358 lines
12 KiB
Python
358 lines
12 KiB
Python
# Copyright 2013-2014 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.
|
|
|
|
from collections import defaultdict, deque
|
|
import logging
|
|
import os
|
|
import socket
|
|
from threading import Event, Lock, Thread
|
|
|
|
from cassandra import OperationTimedOut
|
|
from cassandra.connection import Connection, ConnectionShutdown, NONBLOCKING
|
|
from cassandra.decoder import RegisterMessage
|
|
from cassandra.marshal import int32_unpack
|
|
try:
|
|
import cassandra.io.libevwrapper as libev
|
|
except ImportError:
|
|
raise ImportError(
|
|
"The C extension needed to use libev was not found. This "
|
|
"probably means that you didn't have the required build dependencies "
|
|
"when installing the driver. See "
|
|
"http://datastax.github.io/python-driver/installation.html#c-extensions "
|
|
"for instructions on installing build dependencies and building "
|
|
"the C extension.")
|
|
|
|
try:
|
|
from cStringIO import StringIO
|
|
except ImportError:
|
|
from StringIO import StringIO # ignore flake8 warning: # NOQA
|
|
|
|
try:
|
|
import ssl
|
|
except ImportError:
|
|
ssl = None # NOQA
|
|
|
|
log = logging.getLogger(__name__)
|
|
|
|
_loop = libev.Loop()
|
|
_loop_notifier = libev.Async(_loop)
|
|
_loop_notifier.start()
|
|
|
|
# prevent _loop_notifier from keeping the loop from returning
|
|
_loop.unref()
|
|
|
|
_loop_started = None
|
|
_loop_lock = Lock()
|
|
|
|
|
|
def _run_loop():
|
|
while True:
|
|
end_condition = _loop.start()
|
|
# there are still active watchers, no deadlock
|
|
with _loop_lock:
|
|
if end_condition:
|
|
log.debug("Restarting event loop")
|
|
continue
|
|
else:
|
|
# all Connections have been closed, no active watchers
|
|
log.debug("All Connections currently closed, event loop ended")
|
|
global _loop_started
|
|
_loop_started = False
|
|
break
|
|
|
|
|
|
def _start_loop():
|
|
global _loop_started
|
|
should_start = False
|
|
with _loop_lock:
|
|
if not _loop_started:
|
|
log.debug("Starting libev event loop")
|
|
_loop_started = True
|
|
should_start = True
|
|
|
|
if should_start:
|
|
t = Thread(target=_run_loop, name="event_loop")
|
|
t.daemon = True
|
|
t.start()
|
|
|
|
return should_start
|
|
|
|
|
|
class LibevConnection(Connection):
|
|
"""
|
|
An implementation of :class:`.Connection` that uses libev for its event loop.
|
|
"""
|
|
|
|
# class-level set of all connections; only replaced with a new copy
|
|
# while holding _conn_set_lock, never modified in place
|
|
_live_conns = set()
|
|
# newly created connections that need their write/read watcher started
|
|
_new_conns = set()
|
|
# recently closed connections that need their write/read watcher stopped
|
|
_closed_conns = set()
|
|
_conn_set_lock = Lock()
|
|
|
|
_write_watcher_is_active = False
|
|
|
|
_total_reqd_bytes = 0
|
|
_read_watcher = None
|
|
_write_watcher = None
|
|
_socket = None
|
|
|
|
@classmethod
|
|
def factory(cls, *args, **kwargs):
|
|
timeout = kwargs.pop('timeout', 5.0)
|
|
conn = cls(*args, **kwargs)
|
|
conn.connected_event.wait(timeout)
|
|
if conn.last_error:
|
|
raise conn.last_error
|
|
elif not conn.connected_event.is_set():
|
|
conn.close()
|
|
raise OperationTimedOut("Timed out creating new connection")
