From c3a17c7ccfda53c59368e41066f1dcb61d4be315 Mon Sep 17 00:00:00 2001
From: Michael Zanger <michaelzanger@Michaels-MacBook-Air.fritz.box>
Date: Tue, 16 Jan 2024 16:41:56 +0100
Subject: [PATCH] fix update cache
---
server.py | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 84 insertions(+), 7 deletions(-)
diff --git a/server.py b/server.py
index 51042d9..d129148 100644
--- a/server.py
+++ b/server.py
@@ -6,6 +6,7 @@ import time
import ipaddress
import netifaces as ni
import platform
+import uuid
client_broadcast_listener_port = 49153
server_broadcast_listener_port = 49154
@@ -15,10 +16,16 @@ server_heartbeat_tcp_listener_port = 49152
client_receive_chat_tcp_port = 50001
client_forward_message_multicast_port = 51000
+leader_election_port = 49155
+
multicast_group_ip = '224.0.1.1'
last_heartbeat_timestamp = None
+# create election sockets
+ring_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+ring_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+
class Server(multiprocessing.Process):
client_cache_key_offset = 0
local_servers_cache = dict()
@@ -38,6 +45,10 @@ class Server(multiprocessing.Process):
self.local_servers_cache = server_cache
self.local_clients_cache = clients_cache
self.last_heartbeat_timestamp = last_heartbeat_timestamp
+ ring_socket.bind((self.server_address, leader_election_port))
+ self.server_uuid = self.generate_server_uuid()
+ print("My UUID: ", self.server_uuid)
+ self.participant = True
@staticmethod
def get_local_ip_address():
@@ -104,6 +115,10 @@ class Server(multiprocessing.Process):
return "macOS"
else:
return "Unknown"
+
+ @staticmethod
+ def generate_server_uuid():
+ return str(uuid.uuid4())
def run(self):
print(self.server_id+": "+"Up and running")
@@ -203,7 +218,8 @@ class Server(multiprocessing.Process):
if current_time - self.last_heartbeat_timestamp >= timeout_duration:
print(f"No heartbeats received for {timeout_duration} seconds. Initiating LCR...")
# Call a function to initiate the LCR algorithm here
- self.initiate_lcr_algorithm()
+ print(self.local_servers_cache)
+ self.start_leader_election(self.server_uuid, self.local_servers_cache)
# find highest server ID in cache
def get_last_server_id(self):
@@ -393,13 +409,15 @@ class Server(multiprocessing.Process):
separator = "_"
MSG = servers_cache_as_string + separator.encode('utf-8') + clients_cache_as_string
-
broadcast_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
broadcast_socket.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
+ broadcast_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+ time.sleep(3)
if self.os == "macOS":
broadcast_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
broadcast_socket.sendto(MSG, (BROADCAST_ADDRESS, PORT))
+ print("broadcast sent to", BROADCAST_ADDRESS, PORT, "with message", MSG)
else:
broadcast_socket.sendto(MSG, (BROADCAST_ADDRESS, PORT))
broadcast_socket.close()
@@ -408,10 +426,11 @@ class Server(multiprocessing.Process):
BROADCAST_ADDRESS = self.get_broadcast_address()
BROADCAST_PORT = 5980
print("listen for cache update")
+
# Local host information
- MY_HOST = socket.gethostname()
- MY_IP = socket.gethostbyname(MY_HOST)
- print("listen for cache update")
+ # MY_HOST = socket.gethostname()
+ # MY_IP = socket.gethostbyname(MY_HOST)
+
# Create a UDP socket
listen_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
# Set the socket to broadcast and enable reusing addresses
@@ -419,7 +438,6 @@ class Server(multiprocessing.Process):
listen_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
if self.os == "macOS":
- print("listening for cache updates")
listen_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
listen_socket.bind((BROADCAST_ADDRESS, BROADCAST_PORT))
else:
@@ -496,4 +514,63 @@ class Server(multiprocessing.Process):
multicast_socket.close()
-
\ No newline at end of file
+ def start_leader_election(self, server, neighbor_dict):
+ self.send_election_message(server, neighbor_dict['server_address'])
+ self.set_participant(True)
+
+ def send_election_message(server, neighbor_address):
+ election_message = {"mid": server, "isLeader": False}
+ ring_socket.sendto(json.dumps(election_message).encode(), neighbor_address)
+
+ def get_neighbour(servers, current_server, direction):
+ if not servers:
+ return None
+
+ server_ids = list(servers.keys())
+ current_index = server_ids.index(current_server)
+
+ if direction == 'left':
+ neighbor_index = (current_index - 1) % len(server_ids)
+ elif direction == 'right':
+ neighbor_index = (current_index + 1) % len(server_ids)
+ else:
+ return None
+
+ neighbor_server_id = server_ids[neighbor_index]
+ neighbor_server_info = servers[neighbor_server_id]
+
+ return {'server_id': neighbor_server_id, 'server_address': neighbor_server_info}
+
+ def set_participant(p):
+ global participant
+ participant = p
+
+ def leader_election(self):
+ while True:
+ data, address = ring_socket.recvfrom(4096)
+ if data:
+ election_message = json.loads(data.decode())
+ received_mid = election_message.get('mid')
+ received_mid_id = received_mid['server_uuid'] # Correctly access the server UUID
+
+ # Compare received_mid_id with self.server_uuid (UUID comparison)
+ if received_mid_id > self.server_uuid:
+ self.send_election_message(self.server_uuid, self.get_neighbour(self.local_servers_cache, self.server_uuid, 'left')['server_address'])
+ elif received_mid_id == self.server_uuid and self.participant:
+ self.send_election_message(self.server_uuid, self.get_neighbour(self.local_servers_cache, self.server_uuid, 'left')['server_address'])
+ elif received_mid_id < self.server_uuid and not self.participant:
+ self.send_election_message(self.server_uuid, self.get_neighbour(self.local_servers_cache, self.server_uuid, 'left')['server_address'])
+
+ # Determine participant status and leader
+ self.participant = True # You may adjust this logic
+ if election_message['isLeader']:
+ self.set_leader(election_message['mid'])
+ if self.server_uuid != received_mid_id:
+ self.set_is_leader(False)
+ self.send_election_message(self.server_uuid, self.get_neighbour(self.local_servers_cache, self.server_uuid, 'left')['server_address'])
+ else:
+ self.set_is_leader(True)
+ self.participant = False # You may set this as not a participant
+
+
+
--
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