def process_election_voted(self, message):
leader = message.payload['leader']
if self.state in (GateNode.STATE_ELECTING, GateNode.STATE_INITIATED):
self.answers[message.sender] = leader
if self.has_all_answers(): # all children have responded now
leader = self.get_best_answer() # select the leader
if self.state == GateNode.STATE_ELECTING: # this is an intermediate node
self.state = GateNode.STATE_WAITING
yield NetworkMessage('election_voted',
self.info,
self.parent,
leader=leader)
else: # this is the node which started the election
self.state = GateNode.STATE_IDLE
self.leader = leader
for neighbour in self.neighbours:
yield NetworkMessage('election_finished',
self.info,
neighbour,
leader=leader)
else:
self.handle_error('Unexpected state')
def test_start_election(visitor_repository):
node = GateNode(nodes[0], [nodes[1], nodes[2]], visitor_repository)
assert list(node.process_message(LocalMessage('start_election'))) == \
[NetworkMessage('election_started', nodes[0], nodes[1]), NetworkMessage('election_started', nodes[0], nodes[2])]
assert node.state == GateNode.STATE_INITIATED
def test_leader_removed():
node = GateNode(nodes[0], [nodes[1], nodes[2]], visitor_repository)
node.leader = nodes[5]
assert list(node.process_message(NetworkMessage('leader_removed', nodes[1], nodes[0]))) == \
[NetworkMessage('leader_removed', nodes[0], nodes[2])]
assert node.leader is None
def test_terminate():
node = GateNode(nodes[0], [nodes[1], nodes[2]], visitor_repository)
assert list(node.process_message(LocalMessage('terminate'))) == \
[NetworkMessage('terminated', nodes[0], nodes[1]),
NetworkMessage('terminated', nodes[0], nodes[2]),
None]
def process_election_started(self, message):
if self.state == GateNode.STATE_IDLE:
self.state = GateNode.STATE_ELECTING
self.parent = message.sender
self.leader = None
self.answers = {}
for child in self.get_children():
yield NetworkMessage('election_started', self.info, child)
if self.has_all_answers():
# in this case there are no children for this node, so it votes for itself as the leader
self.state = GateNode.STATE_WAITING
yield NetworkMessage('election_voted',
self.info,
message.sender,
leader=self.info)
elif self.state in (GateNode.STATE_ELECTING, GateNode.STATE_INITIATED):
yield NetworkMessage('election_voted',
self.info,
message.sender,
leader=None)
else:
self.handle_error('Unexpected state')
def test_election_start_without_children(visitor_repository):
node = GateNode(nodes[0], [nodes[1]], visitor_repository)
assert list(node.process_message(NetworkMessage('election_started', nodes[1], nodes[0]))) == \
[NetworkMessage('election_voted', nodes[0], nodes[1], leader=nodes[0])]
assert node.state == GateNode.STATE_WAITING
assert node.parent == nodes[1]
def test_first_election_message(visitor_repository):
node = GateNode(nodes[0], [nodes[1], nodes[2], nodes[3]], visitor_repository)
assert list(node.process_message(NetworkMessage('election_started', nodes[1], nodes[0]))) == \
[NetworkMessage('election_started', nodes[0], nodes[2]), NetworkMessage('election_started', nodes[0], nodes[3])]
assert node.state == GateNode.STATE_ELECTING
assert node.parent == nodes[1]
def test_hello(visitor_repository):
node = GateNode(nodes[0], [nodes[1], nodes[2]], visitor_repository)
assert list(node.process_message(LocalMessage('say_hello'))) == \
[NetworkMessage('hello', nodes[0], nodes[1]), NetworkMessage('hello', nodes[0], nodes[2])]
assert list(node.process_message(NetworkMessage('hello', nodes[1], nodes[0]))) == \
[NetworkMessage('hey', nodes[0], nodes[1])]
def test_finishing_election(visitor_repository):
node = GateNode(nodes[0], [nodes[1], nodes[2], nodes[3]], visitor_repository)
node.state = GateNode.STATE_WAITING
assert list(node.process_message(NetworkMessage('election_finished', nodes[1], nodes[0], leader=nodes[5]))) == \
[NetworkMessage('election_finished', nodes[0], nodes[2], leader=nodes[5]), NetworkMessage('election_finished', nodes[0], nodes[3], leader=nodes[5])]
assert node.state == GateNode.STATE_IDLE
assert node.leader == nodes[5]
def test_another_election_message(visitor_repository):
node = GateNode(nodes[0], [nodes[1], nodes[2], nodes[3]], visitor_repository)
node.state = GateNode.STATE_ELECTING
node.parent = nodes[1]
