class Proposer (object):
_sync = {}
_async = ['set_multi', 'prepare', 'promise', 'set_proposal']
_ref = ['set_multi']
_parallel = []
def __init__(self, quorum_size):
self.quorum_size = quorum_size
self.proposed_value = None
self.last_accepted_id = None
self.next_proposal_number = 1
#async, ref
def set_multi(self, list_acceptors):
self.list_acceptors = list_acceptors
self.amulti = AMulti(self.list_acceptors)
self.smulti = SMulti(self.list_acceptors, self._atom)
def set_proposal(self, value):
'''
Sets the proposal value for this node if this node is not already aware of
another proposal having already been accepted.
'''
if self.proposed_value is None:
self.proposed_value = value
def prepare(self):
'''
Sends a prepare request to all Acceptors as the first step in attempting to
acquire leadership of the Paxos instance.
'''
self.promises_rcvd = set()
self.proposal_id = ProposalID(self.next_proposal_number, self.id)
print 'holaa', self.proposal_id
self.next_proposal_number += 1
#multi to all acceptors!!
result = self.smulti.onPrepare(self.proxy, self.proposal_id)
self.promise(result)
def promise(self, infoAcceptors):
'''
Called when a Promise message is received from an Acceptor
'''
for a in infoAcceptors:
# Ignore the message if it's for an old proposal or we have already received
# a response from this Acceptor
if a[1] != self.proposal_id or a[0] in self.promises_rcvd:
None
else:
self.promises_rcvd.add( a[0] )
if a[2] > self.last_accepted_id:
self.last_accepted_id = a[2]
# If the Acceptor has already accepted a value, we MUST set our proposal
# to that value.
if a[2] is not None:
self.proposed_value = a[3]
if len(self.promises_rcvd) > self.quorum_size/2:
if self.proposed_value is not None:
self.amulti.accept(self.id, self.proposal_id, self.proposed_value)
break
