circuit_threshold_1() - Code Metrics - Inspection of "Add unit and functional test setup" - fabfuel/circuitbreaker - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Branch — develop (641d1e)

by Fabian

created 2016-10-29 11:53 UTC

circuit_threshold_1() A

↳ Parent: Project

Complexity

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Total Lines

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
cc	1
c	1
b	0
f	0
dl	0
loc	3
rs	10

from time import sleep

from mock.mock import patch, Mock
from pytest import raises

from circuitbreaker import CircuitBreaker, CircuitBreakerError, \
    CircuitBreakerMonitor, STATE_CLOSED, STATE_HALF_OPEN, STATE_OPEN


def pseudo_remote_call():
    return True


@CircuitBreaker()
def circuit_success():
    return pseudo_remote_call()


@CircuitBreaker(failure_threshold=1, name="circuit_failure")
def circuit_failure():
    raise ConnectionError()


@CircuitBreaker(failure_threshold=1, name="threshold_1")
def circuit_threshold_1():
    return pseudo_remote_call()


@CircuitBreaker(failure_threshold=2, recover_timeout=1, name="threshold_2")
def circuit_threshold_2_timeout_1():
    return pseudo_remote_call()


@CircuitBreaker(failure_threshold=3, recover_timeout=1, name="threshold_3")
def circuit_threshold_3_timeout_1():
    return pseudo_remote_call()


def test_circuit_pass_through():
    assert circuit_success() is True


def test_circuitbreaker_monitor():
    assert CircuitBreakerMonitor.all_closed() is True
    assert len(list(CircuitBreakerMonitor.get_circuits())) == 5
    assert len(list(CircuitBreakerMonitor.get_closed())) == 5
    assert len(list(CircuitBreakerMonitor.get_open())) == 0

    with raises(ConnectionError):
        circuit_failure()

    assert CircuitBreakerMonitor.all_closed() is False
    assert len(list(CircuitBreakerMonitor.get_circuits())) == 5
    assert len(list(CircuitBreakerMonitor.get_closed())) == 4
    assert len(list(CircuitBreakerMonitor.get_open())) == 1


@patch('test_functional.pseudo_remote_call', return_value=True)
def test_threshold_hit_prevents_consequent_calls(mock_remote: Mock):
    mock_remote.side_effect = ConnectionError('Connection refused')
    circuitbreaker = CircuitBreakerMonitor.get('threshold_1')

    assert circuitbreaker.closed

    with raises(ConnectionError):
        circuit_threshold_1()

    assert circuitbreaker.opened

    with raises(CircuitBreakerError):
        circuit_threshold_1()

    mock_remote.assert_called_once()


@patch('test_functional.pseudo_remote_call', return_value=True)
def test_circuitbreaker_recover_half_open(mock_remote: Mock):
    circuitbreaker = CircuitBreakerMonitor.get('threshold_3')

    # initial state: closed
    assert circuitbreaker.closed
    assert circuitbreaker.state == STATE_CLOSED

    # no exception -> success
    assert circuit_threshold_3_timeout_1()

    # from now all subsequent calls will fail
    mock_remote.side_effect = ConnectionError('Connection refused')

    # 1. failed call -> original exception
    with raises(ConnectionError):
        circuit_threshold_3_timeout_1()
    assert circuitbreaker.closed
    assert circuitbreaker.failure_count == 1

    # 2. failed call -> original exception
    with raises(ConnectionError):
        circuit_threshold_3_timeout_1()
    assert circuitbreaker.closed
    assert circuitbreaker.failure_count == 2

    # 3. failed call -> original exception
    with raises(ConnectionError):
        circuit_threshold_3_timeout_1()

    # Circuit breaker opens, threshold has been reached
    assert circuitbreaker.opened
    assert circuitbreaker.state == STATE_OPEN
    assert circuitbreaker.failure_count == 3
    assert 0 < circuitbreaker.open_remaining <= 1

    # 4. failed call -> not passed to function -> CircuitBreakerError
    with raises(CircuitBreakerError):
        circuit_threshold_3_timeout_1()
    assert circuitbreaker.opened
    assert circuitbreaker.failure_count == 3
    assert 0 < circuitbreaker.open_remaining <= 1

