/
net.py
273 lines (230 loc) · 7.28 KB
/
net.py
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""" helper package for sending object asynchronously over sockets
"""
import sys
import socket
import cPickle
import select
from log import log as _log, err as _err
import msg
PAK_VER = 20100720
# logging_enabled = True
logging_enabled = False
def log(name,str):
if(logging_enabled):
_log("[%s] %s " % (name,str))
def err(name,str):
_err("[%s] %s " % (name,str))
def can_recv(sock):
'''helper for testing sock status.
NOTE: not atomic, i.e. a return of true is not a guarantee that you can recv data'''
rds,_,_ = select.select([sock],[],[],0)
return len(rds) > 0
def can_send(sock):
'''helper for testing sock status.
NOTE: not atomic, i.e. a return of true is not a guarantee that you can send'''
_,ws,_ = select.select([],[sock],[],0)
return len(ws) > 0
def conn_refused(sock):
err = sock.getsockopt(socket.SOL_SOCKET,socket.SO_ERROR)
return err == 10061
def sock_err(sock):
i = sock.getsockopt(socket.SOL_SOCKET,socket.SO_ERROR)
if i != 0:
return socket.errorTab[i]
return None
class VersionMismatch(Exception):
def __init__(self,value):
self.value = value
def __str__(self):
return self.value
class PakSender:
"""simple class for sending packet switched data .
Use this along with PakReceiver to send objects over a network
TODO: optimizations, version can be once per connection, for example
object sends could be coalesced, etc.
"""
def __init__(self,sock,name):
self.sock = sock
self.objs = []
self.name = name
def _send_int(self, n):
log(self.name, "send_int %i" % n)
n = "%16i" % n
self.sock.send(n)
def _send_obj(self, o):
"send object directly on link. fails if socket not ready"
try:
self._send_int(PAK_VER)
log(self.name, "send_obj " + str(o))
p = cPickle.dumps(o) # if it fails here, obj probably not pickle-able
self._send_int(len(p))
self.sock.send(p)
return True
except socket.error as e:
err(self.name, "error " + str(e))
return False
def send_obj(self,o):
"queues object for sending until tick"
self.objs.append(o)
def send_pending(self):
return len(self.objs)
def tick(self):
n_sent = 0
for o in self.objs:
if not self._send_obj(o):
log(self.name, "couldn't send object")
break
n_sent += 1
self.objs = self.objs[n_sent:]
log(self.name, "sent %i, %i remain" %(n_sent,len(self.objs)))
return not sock_err(self.sock)
class PakReceiver:
"""class for receiving packet switched network traffic
"""
def __init__(self,sock,name):
self.sock = sock
self.name = name
def _recv_int(self):
s = self.sock.recv(16)
if not s:
return 0
return int(s)
def recv_obj(self):
if not can_recv(self.sock):
return None
ver = self._recv_int()
if not ver:
log(self.name,"recv_obj: socket closed on other end")
return None
if(ver != PAK_VER):
raise VersionMismatch("recv_obj")
n = self._recv_int()
s = self.sock.recv(n)
obj = cPickle.loads(s)
log(self.name, "loading %s instance" % type(obj))
return obj
def can_recv(self):
return can_recv(self.sock)
class PakComm(PakReceiver,PakSender):
'''helper for combining a sender and receiver.
Use this class for bideractional communication with a PakServer
- relies on the PakSender tick function to pump send data
'''
def __init__(self,sock_or_addrinfo,name):
self.sock = None
if isinstance(sock_or_addrinfo,tuple):
addr,port = sock_or_addrinfo
self.sock = client_sock(addr,port)
elif isinstance(sock_or_addrinfo,socket.socket):
self.sock = sock_or_addrinfo
self.objs = []
self.name = name
class PakClientMsg:
'dummy class that shows a callable client message'
def __init__(self,str):
self.str = str
def __call__(self):
log("PakClientMsg: %s" % self.str)
class PakServer:
"""handles a listen socket that receives packets from a PakSender
- listens for and accepts new connections
- keeps a list of clients that have connected
- removes clients that have disconnected
- receives objects from clients via the PakSend/Recv interface
- invokes sent objects via the callable interface"""
def __init__(self, listen_sock, name):
self.listen_sock = listen_sock
self.client_socks = {}
self.name = name
def tick(self, obj_handler=None):
"""
Check for any incoming connections, and listen for any objects
from open connections.
obj_handler -- optional callback function, if this is None, any received objects are invoked via the __call__ interface
"""
try:
conn, addr = self.listen_sock.accept()
self.log('conn from %s' % str(addr))
if addr in self.client_socks:
self.log("duplicate connection from %s" % str(addr))
self.client_socks[addr] = conn
except socket.error:
pass # no conn
if not self.client_socks:
return
rds,_,_ = select.select(self.client_socks.values(),[],[],0)
if(len(rds)):
self.log("reading %i sockets" % len(rds))
for r in rds:
recvr = PakReceiver(r,self.name)
obj = recvr.recv_obj()
if obj:
self.log("recv " + str(obj))
if(obj_handler):
obj_handler(obj,r)
else:
obj(r)
else:
# client disconnect, drop it
self.client_socks.pop(r.getpeername())
r.close()
def close_client(self,sock):
"helper for closing a client by socket"
self.log("close_client %s" % sock)
try:
self.log("removing sock")
self.client_socks.pop(sock.getpeername())
self.log("closing socket")
sock.close()
except:
self.log("error closing client %s" % str(sock))
def log(self, str):
log(self.name, str)
class PakSenderTracker(object):
"""helper class for pumping PakSenders
- a PakSender doesn't send objects until its tick function, and something
needs to call that tick function, so if you're running a server it is handy to have a couple of methods for tracking senders and making sure your objects get sent.
"""
def make_tracked_sender(self,sock_or_addrinfo, log_ctxt = ""):
"create a sender that is tracked by this ChunkServer, and is removed once its send queue is empty"
sender = PakSender(sock_or_addrinfo,"master:%s" % log_ctxt)
self.senders.append(sender)
return sender
def send_obj_to(self, sock_or_addrinfo, obj, log_ctxt=""):
"send the object to the destination"
sender = self.make_tracked_sender(sock_or_addrinfo)
sender.send_obj(obj)
def tick_senders(self):
for sender in self.senders[:]:
self.log("ticking sender " + str(sender))
sender.tick()
if len(sender.objs) == 0:
self.senders.remove(sender)
def listen_sock(port):
# _log("listening on port %i" % port)
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(('',port))
s.setblocking(0)
s.listen(1024) # arbitrary number of outstanding connects allowed
return s
def client_sock(addr,port):
"standard client sock for my code: non blocking, connects to addr/port over TCP"
# _log('connecting to ' + addr + ' ' + str(port))
c = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
c.setblocking(False)
errval = c.connect_ex((addr,port)) # since this is async, may get block error
if errval != 0 and errval != 10035: # magic code for 'would block'
return None
return c
def test():
port = 12346
ps = PakServer(listen_sock(port),"testserver")
pc0 = PakSender(client_sock('localhost',port),"testserver")
pc1 = PakSender(client_sock('localhost',port),"testserver")
ps.tick() # should see 2 accepts
pc0.send_obj(PakClientMsg("0: hello port %i" % port))
pc1.send_obj(PakClientMsg("1: hello port %i" % port))
pc0.tick()
pc1.tick()
ps.tick()
del ps