def test_invalid_sequence_9():
m = AQStateMachine()
with pytest.raises(AssertionError):
m.transition_to_add()
m.transition_to_execute()
m.transition_to_execute_complete()
m.transition_to_execute()
def test_valid_sequence():
m = AQStateMachine()
m.transition_to_add()
m.transition_to_add()
m.transition_to_execute()
m.transition_to_rollback()
m.transition_to_rollback_complete()
class ActionQueue(object):
"""Queue of Action objects ready for execution."""
def __init__(self):
self._actions = list()
self._executed_actions = list()
self._state_machine = AQStateMachine()
def add(self, action):
"""Add an action to the execution queue."""
self._state_machine.transition_to_add()
self._actions.append(action)
def execute(self):
"""Execute all actions, throwing an ExecutionException on failure.
Catch the ExecutionException and call rollback() to rollback.
"""
self._state_machine.transition_to_execute()
for action in self._actions:
self._executed_actions.append(action)
self.execute_with_retries(action, lambda a: a.execute())
self._state_machine.transition_to_execute_complete()
def rollback(self):
"""Call rollback on executed actions."""
self._state_machine.transition_to_rollback()
for action in reversed(self._executed_actions):
try:
self.execute_with_retries(action, lambda a: a.rollback())
except: # pylint: disable=bare-except
pass # on exception, carry on with rollback of other steps
self._state_machine.transition_to_rollback_complete()
def execute_with_retries(self, action, f):
"""Execute function f with single argument action. Retry if
ActionRetryException is raised.
"""
# Run action until either it succeeds or throws an exception
# that's not an ActionRetryException
retry = True
while retry:
retry = False
try:
f(action)
except ActionRetryException as ex: # other exceptions should bubble out
retry = True
time.sleep(ex.ms_backoff / 1000.0)
def __init__(self):
self._actions = list()
self._executed_actions = list()
self._state_machine = AQStateMachine()
def test_invalid_sequence_11():
m = AQStateMachine()
with pytest.raises(AssertionError):
m.transition_to_add()
m.transition_to_rollback_complete()
def test_invalid_sequence_2():
m = AQStateMachine()
with pytest.raises(AssertionError):
m.transition_to_rollback()