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connection to two RabbitMQ servers

I'm using python with pika, and have the following two similar use cases:
Connect to RabbitMQ server A and server B (at different IP addrs with different credentials), listen on exchange A1 on server A; when a message arrives, process it and send to an exchange on server B
Open an HTTP listener and connect to RabbitMQ server B; when a specific HTTP request arrives, process it and send to an exchange on server B
Alas, in both these cases using my usual techniques, by the time I get to sending to server B the connection throws ConnectionClosed or ChannelClosed.
I assume this is the cause: while waiting on the incoming messages, the connection to server B (its "driver") is starved of CPU cycles, and it never gets a chance to service is connection socket, thus it can't respond to heartbeats from server B, thus the servers shuts down the connection.
But I can't noodle out the fix. My current work around is lame: I catch the ConnectionClosed, reopen a connection to server B, and retry sending my message.
But what is the "right" way to do this? I've considered these, but don't really feel I have all the parts to solve this:
Don't just sit forever in server A's basic_consume (my usual pattern), but rather, use a timeout, and when I catch the timeout somehow "service" heartbeats on server B's driver, before returning to a "consume with timeout"... but how do I do that? How do I "let service B's connection driver service its heartbeats"?
I know the socket library's select() call can wait for messages on several sockets and once, then service the socket who has packets waiting. So maybe this is what pika's SelectConnection is for? a) I'm not sure, this is just a hunch. b) Even if right, while I can find examples of how to create this connection, I can't find examples of how to use it to solve my multiconnection case.
Set up the the two server connections in different processes... and use Python interprocess queues to get the processed message from one process to the next. The concept is "two different RabbitMQ connections in two different processes should thus then be able to independently service their heartbeats". Except... I think this has a fatal flaw: the process with "server B" is, instead, going to be "stuck" waiting on the interprocess queue, and the same "starvation" is going to happen.
I've checked StackOverflow and Googled this for an hour last night: I can't for the life of me find a blog post or sample code for this.
Any input? Thanks a million!

I managed to work it out, basing my solution on the documentation and an answer in the pika-python Google group.
First of all, your assumption is correct — the client process that's connected to server B, responsible for publishing, cannot reply to heartbeats if it's already blocking on something else, like waiting a message from server A or blocking on an internal communication queue.
The crux of the solution is that the publisher should run as a separate thread and use BlockingConnection.process_data_events to service heartbeats and such. It looks like that method is supposed to be called in a loop that checks if the publisher still needs to run:
def run(self):
while self.is_running:
# Block at most 1 second before returning and re-checking
self.connection.process_data_events(time_limit=1)
Proof of concept
Since proving the full solution requires having two separate RabbitMQ instances running, I have put together a Git repo with an appropriate docker-compose.yml, the application code and comments to test this solution.
https://github.com/karls/rabbitmq-two-connections
Solution outline
Below is a sketch of the solution, minus imports and such. Some notable things:
Publisher runs as a separate thread
The only "work" that the publisher does is servicing heartbeats and such, via Connection.process_data_events
The publisher registers a callback whenever the consumer wants to publish a message, using Connection.add_callback_threadsafe
The consumer takes the publisher as a constructor argument so it can publish the messages it receives, but it can work via any other mechanism as long as you have a reference to an instance of Publisher
The code is taken from the linked Git repo, which is why certain details are hardcoded, e.g the queue name etc. It will work with any RabbitMQ setup needed (direct-to-queue, topic exchange, fanout, etc).
class Publisher(threading.Thread):
def __init__(
self,
connection_params: ConnectionParameters,
*args,
**kwargs,
):
super().__init__(*args, **kwargs)
self.daemon = True
self.is_running = True
self.name = "Publisher"
self.queue = "downstream_queue"
self.connection = BlockingConnection(connection_params)
self.channel = self.connection.channel()
self.channel.queue_declare(queue=self.queue, auto_delete=True)
self.channel.confirm_delivery()
def run(self):
while self.is_running:
self.connection.process_data_events(time_limit=1)
def _publish(self, message):
logger.info("Calling '_publish'")
self.channel.basic_publish("", self.queue, body=message.encode())
def publish(self, message):
logger.info("Calling 'publish'")
self.connection.add_callback_threadsafe(lambda: self._publish(message))
def stop(self):
logger.info("Stopping...")
self.is_running = False
# Call .process_data_events one more time to block
# and allow the while-loop in .run() to break.
# Otherwise the connection might be closed too early.
#
self.connection.process_data_events(time_limit=1)
if self.connection.is_open:
self.connection.close()
logger.info("Connection closed")
logger.info("Stopped")
class Consumer:
def __init__(
self,
connection_params: ConnectionParameters,
publisher: Optional["Publisher"] = None,
):
self.publisher = publisher
self.queue = "upstream_queue"
self.connection = BlockingConnection(connection_params)
self.channel = self.connection.channel()
self.channel.queue_declare(queue=self.queue, auto_delete=True)
self.channel.basic_qos(prefetch_count=1)
def start(self):
self.channel.basic_consume(
queue=self.queue, on_message_callback=self.on_message
)
try:
self.channel.start_consuming()
except KeyboardInterrupt:
logger.info("Warm shutdown requested...")
except Exception:
traceback.print_exception(*sys.exc_info())
finally:
self.stop()
def on_message(self, _channel: Channel, m, _properties, body):
try:
message = body.decode()
logger.info(f"Got: {message!r}")
if self.publisher:
self.publisher.publish(message)
else:
logger.info(f"No publisher provided, printing message: {message!r}")
self.channel.basic_ack(delivery_tag=m.delivery_tag)
except Exception:
traceback.print_exception(*sys.exc_info())
self.channel.basic_nack(delivery_tag=m.delivery_tag, requeue=False)
def stop(self):
logger.info("Stopping consuming...")
if self.connection.is_open:
logger.info("Closing connection...")
self.connection.close()
if self.publisher:
self.publisher.stop()
logger.info("Stopped")

