Context-manager/Decorator that prevents function execution from timeout

timeout.py

# -*- coding: utf-8 -*-

import functools
import signal


class timeout(object):
    r"""Context-manager that prevents function execution from timeout.

    Also functions as a decorator.

    Example::
        >>> @timeout(2.5)
        ... def f(n):
        ...     time.sleep(n)
        >>> f(3)
        >>> with timeout(2.5):
        ...     time.sleep(3)
    """

    def __init__(self, seconds=1):
        super(timeout, self).__init__()

        self.seconds = seconds

    def __enter__(self):
        signal.signal(signal.SIGALRM, self.handler)
        # here float is accepted, different from alarm()
        signal.setitimer(signal.ITIMER_REAL, self.seconds)

    def __exit__(self, type, value, traceback):
        signal.setitimer(signal.ITIMER_REAL, 0)

    def __call__(self, func):
        @functools.wraps(func)
        def decorate_timeout(*args, **kwargs):
            with self:
                return func(*args, **kwargs)
        return decorate_timeout

    def handler(self, signum, frame):
        raise TimeoutError(f"Execution time exceeded {self.seconds:.3}s.")