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:
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."""
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:
projects / plomrogue2-experiments / commitdiff