Cant receive data from socket

I'm making a client-server program, and there is problem with client part.
Problem is in infinite receiving data. I've tested this particular class, listed below, in a python interpreter. I've succesfuly(maybe not) connected to google, but then program stoped in function recvData() in data = self.socket.recv(1024)
class client():
def __init__(self, host, port):
self.host = host
self.port = port
self.socket = self.connect()
self.command = commands()
def connect(self):
'''
Connect to a remote host.
'''
try:
import socket
return socket.create_connection((self.host, self.port))
except socket.error:
print(":: Failed to connect to a remote port : ")
def sendCommand(self, comm):
'''
Send command to remote host
Returns server output
'''
comman = comm.encode()
# for case in switch(comman):
# if case(self.command.RETRV_FILES_LIST.encode()):
# self.socket.send(b'1')
# return self.recvData()
# if case():
# print(":: Got wrong command")
if (comman == b'1'):
self.socket.send(b'1')
return self.recvData()
def recvData(self):
'''
Receives all the data
'''
i = 0
total_data = []
while(True):
data = self.socket.recv(1024)
if not data: break
total_data.append(data)
i += 1
if i > 9:
break
return total_data
about commented part :
I thought problem in Case realization, so used just if-then statement. But it's not.

Your problem is that self.socket.recv(1024) only returns an empty string when the socket has been shut down on the server side and all data has been received. The way you coded your client, it has no idea that the full message has been received and waits for more. How you deal with the problem depends very much on the protocol used by the server.
Consider a web server. It sends a line-delimited header including a content-length parameter telling the client exactly how many bytes it should read. The client scans for newlines until the header is complete and then uses that value to do recv(exact_size) (if large, it can read chunks instead) so that the recv won't block when the last byte comes in.
Even then, there a decisions to make. The client knows how large the web page is but may want to send a partial data to the caller so it can start painting the page before all the data is received. Of course, the caller needs to know that is what happens - there is a protocol or set of rules for the API itself.
You need to define how the client knows a message is complete and what exactly it passes back to its caller. A great way to deal with the problem is to let some other protocol such as [zeromq](http://zeromq.org/ do the work for you. A simple python client / server can be implemented with xmlrpc. And there are many other ways.
You said you are implementing a client/server program then you mentioned "connected to google" and telnet... These are all very different things and a single client strategy won't work with all of them.

