def gossip():
# checks if I am currently gossiping with someone else
if not shard.gossiping:
shard.lastToGossip = False
incoming_data = json.loads(request.get_json())
shard.gossiping = True
# causal context of the incoming node trying to gossip
other_context = incoming_data["causal-context"]
# key store of incoming node trying to gossip
other_kvstore = incoming_data["kv-store"]
# this is true if the other node determined i will be the tiebreaker
tiebreaker = True if incoming_data["tiebreaker"] == ADDRESS else False
incoming_Vc = VectorClock(view=None, clock=other_context)
if other_kvstore == shard.keystore:
shard.gossiping = False
return jsonify({"message": "We're equal."}), 201
elif incoming_Vc.allFieldsZero():
shard.gossiping = False
return jsonify({"message": "You dont have any data"}), 201
elif incoming_Vc.selfHappensBefore(shard.VC.__repr__()):
# I am at least concurrent or after
shard.gossiping = False
return jsonify({"message": "I Don't need yours."}), 201
elif incoming_Vc.__repr__() != shard.VC.__repr__():
shard.keystore = other_kvstore
shard.VC.merge(other_context, ADDRESS)
shard.gossiping = False
return jsonify({"message": "I took your data"}), 200
return jsonify({"message": "gossiping"}), 201
def gossip():
# checks if I am currently gossiping with someone else
if not shard.gossiping:
incoming_data = json.loads(request.get_json())
shard.gossiping = True
# causal context of the incoming node trying to gossip
other_context = incoming_data["context"]
# key store of incoming node trying to gossip
other_kvstore = incoming_data["kv-store"]
if other_kvstore == shard.keystore:
return jsonify({"message": "We're equal."}), 200
# this is true if the other node determined i will be the tiebreaker
tiebreaker = True if incoming_data["tiebreaker"] == ADDRESS else False
incoming_Vc = VectorClock(view=None, clock=other_context)
if shard.VC.selfHappensBefore(other_context):
# I am before
# i accept your data
shard.keystore = other_kvstore
shard.VC.merge(other_context, ADDRESS)
shard.gossiping = False
print("I HAPPENED BEFORE, I TAKE YOU" + str(shard.keystore),
file=sys.stderr)
return jsonify({"message": "I took your data"}), 200
elif incoming_Vc.selfHappensBefore(shard.VC.__repr__()):
# I am after the incoming one, so return my data
shard.gossiping = False
return jsonify({
"message": "I am after you, take my data",
"context": shard.VC.__repr__(),
"kv-store": shard.keystore,
}), 501
elif tiebreaker:
shard.gossiping = False
return jsonify({
"message": "I am the tiebreaker, take my data",
"context": shard.VC.__repr__(),
"kv-store": shard.keystore,
}), 501
elif not tiebreaker:
if bool(other_kvstore) and not incoming_Vc.allFieldsZero():
shard.keystore = other_kvstore
shard.VC.merge(other_context, ADDRESS)
shard.gossiping = False
print("I DID NOT HAPPEN BEFORE BUT AM NOT THE TIEBREAKER" +
str(shard.keystore),
file=sys.stderr)
return jsonify({"message": "I took your data"}), 200
shard.gossiping = False
return jsonify({"message": "I am gossiping with someone else"}), 400
def gossip(self):
if (self.gossiping == False):
current_key_store = self.keystore
self.gossiping = True
replica_ip_addresses = self.shard_replicas(self.shard_ID)
replica = replica_ip_addresses[(random.randint(
0,
len(replica_ip_addresses) - 1))]
while (self.ADDRESS == replica):
replica = replica_ip_addresses[(random.randint(
0,
len(replica_ip_addresses) - 1))]
myNumber = int((self.ADDRESS.split(".")[3]).split(":")[0])
otherNumber = int((replica.split(".")[3]).split(":")[0])
tiebreaker = replica if (otherNumber > myNumber) else self.ADDRESS
data = {
"context": self.VC.__repr__(),
"kv-store": current_key_store,
"tiebreaker": tiebreaker
}
print("sending to node: " + replica + " " + str(data),
file=sys.stderr)
try:
response = self.router.PUT(replica,
'/kv-store/internal/gossip/',
json.dumps(data))
except:
code = -1
code = response.status_code
if (code == 200):
# 200: They took my data
self.gossiping = False
elif (code == 501):
content = response.json()
# 501:
# the other node was either the tiebreaker or happened after self
# so this node takes its data
# context of node
other_context = content["context"]
# key store of incoming node trying to gossip
other_kvstore = content["kv-store"]
incoming_Vc = VectorClock(view=None, clock=other_context)
if bool(other_kvstore) and not incoming_Vc.allFieldsZero():
if current_key_store == self.keystore:
print("I TOOK DATA: " + str(self.keystore),
file=sys.stderr)
self.VC.merge(other_context, self.ADDRESS)
self.keystore = other_kvstore
else:
print("I RECIEVED AN UPDATE WHILE GOSSIPING, ABORT",
file=sys.stderr)
self.gossip = False
#self happened before other, take its kvstore and merge with my clock
# concurrent but other is tiebreaker
else:
# 400: Other is already gossiping with someone else
# ELSE: unresponsive node (maybe itll be code 404?)
self.gossiping = False
else:
# Curretly gossiping,
# Will call after gossip backoff again
self.gossiping = False
return 200
