Add initial master server code.

Subversion-branch: /master
Subversion-revision: 2183
This commit is contained in:
Simon Howard 2010-12-02 19:28:06 +00:00
commit 12d3df6db9
4 changed files with 469 additions and 0 deletions

17
.gitignore vendored Normal file
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# These are the default patterns globally ignored by Subversion:
*.o
*.lo
*.la
*.al
.libs
*.so
*.so.[0-9]*
*.a
*.pyc
*.pyo
*.rej
*~
.#*
.*.swp
.DS_store

201
chocolate-master Executable file
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#!/usr/bin/env python
#
# Copyright(C) 2010 Simon Howard
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
# 02111-1307, USA.
#
#
# Chocolate Doom master server.
#
import socket
import struct
from select import select
from time import time, strftime
# Filename of log file.
LOG_FILE = "chocolate-master.log"
# Servers must refresh themselves periodically. If nothing happens
# after this many seconds, remove them from the list.
SERVER_TIMEOUT = 2 * 60 * 60 # 2 hours
# Maximum length of a query response.
MAX_RESPONSE_LEN = 1000
# Packet types, matches the constants in net_defs.h.
NET_MASTER_PACKET_TYPE_ADD = 0
NET_MASTER_PACKET_TYPE_ADD_RESPONSE = 1
NET_MASTER_PACKET_TYPE_QUERY = 2
NET_MASTER_PACKET_TYPE_QUERY_RESPONSE = 3
# Address and port to listen on.
UDP_ADDRESS = socket.inet_ntoa(struct.pack(">l", socket.INADDR_ANY))
UDP_PORT = 2342
class Server:
""" A server that has registered itself. """
def __init__(self, addr):
self.addr = addr
self.refresh()
def refresh(self):
self.add_time = time()
def timed_out(self):
return time() - self.add_time > SERVER_TIMEOUT
def encode_addr(self):
s = "%s:%i" % self.addr
# Encode string along with terminating NUL.
return struct.pack("%is" % (len(s) + 1), s)
class MasterServer:
def open_log_file(self):
self.log_file = open(LOG_FILE, "a")
def log_output(self, addr, s):
timestamp = strftime("%b %d %H:%M:%S")
self.log_file.write("%s %s:%i: %s\n" % ((timestamp,) + addr + (s,)))
self.log_file.flush()
def __init__(self, address, port):
""" Initialise a new master server. """
self.servers = {}
self.open_log_file()
self.server_addr = (address, port)
self.open_socket()
def send_message(self, addr, message_type, payload):
""" Send a message of the specified type to the specified
remote address. """
header = struct.pack(">h", message_type)
packet = header + payload
self.sock.sendto(packet, addr)
def response_packets(self):
""" Convert the list of servers into a list of payload strings
for responding to queries. """
packets = [struct.pack("")]
for server in self.servers.values():
encoded_addr = server.encode_addr()
# Start a new packet?
if len(packets[-1]) + len(encoded_addr) > MAX_RESPONSE_LEN:
packets.append(struct.pack(""))
packets[-1] += encoded_addr
return packets
def process_add_to_master(self, addr):
""" Process an "add to master" request received from a server. """
if addr in self.servers:
self.log_output(addr, "Refresh server")
server = self.servers[addr]
server.refresh()
else:
self.log_output(addr, "Add to master")
server = Server(addr)
self.servers[addr] = server
# Send a reply indicating successful
self.send_message(addr,
NET_MASTER_PACKET_TYPE_ADD_RESPONSE,
struct.pack(">h", 1))
def process_query(self, addr):
""" Process a query message received from a client. """
self.log_output(addr, "Query")
packets = self.response_packets()
for packet in packets:
self.send_message(addr,
NET_MASTER_PACKET_TYPE_QUERY_RESPONSE,
packet)
def process_packet(self, data, addr):
""" Process a packet received from a server. """
packet_type, = struct.unpack(">h", data[0:2])
if packet_type == NET_MASTER_PACKET_TYPE_ADD:
self.process_add_to_master(addr)
elif packet_type == NET_MASTER_PACKET_TYPE_QUERY:
self.process_query(addr)
def rx_packet(self):
""" Invoked when a packet is received. """
data, addr = self.sock.recvfrom(1024)
try:
self.process_packet(data, addr)
except Exception, e:
print e
def age_servers(self):
""" Check server timestamps and flush out stale servers. """
for server in self.servers.values():
if server.timed_out():
self.log_output(server.addr,
"Timed out: no heartbeat in %i secs" %
(time() - server.add_time))
del self.servers[server.addr]
def open_socket(self):
""" Open the server socket and bind to the listening address. """
self.sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
self.sock.bind(self.server_addr)
def run(self):
""" Run the server main loop, listening for packets. """
self.log_output(self.server_addr, "Server started.")
while True:
r, w, x = select([self.sock], [], [], 5)
self.age_servers()
if self.sock in r:
self.rx_packet()
if __name__ == "__main__":
server = MasterServer(UDP_ADDRESS, UDP_PORT)
server.run()

