From 7cd634da51a8d9d93216dd26e6d89e61a4a764ca Mon Sep 17 00:00:00 2001 From: Christian Heller Date: Sat, 29 Apr 2017 02:33:09 +0200 Subject: [PATCH] Improve server by using queues. --- server.py | 192 +++++++++++++++++++++++++++++++++--------------------- 1 file changed, 118 insertions(+), 74 deletions(-) diff --git a/server.py b/server.py index b088206..82a10a6 100755 --- a/server.py +++ b/server.py @@ -4,22 +4,23 @@ import socketserver import plom_socket_io import threading import time +import queue # Avoid "Address already in use" errors. socketserver.TCPServer.allow_reuse_address = True class Server(socketserver.ThreadingTCPServer): - """Bind together threaded IO handling server and world state (counter).""" + """Bind together threaded IO handling server and message queue.""" - def __init__(self, counter, *args, **kwargs): + def __init__(self, queue, *args, **kwargs): super().__init__(*args, **kwargs) - self.counter = counter + self.queue_out = queue self.daemon_threads = True # Else, server's threads have daemon=False. def fib(n): - """Calculate n-th Fibonacci number.""" + """Calculate n-th Fibonacci number. Very inefficiently.""" if n in (1, 2): return 1 else: @@ -29,10 +30,23 @@ def fib(n): class IO_Handler(socketserver.BaseRequestHandler): def handle(self): - """Loop recv for input, send replies; also, send regular counter value. - - If input is 'QUIT', send reply 'BYE' and end loop / connection. - Otherwise, use handle_message to interpret and enact commands. + """Move messages between network socket and main thread via queues. + + On start, sets up new queue, sends it via self.server.queue_out to + main thread, and from then on receives messages to send back from the + main thread via that new queue. + + At the same time, loops over socket's recv to get messages from the + outside via self.server.queue_out into the main thread. Ends connection + once a 'QUIT' message is received from socket, and then also kills its + own queue. + + All messages to the main thread are tuples, with the first element a + meta command ('ADD_QUEUE' for queue creation, 'KILL_QUEUE' for queue + deletion, and 'COMMAND' for everything else), the second element a UUID + that uniquely identifies the thread (so that the main thread knows whom + to send replies back to), and optionally a third element for further + instructions. """ def caught_send(socket, message): """Send message by socket, catch broken socket connection error.""" @@ -41,87 +55,117 @@ class IO_Handler(socketserver.BaseRequestHandler): except plom_socket_io.BrokenSocketConnection: pass - def send_counter_loop(socket, counter, kill): - """Every 5 seconds, send state of counter[0] until kill[0] set.""" - while not kill[0]: - caught_send(socket, 'COUNTER ' + str(counter[0])) - time.sleep(5) - - def handle_message(message): - """Evaluate message for tasks to perform, yield result. - - Accepts one command: FIB, followed by positive integers, all tokens - separated by whitespace. Will calculate and return for each such - integer n the n-th Fibonacci number. Uses multiprocessing to - perform multiple such calculations in parallel. Yields a - 'CALCULATING …' message before the calculation starts, and finally - yields a message containing the results. (The 'CALCULATING …' - message coming before the results message is currently the main - reason this works as a generator function using yield.) - - When no command can be read into the message, just yields a 'NO - COMMAND UNDERSTOOD:', followed by the message. - """ - from multiprocessing import Pool - tokens = message.split(' ') - if tokens[0] == 'FIB': - msg_fail_fib = 'MALFORMED FIB REQUEST' - if len(tokens) < 2: - yield msg_fail_fib - return - numbers = [] - for token in tokens[1:]: - if token != '0' and token.isdigit(): - numbers += [int(token)] - elif token == '': - continue - else: - yield msg_fail_fib - return - yield 'CALCULATING …' - reply = '' - with Pool(len(numbers)) as p: - results = p.map(fib, numbers) - reply = ' '.join([str(r) for r in results]) - yield reply - return - yield 'NO COMMAND UNDERSTOOD: %s' % message + def send_queue_messages(socket, queue_in, thread_alive): + """Send messages via socket from queue_in while thread_alive[0].""" + while thread_alive[0]: + try: + msg = queue_in.get(timeout=1) + except queue.Empty: + continue + caught_send(socket, msg) + import