def isCloser(self, peerB, targetPosition):
""" Return True if this peer is closer than peerB to targetPosition
"""
d1 = Geometry.distance(self.getPosition(), targetPosition)
d2 = Geometry.distance(peerB.getPosition(), targetPosition)
return d1 < d2
def getPeerAround(self, targetPosition, emitter_id, isClockWise=True):
""" Return the peer that is the closest to a target position and that
is in the right half plane.
targetPosition : target position which we are looking around
isClockWise : boolean indicating if we we searching in the right or the
left half-plane - optional
Return : a peer or None if there is no peer in the half plane
"""
found = False
around = None
distClosest = 0
nodePosition = self.node.getPosition()
for p in self.peers.values():
if p.getId() == emitter_id:
continue
if Geometry.inHalfPlane(nodePosition, targetPosition,
p.getPosition()) == isClockWise:
# first entity in right half-plane
if not found:
found = True
around = p
distClosest = Geometry.distance(targetPosition, p.getPosition())
else:
dist = Geometry.distance(targetPosition, p.getPosition())
# this peer is closer
if dist < distClosest:
around = p
distClosest = dist
return around
def NEAREST(self, event):
""" While scanning around our target a position, a peer informs us that
there exists a peer that is closer than our current best.
"""
peerPos = event.getArg(protocol.ARG_REMOTE_POSITION)
# check if this peer is closer than our current best
currentBestDistance = Geometry.distance(self.best.getPosition(),
self.node.getPosition())
newDist = Geometry.distance(peerPos, self.node.getPosition())
if newDist < currentBestDistance:
super(Scanning,self).NEAREST(event)
self.node.setState(Locating())
def getBadGlobalConnectivityPeers(self):
""" Check if global connectivity is ensured
Return a pair of entities not respecting property or an empty set.
First entity should be used to search clockwise and the second one ccw"""
result = []
nodePos = self.node.getPosition()
length = self.getNumberOfPeers()
if length == 0:
return []
if length == 1:
(peer,) = self.peers.values()
return [peer, peer]
for index in range(length):
ent = self.ccwPeers.ll[index]
nextEnt = self.ccwPeers.ll[ (index+1) % length ]
entPos = ent.getPosition()
nextEntPos = nextEnt.getPosition()
if not Geometry.inHalfPlane(entPos, nodePos, nextEntPos):
return [ent, nextEnt]
return []
def BEST(self, event):
""" A peer sent us a BEST message
This is the default behaviour
"""
# unexpected message, do not process it
msg = 'BEST'
if not self.isExpected(msg):
self.logger.debug('Error, reception of a ' + msg + 'message in state '
+ str(self.__class__))
return
self.timer.cancel()
# Get the ID and the position of the BEST peer
bestId = event.getArg(protocol.ARG_ID)
bestPos = event.getArg(protocol.ARG_POSITION)
bestAddress = event.getSenderAddress()
# send a queryaround message
bestDistance = Geometry.distance(self.node.getPosition(), bestPos)
factory = EventFactory.getInstance(PeerEvent.TYPE)
queryaround = factory.createQUERYAROUND(bestId, bestDistance)
queryaround.setRecipientAddress(bestAddress)
self.node.dispatch(queryaround)
# Create a turning state and store the Best peer
bestPeer = Peer(id=bestId, address=event.getSenderAddress(),
position=bestPos)
scanning = Scanning()
scanning.setBestPeer(bestPeer)
# go to the Scanning state
self.node.setState(scanning)
def QUERYAROUND(self, event):
""" A peer sent us a QUERYAROUND message """
#peer, idNearest, distNearest:
source_id = event.getArg(protocol.ARG_ID)
idNearest = event.getArg(protocol.ARG_BEST_ID)
distNearest = event.getArg(protocol.ARG_BEST_DISTANCE)
manager = self.node.getPeersManager()
target = event.getArg(protocol.ARG_POSITION)
closest = manager.getClosestPeer(target, source_id)
factory = EventFactory.getInstance(PeerEvent.TYPE)
