def run(self):
while self.alive:
succ = self.node.get_successor()
if succ is not None and isinstance(succ, Address) == False:
succ = Address.get_address_from_string(succ)
if succ is None or succ == self.node.local_address:
self.node.fillsuc()
succ = self.node.get_successor()
if succ is not None and succ != self.node.local_address:
succ_pre_q = queryadd(succ, Message.getjson("get_your_pre"))
if succ_pre_q is None:
self.node.delete_successor()
else:
succ_pre = Address.get_address_from_string(
succ_pre_q["payload"])
if succ_pre is not None:
if succ_pre == succ:
self.node.notify(succ)
else:
succ_offset = find_offset(self.node.id,
hashadd(succ))
succ_pre_offset = find_offset(
self.node.id, hashadd(succ_pre))
if succ_pre_offset > 0 and succ_pre_offset < succ_offset:
self.node.update_ith_finger(1, succ_pre)
time.sleep(1)
def join_(self, receiving_node_addr):
response = queryadd(receiving_node_addr,
Message.getjson("find_succ_for_id", self.id))
if response is not None and response["subject"] == "set_your_succ":
self.update_ith_finger(
1, Address.get_address_from_string(response["payload"]))
response = queryadd(self.finger_table[1],
Message.getjson("get_your_pre"))
if response is not None and response["subject"] == "my_pre":
self.set_predecessor(
Address.get_address_from_string(response["payload"]))
self.notify(self.finger_table[1])
def closestprecedfinger(self, search_id):
if search_id is None:
return
search_id_offset = find_offset(self.id, search_id)
for i in range(M, 0, -1):
ith_finger = self.finger_table[i]
if ith_finger is None:
continue
if isinstance(ith_finger,
Address) == False and len(ith_finger) > 10:
ith_finger = Address.get_address_from_string(ith_finger)
else:
continue
ith_finger_id = hashadd(ith_finger)
ith_finger_offset = find_offset(self.id, ith_finger_id)
if ith_finger_offset > 0 and ith_finger_offset < search_id_offset:
query = queryadd(ith_finger, Message.getjson("areyoualive"))
if query["subject"] == "iamalive":
return ith_finger
self.finger_table[i] = None
return self.local_address
def update_ith_finger(self, pos, address):
if isinstance(address, Address) == False and address is not None:
address = Address.get_address_from_string(address)
if pos == 1:
print("Successor for {0} set to id {1}".format(
self.id, hashadd(address)))
if pos > 0 and pos <= 2**M:
self.finger_table[pos] = address
def __eq__(self, other):
if self is None or other is None:
return False
if isinstance(other, Address) == False:
if len(other) > 10:
other = Address.get_address_from_string(other)
else:
return False
return self.ipv4 == other.ipv4 and self.port == other.port
def hashadd(addr):
if addr is None:
return None
if isinstance(addr, Address) == False and len(addr) > 0:
addr = Address.get_address_from_string(addr)
s = "{0}:{1}".format(addr.port, addr.ipv4)
hash = hashlib.sha1()
hash.update(s.encode())
hash_value = int(hash.hexdigest(), 16)
return hash_value % (2**M)
def queryadd(address, msg):
if address is None or msg is None or len(msg) == 0:
return
if isinstance(address, Address) == False and len(address) > 0:
address = Address.get_address_from_string(address)
addr = (address.ipv4, address.port)
try:
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect(addr)
except Exception:
return None
return socketquery(sock, msg)
def ask_for_ip_port(self):
if self.seed == False:
while True:
print(
"\nEnter the address of the node you wish to join. For example, 'localhost:8433' or '172.32.21.1:64356'."
