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NodeConsensusServer.py
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NodeConsensusServer.py
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import sys
import time
import json
import socket
import thread
import random
import pickle
import logging
import threading
from multiprocessing import Process
from KThread import *
from messages.append_entries_messages import AppendEntriesMessage
from messages.vote_messages import RequestForVoteMessage
from messages.config_messages import ServerConfig
#from CommunicationsHandler import *
from AcceptorFile import *
logger = logging.getLogger(__name__)
class Server(object):
def __init__(self, id_):
self.id = id_
self.config_file = 'config-%d' % self.id
logger.debug('Server Init. Config File = {}'.format(self.config_file))
self.role = 'follower'
self.commitIndex = 0
self.lastApplied = 0
self.leaderID = 0
address = json.load(file('config.json'))
port_list = address['AddressBook']
running = address['running']
self.initial_state = address['initial_state']
self.addressbook = {}
for id_ in running:
self.addressbook[id_] = port_list[id_ - 1]
# need to put it into file later on
self.load()
self.port = self.addressbook[self.id]
self.request_votes = self.peers[:]
self.numVotes = 0
self.oldVotes = 0
self.newVotes = 0
self.lastLogIndex = 0
self.lastLogTerm = 0
self.listener = KThread(target = self.listen, args= (acceptor,))
self.listener.start()
logger.debug('Started listening on port {}'.format(self.port))
self.during_change = 0
self.newPeers = []
self.new = None
self.old = None
def listen(self, on_accept):
logger.info('Server Listen Method')
srv = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
srv.bind(("", self.port))
print 'start listenning ', self.id, " ", self.currentTerm
while True:
data,addr = srv.recvfrom(1024)
#print 'listening ', self.id
thr = KThread(target=on_accept, args=(self,data,addr))
thr.start()
'''
data, addr = srv.recvfrom(1024)
logger.info('------ from listening method------------')
#logger.info(data,addr)
thr = KThread(target=on_accept, args=(self, data, addr))
thr.start()
'''
srv.close()
def follower(self):
logger.info('Server Follower Method')
print 'Running as a follower ', self.id, " ", self.currentTerm
self.role = 'follower'
self.last_update = time.time()
election_timeout = 5 * random.random() + 5
while time.time() - self.last_update <= election_timeout:
pass
self.start_election()
while True:
self.last_update = time.time()
election_timeout = 5 * random.random() + 5
while time.time() - self.last_update <= election_timeout:
pass
if self.election.is_alive():
self.election.kill()
self.start_election()
def start_election(self):
print 'Server start_election Method ', self.id, " ", self.currentTerm
self.role = 'candidate'
self.election = KThread(target =self.thread_election,args = ())
if len(self.peers) != 0:
self.currentTerm += 1
self.votedFor = self.id
self.save()
self.numVotes = 1
if self.during_change == 1:
self.newVotes = 0
self.oldVotes = 0
if self.id in self.new:
self.newVotes = 1
if self.id in self.old:
self.oldVotes = 1
elif self.during_change == 2:
self.newVotes = 0
if self.id in self.new:
self.newVotes = 1
self.election.start()
def thread_election(self):
logger.info('Server thread_election Method')
print 'timouts, start a new election with term %d' % self.currentTerm
self.role = 'candidate'
self.request_votes = self.peers[:]
sender = self.id
while 1:
# print 'Send vote request to ', self.request_votes
#logger.info(self.peers,self.request_votes)
for peer in self.peers:
if peer in self.request_votes:
Msg = str(self.lastLogTerm) + ' ' + str(self.lastLogIndex)
msg = RequestForVoteMessage(sender, peer, self.currentTerm, Msg)
data = pickle.dumps(msg)
sock = socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
sock.sendto(data, ("", self.addressbook[peer]))
time.sleep(1) # wait for servers to receive
def leader(self):
logger.info('Server leader Method')
print 'Running as a leader ', self.id, " ", self.currentTerm
self.role = 'leader'
self.nextIndex = {}
self.matchIndex = {}
for peer in self.peers:
self.nextIndex[peer] = len(self.log) + 1
self.matchIndex[peer] = 0
self.append_entries()
def append_entries(self):
print 'Server append_entries Method ', self.id, " ", self.currentTerm
receipts = self.peers[:]
while 1:
receipts = self.peers[:]
if self.during_change != 0:
for peer in receipts:
if peer not in self.nextIndex:
self.nextIndex[peer] = len(self.log) + 1
self.matchIndex[peer] = 0
for peer in receipts:
if len(self.log) >= self.nextIndex[peer]:
prevLogIndex = self.nextIndex[peer] - 1
if prevLogIndex != 0:
prevLogTerm = self.log[prevLogIndex-1].term
else:
prevLogTerm = 0
entries = [self.log[self.nextIndex[peer]-1]]
else:
entries = []
prevLogIndex = len(self.log)
if prevLogIndex != 0:
prevLogTerm = self.log[prevLogIndex-1].term
else:
prevLogTerm = 0
Msg = AppendEntriesMessage(self.id, peer, self.currentTerm, entries, self.commitIndex, prevLogIndex, prevLogTerm)
data = pickle.dumps(Msg)
sock = socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
sock.sendto(data, ("", self.addressbook[peer]))
time.sleep(0.5)
def step_down(self):
logger.info('Server step_down Method')
if self.role == 'candidate':
print 'candidate step down when higher term and becomes follower', self.id, " ", self.currentTerm
self.election.kill()
self.last_update = time.time()
self.role = 'follower'
elif self.role == 'leader':
self.leader_state.kill()
self.follower_state = KThread(target = self.follower, args = ())
self.follower_state.start()
def load(self):
print 'Server load config Method ', self.id
initial_running = [1,2,3]
# new_quorom = []
try:
with open(self.config_file) as f:
serverConfig = pickle.load(f)
except Exception as e:
if self.id not in initial_running:
serverConfig = ServerConfig(100, 0, -1, [], [])
else:
initial_running.remove(self.id)
serverConfig = ServerConfig(100, 0, -1, [], initial_running)
self.poolsize = serverConfig.poolsize
self.currentTerm = serverConfig.currentTerm
self.votedFor = serverConfig.votedFor
self.log = serverConfig.log
self.peers = serverConfig.peers
self.majority = (len(self.peers) + 1)/2 + 1
# self.new_quorom = new_quorom
#self.majority_1 = (len(self.new_quorom) + 1)/2 + 1
def save(self):
print 'Server save config Method ', self.id, " ", self.currentTerm
serverConfig = ServerConfig(self.poolsize, self.currentTerm, self.votedFor, self.log, self.peers)
with open(self.config_file, 'w') as f:
pickle.dump(serverConfig, f)
def run(self):
print 'Server thread run Method ', self.id, " ", self.currentTerm
time.sleep(1)
self.follower_state = KThread(target = self.follower, args = ())
self.follower_state.start()
# while self.role != 'leader':
# pass
# self.follower_state.kill()
# self.listener.kill()
# print 'Now I am the leader for term %d' % self.currentTerm
# self.leader_state.start()