Python: How to interrupt raw_input() in other thread

I am writing a simple client-server program in python. In the client program, I am creating two threads (using Python's threading module), one for receiving, one for sending. The receiving thread continuously receives strings from the server side; while the sending thread continuously listens to the user input (using raw_input()) and send it to the server side. The two threads communicate using a Queue (which is natively synchronized, LIKE!).
The basic logic is like following:
Receiving thread:
global queue = Queue.Queue(0)
def run(self):
while 1:
receive a string from the server side
if the string is QUIT signal:
sys.exit()
else:
put it into the global queue
Sending thread:
def run(self):
while 1:
str = raw_input()
send str to the server side
fetch an element from the global queue
deal with the element
As you can see, in the receiving thread, I have a if condition to test whether the server has sent a "QUIT signal" to the client. If it has, then I want the whole program to stop.
The problem here is that for most of its time, the sending thread is blocked by "raw_input()" and waiting for the user input. When it is blocked, calling "sys.exit()" from the other thread (receiving thread) will not terminate the sending thread immediately. The sending thread has to wait for the user to type something and hit the enter button.
Could anybody inspire me how to get around with this? I do not mind using alternatives of "raw_input()". Actually I do not even mind changing the whole structure.
-------------EDIT-------------
I am running this on a linux machine, and my Python version is 2.7.5

You could just make the sending thread daemonic:
send_thread = SendThread() # Assuming this inherits from threading.Thread
send_thread.daemon = True # This must be called before you call start()
The Python interpreter won't be blocked from exiting if the only threads left running are daemons. So, if the only thread left is send_thread, your program will exit, even if you're blocked on raw_input.
Note that this will terminate the sending thread abruptly, no matter what its doing. This could be dangerous if it accesses external resources that need to be cleaned up properly or shouldn't be interrupted (like writing to a file, for example). If you're doing anything like that, protect it with a threading.Lock, and only call sys.exit() from the receiving thread if you can acquire that same Lock.

The short answer is you can't. input() like a lot of such input commands is blocking and it's blocking whether everything about the thread has been killed. You can sometimes call sys.exit() and get it to work depending on the OS, but it's not going to be consistent. Sometimes you can kill the program by deferring out to the local OS. But, then you're not going to be widely cross platform.
What you might want to consider if you have this is to funnel the functionality through the sockets. Because unlike input() we can do timeouts, and threads and kill things rather easily. It also gives you the ability to do multiple connections and maybe accept connections more broadly.
import socket
import time
from threading import Thread
def process(command, connection):
print("Command Entered: %s" % command)
# Any responses are written to connection.
connection.send(bytes('>', 'utf-8'))
class ConsoleSocket:
def __init__(self):
self.keep_running_the_listening_thread = True
self.data_buffer = ''
Thread(target=self.tcp_listen_handle).start()
def stop(self):
self.keep_running_the_listening_thread = False
def handle_tcp_connection_in_another_thread(self, connection, addr):
def handle():
while self.keep_running_the_listening_thread:
try:
data_from_socket = connection.recv(1024)
if len(data_from_socket) != 0:
self.data_buffer += data_from_socket.decode('utf-8')
else:
break
while '\n' in self.data_buffer:
pos = self.data_buffer.find('\n')
command = self.data_buffer[0:pos].strip('\r')
self.data_buffer = self.data_buffer[pos + 1:]
process(command, connection)
except socket.timeout:
continue
except socket.error:
if connection is not None:
connection.close()
break
Thread(target=handle).start()
connection.send(bytes('>', 'utf-8'))
def tcp_listen_handle(self, port=23, connects=5, timeout=2):
"""This is running in its own thread."""
sock = socket.socket()
sock.settimeout(timeout)
sock.bind(('', port))
sock.listen(connects) # We accept more than one connection.
while self.keep_running_the_listening_thread:
connection = None
try:
connection, addr = sock.accept()
address, port = addr
if address != '127.0.0.1': # Only permit localhost.
connection.close()
continue
# makes a thread deals with that stuff. We only do listening.
connection.settimeout(timeout)
self.handle_tcp_connection_in_another_thread(connection, addr)
except socket.timeout:
pass
except OSError:
# Some other error.
if connection is not None:
connection.close()
sock.close()
c = ConsoleSocket()
def killsocket():
time.sleep(20)
c.stop()
Thread(target=killsocket).start()
This launches a listener thread for the connections set on port 23 (telnet), and you connect and it passes that connection off to another thread. And it starts a killsocket thread that disables the various threads and lets them die peacefully (for demonstration purposes). You cannot however connect localhost within this code, because you'd need input() to know what to send to the server, which recreates the problem.

