# Copyright 2014 Symantec Corporation # Copyright DataStax, Inc. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. # Originally derived from MagnetoDB source: # https://github.com/stackforge/magnetodb/blob/2015.1.0b1/magnetodb/common/cassandra/io/eventletreactor.py import eventlet from eventlet.green import socket from eventlet.queue import Queue from greenlet import GreenletExit import logging from threading import Event import time from six.moves import xrange from cassandra.connection import Connection, ConnectionShutdown, Timer, TimerManager try: from eventlet.green.OpenSSL import SSL _PYOPENSSL = True except ImportError as e: _PYOPENSSL = False no_pyopenssl_error = e log = logging.getLogger(__name__) def _check_pyopenssl(): if not _PYOPENSSL: raise ImportError( "{}, pyOpenSSL must be installed to enable " "SSL support with the Eventlet event loop".format(str(no_pyopenssl_error)) ) class EventletConnection(Connection): """ An implementation of :class:`.Connection` that utilizes ``eventlet``. This implementation assumes all eventlet monkey patching is active. It is not tested with partial patching. """ _read_watcher = None _write_watcher = None _socket_impl = eventlet.green.socket _ssl_impl = eventlet.green.ssl _timers = None _timeout_watcher = None _new_timer = None @classmethod def initialize_reactor(cls): eventlet.monkey_patch() if not cls._timers: cls._timers = TimerManager() cls._timeout_watcher = eventlet.spawn(cls.service_timeouts) cls._new_timer = Event() @classmethod def create_timer(cls, timeout, callback): timer = Timer(timeout, callback) cls._timers.add_timer(timer) cls._new_timer.set() return timer @classmethod def service_timeouts(cls): """ cls._timeout_watcher runs in this loop forever. It is usually waiting for the next timeout on the cls._new_timer Event. When new timers are added, that event is set so that the watcher can wake up and possibly set an earlier timeout. """ timer_manager = cls._timers while True: next_end = timer_manager.service_timeouts() sleep_time = max(next_end - time.time(), 0) if next_end else 10000 cls._new_timer.wait(sleep_time) cls._new_timer.clear() def __init__(self, *args, **kwargs): Connection.__init__(self, *args, **kwargs) self.uses_legacy_ssl_options = self.ssl_options and not self.ssl_context self._write_queue = Queue() self._connect_socket() self._read_watcher = eventlet.spawn(lambda: self.handle_read()) self._write_watcher = eventlet.spawn(lambda: self.handle_write()) self._send_options_message() def _wrap_socket_from_context(self): _check_pyopenssl() self._socket = SSL.Connection(self.ssl_context, self._socket) self._socket.set_connect_state() if self.ssl_options and 'server_hostname' in self.ssl_options: # This is necessary for SNI self._socket.set_tlsext_host_name(self.ssl_options['server_hostname'].encode('ascii')) def _initiate_connection(self, sockaddr): if self.uses_legacy_ssl_options: super(EventletConnection, self)._initiate_connection(sockaddr) else: self._socket.connect(sockaddr) if self.ssl_context or self.ssl_options: self._socket.do_handshake() def _match_hostname(self): if self.uses_legacy_ssl_options: super(EventletConnection, self)._match_hostname() else: cert_name = self._socket.get_peer_certificate().get_subject().commonName if cert_name != self.endpoint.address: raise Exception("Hostname verification failed! Certificate name '{}' " "doesn't endpoint '{}'".format(cert_name, self.endpoint.address)) def close(self): with self.lock: if self.is_closed: return self.is_closed = True log.debug("Closing connection (%s) to %s" % (id(self), self.endpoint)) cur_gthread = eventlet.getcurrent() if self._read_watcher and self._read_watcher != cur_gthread: self._read_watcher.kill() if self._write_watcher and self._write_watcher != cur_gthread: self._write_watcher.kill() if self._socket: self._socket.close() log.debug("Closed socket to %s" % (self.endpoint,)) if not self.is_defunct: self.error_all_requests( ConnectionShutdown("Connection to %s was closed" % self.endpoint)) # don't leave in-progress operations hanging self.connected_event.set() def handle_close(self): log.debug("connection closed by server") self.close() def handle_write(self): while True: try: next_msg = self._write_queue.get() self._socket.sendall(next_msg) except socket.error as err: log.debug("Exception during socket send for %s: %s", self, err) self.defunct(err) return # Leave the write loop except GreenletExit: # graceful greenthread exit return def handle_read(self): while True: try: buf = self._socket.recv(self.in_buffer_size) self._iobuf.write(buf) except socket.error as err: log.debug("Exception during socket recv for %s: %s", self, err) self.defunct(err) return # leave the read loop except GreenletExit: # graceful greenthread exit return if buf and self._iobuf.tell(): self.process_io_buffer() else: log.debug("Connection %s closed by server", self) self.close() return def push(self, data): chunk_size = self.out_buffer_size for i in xrange(0, len(data), chunk_size): self._write_queue.put(data[i:i + chunk_size])