|
|
else:
|
|
return conn
|
|
|
|
@classmethod
|
|
def _connection_created(cls, conn):
|
|
with cls._conn_set_lock:
|
|
new_live_conns = cls._live_conns.copy()
|
|
new_live_conns.add(conn)
|
|
cls._live_conns = new_live_conns
|
|
|
|
new_new_conns = cls._new_conns.copy()
|
|
new_new_conns.add(conn)
|
|
cls._new_conns = new_new_conns
|
|
|
|
@classmethod
|
|
def _connection_destroyed(cls, conn):
|
|
with cls._conn_set_lock:
|
|
new_live_conns = cls._live_conns.copy()
|
|
new_live_conns.discard(conn)
|
|
cls._live_conns = new_live_conns
|
|
|
|
new_closed_conns = cls._closed_conns.copy()
|
|
new_closed_conns.add(conn)
|
|
cls._closed_conns = new_closed_conns
|
|
|
|
@classmethod
|
|
def loop_will_run(cls, prepare):
|
|
changed = False
|
|
for conn in cls._live_conns:
|
|
if not conn.deque and conn._write_watcher_is_active:
|
|
if conn._write_watcher:
|
|
conn._write_watcher.stop()
|
|
conn._write_watcher_is_active = False
|
|
changed = True
|
|
elif conn.deque and not conn._write_watcher_is_active:
|
|
conn._write_watcher.start()
|
|
conn._write_watcher_is_active = True
|
|
changed = True
|
|
|
|
if cls._new_conns:
|
|
with cls._conn_set_lock:
|
|
to_start = cls._new_conns
|
|
cls._new_conns = set()
|
|
|
|
for conn in to_start:
|
|
conn._read_watcher.start()
|
|
|
|
changed = True
|
|
|
|
if cls._closed_conns:
|
|
with cls._conn_set_lock:
|
|
to_stop = cls._closed_conns
|
|
cls._closed_conns = set()
|
|
|
|
for conn in to_stop:
|
|
if conn._write_watcher:
|
|
conn._write_watcher.stop()
|
|
if conn._read_watcher:
|
|
conn._read_watcher.stop()
|
|
|
|
changed = True
|
|
|
|
if changed:
|
|
_loop_notifier.send()
|
|
|
|
def __init__(self, *args, **kwargs):
|
|
Connection.__init__(self, *args, **kwargs)
|
|
|
|
self.connected_event = Event()
|
|
self._iobuf = StringIO()
|
|
|
|
self._callbacks = {}
|
|
self._push_watchers = defaultdict(set)
|
|
self.deque = deque()
|
|
self._deque_lock = Lock()
|
|
|
|
self._socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
|
|
if self.ssl_options:
|
|
if not ssl:
|
|
raise Exception("This version of Python was not compiled with SSL support")
|
|
self._socket = ssl.wrap_socket(self._socket, **self.ssl_options)
|
|
self._socket.settimeout(1.0) # TODO potentially make this value configurable
|
|
self._socket.connect((self.host, self.port))
|
|
self._socket.setblocking(0)
|
|
|
|
if self.sockopts:
|
|
for args in self.sockopts:
|
|
self._socket.setsockopt(*args)
|
|
|
|
with _loop_lock:
|
|
self._read_watcher = libev.IO(self._socket._sock, libev.EV_READ, _loop, self.handle_read)
|
|
self._write_watcher = libev.IO(self._socket._sock, libev.EV_WRITE, _loop, self.handle_write)
|
|
|
|
self._send_options_message()
|
|
|
|
self.__class__._connection_created(self)
|
|
|
|
# start the global event loop if needed
|
|
_start_loop()
|
|
_loop_notifier.send()
|
|
|
|
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)
|
|
self.__class__._connection_destroyed(self)
|
|
_loop_notifier.send()
|
|
self._socket.close()
|
|
|
|
# don't leave in-progress operations hanging
|
|
if not self.is_defunct:
|
|
self.error_all_callbacks(
|
|
ConnectionShutdown("Connection to %s was closed" % self.host))
|
|
|
|
def handle_write(self, watcher, revents, errno=None):
|
