A Simple Loading Animation Decorator and Context Manger for the Command Line Using Python 3

Loading_animation.py

"""
  This program is designed to create
  and animate a simple loading animation.
"""

from sys import stdout as terminal
from time import sleep
from itertools import cycle
from threading import Thread
from contextlib import contextmanager
from timeit import default_timer as timer


@contextmanager
def loading_animation(running_text: str = "Running", finished_text: str = "Done!"):
    done = False

    def animation():
        timer_start = timer()
        for c in cycle(["|", "/", "-", "\\"]):
            if done:
                break
            time_in_sec = timer() - timer_start
            text_to_display = f"\r{running_text} " + "{:.2f}".format(time_in_sec) + "s " + c
            terminal.write(text_to_display)
            terminal.flush()
            sleep(0.1)

        diff = len(text_to_display) - len(finished_text) + 2
        spaces = " " * diff if diff > 0 else ""
        terminal.write(f"\r{finished_text}" + spaces + "\n")
        terminal.flush()

    try:
        t = Thread(target=animation)
        t.start()
        yield t
    finally:
        done = True
        t.join()



def with_loading_animation(running_text: str = "Running", finished_text: str = "Done!"):
    def wrapper(f):
        def wrapped(*args, **kwargs):
            with loading_animation(running_text, finished_text):
                return f(*args, **kwargs)
        return wrapped
    return wrapper


  # Usage examples
if __name__ == "__main__":

    # As decorator
    # Custom text
    @with_loading_animation("Sleeping", "Had a good nap")
    def test_function(time: int):
        sleep(time)

    # Default text
    @with_loading_animation()
    def test_function2(time: int):
        sleep(time)

    test_function(3)
    test_function2(3)

    # With with statement
    # Custom text
    with loading_animation("Wallowing in context", "Had a nice little block"):
        sleep(3)

    # With default
    with loading_animation():
        sleep(3)