def __init__(self, *args, **kwargs):
super(Proposer, self).__init__(*args, **kwargs)
self.highest_proposal = None
self.received_promises = dict()
self.selector = Selector()
class Proposer(Role):
def __init__(self, *args, **kwargs):
super(Proposer, self).__init__(*args, **kwargs)
self.highest_proposal = None
self.received_promises = dict()
self.selector = Selector()
@Role.receive.register(Request)
def _(self, message, channel, create_reply=Prepare.create):
"""Prepare Phase.
A proposer selects a proposal number n and sends a prepare request
with number n to a majority of acceptors.
"""
LOG.debug("RECEIVED message {0}".format(message))
if message.value:
self.selector.add(message.value)
if not self.selector.is_empty():
current_proposal = self.state.read(Role.PROPOSED)
reply = create_reply(sender=message.receiver,
proposal=current_proposal)
channel.broadcast(reply)
self.notification.wait(current_proposal)
@Role.receive.register(Promise)
@Role.update_proposal
def _(self, message, channel, create_reply=Accept.create):
"""Accept Phase.
If the proposer receives a response to its prepare requests (numbered
n) from a majority of acceptors, then it sends an accept request to
each of those acceptors for a proposal numbered n with a value v, where
v is the value of the highest-numbered proposal among the responses, or
is any value if the responses reported no proposals.
"""
LOG.debug("RECEIVED message {0}".format(message))
self.received_promises.setdefault(message.proposal, set()) \
.add(message.sender)
if (self.highest_proposal is None or
message.accepted_proposal >= self.highest_proposal):
self.highest_proposal = message.proposal
if message.value:
self.selector.set(message.proposal, message.value)
value = self.selector.get(message.proposal)
minimum_quorum = len(channel.replicas) // 2 + 1
received_promises = len(self.received_promises.get(message.proposal))
if received_promises >= minimum_quorum:
reply = create_reply(sender=message.receiver,
proposal=message.proposal,
value=value)
channel.broadcast(reply)
#@Role.receive.register(Accepted)
#def _(self, message):
# pass
@Role.receive.register(Response)
def _(self, message, channel):
pass
