Coding.txt

Complete this Two-Stage (Open-and-Closed) circuit breaker implementation.

    Initial state is set to _is_closed = True.
    When the number of failure reaches to the limit, set the status to _is_closed = False along with _open_since time. Whenever the current time passes _open_since + _reset_timeout, the circuit breaker will let the call go through.
    If the attempt is successful, reset the status to _is_closed = True and reset the failure count to zero.

To test your code, place this cbdemo.py (Links to an external site.) under the same location as cb.py. See the expected output (Links to an external site.) for a correct solution.

### cbdemo.py ####
https://gist.github.com/sithu/6aa4c0b1832f50704a5dc9f733b91a61

### Expected Output ####
https://gist.github.com/sithu/d23d354d21ca5d6273c5a6f934b7d8c3

FEEL FREE TO ADD ANY FUNCTION YOU NEED.

############ cb.py ##############

from functools import wraps
from datetime import datetime, timedelta

class CircuitBreaker(object):
    def __init__(self, name=None, expected_exception=Exception, max_failure_to_open=3, reset_timeout=10):
        """
        DO NOT ALTER FUNCTION ARGUMENTS AND THEIR DEFAULT VALUES!
        """
        self._name = name
        self._expected_exception = expected_exception
        self._max_failure_to_open = max_failure_to_open
        self._reset_timeout = reset_timeout
        # Set the initial state
        self.close()
 
    def close(self):
        """
        Your solution must work with this '_is_closed' boolean flag variable only.
        DO NOT SET ANYTHING OTHER THAN True OR False, OR YOU WILL GET ZERO!
        """
        self._is_closed = True
        self._failure_count = 0
        
    def open(self):
        self._is_closed = False
        self._opened_since = datetime.utcnow()
        
    def __call__(self, func):
        if self._name is None:
            self._name = func.__name__

        @wraps(func)
        def with_circuitbreaker(*args, **kwargs):
            return self.call(func, *args, **kwargs)

        return with_circuitbreaker

    def call(self, func, *args, **kwargs):
        """
        Steps:
        1. If the cricuitbreaker is NOT in the executable state, then
           throw an Exception with this error message format -
            'CircuitBreaker[%s] is OPEN until %s (%d failures, %d sec remaining)'
                          {name}             {open_until} {failure_count}  {open_remaining}
        2. Call the given 'func' and handle the 'expected_exception'.
        """