def exchange(self, vault=None):
'''
First thing first, the initiator issues a "exchange request".
In Cyclon protocol, the exchange request consists in generating a
subset of peers to exchange with the oldest peer. The "age" of a peer
is based on the how many exchanges have passed since I last updated
the state of that peer of my neighboring list.
'''
if self.itsExchanging():
return True
Cyclon.peerList.increaseAges()
try:
oldestPeer = Cyclon.peerList.getOldest()
except IndexError:
print ' * No peer available for exchanging'
return True
print '''Starting an exchange with ''' + oldestPeer.getName()
self.exchangeStarted()
print >> stderr, ''' * computing subset '''
shuffleSize = randint(1, self.getShuffleLength()) - 1
randomSubset = Cyclon.peerList.drop(oldestPeer).getSubset(shuffleSize)
sentSet = CyclonPeerList([ oldestPeer ]) + randomSubset
message = Message(kind='exchange',
source=Cyclon.myself.getName(),
destination=oldestPeer.getName())
randomSubset.insert(0, Cyclon.myself)
body = message.getBody()
print >> stderr, ''' * building message '''
for p in randomSubset:
node = body.appendChild(message.createElement('node'))
node.setAttribute('name', p.getName())
node.childNodes = p.getConnectionsXML()
print >> stderr, ''' * Sending request '''
message.send(
oldestPeer.transport, 3, 3
).addCallback(
self.exchangeReplyReceived, sentSet=sentSet
).addErrback(
self.removePeerErrback, peer=oldestPeer.getName(), success=False
).addErrback(
self.exchangeFinished, success=False
).addErrback(
self.exchange)
return True
def replyIntroduction(self, peer, introduced):
replyMessage = Message('intro reply',
source=Cyclon.myself.getName(), destination=peer.getName(),
annotations={ 'introduced': introduced })
node = replyMessage.body.appendChild(Message.createElement("node"))
node.setAttribute('name', introduced.getName())
for c in introduced.getConnectionsXML():
node.appendChild(c)
replyMessage.send(
peer.transport, 5, 3
).addCallback(
lambda m: (
Cyclon.peerList.addPeer(peer),
(Cyclon.peerList.remove(m.introduced) or True
if m.introduced in Cyclon.peerList else True)
)
).addErrback(lambda m: True)
def sendIntroductions(self, peer, candidatesSet, replacersSet=None):
# Building the newcomers peer' description
nodeInfo = Message.createElement('node', { 'name':peer.getName() })
for c in peer.getConnectionsXML():
nodeInfo.appendChild(c)
# The replacersSet is used for replace unreachable peers in the
# errback method 'introductionErrback'.
if replacersSet == None:
replacersSet = Cyclon.peerList.drop(candidatesSet)
print ' | Sending introduction to the following peers: '
# Sending the introductory message to the random candidatesSet
for q in candidatesSet:
# One message per peer as the destination must be explicit
introMessage = Message(kind='introduction',
source=Cyclon.myself.getName(),
destination=q.getName(),
extraAttributes={
'ttl': str(self.getTTL())},
annotations={
'candidatesSset': candidatesSet,
'newcomer': peer,
'replacersSet': replacersSet})
# Appending newcomers info
introMessage.getBody().appendChild(nodeInfo)
print ' |->', q.getName()
# The actual sending
introMessage.send(
q.transport, 3, 3
).addCallback(
lambda m: True
).addErrback(
self.introductionErrback, message=introMessage)
