deb-python-cassandra-driver/cassandra/io/geventreactor.py
2017-04-24 17:20:57 -04:00

139 lines
4.2 KiB
Python

# Copyright 2013-2017 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.
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__)
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), self.host))
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" % (self.host,))
if not self.is_defunct:
self.error_all_requests(
ConnectionShutdown("Connection to %s was closed" % self.host))
# 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])