assert list(node.process_message(NetworkMessage('election_started', nodes[2], nodes[0]))) == \
[NetworkMessage('election_voted', nodes[0], nodes[2], leader=None)]
assert node.state == GateNode.STATE_ELECTING
assert node.parent == nodes[1]
def test_last_ack_starting_node(visitor_repository):
node = GateNode(nodes[0], [nodes[1], nodes[2]], visitor_repository)
node.state = GateNode.STATE_INITIATED
node.answers = {nodes[1]: nodes[4]}
assert list(node.process_message(NetworkMessage('election_voted', nodes[2], nodes[0], leader=nodes[5]))) == \
[NetworkMessage('election_finished', nodes[0], nodes[1], leader=nodes[5]), NetworkMessage('election_finished', nodes[0], nodes[2], leader=nodes[5])]
assert node.state == GateNode.STATE_IDLE
assert node.leader == nodes[5]
def test_request_mutex(visitor_repository):
node = GateNode(nodes[0], [], visitor_repository)
node.leader = nodes[0]
assert list(node.process_message(NetworkMessage('mutex_requested', nodes[1], nodes[0]))) == \
[NetworkMessage('mutex_granted', nodes[0], nodes[1])]
assert node.mutex_holder == nodes[1]
assert not node.mutex_queue
assert list(node.process_message(NetworkMessage('mutex_requested', nodes[2], nodes[0]))) == []
assert node.mutex_queue == [nodes[2]]
assert list(node.process_message(NetworkMessage('mutex_requested', nodes[3], nodes[0]))) == []
assert node.mutex_queue == [nodes[2], nodes[3]]
assert list(node.process_message(NetworkMessage('mutex_released', nodes[1], nodes[0]))) == \
[NetworkMessage('mutex_granted', nodes[0], nodes[2])]
assert node.mutex_holder == nodes[2]
assert node.mutex_queue == [nodes[3]]
assert list(node.process_message(NetworkMessage('mutex_released', nodes[2], nodes[0]))) == \
[NetworkMessage('mutex_granted', nodes[0], nodes[3])]
assert node.mutex_holder == nodes[3]
assert node.mutex_queue == []
assert list(node.process_message(NetworkMessage('mutex_released', nodes[3], nodes[0]))) == []
assert node.mutex_holder is None
assert node.mutex_queue == []
def test_last_ack_intermediate_node(visitor_repository):
node = GateNode(nodes[0], [nodes[1], nodes[2], nodes[3]], visitor_repository)
node.state = GateNode.STATE_ELECTING
node.parent = nodes[1]
node.answers = {nodes[2]: nodes[5]}
assert list(node.process_message(NetworkMessage('election_voted', nodes[3], nodes[0], leader=nodes[4]))) == \
[NetworkMessage('election_voted', nodes[0], nodes[1], leader=nodes[5])]
assert node.state == GateNode.STATE_WAITING
assert node.answers == {nodes[2]: nodes[5], nodes[3]: nodes[4]}
def test_enter_refused():
node = VisitorNode(nodes[0])
assert list(node.process_message(LocalMessage('enter_park', gate=nodes[1]))) == \
[NetworkMessage('enter_request', nodes[0], nodes[1])]
assert node.state == VisitorNode.STATE_ENTERING
assert not list(
node.process_message(
NetworkMessage('enter_response', nodes[1], nodes[0],
allowed=False)))
assert node.state == VisitorNode.STATE_IDLE
def test_leave_rejected():
node = VisitorNode(nodes[0])
node.state = VisitorNode.STATE_ENTERED
assert list(node.process_message(LocalMessage('leave_park', gate=nodes[1]))) == \
[NetworkMessage('leave_request', nodes[0], nodes[1])]
assert node.state == VisitorNode.STATE_LEAVING
assert not list(
node.process_message(
NetworkMessage('leave_response', nodes[1], nodes[0],
allowed=False)))
assert node.state == VisitorNode.STATE_ENTERED
def leave_park(self, message):
gate = message.payload['gate']
if self.state == VisitorNode.STATE_ENTERED:
yield NetworkMessage('leave_request', self.info, gate)
self.state = VisitorNode.STATE_LEAVING
else:
self.handle_unexpected_state()
def terminate(self):
if self.state == GateNode.STATE_IDLE:
for neighbour in self.neighbours:
yield NetworkMessage('terminated', self.info, neighbour)
yield None # no more messages will be sent by this node
else:
self.handle_error('Unexpected state')
def test_first_ack(visitor_repository):
node = GateNode(nodes[0], [nodes[1], nodes[2], nodes[3]], visitor_repository)
node.state = GateNode.STATE_INITIATED
assert list(node.process_message(NetworkMessage('election_voted', nodes[1], nodes[0], leader=nodes[5]))) == []
assert node.state == GateNode.STATE_INITIATED
assert node.answers == {nodes[1]: nodes[5]}
def enter_park(self, message):
gate = message.payload['gate']
if self.state == VisitorNode.STATE_IDLE:
