interrupt.py

#
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from __future__ import print_function
from __future__ import absolute_import

from scancode.timeouts import Timeout


DEFAULT_TIMEOUT = 120  # seconds


class TimeoutError(Exception):
    pass


def interruptible(func, args=(), kwargs={}, timeout=DEFAULT_TIMEOUT):
    """
    Call `func` function with `args` and `kwargs` arguments and return a tuple of
    (success, return value). `func` is invoked through an OS-specific wrapper and
    will be interrupted if it does not return within `timeout` seconds.

    `func` returned results must be pickable.
    `timeout` in seconds defaults to DEFAULT_TIMEOUT.

    `args` and `kwargs` are passed to `func` as *args and **kwargs.

    In the returned tuple of (success, value), success is True or False.
    If success is True, the call was successful and the second item in the tuple is
    the returned value of `func`.
    
    If success is False, the call did not complete within `timeout`
    seconds and was interrupted. In this case, the second item in the
    tuple is an error message string.
    """

    runner = Timeout(timeout, TimeoutError)

    def runnable(): 
        return func(*args, **kwargs)

    try:
        return True, runner.execute(runnable)
    except:
        import traceback
        traceback.print_exc()
        return False, ('ERROR: Processing interrupted: timeout after '
                       '%(timeout)d seconds.' % locals())