useful python contexts

my_ctxs.py

import os
from contextlib import contextmanager

@contextmanager
def dir_ctx(path):
    original_dir = os.getcwd()
    try:
        os.chdir(path)
        yield
    finally:
        os.chdir(original_dir)


@contextmanager
def spawn_ctx(args, path, print_output=False, use_sigkill=False, sleep_after=1):
    with dir_ctx(path):
        proc = subprocess.Popen(
            args,
            stdout=sys.stdout if print_output else subprocess.DEVNULL,
            stderr=sys.stderr if print_output else subprocess.DEVNULL
        )
        if sleep_after:
            time.sleep(sleep_after)
        try:
            yield proc
        finally:
            if use_sigkill:
                proc.kill()
            else:
                proc.terminate()


@contextmanager
def spawn_and_wait_ctx(args, path, print_output=False, use_sigkill=False, sleep_after=1):
    """Compared to `spawn_ctx`, this one doesn't terminate, but awaits the process continuation"""
    with dir_ctx(path):
        proc = subprocess.Popen(
            args,
            stdout=sys.stdout if print_output else subprocess.DEVNULL,
            stderr=sys.stderr if print_output else subprocess.DEVNULL
        )
    if sleep_after:
        time.sleep(sleep_after)
    try:
        yield proc
    finally:
        # Wait for completion instead of killing
        proc.wait()