    # 5. failed call -> not passed to function -> CircuitBreakerError
    with raises(CircuitBreakerError):
        circuit_threshold_3_timeout_1()
    assert circuitbreaker.opened
    assert circuitbreaker.failure_count == 3
    assert 0 < circuitbreaker.open_remaining <= 1

    # wait for 1 second (recover timeout)
    sleep(1)

    # circuit half-open -> next call will be passed through
    assert circuitbreaker.closed
    assert circuitbreaker.open_remaining < 0
    assert circuitbreaker.state == STATE_HALF_OPEN

    # State half-open -> function is executed -> original exception
    with raises(ConnectionError):
        circuit_threshold_3_timeout_1()
    assert circuitbreaker.opened
    assert circuitbreaker.failure_count == 4
    assert 0 < circuitbreaker.open_remaining <= 1

    # State open > not passed to function -> CircuitBreakerError
    with raises(CircuitBreakerError):
        circuit_threshold_3_timeout_1()


@patch('test_functional.pseudo_remote_call', return_value=True)
def test_circuitbreaker_reopens_after_successful_call(mock_remote: Mock):
    circuitbreaker = CircuitBreakerMonitor.get('threshold_2')

    assert str(circuitbreaker) == 'threshold_2'

    # initial state: closed
    assert circuitbreaker.closed
    assert circuitbreaker.state == STATE_CLOSED
    assert circuitbreaker.failure_count == 0

    # successful call -> no exception
    assert circuit_threshold_2_timeout_1()

    # from now all subsequent calls will fail
    mock_remote.side_effect = ConnectionError('Connection refused')

    # 1. failed call -> original exception
    with raises(ConnectionError):
        circuit_threshold_2_timeout_1()
    assert circuitbreaker.closed
    assert circuitbreaker.failure_count == 1

    # 2. failed call -> original exception
    with raises(ConnectionError):
        circuit_threshold_2_timeout_1()

    # Circuit breaker opens, threshold has been reached
    assert circuitbreaker.opened
    assert circuitbreaker.state == STATE_OPEN
    assert circuitbreaker.failure_count == 2
    assert 0 < circuitbreaker.open_remaining <= 1

    # 4. failed call -> not passed to function -> CircuitBreakerError
    with raises(CircuitBreakerError):
        circuit_threshold_2_timeout_1()
    assert circuitbreaker.opened
    assert circuitbreaker.failure_count == 2
    assert 0 < circuitbreaker.open_remaining <= 1

    # from now all subsequent calls will succeed
    mock_remote.side_effect = None

    # but recover timeout has not been reached -> still open
    # 5. failed call -> not passed to function -> CircuitBreakerError
    with raises(CircuitBreakerError):
        circuit_threshold_2_timeout_1()
    assert circuitbreaker.opened
    assert circuitbreaker.failure_count == 2
    assert 0 < circuitbreaker.open_remaining <= 1

    # wait for 1 second (recover timeout)
    sleep(1)

    # circuit half-open -> next call will be passed through
    assert circuitbreaker.closed
    assert circuitbreaker.failure_count == 2
    assert circuitbreaker.open_remaining < 0
    assert circuitbreaker.state == STATE_HALF_OPEN

    # successful call
    assert circuit_threshold_2_timeout_1()

    # circuit closed and reset'ed
    assert circuitbreaker.closed
    assert circuitbreaker.state == STATE_CLOSED
    assert circuitbreaker.failure_count == 0

    # some another successful calls
    assert circuit_threshold_2_timeout_1()
    assert circuit_threshold_2_timeout_1()
    assert circuit_threshold_2_timeout_1()






# @CircuitBreaker(failure_threshold=2, recover_timeout=4)
# def external_call(call_id):
#     if call_id in (2, 3, 6, 7, 10, 12, 15):
#         raise ConnectionError('Connection refused')
#     return 'SUCCESS'
#
# for i in range(0, 20):
#     try:
#         print('CALL: %d' % i)
#         print(' ## %s ' % external_call(i))
#     except Exception as e:
#         print('  \__ %s ' % e)
#
#     sleep(0.5)


