Source code for

# 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
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# See the License for the specific language governing permissions and
# limitations under the License.
import gevent
import gevent.event
from gevent.queue import Queue
from gevent import socket
import gevent.ssl

import logging
import time

from six.moves import range

from cassandra.connection import Connection, ConnectionShutdown, Timer, TimerManager

log = logging.getLogger(__name__)

[docs]class GeventConnection(Connection): """ An implementation of :class:`.Connection` that utilizes ``gevent``. This implementation assumes all gevent monkey patching is active. It is not tested with partial patching. """ _read_watcher = None _write_watcher = None _socket_impl = gevent.socket _ssl_impl = gevent.ssl _timers = None _timeout_watcher = None _new_timer = None @classmethod def initialize_reactor(cls): if not cls._timers: cls._timers = TimerManager() cls._timeout_watcher = gevent.spawn(cls.service_timeouts) cls._new_timer = gevent.event.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): timer_manager = cls._timers timer_event = cls._new_timer while True: next_end = timer_manager.service_timeouts() sleep_time = max(next_end - time.time(), 0) if next_end else 10000 timer_event.wait(sleep_time) timer_event.clear() def __init__(self, *args, **kwargs): Connection.__init__(self, *args, **kwargs) self._write_queue = Queue() self._connect_socket() self._read_watcher = gevent.spawn(self.handle_read) self._write_watcher = gevent.spawn(self.handle_write) self._send_options_message() def close(self): with self.lock: if self.is_closed: return self.is_closed = True log.debug("Closing connection (%s) to %s" % (id(self), if self._read_watcher: self._read_watcher.kill(block=False) if self._write_watcher: self._write_watcher.kill(block=False) if self._socket: self._socket.close() log.debug("Closed socket to %s" % (,)) if not self.is_defunct: self.error_all_requests( ConnectionShutdown("Connection to %s was closed" % # 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 in send for %s: %s", self, err) self.defunct(err) 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 in read for %s: %s", self, err) self.defunct(err) return # leave the read loop 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 range(0, len(data), chunk_size): self._write_queue.put(data[i:i + chunk_size])