yield NetworkMessage('enter_request', self.info, gate)
self.state = VisitorNode.STATE_ENTERING
else:
self.handle_unexpected_state()
def process_leader_removed(self, message):
if self.leader is None: # leader was already removed by a previous message
return
self.leader = None
for neighbour in self.neighbours:
if neighbour != message.sender:
yield NetworkMessage('leader_removed', self.info, neighbour)
def remove_leader(self):
if self.state != GateNode.STATE_IDLE:
self.handle_error('Unexpected state')
if self.leader != self.info:
self.handle_error('Not the leader')
self.leader = None
for neighbour in self.neighbours:
yield NetworkMessage('leader_removed', self.info, neighbour)
def start_election(self):
if self.state == GateNode.STATE_IDLE:
self.state = GateNode.STATE_INITIATED
self.parent = None
self.leader = None
self.answers = {}
for neighbour in self.neighbours:
yield NetworkMessage('election_started', self.info, neighbour)
else:
self.handle_error('Unexpected state')
def process_mutex_granted(self, message):
if not self.mutex_requested:
self.handle_error('Mutex not requested')
state = self.repository.read_state()
for entering_node in self.enter_queue:
try:
state.enter(entering_node.id)
yield NetworkMessage('enter_response',
self.info,
entering_node,
allowed=True)
except AssertionError: # if node cannot enter
yield NetworkMessage('enter_response',
self.info,
entering_node,
allowed=False)
for leaving_node in self.leave_queue:
try:
state.leave(leaving_node.id)
yield NetworkMessage('leave_response',
self.info,
leaving_node,
allowed=True)
except AssertionError: # if node cannot leave
yield NetworkMessage('leave_response',
self.info,
leaving_node,
allowed=False)
self.repository.write_state(state)
self.mutex_requested = False
self.enter_queue = []
self.leave_queue = []
yield NetworkMessage('mutex_released', self.info, self.leader)
def process_election_finished(self, message):
leader = message.payload['leader']
if self.state == GateNode.STATE_WAITING:
self.state = GateNode.STATE_IDLE
self.leader = leader
for neighbour in self.neighbours:
if neighbour != message.sender:
yield NetworkMessage('election_finished',
self.info,
neighbour,
leader=leader)
def process_mutex_released(self, message):
if self.leader != self.info:
self.handle_error('Not a leader')
if self.mutex_holder is None:
self.handle_error('No mutex holder')
if self.mutex_holder != message.sender:
self.handle_error('Invalid sender')
if self.mutex_queue: # some nodes are waiting in the queue
self.mutex_holder = self.mutex_queue.pop(0)
yield NetworkMessage('mutex_granted', self.info, self.mutex_holder)
else:
self.mutex_holder = None
def test_leave_request(visitor_repository):
visitor_repository.write_state(State(capacity=1, visitors=[nodes[1].id]))
node = GateNode(nodes[0], [], visitor_repository)
node.leader = nodes[5]
assert list(node.process_message(NetworkMessage('leave_request', nodes[1], nodes[0]))) == \
[NetworkMessage('mutex_requested', nodes[0], nodes[5])]
assert node.leave_queue == [nodes[1]]
assert list(node.process_message(NetworkMessage('leave_request', nodes[2], nodes[0]))) == []
assert node.leave_queue == [nodes[1], nodes[2]]
assert list(node.process_message(NetworkMessage('mutex_granted', nodes[5], nodes[0]))) == \
[NetworkMessage('leave_response', nodes[0], nodes[1], allowed=True),
NetworkMessage('leave_response', nodes[0], nodes[2], allowed=False),
NetworkMessage('mutex_released', nodes[0], nodes[5])]
assert node.leave_queue == []
assert list(node.process_message(NetworkMessage('leave_request', nodes[3], nodes[0]))) == \
[NetworkMessage('mutex_requested', nodes[0], nodes[5])]
assert node.leave_queue == [nodes[3]]
def process_hello(self, message):
yield NetworkMessage('hey', self.info, message.sender)
def say_hello(self):
for neighbour in self.neighbours:
yield NetworkMessage('hello', self.info, neighbour)
def process_leave_request(self, message):
if not self.mutex_requested:
yield NetworkMessage('mutex_requested', self.info, self.leader)
self.mutex_requested = True
self.leave_queue.append(message.sender)
def process_mutex_requested(self, message):
if self.mutex_holder is None:
self.mutex_holder = message.sender
yield NetworkMessage('mutex_granted', self.info, self.mutex_holder)
else:
self.mutex_queue.append(message.sender)