class Synchronizer():
def __init__(self, fog):
self.multicast_address = ('239.255.4.3', 1234)
self.sock = self.create_socket('239.255.4.3', 1234)
self.fog = fog
self.factory = Factory()
def create_socket(self, multicast_ip, port):
"""
Creates a socket, sets the necessary options on it, then binds it. The socket is then returned for use.
"""
local_ip = socket.gethostbyname(socket.gethostname())
# create a UDP socket
my_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
# allow reuse of addresses
my_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
# set multicast interface to local_ip
my_socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_IF, socket.inet_aton(local_ip))
# Set multicast time-to-live to 2...should keep our multicast packets from escaping the local network
my_socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 2)
# Construct a membership request...tells router what multicast group we want to subscribe to
membership_request = socket.inet_aton(multicast_ip) + socket.inet_aton(local_ip)
# Send add membership request to socket
# See http://www.tldp.org/HOWTO/Multicast-HOWTO-6.html for explanation of sockopts
my_socket.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, membership_request)
my_socket.bind(('', port))
return my_socket
def senddata(self, data, address):
sent = self.sock.sendto(data, address)
if sent == 0:
raise RuntimeError('socket connection broken')
return sent
def recvdata(self):
datagram = ''
try:
while True:
datagram, address = self.sock.recvfrom(1024)
if address == '':
raise RuntimeError('socket connection broken')
if address[0] == self.fog.ip: #myself
continue
response = self.factory.parse_response(datagram)
# validar pacote. verificar se eh ACK
if response.messagetype == 'ack':
self.fog.ack(address[0])
# validar pacote. verificar se eh k.a
elif response.messagetype == 'keepalive':
# valida se deve inserir novo nodo ou atualizar
if self.fog.containsResource(ip=address[0]):
# utiliza epoch recebida para validar se houve alteracoes
if self.fog.epochHasChanged(ip=address[0], epoch=response.epoch):
# se houve alteracoes(atualizacao de recurso). realiza requisicao coap
client = HelperClient(server=(address[0], 5683))
responseCoap = client.get('/.well-known/core')
# utiliza epoca do recurso que foi recebido por broadcast
self.fog.updateResource(ip=responseCoap.source[0], resources=responseCoap.payload, epoch=response.epoch)
# utiliza epoca do recurso que foi recebido por broadcast
# se houve alteracoes(inclusao de novo nodo). realiza requisicao coap
else:
client = HelperClient(server=(address[0], 5683))
# tratar timeout
responseCoap = client.get('/.well-known/core')
if responseCoap == None:
pass
self.fog.insertResource(ip=responseCoap.source[0], resources=responseCoap.payload, epoch=response.epoch)
# responde ACK para qm enviou o ka.
datagram = self.factory.build_request(epoch=self.fog.epoch, seq_number=self.fog.seq_number, message_type='ack')
self.senddata(datagram, address)
except socket.timeout as error:
print 'timeout'
print error.message
except Exception as error:
print error.message
# self.sock.close()
def observer(self):
# busca em coapserver os proprios recursos
# frequentemente realizar esse request para se monitorar.
# caso haja alteracoes nos recursos, incrementar epoca
print 'observer'
client = HelperClient(server=(self.fog.ip, 5683))
responseCoap = client.get('/.well-known/core')
if responseCoap.payload == None:
responseCoap.payload = []
# atualiza epoca se estiver diferente
self.fog.checkMyResources(responseCoap.payload)
self.fog.resources = responseCoap.payload
time.sleep(10)
return self.observer()
def keepalive(self):
print 'send keepalive'
datagram = self.factory.build_request(epoch=self.fog.epoch, seq_number=self.fog.seq_number, message_type='keepalive')
self.fog.sendingKeepAlive()
self.senddata(datagram, self.multicast_address)
time.sleep(30)
self.fog.removeInactiveNodes()
return self.keepalive()
def worker(self):
worker_server_address = (socket.gethostbyname(socket.gethostname()), 5001)
sock_worker = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sock_worker.bind(worker_server_address)
print 'sync worker running on address: ' + str(worker_server_address[0]) + ' and port ' + str(worker_server_address[1])
while True:
try:
data, client_address = sock_worker.recvfrom(1024)
operation = data[0]
if operation == 'p':
sock_worker.sendto(self.fog.printResources(), client_address)
continue
else:
sock_worker.sendto('Missing params', client_address)
continue
except socket.timeout:
print 'TIMEOUT'
continue