)
print("Hit Return if you are the seed node.")
join_addr = input()
if len(join_addr) == 0:
break
elif len(join_addr) > 10:
self.join_(Address.get_address_from_string(join_addr))
return
else:
print("\nInvalid address. Please try again.\n")
print(
"\nSeed node initialized with address {0} and id {1}. Waiting for other nodes to join the chord network.\n"
.format(self.local_address.to_string(), self.id))
def findsucc(self, search_id):
if search_id is None:
return
if search_id == self.id:
return self.get_successor()
ret = self.get_successor()
pre = self.findpredec(search_id)
if pre is not None and pre != self.local_address:
ret_q = queryadd(pre, Message.getjson("get_your_succ"))
if ret_q is not None and ret_q["subject"] == "my_succ":
ret = Address.get_address_from_string(ret_q["payload"])
if ret is None:
ret = self.local_address
return ret
def handle_message(self, msg):
msg_dict = Message.parse_message(msg)
subject = msg_dict["subject"]
payload = msg_dict["payload"]
result = ""
if subject == "find_succ_for_id":
successor = self.node.findsucc(payload)
result = Message.getjson("set_your_succ", str(successor))
elif subject == "get_your_succ":
result = Message.getjson("my_succ", str(self.node.get_successor()))
elif subject == "get_your_pre":
result = Message.getjson("my_pre", str(self.node.predecessor))
elif subject == "find_closest_p":
result = Message.getjson(
"closest_p", str(self.node.closestprecedfinger(payload)))
elif subject == "i_am_your_pre":
addr = Address.get_address_from_string(payload)
self.node.notified(addr)
return
elif subject == "get_your_finger_table":
result = Message.getjson("my_finger_table", self.node.finger_table)
elif subject == "log":
print(str(payload))
return
elif subject == "areyoualive":
result = Message.getjson("iamalive")
else:
result = Message.getjson("log", "Invalid command!")
sendsock(self.from_socket, result)
def fillsuc(self):
succ = self.get_successor()
if succ is None or succ == self.local_address:
for i in range(2, M + 1):
ith_finger = self.finger_table[i]
if ith_finger is not None and isinstance(
ith_finger, Address) == False and len(ith_finger) > 10:
ith_finger = Address.get_address_from_string(ith_finger)
if ith_finger is not None and ith_finger != self.local_address:
# Push this value "up" in the table
for j in range(i - 1, 0, -1):
self.update_ith_finger(j, ith_finger)
break
new_succ = self.get_successor()
if (
new_succ is None or new_succ == self.local_address
) and self.predecessor is not None and self.predecessor != self.local_address:
self.update_ith_finger(1, self.predecessor)
if (self.get_successor() is None and self.predecessor is None):
self.update_ith_finger(1, self.local_address)
def findpredec(self, search_id):
if search_id is None:
return
ret = self.local_address
ret_succ = self.get_successor()
most_recently_alive = self.local_address
ret_succ_offset = 0
if ret_succ is not None:
ret_succ_offset = find_offset(hashadd(ret), hashadd(ret_succ))
search_id_offset = find_offset(self.id, search_id)
while not (search_id_offset > 0
and search_id_offset <= ret_succ_offset):
curr_node_temp = ret
if ret == self.local_address:
ret = self.closestprecedfinger(search_id)
else:
result_q = queryadd(
ret, Message.getjson("find_closest_p", search_id))
if result_q is not None and result_q["subject"] == "closest_p":
result = None if result_q[
"payload"] is None else Address.get_address_from_string(
result_q["payload"])
else:
result = None
if result is None:
ret = most_recently_alive
ret_succ_q = queryadd(ret,
Message.getjson("get_your_succ"))
ret_succ = Address.get_address_from_string(
ret_succ_q["payload"]
) if ret_succ_q is not None and ret_succ_q[
"subject"] == "my_succ" else None
if ret_succ is None:
return self.local_address
continue
elif result == ret:
return result
else:
most_recently_alive = ret
ret_succ_q = queryadd(result,
Message.getjson("get_your_succ"))
ret_succ = Address.get_address_from_string(
ret_succ_q["payload"])
if ret_succ is not None:
ret = result
else:
ret_succ_q = queryadd(ret,
Message.getjson("get_your_succ"))
ret_succ = Address.get_address_from_string(
ret_succ_q["payload"])
ret_succ_offset = find_offset(hashadd(ret), hashadd(ret_succ))
search_id_offset = find_offset(hashadd(ret), search_id)
if curr_node_temp == ret:
break
return ret
