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server.py
179 lines (144 loc) · 5.62 KB
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server.py
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from __future__ import print_function
import socket
import replicated
from time_table import TimeTable
import sys
import threading
import pickle
import signal
server_addresses = ['128.111.84.159', # Server0
'128.111.84.210', # Server1
'128.111.84.221'] # Server2
class Server:
def __init__(self, server_id, port=80):
self.socket = socket.socket()
self.host = socket.gethostname()
self.socket.bind((self.host, port))
self.data = replicated.ReplicatedDictionary()
self.log = replicated.ReplicatedLog()
self.server_id = int(server_id)
self.time_table = TimeTable(self.server_id, 3)
self.threads = []
# self.run = True
self.init_connection()
def init_connection(self):
self.socket.listen(5)
print("Server with id=", self.server_id, " is running and listening for incoming connections", sep="")
while True:
# close = raw_input("Close server? y/n")
# if close == "y":
# break
c, addr = self.socket.accept()
print("Connected to", addr)
c.send("Connection to server was successful")
client = ClientHandler(c, addr, self)
client.start()
self.threads.append(client)
self.socket.close()
for client in self.threads:
client.join()
def send_message(self, msg, ip):
data = pickle.dumps(msg)
address = (ip, 80)
self.socket.sendto(data, address)
def post(self, msg, author):
self.increment_time()
entry = replicated.Entry(msg, author, self.time_table.get_self_clock(), self.server_id)
self.data.add_post(entry)
self.log.add_entry(entry)
print("Post has been submitted at local time", self.time_table.get_self_clock())
def lookup(self, c):
package = pickle.dumps(self.data)
c.send(package)
def sync(self, sync_server):
address = (server_addresses[sync_server], 80)
sock = socket.socket()
sock.connect(address)
sock.recv(4096)
sock.send("update_contents_on_my_server")
recv = sock.recv(4096)
(other_log, other_time_table) = pickle.loads(recv)
sock.close()
for e in other_log:
not_in = self.data.is_not_in(e)
if not_in:
self.data.add_post(e)
self.log.add_entry(e)
# for e in other_log:
# for k in self.data.dict.values():
# if (e.get_time_stamp() != k.get_time_stamp()) and (e.get_parent_server() != k.get_parent_server()):
# self.data.add_post(e)
# self.log.add_entry(e)
self.time_table.sync_tables(other_time_table)
self.garbage_collect_log()
def received_sync(self, client, id):
log = self.compile_log(other_server_id=id)
data = (log, self.time_table)
data_pickled = pickle.dumps(data)
client.send(data_pickled)
#print("Msg sent")
# Compiles log to send when another server wants to sync with this server
def compile_log(self, other_server_id):
subLog = []
for e in self.log.get_log():
# The id of server where entry was first posted
entry_server_id = e.get_parent_server()
if self.time_table.table[other_server_id][entry_server_id] < e.get_time_stamp():
subLog.append(e)
return subLog
def garbage_collect_log(self):
# Entry i is the clock time at server i, to which point this server knows
# that all other servers know about events at server i
max_common_clocks = column_min_vals(self.time_table.table)
for e in self.log.get_log():
if e.get_time_stamp() <= max_common_clocks[e.get_parent_server()]:
self.log.remove_entry(e)
def increment_time(self):
self.time_table.increment_self()
def close_connection(self):
self.socket.close()
class ClientHandler(threading.Thread):
def __init__(self, client, address, parent_server):
threading.Thread.__init__(self)
self.client = client
self.address = address
self.parent_server = parent_server
def run(self):
while True:
recv = self.client.recv(4096)
inp = recv.split(' ', 1)
if recv == 'close':
print("Closing client connection")
self.client.close()
# self.parent_server.query_close()
break
elif inp[0] == 'post':
self.parent_server.post(inp[1], self.address)
elif inp[0] == 'lookup':
self.parent_server.lookup(self.client)
elif inp[0] == 'sync' and len(inp)>1:
sync_server = int(inp[1])
self.parent_server.sync(sync_server)
elif recv == "update_contents_on_my_server":
id = server_addresses.index(self.address[0])
self.parent_server.received_sync(self.client, id)
elif len(recv)>0:
print("Received message:", recv)
# Returns a list of minimum values for each column in a 2D list
def column_min_vals(table):
result = []
for i in range(len(table)):
minval = min([row[i] for row in table])
result.append(minval)
return result
# def handler(signum, frame):
# try:
# print('Ctrl+Z pressed')
# finally:
# server.close_connection()
id = int(sys.argv[1])
pport = 80
server = Server(server_id=id, port=pport)
#server = Server(port=18852)
# signal.signal(signal.SIGTSTP, handler)
#server = Server(port=18867)