# found a closest peer and this peer is a new one (it isn't idNearest moving
# toward target position).
if ( (Geometry.distance(closest.getPosition(), target) < distNearest) and
closest.getId() <> idNearest ):
# send a nearest message
nearestEvent = factory.createNEAREST(closest)
nearestEvent.setRecipientAddress(event.getSenderAddress())
self.node.dispatch(nearestEvent)
else:
# search for a peer around target position
around = manager.getPeerAround(target, source_id)
if around is not None:
aroundEvt = factory.createAROUND(around)
aroundEvt.setRecipientAddress(event.getSenderAddress())
self.node.dispatch(aroundEvt)
else:
self.logger.debug('no peer around position: ' + str(target))
def computeAwarenessRadius(self):
""" Based on curent the repartition of our peers (number, position),
compute what should be our awareness radius
Return an awareness radius (integer)
"""
if self.hasTooManyPeers():
offset = self.getNumberOfPeers() - self.maxPeers
# get the awareness radius of the last peer that is inside our AR
# in distance order
index = len(self.distPeers) - offset -1
return self.distPeers.ll[index].getAwarenessRadius()
elif self.hasTooFewPeers():
fartherPeerPos = self.distPeers.ll[len(self.distPeers) - 1].getPosition()
maxDist = Geometry.distance(self.node.getPosition(), fartherPeerPos)
density = maxDist / self.getNumberOfPeers()
return self.expectedPeers / density
else:
fartherPeerPos = self.distPeers.ll[len(self.distPeers) - 1].getPosition()
return Geometry.distance(self.node.getPosition(), fartherPeerPos)
def getWorstPeers(self):
""" Return a list of peers with which we should disconnect. Removing these
peers must NOT break the global connectivity rule.
Return a list of peers or [] if we cannot remove a peer
"""
if not self.hasTooManyPeers():
return []
# filter list of neighbors
# keep only entities not in Awareness Area which do not provoke mis-respect
# of Global Connectivity Rule
FilterList = []
endFilter = True
indexFilter = len(self.distPeers) - 1
nodePos = self.node.getPosition()
while endFilter and indexFilter > 0:
ent = self.distPeers.ll[indexFilter]
distEnt = Geometry.distance(ent.getPosition(), nodePos)
# first, verify that ent is not in Awareness Area
if distEnt > self.node.getAwarenessRadius() :
# and that we are not in its AR
if distEnt > ent.getAwarenessRadius():
indInCcw = self.ccwPeers.ll.index(ent)
successor = self.ccwPeers.ll[(indInCcw + 1) % len(self.ccwPeers)]
predecessor = self.ccwPeers.ll[indInCcw - 1]
# then verify that ent is not mandatory for Rule respect
if Geometry.inHalfPlane(predecessor.getPosition(), nodePos,
successor.getPosition()):
FilterList.append(ent)
else:
# stop iteration because all following entities are in Awareness
# Radius
endFilter = False
indexFilter -= 1
return FilterList
def computeAwarenessRadius(self):
""" Based on curent the repartition of our peers (number, position),
compute what should be our awareness radius
Return an awareness radius (integer)
"""
if self.hasTooManyPeers():
offset = self.getNumberOfPeers() - self.maxPeers
index = len(self.distPeers) - offset - 1
# Get the average between the max inside distance and the min outside distance
pos_outside = self.distPeers.ll[index].getPosition()
pos_inside = self.distPeers.ll[index - 1].getPosition()
dist_outside = Geometry.distance(self.node.getPosition(), pos_outside)
dist_inside = Geometry.distance(self.node.getPosition(), pos_inside)
return (dist_outside + dist_inside) // 2
if self.hasTooFewPeers():
fartherPeerPos = self.distPeers.ll[len(self.distPeers) - 1].getPosition()
maxDist = Geometry.distance(self.node.getPosition(), fartherPeerPos)
# Areal density
return maxDist * math.sqrt(self.expectedPeers / self.getNumberOfPeers())
else:
fartherPeerPos = self.distPeers.ll[len(self.distPeers) - 1].getPosition()
return Geometry.distance(self.node.getPosition(), fartherPeerPos)
def necessaryPeers(self):
""" Returns the list of peers that are necessary for our global connectivity. """
n = len(self.ccwPeers)
if n < 4:
return self.enumeratePeers()
result = []
for i in xrange(n):
pred_pos = self.ccwPeers.ll[i - 2].getPosition()
pos = self.node.getPosition()
succ_pos = self.ccwPeers.ll[i].getPosition()
if not Geometry.inHalfPlane(pred_pos, pos, succ_pos):
result.append(self.ccwPeers.ll[i - 1])
return result
def AROUND(self, event):
""" A peer sent us an AROUND message """
# cancel timer since we got our response
self.timer.cancel()
peer = event.createRemotePeer()
# current number of neighbours
nbNeighbours = len(self.neighbours)
# last neighbour found
last = self.neighbours[nbNeighbours-1]
nodePos = self.node.getPosition() # our position
bestPos = self.best.getPosition() # position of best node
peerPos = Geometry.relativePosition(peer.getPosition(),
self.node.getPosition())
# check if turn ends : we have at least 3 neighbours and either we got back
# to the first peer (=> turn completed) or our last neighbour was in the
# left half plane and this peer is in the right half plane
if ( nbNeighbours > 2 ) and (peer.getId() == self.best.getId()) or (
not Geometry.inHalfPlane(bestPos, nodePos, last.getPosition())
and Geometry.inHalfPlane(bestPos, nodePos, peerPos) ):
# Our awarenesse radius is the distance between us and our closest
# neighbour, because we are sure to know all the entities between us
# and the best.
bestRelativePos = Geometry.relativePosition(bestPos, nodePos)
minDistance = Geometry.distance(bestRelativePos, nodePos)
self.node.setAwarenessRadius(minDistance)
