# (C) Copyright 2017 Inova Development Inc.
# All Rights Reserved
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""
    Disgnostic code to timeout a function.  Used only during development
"""
from functools import wraps
import errno
import os
import signal


class FunctionTimeoutError(Exception):
    pass


def functiontimeout(seconds=10, error_message=os.strerror(errno.ETIME)):
    """Defines a timeout decorator that can be applied other
       functions with the statement @timeout(number-of-seconds).
       Generates a timeout exception if the function execution exceeds the
       timeout time in seconds.
    """
    def decorator(func):
        def _handle_timeout(signum, frame):
            raise FunctionTimeoutError(error_message)

        def wrapper(*args, **kwargs):
            signal.signal(signal.SIGALRM, _handle_timeout)
            signal.alarm(seconds)
            try:
                result = func(*args, **kwargs)
            finally:
                signal.alarm(0)
            return result

        return wraps(func)(wrapper)

    return decorator
