X-Git-Url: https://plomlompom.com/repos/berlin_corona.txt?a=blobdiff_plain;f=server.py;h=ed60b6a34b455b95a1511db4512cb0268e636ba2;hb=c26fe38bd460cb28bf01d06df94310bcc4219c3b;hp=b326768ea4a5499818f141afe8b4b7a1e8d3d1ad;hpb=f5287b7235704555925ed2a24113258fe61b40c1;p=plomrogue2-experiments diff --git a/server.py b/server.py index b326768..ed60b6a 100755 --- a/server.py +++ b/server.py @@ -1,95 +1,215 @@ #!/usr/bin/env python3 import socketserver -import plom_socket_io +import threading +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 message queue.""" + + def __init__(self, queue, *args, **kwargs): + super().__init__(*args, **kwargs) + self.queue_out = queue + self.daemon_threads = True # Else, server's threads have daemon=False. + + +class IO_Handler(socketserver.BaseRequestHandler): + + def handle(self): + """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. + """ + import plom_socket_io + + def caught_send(socket, message): + """Send message by socket, catch broken socket connection error.""" + try: + plom_socket_io.send(socket, message) + except plom_socket_io.BrokenSocketConnection: + pass + + 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)) + 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: + caught_send(self.request, 'BAD MESSAGE') + elif 'QUIT' == message: + caught_send(self.request, 'BYE') + break + else: + 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 FROM:', str(self.client_address)) + self.request.close() + + +class World: + turn = 0 + + def fib(n): - """Calculate n-th Fibonacci number.""" + """Calculate n-th Fibonacci number. Very inefficiently.""" if n in (1, 2): return 1 else: return fib(n-1) + fib(n-2) -def handle_message(message): - """Evaluate message for computing-heavy tasks to perform, yield result. +class CommandHandler: - 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.) + def __init__(self, queues_out): + from multiprocessing import Pool + self.queues_out = queues_out + self.pool = Pool() + self.world = World() - When no command can be read into the message, just yields a 'NO COMMAND - UNDERSTOOD:', followed by the message. - """ - tokens = message.split(' ') - if tokens[0] == 'FIB': - msg_fail_fib = 'MALFORMED FIB REQUEST' + def send_to(self, connection_id, msg): + """Send msg to client of connection_id.""" + self.queues_out[connection_id].put(msg) + + def send_all(self, msg): + """Send msg to all clients.""" + for connection_id in self.queues_out: + self.send_to(connection_id, msg) + + def cmd_fib(self, tokens, connection_id): + """Reply with n-th Fibonacci numbers, n taken from tokens[1:]. + + Numbers are calculated in parallel as far as possible, using fib(). + A 'CALCULATING …' message is sent to caller before the result. + """ + fib_fail = 'MALFORMED FIB REQUEST' if len(tokens) < 2: - yield msg_fail_fib + self.send_to(connection_id, fib_fail) return numbers = [] - fail = False for token in tokens[1:]: if token != '0' and token.isdigit(): numbers += [int(token)] - elif token == '': - continue else: - yield msg_fail_fib + self.send_to(connection_id, fib_fail) return - yield 'CALCULATING …' - reply = '' - from multiprocessing import Pool - with Pool(len(numbers)) as p: - results = p.map(fib, numbers) + self.send_to(connection_id, 'CALCULATING …') + results = self.pool.map(fib, numbers) reply = ' '.join([str(r) for r in results]) - yield reply - return - yield 'NO COMMAND UNDERSTOOD: %s' % message - - -class ThreadedTCPServer(socketserver.ThreadingMixIn, socketserver.TCPServer): - """Enables threading on TCP server for asynchronous IO handling.""" - pass - - -class MyTCPHandler(socketserver.BaseRequestHandler): - - def handle(self): - """Loop recv for input, act on it, send reply. - - If input is 'QUIT', send reply 'BYE' and end loop / connection. - Otherwise, use handle_message. - """ - - print('CONNECTION FROM:', str(self.client_address)) - for message in plom_socket_io.recv(self.request): - if message is None: - print('RECEIVED MALFORMED MESSAGE') - plom_socket_io.send(self.request, 'bad message') - elif 'QUIT' == message: - plom_socket_io.send(self.request, 'BYE') - break - else: - print('RECEIVED MESSAGE:', message) - for reply in handle_message(message): - plom_socket_io.send(self.request, reply) - print('CONNECTION CLOSED:', str(self.client_address)) - self.request.close() - - -server = ThreadedTCPServer(('localhost', 5000), MyTCPHandler) + self.send_to(connection_id, reply) + + def cmd_inc(self, connection_id): + """Increment world.turn, send TURN_FINISHED, NEW_TURN to everyone.""" + self.send_all('TURN_FINISHED ' + str(self.world.turn)) + self.world.turn += 1 + self.send_all('NEW_TURN ' + str(self.world.turn)) + + def cmd_get_turn(self, connection_id): + """Send world.turn to caller.""" + self.send_to(connection_id, str(self.world.turn)) + + def cmd_echo(self, tokens, input_, connection_id): + """Send message in input_ beyond tokens[0] to caller.""" + msg = input_[len(tokens[0]) + 1:] + self.send_to(connection_id, msg) + + def cmd_all(self, tokens, input_): + """Send message in input_ beyond tokens[0] to all clients.""" + msg = input_[len(tokens[0]) + 1:] + self.send_all(msg) + + def handle_input(self, input_, connection_id): + """Process input_ to command grammar, call command handler if found.""" + tokens = [token for token in input_.split(' ') if len(token) > 0] + if len(tokens) == 0: + self.send_to(connection_id, 'EMPTY COMMAND') + elif len(tokens) == 1 and tokens[0] == 'INC': + self.cmd_inc(connection_id) + elif len(tokens) == 1 and tokens[0] == 'GET_TURN': + self.cmd_get_turn(connection_id) + elif len(tokens) >= 1 and tokens[0] == 'ECHO': + self.cmd_echo(tokens, input_, connection_id) + elif len(tokens) >= 1 and tokens[0] == 'ALL': + self.cmd_all(tokens, input_) + elif len(tokens) >= 1 and tokens[0] == 'FIB': + # TODO: Should this really block the whole loop? + self.cmd_fib(tokens, connection_id) + else: + self.send_to(connection_id, 'UNKNOWN COMMAND') + + +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. CommandHandler takes care of processing this and + sending out replies. + """ + queues_out = {} + command_handler = CommandHandler(queues_out) + while True: + 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': + command_handler.handle_input(content, connection_id) + elif command_type == 'KILL_QUEUE': + del queues_out[connection_id] + + +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: pass finally: + print('Killing server') server.server_close()