uuid print('CONNECTION FROM:', str(self.client_address)) - counter_loop_killer = [False] - send_count = threading.Thread(target=send_counter_loop, - kwargs={'counter': self.server.counter, - 'socket': self.request, - 'kill': counter_loop_killer}) - send_count.start() + connection_id = uuid.uuid4() + queue_in = queue.Queue() + self.server.queue_out.put(('ADD_QUEUE', connection_id, queue_in)) + thread_alive = [True] + t = threading.Thread(target=send_queue_messages, + args=(self.request, queue_in, thread_alive)) + t.start() for message in plom_socket_io.recv(self.request): if message is None: - print('RECEIVED MALFORMED MESSAGE') - caught_send(self.request, 'bad message') + caught_send(self.request, 'BAD MESSAGE') elif 'QUIT' == message: caught_send(self.request, 'BYE') break else: - print('RECEIVED MESSAGE:', message) - for reply in handle_message(message): - caught_send(self.request, reply) - counter_loop_killer = [True] + self.server.queue_out.put(('COMMAND', connection_id, message)) + self.server.queue_out.put(('KILL_QUEUE', connection_id)) + thread_alive[0] = False print('CONNECTION CLOSED:', str(self.client_address)) self.request.close() -def inc_loop(counter, interval): - """Loop incrementing counter every interval seconds.""" +def io_loop(q): + """Handle commands coming through queue q, send results back. + + Commands from q are expected to be tuples, with the first element either + 'ADD_QUEUE', 'COMMAND', or 'KILL_QUEUE', the second element a UUID, and + an optional third element of arbitrary type. The UUID identifies a + receiver for replies. + + An 'ADD_QUEUE' command should contain as third element a queue through + which to send messages back to the sender of the command. A 'KILL_QUEUE' + command removes the queue for that receiver from the list of queues through + which to send replies. + + A 'COMMAND' command is specified in greater detail by a string that is the + tuple's third element. Here, the following commands are understood: + - A string starting with 'PRIVMSG' returns the space-separated tokens + following 'PRIVMSG' to the sender via its receiver queue. + - A string starting with 'ALL' sends the space-separated tokens following + 'ALL' to all receiver queues. + - A string starting with 'FIB' followed by space-separated positive + integers returns to the receiver queue first a 'CALCULATING …' messsage, + and afterwards for each such integer n the n-th Fibonacci number as a + space-separated sequence of integers. Fibonacci numbers are calculated + in parallel if possible. + """ + from multiprocessing import Pool + queues_out = {} while True: - time.sleep(interval) - counter[0] += 1 + x = q.get() + command_type = x[0] + connection_id = x[1] + content = None if len(x) == 2 else x[2] + if command_type == 'ADD_QUEUE': + queues_out[connection_id] = content + elif command_type == 'COMMAND': + tokens = [token for token in content.split(' ') if len(token) > 0] + if len(tokens) == 0: + queues_out[connection_id].put('EMPTY COMMAND') + continue + if tokens[0] == 'PRIVMSG': + reply = ' '.join(tokens[1:]) + queues_out[connection_id].put(reply) + elif tokens[0] == 'ALL': + reply = ' '.join(tokens[1:]) + for key in queues_out: + queues_out[key].put(reply) + elif tokens[0] == 'FIB': + fib_fail = 'MALFORMED FIB REQUEST' + if len(tokens) < 2: + queues_out[connection_id].put(fib_fail) + continue + numbers = [] + fail = False + for token in tokens[1:]: + if token != '0' and token.isdigit(): + numbers += [int(token)] + else: + queues_out[connection_id].put(fib_fail) + fail = True + break + if fail: + continue + queues_out[connection_id].put('CALCULATING …') + reply = '' + # this blocks the whole loop, BAD + with Pool(len(numbers)) as p: + results = p.map(fib, numbers) + reply = ' '.join([str(r) for r in results]) + queues_out[connection_id].put(reply) + else: + queues_out[connection_id].put('UNKNOWN COMMAND') + elif command_type == 'KILL_QUEUE': + del queues_out[connection_id] -counter = [0] -b = threading.Thread(target=inc_loop, daemon=True, kwargs={'counter': counter, - 'interval': 1}) -b.start() -server = Server(counter, ('localhost', 5000), IO_Handler) +q = queue.Queue() +c = threading.Thread(target=io_loop, daemon=True, args=(q,)) +c.start() +server = Server(q, ('localhost', 5000), IO_Handler) try: server.serve_forever() except KeyboardInterrupt: -- 2.30.2