295 lines
8.7 KiB
Python
295 lines
8.7 KiB
Python
from collections import defaultdict, deque
|
|
from functools import partial
|
|
import logging
|
|
import socket
|
|
import sys
|
|
from threading import Event, Lock, Thread
|
|
import traceback
|
|
from Queue import Queue
|
|
|
|
import asyncore
|
|
|
|
from cassandra.connection import (Connection, ResponseWaiter, ConnectionShutdown,
|
|
ConnectionBusy, NONBLOCKING)
|
|
from cassandra.decoder import RegisterMessage
|
|
from cassandra.marshal import int32_unpack
|
|
|
|
log = logging.getLogger(__name__)
|
|
|
|
_loop_started = False
|
|
_loop_lock = Lock()
|
|
|
|
_starting_conns = set()
|
|
_starting_conns_lock = Lock()
|
|
|
|
def _run_loop():
|
|
global _loop_started
|
|
log.debug("Starting asyncore event loop")
|
|
with _loop_lock:
|
|
while True:
|
|
try:
|
|
asyncore.loop(timeout=0.001, use_poll=True, count=None)
|
|
except Exception:
|
|
log.debug("Asyncore event loop stopped unexepectedly", exc_info=True)
|
|
break
|
|
|
|
with _starting_conns_lock:
|
|
if not _starting_conns:
|
|
break
|
|
|
|
_loop_started = False
|
|
if log:
|
|
# this can happen during interpreter shutdown
|
|
log.debug("Asyncore event loop ended")
|
|
|
|
|
|
def _start_loop():
|
|
global _loop_started
|
|
should_start = False
|
|
did_acquire = False
|
|
try:
|
|
did_acquire = _loop_lock.acquire(False)
|
|
if did_acquire and not _loop_started:
|
|
_loop_started = True
|
|
should_start = True
|
|
finally:
|
|
if did_acquire:
|
|
_loop_lock.release()
|
|
|
|
if should_start:
|
|
t = Thread(target=_run_loop, name="event_loop")
|
|
t.daemon = True
|
|
t.start()
|
|
|
|
|
|
class AsyncoreConnection(Connection, asyncore.dispatcher):
|
|
"""
|
|
An implementation of :class:`.Connection` that utilizes the ``asyncore``
|
|
module in the Python standard library for its event loop.
|
|
"""
|
|
|
|
_buf = ""
|
|
_total_reqd_bytes = 0
|
|
_writable = False
|
|
_readable = False
|
|
_have_listeners = False
|
|
|
|
@classmethod
|
|
def factory(cls, *args, **kwargs):
|
|
conn = cls(*args, **kwargs)
|
|
conn.connected_event.wait()
|
|
if conn.last_error:
|
|
raise conn.last_error
|
|
else:
|
|
return conn
|
|
|
|
def __init__(self, *args, **kwargs):
|
|
Connection.__init__(self, *args, **kwargs)
|
|
asyncore.dispatcher.__init__(self)
|
|
|
|
self.connected_event = Event()
|
|
|
|
self._callbacks = {}
|
|
self._push_watchers = defaultdict(set)
|
|
self.deque = deque()
|
|
|
|
with _starting_conns_lock:
|
|
_starting_conns.add(self)
|
|
|
|
log.debug("Opening socket to %s", self.host)
|
|
self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
|
|
self.connect((self.host, self.port))
|
|
|
|
if self.sockopts:
|
|
for args in self.sockopts:
|
|
self.socket.setsockopt(*args)
|
|
|
|
self._writable = True
|
|
self._readable = True
|
|
|
|
# start the global event loop if needed
|
|
_start_loop()
|
|
|
|
def close(self):
|
|
with self.lock:
|
|
if self.is_closed:
|
|
return
|
|
self.is_closed = True
|
|
|
|
log.debug("Closing connection to %s" % (self.host,))
|
|
self._writable = False
|
|
self._readable = False
|
|
asyncore.dispatcher.close(self)
|
|
log.debug("Closed socket to %s" % (self.host,))
|
|
|
|
with _starting_conns_lock:
|
|
_starting_conns.discard(self)
|
|
|
|
# don't leave in-progress operations hanging
|
|
self.connected_event.set()
|
|
if not self.is_defunct:
|
|
self._error_all_callbacks(
|
|
ConnectionShutdown("Connection to %s was closed" % self.host))
|
|
|
|
def __del__(self):
|
|
try:
|
|
self.close()
|
|
except TypeError:
|
|
pass
|
|
|
|
def defunct(self, exc):
|
|
with self.lock:
|
|
if self.is_defunct:
|
|
return
|
|
self.is_defunct = True
|
|
|
|
trace = traceback.format_exc(exc)
|
|
if trace != "None":
|
|
log.debug("Defuncting connection to %s: %s\n%s",