Using Processes as Threads with Networking in Python

Basically, my idea was to write some sort of basic server where I could connect to my computer and then run a command remotely. This didn't seem to be much of a problem; but then I had the bright idea that the next step would logically be to add some sort of threading so I could spawn multiple connections.
I read that, because of the GIL, multiprocessing.Process would be the best to try to do this. I don't completely understand threading and it's hard to find good documentation on it; so I'm kind of just throwing stuff and trying to figure out how it works.
Well, it seems like I might be close to doing this right; but I have a feeling I'm just as likely to be no where near doing this correctly. My program now does allow multiple connections, which it didn't when I first started working with threading; but once a connection is established, and then another is established, the first connection is no longer able to send a command to the server. I would appreciate it if someone could give me any help, or point me in the right direction on what I need to learn and understand.
Here's my code:
class server:
def __init__(self):
self.s = socket.socket()
try:
self.s.bind(("",69696))
self.s.listen(1)
except socket.error,(value,message):
if self.s:
self.s.close()
def connection(self):
while True:
client , address = self.s.accept()
data = client.recv(5)
password = 'hello'
while 1:
if data == password:
subprocess.call('firefox')
client.close()
else:
client.send('wrong password')
data = client.recv(5)
p = Process(target=x.connection())
p.start()
x = server()
if __name__ == '__main':
main()

Well, this answer only applies if you're on a unix or unix-like operating system(windows does not have os.fork() which we use).
One of the most common approaches for doing these things on unix platforms is to fork a new process to handle the client connection while the master process continues to listen for requests.
Below is code for a simple echo server that can handle multiple simultaneous connections. You just need to modify handle_client_connection() to fit your needs
import socket
import os
class ForkingServer:
def serve_forever(self):
self.s = socket.socket()
try:
self.s.bind(("", 9000))
self.s.listen(1)
except socket.error, (value,message):
print "error:", message
if self.s:
self.s.close()
return
while True:
client,address = self.s.accept()
pid = os.fork()
# You should read the documentation for how fork() works if you don't
# know it already
# The short version is that at this point in the code, there are 2 processes
# completely identical to each other which are simulatenously executing
# The only difference is that the parent process gets the pid of the child
# returned from fork() and the child process gets a value of 0 returned
if pid == 0:
# only the newly spawned process will execute this
self.handle_client_connection(client, address)
break
# In the meantime the parent process will continue on to here
# thus it will go back to the beginning of the loop and accept a new connection
def handle_client_connection(self, client,address):
#simple echo server
print "Got a connection from:", address
while True:
data = client.recv(5)
if not data:
# client closed the connection
break
client.send(data)
print "Connection from", address, "closed"
server = ForkingServer()
server.serve_forever()

