmd in sys_proc:
                os.system("kill "+sys_proc.split(' ')[2])

    def killall(self):
        for proc_key in self.process_dict:
            self.kill_session_process(proc_key) 

    def on_exit(self,cmd,exit_code):
        "Runs on command exit"
        if exit_code==0:
            print("{0} exited with exit code 0".format(cmd))
        else:
            print("{0} existed with NON zero exit code ".format(cmd))