1			from time import sleep
2
3			from mock.mock import patch, Mock
4			from pytest import raises
5
6			from circuitbreaker import CircuitBreaker, CircuitBreakerError, \
7			CircuitBreakerMonitor, STATE_CLOSED, STATE_HALF_OPEN, STATE_OPEN
8
9
10			def pseudo_remote_call():
11			return True
12
13
14			@CircuitBreaker()
15			def circuit_success():
16			return pseudo_remote_call()
17
18
19			@CircuitBreaker(failure_threshold=1, name="circuit_failure")
20			def circuit_failure():
21			raise ConnectionError()
22
23
24			@CircuitBreaker(failure_threshold=1, name="threshold_1")
25			def circuit_threshold_1():
26			return pseudo_remote_call()
27
28
29			@CircuitBreaker(failure_threshold=2, recover_timeout=1, name="threshold_2")
30			def circuit_threshold_2_timeout_1():
31			return pseudo_remote_call()
32
33
34			@CircuitBreaker(failure_threshold=3, recover_timeout=1, name="threshold_3")
35			def circuit_threshold_3_timeout_1():
36			return pseudo_remote_call()
37
38
39			def test_circuit_pass_through():
40			assert circuit_success() is True
41
42
43			def test_circuitbreaker_monitor():
44			assert CircuitBreakerMonitor.all_closed() is True
45			assert len(list(CircuitBreakerMonitor.get_circuits())) == 5
46			assert len(list(CircuitBreakerMonitor.get_closed())) == 5
47			assert len(list(CircuitBreakerMonitor.get_open())) == 0
48
49			with raises(ConnectionError):
50			circuit_failure()
51
52			assert CircuitBreakerMonitor.all_closed() is False
53			assert len(list(CircuitBreakerMonitor.get_circuits())) == 5
54			assert len(list(CircuitBreakerMonitor.get_closed())) == 4
55			assert len(list(CircuitBreakerMonitor.get_open())) == 1
56
57
58			@patch('test_functional.pseudo_remote_call', return_value=True)
59			def test_threshold_hit_prevents_consequent_calls(mock_remote: Mock):
60			mock_remote.side_effect = ConnectionError('Connection refused')
61			circuitbreaker = CircuitBreakerMonitor.get('threshold_1')
62
63			assert circuitbreaker.closed
64
65			with raises(ConnectionError):
66			circuit_threshold_1()
67
68			assert circuitbreaker.opened
69
70			with raises(CircuitBreakerError):
71			circuit_threshold_1()
72
73			mock_remote.assert_called_once()
74
75
76			@patch('test_functional.pseudo_remote_call', return_value=True)
77			def test_circuitbreaker_recover_half_open(mock_remote: Mock):
78			circuitbreaker = CircuitBreakerMonitor.get('threshold_3')
79
80			# initial state: closed
81			assert circuitbreaker.closed
82			assert circuitbreaker.state == STATE_CLOSED
83
84			# no exception -> success
85			assert circuit_threshold_3_timeout_1()
86
87			# from now all subsequent calls will fail
88			mock_remote.side_effect = ConnectionError('Connection refused')
89
90			# 1. failed call -> original exception
91			with raises(ConnectionError):
92			circuit_threshold_3_timeout_1()
93			assert circuitbreaker.closed
94			assert circuitbreaker.failure_count == 1
95
96			# 2. failed call -> original exception
97			with raises(ConnectionError):
98			circuit_threshold_3_timeout_1()
99			assert circuitbreaker.closed
100			assert circuitbreaker.failure_count == 2
101
102			# 3. failed call -> original exception
103			with raises(ConnectionError):
104			circuit_threshold_3_timeout_1()
105
106			# Circuit breaker opens, threshold has been reached
107			assert circuitbreaker.opened
108			assert circuitbreaker.state == STATE_OPEN
109			assert circuitbreaker.failure_count == 3
110			assert 0 < circuitbreaker.open_remaining <= 1
111
112			# 4. failed call -> not passed to function -> CircuitBreakerError
113			with raises(CircuitBreakerError):
114			circuit_threshold_3_timeout_1()
115			assert circuitbreaker.opened
116			assert circuitbreaker.failure_count == 3
117			assert 0 < circuitbreaker.open_remaining <= 1
118
119			# 5. failed call -> not passed to function -> CircuitBreakerError
120			with raises(CircuitBreakerError):
121			circuit_threshold_3_timeout_1()
122			assert circuitbreaker.opened
123			assert circuitbreaker.failure_count == 3