# register these peers with the peerManager and connect !
manager = self.node.getPeersManager()
for p in self.neighbours:
# FIXME : should we add the peer upon receiving the CONNECT msg?
manager.addPeer(p)
factory = EventFactory.getInstance(PeerEvent.TYPE)
hello = factory.createHELLO()
hello.setRecipientAddress(p.getAddress())
self.node.dispatch(hello)
self.node.setState(Connecting())
else:
# add this peer to our list of neighbours
self.addPeerAround(peer)
# send this peer a queryaround message
bestDist = Geometry.distance(bestPos, nodePos)
factory = EventFactory.getInstance(PeerEvent.TYPE)
queryaround = factory.createQUERYAROUND(self.best.getId(), bestDist)
queryaround.setRecipientAddress(peer.getAddress())
self.node.dispatch(queryaround)
self.startTimer()
def DETECT(self, event):
""" Notification that a peer is moving towards us"""
peer = event.createRemotePeer()
id_ = peer.getId()
manager = self.node.getPeersManager()
# Sanity check 1: don't connect with ourselves
if id_ == self.node.getId():
return
# Sanity check 2: don't connect with someone too far from us
dist = Geometry.distance(self.node.getPosition(), peer.getPosition())
ar = self.node.getAwarenessRadius()
if dist > ar:
return
# we are only interested by entities that are not yet in our peer list
if not manager.hasPeer(id_):
# Check we don't have too many peers, or have worse peers than this one
if manager.isPeerAccepted(peer):
# Connect to this peer
factory = EventFactory.getInstance(PeerEvent.TYPE)
hello = factory.createHELLO()
hello.setRecipientAddress(peer.getAddress())
self.node.dispatch(hello)
def setLocalPosition(self, nodePosition):
""" Set the local position in the coordinate system with origin nodePosition
nodePosition: position of the node, e.g. [12,56]
"""
self.localPosition = Geometry.localPosition(self.getPosition(), nodePosition)
def UPDATE(self, event):
""" A peer sent us an UPDATE message."""
# extract the peer from the event
peer = event.createPeer()
id_ = peer.getId()
manager = self.node.getPeersManager()
if not manager.hasPeer(id_):
self.logger.debug('UPDATE from %s, but we are not connected' % peer.getId())
return
# save peer old value
oldPeer = manager.getPeer(event.getArg(protocol.ARG_ID))
# update peer
manager.updatePeer(peer)
# notify the controller that a peer has changed
ctlFact = EventFactory.getInstance(ControlEvent.TYPE)
upd = ctlFact.createUPDATE(peer)
self.node.dispatch(upd)
oldPosition = oldPeer.getPosition()
newPosition = peer.getPosition()
nodePosition = self.node.getPosition()
oldAR = oldPeer.getAwarenessRadius()
newAR = peer.getAwarenessRadius()
peerFct = EventFactory.getInstance(PeerEvent.TYPE)
# peer position changed
if not oldPosition == newPosition:
# verify entities that could be interested by the entity id
for ent in manager.enumeratePeers():
if ent.getId() == id_:
continue
itsAR = ent.getAwarenessRadius()
# get distance between self and ent
ourDist = Geometry.distance(nodePosition, ent.getPosition())
# get distance between ent and entity id
theirDist = Geometry.distance(ent.getPosition(), newPosition)
# get old distance between ent and entity id
theirOldDist = Geometry.distance(ent.getPosition(), oldPosition)
if (theirDist < itsAR < theirOldDist) or \
(theirDist < ourDist < theirOldDist):
# modified entity enters in Awareness Area of ent
# OR moving entity is now closer than us to ent
# The moving peer is notified to a fixed entity
detect = peerFct.createDETECT(peer)
detect.setRecipientAddress(ent.getAddress())
self.node.dispatch(detect)
elif oldAR < theirOldDist and newAR >= theirDist:
# The entity is notified to the moving peer
detect = peerFct.createDETECT(ent)
detect.setRecipientAddress(peer.getAddress())
self.node.dispatch(detect)
# peer awareness radius changed
if not oldAR == newAR:
self.logger.debug('AR updated %d -> %d' % (oldAR, newAR))
# verify entities that could be interested by the modified entity.
for ent in manager.enumeratePeers():
if ent.getId() == id_:
continue
# get distance between ent and modified entity
position = ent.getPosition()
theirDist = Geometry.distance(position, newPosition)
theirOldDist = Geometry.distance(position, oldPosition)
self.logger.debug('peer %s: position (%s), old dist %d, new dist %d' %
(ent.getId(), str(position), theirDist, theirOldDist))
if oldAR < theirOldDist and newAR >= theirDist:
# ent enter in Awareness Area of modified entity.
# DETECT message sent to modified entity.
detect = peerFct.createDETECT(ent)
detect.setRecipientAddress(peer.getAddress())
self.node.dispatch(detect)
