98 lines
2.5 KiB
Python
98 lines
2.5 KiB
Python
# retoor <retoor@molodetz.nl>
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from devplacepy.services.nodes.circuit import CLOSED, HALF_OPEN, OPEN, CircuitBreaker
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class Clock:
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def __init__(self):
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self.now = 0.0
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def __call__(self):
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return self.now
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def make(failures=3, open_seconds=60):
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clock = Clock()
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return CircuitBreaker(failures, open_seconds, clock), clock
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def test_unknown_keys_are_closed():
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breaker, _ = make()
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assert breaker.state("x") == CLOSED and breaker.allows("x")
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def test_it_opens_at_the_threshold_and_not_before():
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breaker, _ = make(failures=3)
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breaker.failure("x")
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breaker.failure("x")
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assert breaker.allows("x")
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breaker.failure("x")
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assert breaker.state("x") == OPEN and not breaker.allows("x")
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def test_a_success_resets_the_streak():
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breaker, _ = make(failures=3)
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breaker.failure("x")
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breaker.failure("x")
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breaker.success("x")
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breaker.failure("x")
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breaker.failure("x")
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assert breaker.allows("x")
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def test_it_goes_half_open_after_the_cooldown_and_admits_one_probe():
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breaker, clock = make(failures=1, open_seconds=60)
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breaker.failure("x")
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clock.now = 59
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assert breaker.state("x") == OPEN
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clock.now = 60
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assert breaker.state("x") == HALF_OPEN and breaker.allows("x")
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breaker.begin("x")
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assert not breaker.allows("x")
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def test_a_failed_probe_reopens_for_a_full_cooldown():
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breaker, clock = make(failures=1, open_seconds=60)
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breaker.failure("x")
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clock.now = 70
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breaker.begin("x")
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breaker.failure("x")
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assert breaker.state("x") == OPEN
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clock.now = 129
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assert breaker.state("x") == OPEN
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clock.now = 131
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assert breaker.state("x") == HALF_OPEN
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def test_a_successful_probe_closes_it():
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breaker, clock = make(failures=1)
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breaker.failure("x")
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clock.now = 100
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breaker.begin("x")
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breaker.success("x")
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assert breaker.state("x") == CLOSED and breaker.allows("x")
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def test_keys_are_independent():
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breaker, _ = make(failures=1)
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breaker.failure(("node", "a"))
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assert not breaker.allows(("node", "a"))
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assert breaker.allows(("node", "b"))
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assert breaker.allows(("destination", "a"))
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def test_open_count_and_forget():
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breaker, _ = make(failures=1)
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breaker.failure("a")
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breaker.failure("b")
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assert breaker.open_count() == 2
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breaker.forget("a")
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assert breaker.open_count() == 1
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def test_a_zero_threshold_still_needs_one_failure():
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breaker = CircuitBreaker(failures=0)
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assert breaker.allows("x")
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breaker.failure("x")
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assert not breaker.allows("x")
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