Thread synchronization in Python

I am currently working on a school project where the assignment, among other things, is to set up a threaded server/client system. Each client in the system is supposed to be assigned its own thread on the server when connecting to it. In addition i would like the server to run other threads, one concerning input from the command line and another concerning broadcasting messages to all clients. However, I can't get this to run as i want to. It seems like the threads are blocking each other. I would like my program to take inputs from the command line, at the "same time" as the server listens to connected clients, and so on.
I am new to python programming and multithreading, and allthough I think my idea is good, I'm not suprised my code doesn't work. Thing is I'm not exactly sure how I'm going to implement the message passing between the different threads. Nor am I sure exactly how to implement the resource lock commands properly. I'm going to post the code for my server file and my client file here, and I hope someone could help me with this. I think this actually should be two relative simple scripts. I have tried to comment on my code as good as possible to some extend.
import select
import socket
import sys
import threading
import client
class Server:
#initializing server socket
def __init__(self, event):
self.host = 'localhost'
self.port = 50000
self.backlog = 5
self.size = 1024
self.server = None
self.server_running = False
self.listen_threads = []
self.local_threads = []
self.clients = []
self.serverSocketLock = None
self.cmdLock = None
#here i have also declared some events for the command line input
#and the receive function respectively, not sure if correct
self.cmd_event = event
self.socket_event = event
def openSocket(self):
#binding server to port
try:
self.server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.server.bind((self.host, self.port))
self.server.listen(5)
print "Listening to port " + str(self.port) + "..."
except socket.error, (value,message):
if self.server:
self.server.close()
print "Could not open socket: " + message
sys.exit(1)
def run(self):
self.openSocket()
#making Rlocks for the socket and for the command line input
self.serverSocketLock = threading.RLock()
self.cmdLock = threading.RLock()
#set blocking to non-blocking
self.server.setblocking(0)
#making two threads always running on the server,
#one for the command line input, and one for broadcasting (sending)
cmd_thread = threading.Thread(target=self.server_cmd)
broadcast_thread = threading.Thread(target=self.broadcast,args=[self.clients])
cmd_thread.daemon = True
broadcast_thread.daemon = True
#append the threads to thread list
self.local_threads.append(cmd_thread)
self.local_threads.append(broadcast_thread)
cmd_thread.start()
broadcast_thread.start()
self.server_running = True
while self.server_running:
#connecting to "knocking" clients
try:
c = client.Client(self.server.accept())
self.clients.append(c)
print "Client " + str(c.address) + " connected"
#making a thread for each clientn and appending it to client list
listen_thread = threading.Thread(target=self.listenToClient,args=[c])
self.listen_threads.append(listen_thread)
listen_thread.daemon = True
listen_thread.start()
#setting event "client has connected"
self.socket_event.set()
except socket.error, (value, message):
continue
#close threads
self.server.close()
print "Closing client threads"
for c in self.listen_threads:
c.join()
def listenToClient(self, c):
while self.server_running:
#the idea here is to wait until the thread gets the message "client
#has connected"
self.socket_event.wait()
#then clear the event immidiately...
self.socket_event.clear()
#and aquire the socket resource
self.serverSocketLock.acquire()
#the below is the receive thingy
try:
recvd_data = c.client.recv(self.size)
if recvd_data == "" or recvd_data == "close\n":
print "Client " + str(c.address) + (" disconnected...")
self.socket_event.clear()
self.serverSocketLock.release()
return
print recvd_data
#I put these here to avoid locking the resource if no message
#has been received
self.socket_event.clear()
self.serverSocketLock.release()
except socket.error, (value, message):
continue
def server_cmd(self):
#this is a simple command line utility
while self.server_running:
#got to have a smart way to make this work
self.cmd_event.wait()
self.cmd_event.clear()
self.cmdLock.acquire()
cmd = sys.stdin.readline()
if cmd == "":
continue
if cmd == "close\n":
print "Server shutting down..."
self.server_running = False
self.cmdLock.release()
def broadcast(self, clients):
while self.server_running:
#this function will broadcast a message received from one
#client, to all other clients, but i guess any thread
#aspects applied to the above, will work here also
try:
send_data = sys.stdin.readline()
if send_data == "":
continue
else:
for c in clients:
c.client.send(send_data)
self.serverSocketLock.release()
self.cmdLock.release()
except socket.error, (value, message):
continue
if __name__ == "__main__":
e = threading.Event()
s = Server(e)
s.run()
And then the client file
import select
import socket
import sys
import server
import threading
class Client(threading.Thread):
#initializing client socket
def __init__(self,(client,address)):
threading.Thread.__init__(self)
self.client = client
self.address = address
self.size = 1024
self.client_running = False
self.running_threads = []
self.ClientSocketLock = None
def run(self):
#connect to server
self.client.connect(('localhost',50000))
#making a lock for the socket resource
self.clientSocketLock = threading.Lock()
self.client.setblocking(0)
self.client_running = True
#making two threads, one for receiving messages from server...
listen = threading.Thread(target=self.listenToServer)
#...and one for sending messages to server
speak = threading.Thread(target=self.speakToServer)
#not actually sure wat daemon means
