def _stabilize(self):
"Periodically verify node's inmediate succesor and tell the successor about it"
# if successor fails find first alive successor in the
# successor list
if not self.is_node_alive(self.successor):
self.successor = self.find_first_successor_alive()
log.debug(
f'set new succesor from successor list: {self.successor.id}')
try:
with self.proxy(self.successor) as remote:
node = remote.predecessor
if node and self.is_node_alive(node) and in_interval_r(
node.id, self.id, self.successor.id):
self.successor = node
log.debug(f'finded new succesor: {node.id}')
self._update_successor_list()
except BaseException as why:
pass
try:
with self.proxy(self.successor) as remote:
remote.notify(self.info)
except Pyro4.errors.ConnectionClosedError: # between remote._update_successor_list remote fails and this is fixed when this method is called again, so i just let ignore this exception for efficiency
pass
def print_info(self):
log.debug(f'''
suc: {self.successor.id if self.successor else None}
pred: {self.predecessor.id if self.predecessor else None}
s_list: {
list(map(lambda node: node.id if node else None,self.successor_list))}
finger: {self.finger.print_fingers()}
keys: {list(map(lambda i:i[0],self.data.items()))}
assured: {list(map(lambda i:i[0],self.assured_data.items()))}''')
def __init__(self, id, ip, port, chord_id: str = 'default'):
self.id = id
self.ip = ip
self.port = port
self.finger = FingerTable(self.id)
self.data = {}
self._successor_list = [None for _ in range(m)]
self.assured_data = {}
self.chord_id = chord_id
log.init_logger(f"Node {self.id}", log.INFO) # init logging
log.debug(f"init")
def inner(*args, **kwargs):
for i in range(attempts):
try:
result = func(*args, **kwargs)
except BaseException as error:
log.error(
f'retry {i+1}/{attempts} {func.__name__}: {error}')
time.sleep(retry_delay)
continue
if i > 0:
log.debug(
f'resolve correctly function: {func.__name__} in attemt {i}'
)
return result
log.exception(f"can't handle exceptions with stabilization")
args[0].print_info()
def notify(self, node: 'NodeInfo'):
"Node think is might be our predecessor"
if not self.predecessor or not self.is_node_alive(
self.predecessor) or in_interval(node.id, self.predecessor.id,
self.id):
self.predecessor = node
log.debug(f'set new predecessor: {node.id}')
# Take dada from storage is needed
for key in list(self.assured_data.keys()):
if in_interval(key, self.predecessor.id, self.id):
value, t = self.assured_data.pop(key)
self.data[key] = value
log.debug(f'assume key assured : {key}')
# Transfer data to predecessor
transference = {}
for key in list(self.data.keys()):
# this interval is all the rign except this node
# interval, is different of key < predecessor.id
# because the rign is circular
if in_interval(key, self.id, self.predecessor.id):
transference[key] = self.data.pop(key)
# send data to predecessor node
try:
with self.proxy(self.predecessor) as remote:
remote.set_data(transference)
log.debug(
f'set data to predecessor (node {self.predecessor.id}): {list(transference.keys())}'
)
except BaseException:
log.exception(
f'problem sending data to node {self.predecessor.id}')
# remerge data again into this node data
self.data = {**self.data, **transference}
def join(self, node: 'NodeInfo'):
"node self joins the network node is a arbitrary node in the network"
self.predecessor = None
log.debug('joint')
with self.proxy(node) as remote:
self.successor = remote.find_successor(self.id)
# initialize successor_list using successor.successor_list
log.debug(f'finded successor: {self.successor.id}')
self._update_successor_list()
log.debug(f"join to {node.id} succesfuly")
def delete(self, key):
log.debug(f"call delete key {key}")
node = self.find_successor(key)
with self.proxy(node) as remote:
return remote.delete_item(key)
def load(self, key):
log.debug(f"call load key {key}")
node = self.find_successor(key)
with self.proxy(node) as remote:
return remote.get_item(key)
def save(self, key: int, value):
log.debug(f"call save key: {key}")
node = self.find_successor(key)
with self.proxy(node) as remote:
remote.set_item(key, value)
def __del__(self):
self.pyro_daemon.close()
log.debug('shutdown')