|
if revents & libev.EV_ERROR:
|
|
if errno:
|
|
exc = IOError(errno, os.strerror(errno))
|
|
else:
|
|
exc = Exception("libev reported an error")
|
|
|
|
self.defunct(exc)
|
|
return
|
|
|
|
while True:
|
|
try:
|
|
with self._deque_lock:
|
|
next_msg = self.deque.popleft()
|
|
except IndexError:
|
|
return
|
|
|
|
try:
|
|
sent = self._socket.send(next_msg)
|
|
except socket.error as err:
|
|
if (err.args[0] in NONBLOCKING):
|
|
with self._deque_lock:
|
|
self.deque.appendleft(next_msg)
|
|
else:
|
|
self.defunct(err)
|
|
return
|
|
else:
|
|
if sent < len(next_msg):
|
|
with self._deque_lock:
|
|
self.deque.appendleft(next_msg[sent:])
|
|
|
|
def handle_read(self, watcher, revents, errno=None):
|
|
if revents & libev.EV_ERROR:
|
|
if errno:
|
|
exc = IOError(errno, os.strerror(errno))
|
|
else:
|
|
exc = Exception("libev reported an error")
|
|
|
|
self.defunct(exc)
|
|
return
|
|
try:
|
|
while True:
|
|
buf = self._socket.recv(self.in_buffer_size)
|
|
self._iobuf.write(buf)
|
|
if len(buf) < self.in_buffer_size:
|
|
break
|
|
except socket.error as err:
|
|
if ssl and isinstance(err, ssl.SSLError):
|
|
if err.args[0] not in (ssl.SSL_ERROR_WANT_READ, ssl.SSL_ERROR_WANT_WRITE):
|
|
self.defunct(err)
|
|
return
|
|
elif err.args[0] not in NONBLOCKING:
|
|
self.defunct(err)
|
|
return
|
|
|
|
if self._iobuf.tell():
|
|
while True:
|
|
pos = self._iobuf.tell()
|
|
if pos < 8 or (self._total_reqd_bytes > 0 and pos < self._total_reqd_bytes):
|
|
# we don't have a complete header yet or we
|
|
# already saw a header, but we don't have a
|
|
# complete message yet
|
|
break
|
|
else:
|
|
# have enough for header, read body len from header
|
|
self._iobuf.seek(4)
|
|
body_len = int32_unpack(self._iobuf.read(4))
|
|
|
|
# seek to end to get length of current buffer
|
|
self._iobuf.seek(0, os.SEEK_END)
|
|
pos = self._iobuf.tell()
|
|
|
|
if pos >= body_len + 8:
|
|
# read message header and body
|
|
self._iobuf.seek(0)
|
|
msg = self._iobuf.read(8 + body_len)
|
|
|
|
# leave leftover in current buffer
|
|
leftover = self._iobuf.read()
|
|
self._iobuf = StringIO()
|
|
self._iobuf.write(leftover)
|
|
|
|
self._total_reqd_bytes = 0
|
|
self.process_msg(msg, body_len)
|
|
else:
|
|
self._total_reqd_bytes = body_len + 8
|
|
break
|
|
else:
|
|
log.debug("Connection %s closed by server", self)
|
|
self.close()
|
|
|
|
def push(self, data):
|
|
sabs = self.out_buffer_size
|
|
if len(data) > sabs:
|
|
chunks = []
|
|
for i in xrange(0, len(data), sabs):
|
|
chunks.append(data[i:i + sabs])
|
|
else:
|
|
chunks = [data]
|
|
|
|
with self._deque_lock:
|
|
self.deque.extend(chunks)
|
|
_loop_notifier.send()
|
|
|
|
def register_watcher(self, event_type, callback):
|
|
self._push_watchers[event_type].add(callback)
|
|
self.wait_for_response(RegisterMessage(event_list=[event_type]))
|
|
|
|
def register_watchers(self, type_callback_dict):
|
|
for event_type, callback in type_callback_dict.items():
|
|
self._push_watchers[event_type].add(callback)
|
|
self.wait_for_response(RegisterMessage(event_list=type_callback_dict.keys()))
|
|
|
|
|
|
_preparer = libev.Prepare(_loop, LibevConnection.loop_will_run)
|
|
# prevent _preparer from keeping the loop from returning
|
|
_loop.unref()
|
|
_preparer.start()
|