listen.daemon = True
speak.daemon = True
#appending the threads to the thread-list
self.running_threads.append(listen)
self.running_threads.append(speak)
listen.start()
speak.start()
#this while-loop is just for avoiding the script terminating
while self.client_running:
dummy = 1
#closing the threads if the client goes down
print "Client operating on its own"
self.client.close()
#close threads
for t in self.running_threads:
t.join()
return
#defining "listen"-function
def listenToServer(self):
while self.client_running:
#here i acquire the socket to this function, but i realize I also
#should have a message passing wait()-function or something
#somewhere
self.clientSocketLock.acquire()
try:
data_recvd = self.client.recv(self.size)
print data_recvd
except socket.error, (value,message):
continue
#releasing the socket resource
self.clientSocketLock.release()
#defining "speak"-function, doing much the same as for the above function
def speakToServer(self):
while self.client_running:
self.clientSocketLock.acquire()
try:
send_data = sys.stdin.readline()
if send_data == "close\n":
print "Disconnecting..."
self.client_running = False
else:
self.client.send(send_data)
except socket.error, (value,message):
continue
self.clientSocketLock.release()
if __name__ == "__main__":
c = Client((socket.socket(socket.AF_INET, socket.SOCK_STREAM),'localhost'))
c.run()
I realize this is quite a few code lines for you to read through, but as I said, I think the concept and the script in it self should be quite simple to understand. It would be very much appriciated if someone could help me synchronize my threads in a proper way =)
Thanks in advance
---Edit---
OK. So I now have simplified my code to just containing send and receive functions in both the server and the client modules. The clients connecting to the server gets their own threads, and the send and receive functions in both modules operetes in their own separate threads. This works like a charm, with the broadcast function in the server module echoing strings it gets from one client to all clients. So far so good!
The next thing i want my script to do, is taking specific commands, i.e. "close", in the client module to shut down the client, and join all running threads in the thread list. Im using an event flag to notify the listenToServer and the main thread that the speakToServer thread has read the input "close". It seems like the main thread jumps out of its while loop and starts the for loop that is supposed to join the other threads. But here it hangs. It seems like the while loop in the listenToServer thread never stops even though server_running should be set to False when the event flag is set.
I'm posting only the client module here, because I guess an answer to get these two threads to synchronize will relate to synchronizing more threads in both the client and the server module also.
import select
import socket
import sys
import server_bygg0203
import threading
from time import sleep
class Client(threading.Thread):
#initializing client socket
def __init__(self,(client,address)):
threading.Thread.__init__(self)
self.client = client
self.address = address
self.size = 1024
self.client_running = False
self.running_threads = []
self.ClientSocketLock = None
self.disconnected = threading.Event()
def run(self):
#connect to server
self.client.connect(('localhost',50000))
#self.client.setblocking(0)
self.client_running = True
#making two threads, one for receiving messages from server...
listen = threading.Thread(target=self.listenToServer)
#...and one for sending messages to server
speak = threading.Thread(target=self.speakToServer)
#not actually sure what daemon means
listen.daemon = True
speak.daemon = True
#appending the threads to the thread-list
self.running_threads.append((listen,"listen"))
self.running_threads.append((speak, "speak"))
listen.start()
speak.start()
while self.client_running:
#check if event is set, and if it is
#set while statement to false
if self.disconnected.isSet():
self.client_running = False
#closing the threads if the client goes down
print "Client operating on its own"
self.client.shutdown(1)
self.client.close()
#close threads
#the script hangs at the for-loop below, and
#refuses to close the listen-thread (and possibly
#also the speak thread, but it never gets that far)
for t in self.running_threads:
print "Waiting for " + t[1] + " to close..."
t[0].join()
self.disconnected.clear()
return
#defining "speak"-function
def speakToServer(self):
#sends strings to server
while self.client_running:
try:
send_data = sys.stdin.readline()
self.client.send(send_data)
#I want the "close" command
#to set an event flag, which is being read by all other threads,
#and, at the same time set the while statement to false
if send_data == "close\n":
print "Disconnecting..."
self.disconnected.set()
self.client_running = False
except socket.error, (value,message):
continue
return
#defining "listen"-function
def listenToServer(self):
#receives strings from server
while self.client_running:
#check if event is set, and if it is
#set while statement to false
if self.disconnected.isSet():
self.client_running = False
try:
data_recvd = self.client.recv(self.size)
print data_recvd
except socket.error, (value,message):
continue
return
if __name__ == "__main__":
c = Client((socket.socket(socket.AF_INET, socket.SOCK_STREAM),'localhost'))
c.run()
Later on, when I get this server/client system up and running, I will use this system on some elevator models we have here on the lab, with each client receiving floor orders or "up" and "down" calls. The server will be running an distribution algorithm and updating the elevator queues on the clients that are most appropriate for the requested order. I realize it's a long way to go, but I guess one should just take one step at the time =)
Hope someone has the time to look into this. Thanks in advance.