|
|
self.host, exc, traceback.format_exc(exc))
|
|
else:
|
|
log.debug("Defuncting connection to %s: %s", self.host, exc)
|
|
|
|
self.last_error = exc
|
|
self._error_all_callbacks(exc)
|
|
self.connected_event.set()
|
|
return exc
|
|
|
|
def _error_all_callbacks(self, exc):
|
|
new_exc = ConnectionShutdown(str(exc))
|
|
for cb in self._callbacks.values():
|
|
cb(new_exc)
|
|
|
|
def handle_connect(self):
|
|
with _starting_conns_lock:
|
|
_starting_conns.discard(self)
|
|
self._send_options_message()
|
|
|
|
def handle_error(self):
|
|
self.defunct(sys.exc_info()[1])
|
|
|
|
def handle_close(self):
|
|
log.debug("connection closed by server")
|
|
self.close()
|
|
|
|
def handle_write(self):
|
|
try:
|
|
next_msg = self.deque.popleft()
|
|
except IndexError:
|
|
self._writable = False
|
|
return
|
|
|
|
try:
|
|
sent = self.send(next_msg)
|
|
except socket.error as err:
|
|
if (err.args[0] in NONBLOCKING):
|
|
self.deque.appendleft(next_msg)
|
|
else:
|
|
self.defunct(err)
|
|
return
|
|
else:
|
|
if sent < len(next_msg):
|
|
self.deque.appendleft(next_msg[sent:])
|
|
|
|
if not self.deque:
|
|
self._writable = False
|
|
|
|
self._readable = True
|
|
|
|
def handle_read(self):
|
|
try:
|
|
buf = self.recv(self.in_buffer_size)
|
|
except socket.error as err:
|
|
if err.args[0] not in NONBLOCKING:
|
|
self.defunct(err)
|
|
return
|
|
|
|
if buf:
|
|
self._buf += buf
|
|
while True:
|
|
if len(self._buf) < 8:
|
|
# we don't have a complete header yet
|
|
break
|
|
elif self._total_reqd_bytes and len(self._buf) < self._total_reqd_bytes:
|
|
# we already saw a header, but we don't have a complete message yet
|
|
break
|
|
else:
|
|
body_len = int32_unpack(self._buf[4:8])
|
|
if len(self._buf) - 8 >= body_len:
|
|
msg = self._buf[:8 + body_len]
|
|
self._buf = self._buf[8 + body_len:]
|
|
self._total_reqd_bytes = 0
|
|
self.process_msg(msg, body_len)
|
|
else:
|
|
self._total_reqd_bytes = body_len + 8
|
|
|
|
if not self._callbacks:
|
|
self._readable = False
|
|
else:
|
|
self.close()
|
|
|
|
def handle_pushed(self, response):
|
|
log.debug("Message pushed from server: %r", response)
|
|
for cb in self._push_watchers.get(response.event_type, []):
|
|
try:
|
|
cb(response.event_args)
|
|
except Exception:
|
|
log.exception("Pushed event handler errored, ignoring:")
|
|
|
|
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.lock:
|
|
self.deque.extend(chunks)
|
|
|
|
self._writable = True
|
|
|
|
def writable(self):
|
|
return self._writable
|
|
|
|
def readable(self):
|
|
return self._readable or (self._have_listeners and not (self.is_defunct or self.is_closed))
|
|
|
|
def send_msg(self, msg, cb):
|
|
if self.is_defunct:
|
|
raise ConnectionShutdown("Connection to %s is defunct" % self.host)
|
|
elif self.is_closed:
|
|
raise ConnectionShutdown("Connection to %s is closed" % self.host)
|
|
|
|
try:
|
|
request_id = self._id_queue.get_nowait()
|
|
except Queue.EMPTY:
|
|
raise ConnectionBusy(
|
|
"Connection to %s is at the max number of requests" % self.host)
|
|
|
|
self._callbacks[request_id] = cb
|
|
self.push(msg.to_string(request_id, compression=self.compressor))
|
|
return request_id
|
|
|
|
def wait_for_response(self, msg):
|
|
return self.wait_for_responses(msg)[0]
|
|
|
|
def wait_for_responses(self, *msgs):
|
|
waiter = ResponseWaiter(len(msgs))
|
|
for i, msg in enumerate(msgs):
|
|
self.send_msg(msg, partial(waiter.got_response, index=i))
|
|
|
|
return waiter.deliver()
|
|
|
|
def register_watcher(self, event_type, callback):
|
|
self._push_watchers[event_type].add(callback)
|
|
self._have_listeners = True
|
|
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._have_listeners = True
|
|
self.wait_for_response(RegisterMessage(event_list=type_callback_dict.keys()))
|