138
chocolate-master-test.py Executable file
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#!/usr/bin/env python
#
# Copyright(C) 2010 Simon Howard
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
# 02111-1307, USA.
#
#
# Test script for querying the master server.
#
import socket
import sys
import struct
NET_MASTER_PACKET_TYPE_ADD = 0
NET_MASTER_PACKET_TYPE_ADD_RESPONSE = 1
NET_MASTER_PACKET_TYPE_QUERY = 2
NET_MASTER_PACKET_TYPE_QUERY_RESPONSE = 3
UDP_PORT = 2342
def send_message(sock, addr, message_type, payload=None):
header = struct.pack(">h", message_type)
packet = header
if payload is not None:
packet += payload
sock.sendto(packet, addr)
def get_response(sock, addr, message_type):
""" Wait for a response of the specified type to be received. """
while True:
packet, remote_addr = sock.recvfrom(1024)
if remote_addr == addr:
type, = struct.unpack(">h", packet[0:2])
if type != message_type:
raise Exception("Wrong type of packet received: %i != %i" %
(type, message_type))
return packet[2:]
print "Rxed from %s, expected %s" % (remote_addr, addr)
def read_string(packet):
terminator = struct.pack("b", 0)
strlen = packet.index(terminator)
result = struct.unpack("%ss" % strlen, packet[0:strlen])
return packet[strlen + 1:], result
def add_to_master(addr_str):
""" Add self to master at specified IP address. """
addr = (socket.gethostbyname(addr_str), UDP_PORT)
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
# Send request
print "Sending request to master at %s" % str(addr)
send_message(sock, addr, NET_MASTER_PACKET_TYPE_ADD)
# Wait for response.
print "Waiting for response..."
response = get_response(sock, addr, NET_MASTER_PACKET_TYPE_ADD_RESPONSE)
success, = struct.unpack(">h", response)
if not success:
raise Exception("Address not successfully added to master.")
print "Address added to master."
def parse_query_response(packet):
servers = []
while len(packet) > 0:
packet, addr_str = read_string(packet)
servers.append(addr_str)
return servers
def query_master(addr_str):
""" Query a master server for its list of server IP addresses. """
addr = (socket.gethostbyname(addr_str), UDP_PORT)
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
# Send request
print "Sending query to master at %s" % str(addr)
send_message(sock, addr, NET_MASTER_PACKET_TYPE_QUERY)
# Receive response
print "Waiting for response..."
response = get_response(sock, addr, NET_MASTER_PACKET_TYPE_QUERY_RESPONSE)
servers = parse_query_response(response)
print "%i servers" % len(servers)
for s in servers:
print "\t%s" % s
if len(sys.argv) > 2 and sys.argv[1] == "query":
query_master(sys.argv[2])
elif len(sys.argv) > 2 and sys.argv[1] == "add":
add_to_master(sys.argv[2])
else:
print "Usage:"
print "chocolate-master-test.py query <address>"
print "chocolate-master-test.py add <address>"

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master-cronjob Executable file
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#!/usr/bin/env python
#
# Copyright(C) 2010 Simon Howard
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
# 02111-1307, USA.
#
#
# Cronjob script that checks the master server is running.
#
import socket
import sys
import struct
from select import select
from time import time
NET_MASTER_PACKET_TYPE_ADD = 0
NET_MASTER_PACKET_TYPE_ADD_RESPONSE = 1
NET_MASTER_PACKET_TYPE_QUERY = 2
NET_MASTER_PACKET_TYPE_QUERY_RESPONSE = 3
QUERY_ATTEMPTS = 5
MASTER_SERVER = "master.chocolate-doom.org"
UDP_PORT = 2342
def send_message(sock, addr, message_type, payload=None):
header = struct.pack(">h", message_type)
packet = header
if payload is not None:
packet += payload
sock.sendto(packet, addr)
def get_response(sock, addr, expected_type, timeout):
""" Wait for a response packet to be received. """
start_time = time()
while time() - start_time < timeout:
r, w, x = select([sock], [], [], 1)
if sock in r:
packet, remote_addr = sock.recvfrom(1024)
type, = struct.unpack(">h", packet[0:2])
if expected_type == type:
return type, packet[2:]
raise Exception("No response received from server in %i seconds"
% (time() - start_time))
def read_string(packet):
terminator = struct.pack("b", 0)
strlen = packet.index(terminator)
result = struct.unpack("%ss" % strlen, packet[0:strlen])
return packet[strlen + 1:], result
def parse_query_response(packet):
servers = []
while len(packet) > 0:
packet, addr_str = read_string(packet)
servers.append(addr_str)
return servers
def query_master(addr_str):
""" Query a master server for its list of server IP addresses. """
addr = (socket.gethostbyname(addr_str), UDP_PORT)
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
send_message(sock, addr, NET_MASTER_PACKET_TYPE_QUERY)
type, response = get_response(sock, addr,
NET_MASTER_PACKET_TYPE_QUERY_RESPONSE,
5)
servers = parse_query_response(response)
# Try several times, as there might be packet loss.
failures = 0
while failures < QUERY_ATTEMPTS:
try:
query_master(MASTER_SERVER)
break
except:
failures += 1
else:
sys.stderr.write("No response from master server after %i attempts.\n"
% failures)