Rework inbound connection handling to use select

Closes #588.

classes.py

@@ -24,7 +24,7 @@ try:
 except ImportError:
     raise ImportError("PyLink requires ircmatch to function; please install it and try again.")
 
-from . import world, utils, structures, conf, __version__
+from . import world, utils, structures, conf, __version__, selectdriver
 from .log import *
 from .utils import ProtocolError  # Compatibility with PyLink 1.x
 
@@ -1300,10 +1300,10 @@ class IRCNetwork(PyLinkNetworkCoreWithUtils):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
 
-        self._connection_thread = None
         self._queue = None
         self._ping_timer = None
         self._socket = None
+        self._selector_key = None
 
     def _init_vars(self, *args, **kwargs):
         super()._init_vars(*args, **kwargs)
@@ -1335,12 +1335,10 @@ class IRCNetwork(PyLinkNetworkCoreWithUtils):
         else:
             log.error(*args, **kwargs)
 
-    def _connect(self):
+    def connect(self):
         """
-        Runs the connect loop for the IRC object. This is usually called by
-        __init__ in a separate thread to allow multiple concurrent connections.
+        Connects to the network.
         """
-        while True:
         self._pre_connect()
 
         ip = self.serverdata["ip"]
@@ -1352,7 +1350,6 @@ class IRCNetwork(PyLinkNetworkCoreWithUtils):
 
             # Creat the socket.
             self._socket = socket.socket(stype)
-                self._socket.setblocking(0)
 
             # Set the socket bind if applicable.
             if 'bindhost' in self.serverdata:
@@ -1394,6 +1391,7 @@ class IRCNetwork(PyLinkNetworkCoreWithUtils):
 
                 self._socket = context.wrap_socket(self._socket)
 
+            self._selector_key = selectdriver.register(self)
             log.info("Connecting to network %r on %s:%s", self.name, ip, port)
             self._socket.connect((ip, port))
             self._socket.settimeout(self.pingtimeout)
@@ -1461,7 +1459,6 @@ class IRCNetwork(PyLinkNetworkCoreWithUtils):
                 self._schedule_ping()
                 log.info('(%s) Server ready; listening for data.', self.name)
                 self.autoconnect_active_multiplier = 1  # Reset any extra autoconnect delays
-                    self._run_irc()
             else:  # Configuration error :(
                 log.error('(%s) A configuration error was encountered '
                           'trying to set up this connection. Please check'
@@ -1474,32 +1471,18 @@ class IRCNetwork(PyLinkNetworkCoreWithUtils):
         # IRC connection from freezing instead.
         except (OSError, RuntimeError, SystemExit) as e:
             self._log_connection_error('(%s) Disconnected from IRC:', self.name, exc_info=True)
-
             if not self._aborted.is_set():
                 self.disconnect()
 
             if not self._run_autoconnect():
                 return
 
-    def connect(self):
-        log.debug('(%s) calling _connect() (world.testing=%s)', self.name, world.testing)
-        if world.testing:
-            # HACK: Don't thread if we're running tests.
-            self._connect()
-        else:
-            if self._connection_thread and self._connection_thread.is_alive():
-                raise RuntimeError("Refusing to start multiple connection threads for network %r!" % self.name)
-
-            self._connection_thread = threading.Thread(target=self._connect,
-                                                      name="Listener for %s" %
-                                                      self.name)
-            self._connection_thread.start()
-
     def disconnect(self):
         """Handle disconnects from the remote server."""
         self._pre_disconnect()
 
         if self._socket is not None:
+            selectdriver.unregister(self)
             try:
                 log.debug('(%s) disconnect: Shutting down socket.', self.name)
                 self._socket.shutdown(socket.SHUT_RDWR)
@@ -1523,6 +1506,9 @@ class IRCNetwork(PyLinkNetworkCoreWithUtils):
             self._ping_timer.cancel()
         self._post_disconnect()
 
+        if self._run_autoconnect():
+            self.connect()
+
     def handle_events(self, line):
         raise NotImplementedError
 
@@ -1547,18 +1533,13 @@ class IRCNetwork(PyLinkNetworkCoreWithUtils):
         return hook_args
 
     def _run_irc(self):
-        """Main IRC loop which listens for messages."""
-        buf = b""
-        data = b""
-        while (not self._aborted.is_set()) and not world.shutting_down.is_set():
-
+        """
+        Message handler, called when select() has data to read.
+        """
+        buf = b''
+        data = b''
         try:
             data = self._socket.recv(2048)
-            except BlockingIOError:
-                log.debug('(%s) No data to read, trying again later...', self.name)
-                if self._aborted.wait(self.SOCKET_REPOLL_WAIT):
-                    break
-                continue
         except OSError:
             # Suppress socket read warnings from lingering recv() calls if
             # we've been told to shutdown.
@@ -1569,9 +1550,11 @@ class IRCNetwork(PyLinkNetworkCoreWithUtils):
         buf += data
         if not data:
             self._log_connection_error('(%s) Connection lost, disconnecting.', self.name)
+            self.disconnect()
             return
         elif (time.time() - self.lastping) > self.pingtimeout:
             self._log_connection_error('(%s) Connection timed out.', self.name)
+            self.disconnect()
             return
 
         while b'\n' in buf:

launcher.py

@@ -44,7 +44,7 @@ def main():
     conf.load_conf(args.config)
 
     from pylinkirc.log import log
-    from pylinkirc import classes, utils, coremods
+    from pylinkirc import classes, utils, coremods, selectdriver
 
     world.daemon = args.daemonize
     if args.daemonize:
@@ -177,3 +177,4 @@ def main():
 
     world.started.set()
     log.info("Loaded plugins: %s", ', '.join(sorted(world.plugins.keys())))
+    selectdriver.start()

selectdriver.py

@@ -0,0 +1,44 @@
+"""
+Socket handling driver using the selectors module. epoll, kqueue, and devpoll
+are used internally when available.
+"""
+
+import selectors
+import threading
+
+from pylinkirc import world
+from pylinkirc.log import log
+
+SELECT_TIMEOUT = 0.5
+
+selector = selectors.DefaultSelector()
+
+def _process_conns():
+    """Main loop which processes connected sockets."""
+
+    while not world.shutting_down.is_set():
+        for socketkey, mask in selector.select(timeout=SELECT_TIMEOUT):
+            irc = socketkey.data
+            if mask & selectors.EVENT_READ:
+                irc._run_irc()
+
+def register(irc):
+    """
+    Registers a network to the global selectors instance.
+    """
+    log.debug('selectdriver: registering %s for network %s', irc._socket, irc.name)
+    selector.register(irc._socket, selectors.EVENT_READ, data=irc)
+
+def unregister(irc):
+    """
+    Removes a network from the global selectors instance.
+    """
+    log.debug('selectdriver: de-registering %s for network %s', irc._socket, irc.name)
+    selector.unregister(irc._socket)
+
+def start():
+    """
+    Starts a thread to process connections.
+    """
+    t = threading.Thread(target=_process_conns, name="Selector driver loop")
+    t.start()