124			assert 0 < circuitbreaker.open_remaining <= 1
125
126			# wait for 1 second (recover timeout)
127			sleep(1)
128
129			# circuit half-open -> next call will be passed through
130			assert circuitbreaker.closed
131			assert circuitbreaker.open_remaining < 0
132			assert circuitbreaker.state == STATE_HALF_OPEN
133
134			# State half-open -> function is executed -> original exception
135			with raises(ConnectionError):
136			circuit_threshold_3_timeout_1()
137			assert circuitbreaker.opened
138			assert circuitbreaker.failure_count == 4
139			assert 0 < circuitbreaker.open_remaining <= 1
140
141			# State open > not passed to function -> CircuitBreakerError
142			with raises(CircuitBreakerError):
143			circuit_threshold_3_timeout_1()
144
145
146			@patch('test_functional.pseudo_remote_call', return_value=True)
147			def test_circuitbreaker_reopens_after_successful_call(mock_remote: Mock):
148			circuitbreaker = CircuitBreakerMonitor.get('threshold_2')
149
150			assert str(circuitbreaker) == 'threshold_2'
151
152			# initial state: closed
153			assert circuitbreaker.closed
154			assert circuitbreaker.state == STATE_CLOSED
155			assert circuitbreaker.failure_count == 0
156
157			# successful call -> no exception
158			assert circuit_threshold_2_timeout_1()
159
160			# from now all subsequent calls will fail
161			mock_remote.side_effect = ConnectionError('Connection refused')
162
163			# 1. failed call -> original exception
164			with raises(ConnectionError):
165			circuit_threshold_2_timeout_1()
166			assert circuitbreaker.closed
167			assert circuitbreaker.failure_count == 1
168
169			# 2. failed call -> original exception
170			with raises(ConnectionError):
171			circuit_threshold_2_timeout_1()
172
173			# Circuit breaker opens, threshold has been reached
174			assert circuitbreaker.opened
175			assert circuitbreaker.state == STATE_OPEN
176			assert circuitbreaker.failure_count == 2
177			assert 0 < circuitbreaker.open_remaining <= 1
178
179			# 4. failed call -> not passed to function -> CircuitBreakerError
180			with raises(CircuitBreakerError):
181			circuit_threshold_2_timeout_1()
182			assert circuitbreaker.opened
183			assert circuitbreaker.failure_count == 2
184			assert 0 < circuitbreaker.open_remaining <= 1
185
186			# from now all subsequent calls will succeed
187			mock_remote.side_effect = None
188
189			# but recover timeout has not been reached -> still open
190			# 5. failed call -> not passed to function -> CircuitBreakerError
191			with raises(CircuitBreakerError):
192			circuit_threshold_2_timeout_1()
193			assert circuitbreaker.opened
194			assert circuitbreaker.failure_count == 2
195			assert 0 < circuitbreaker.open_remaining <= 1
196
197			# wait for 1 second (recover timeout)
198			sleep(1)
199
200			# circuit half-open -> next call will be passed through
201			assert circuitbreaker.closed
202			assert circuitbreaker.failure_count == 2
203			assert circuitbreaker.open_remaining < 0
204			assert circuitbreaker.state == STATE_HALF_OPEN
205
206			# successful call
207			assert circuit_threshold_2_timeout_1()
208
209			# circuit closed and reset'ed
210			assert circuitbreaker.closed
211			assert circuitbreaker.state == STATE_CLOSED
212			assert circuitbreaker.failure_count == 0
213
214			# some another successful calls
215			assert circuit_threshold_2_timeout_1()
216			assert circuit_threshold_2_timeout_1()
217			assert circuit_threshold_2_timeout_1()
218
219
220
221
222
223
224			# @CircuitBreaker(failure_threshold=2, recover_timeout=4)
225			# def external_call(call_id):
226			# if call_id in (2, 3, 6, 7, 10, 12, 15):
227			# raise ConnectionError('Connection refused')
228			# return 'SUCCESS'
229			#
230			# for i in range(0, 20):
231			# try:
232			# print('CALL: %d' % i)
233			# print(' ## %s ' % external_call(i))
234			# except Exception as e:
235			# print(' \__ %s ' % e)
236			#
237			# sleep(0.5)
238

fabfuel / circuitbreaker

Branch — develop (641d1e)

circuit_threshold_1() A

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