The biggest problem I see with this code is that you have far too much going on right away to easily debug your problem. Threading can get extremely complicated because of how non-linear the logic becomes. Especially when you have to worry about synchronizing with locks.
The reason you are seeing clients blocking on each other is because of the way you are using your serverSocketLock in your listenToClient() loop in the server. To be honest this isn't exactly your problem right now with your code, but it became the problem when I started to debug it and turned the sockets into blocking sockets. If you are putting each connection into its own thread and reading from them, then there is no reason to use a global server lock here. They can all read from their own sockets at the same time, which is the purpose of the thread.
Here is my recommendation to you:
Get rid of all the locks and extra threads that you don't need, and start from the beginning
Have the clients connect as you do, and put them in their thread as you do. And simply have them send data every second. Verify that you can get more than one client connecting and sending, and that your server is looping and receiving. Once you have this part working, you can move on to the next part.
Right now you have your sockets set to non-blocking. This is causing them all to spin really fast over their loops when data is not ready. Since you are threading, you should set them to block. Then the reader threads will simply sit and wait for data and respond immediately.
Locks are used when threads will be accessing shared resources. You obviously need to for any time a thread will try and modify a server attribute like a list or a value. But not when they are working on their own private sockets.
The event you are using to trigger your readers doesn't seem necessary here. You have received the client, and you start the thread afterwards. So it is ready to go.
In a nutshell...simplify and test one bit at a time. When its working, add more. There are too many threads and locks right now.
Here is a simplified example of your listenToClient method:
def listenToClient(self, c):
while self.server_running:
try:
recvd_data = c.client.recv(self.size)
print "received:", c, recvd_data
if recvd_data == "" or recvd_data == "close\n":
print "Client " + str(c.address) + (" disconnected...")
return
print recvd_data
except socket.error, (value, message):
if value == 35:
continue
else:
print "Error:", value, message

Backup your work, then toss it - partially.
You need to implement your program in pieces, and test each piece as you go. First, tackle the input part of your program. Don't worry about how to broadcast the input you received. Instead worry that you are able to successfully and repeatedly receive input over your socket. So far - so good.
Now, I assume you would like to react to this input by broadcasting to the other attached clients. Well too bad, you can't do that yet! Because, I left one minor detail out of the paragraph above. You have to design a PROTOCOL.
What is a protocol? It's a set of rules for communication. How does your server know when the client had finished sending it's data? Is it terminated by some special character? Or perhaps you encode the size of the message to be sent as the first byte or two of the message.
This is turning out to be a lot of work, isn't it? :-)
What's a simple protocol. A line-oriented protocol is simple. Read 1 character at a time until you get to the end of record terminator - '\n'. So, clients would send records like this to your server --
HELO\n
MSG DAVE Where Are Your Kids?\n
So, assuming you have this simple protocol designed, implement it. For now, DON'T WORRY ABOUT THE MULTITHREADING STUFF! Just worry about making it work.
Your current protocol is to read 1024 bytes. Which may not be bad, just make sure you send 1024 byte messages from the client.
Once you have the protocol stuff setup, move on to reacting to the input. But for now you need something that will read input. Once that is done, we can worry about doing something with it.
jdi is right, you have too much program to work with. Pieces are easier to fix.