Python script to automatically renice all python processes

renice_python_processes.py

#!/usr/bin/python3
from datetime import datetime

import psutil


DEFAULT_DRAGO_NICENESS_VALUE = 5
DURATION_BEFORE_RENICING = 30


def renice_python_process(proc):
    """
    Renice process to niceness=5 if it matches all conditions below:
    - [x] is a python process
    - [x] is not a root process
    - [x] does not have a positive niceness
    - [x] has started at least 3 min ago
    """
    is_user_process = proc.username() != "root"
    is_python_process = any(["python" in command_line_argument for command_line_argument in proc.cmdline()])
    is_niceness_stricly_positive = proc.nice() > 0
    is_process_old_enough = (datetime.now().timestamp() - proc.create_time()) > DURATION_BEFORE_RENICING

    should_renice_process = (
        is_python_process
        and is_user_process
        and is_process_old_enough
        and (not is_niceness_stricly_positive)
    )
    if should_renice_process:
        print("renicing", proc)
        proc.nice(DEFAULT_DRAGO_NICENESS_VALUE)
        for thread in proc.threads():
            psutil.Process(thread.id).nice(DEFAULT_DRAGO_NICENESS_VALUE)


def renice_python_processes():
    """ Iterator with Exception catches for `renice_python_process` """
    for proc in psutil.process_iter(["cmdline", "username", "nice", "create_time"]):
        try:
            renice_python_process(proc)
        except psutil.NoSuchProcess:
            # Concurrently terminated
            pass
        except (psutil.AccessDenied , psutil.ZombieProcess):
            print("Could not renice", proc)


if __name__ == "__main__":
    renice_python_processes()