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#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you 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 __future__ import absolute_import
import socket
import struct
import logging
logger = logging.getLogger(__name__)
from thrift.transport.TTransport import TTransportException, TTransportBase, TMemoryBuffer
from io import BytesIO
from collections import deque
from contextlib import contextmanager
from tornado import gen, iostream, ioloop, tcpserver, concurrent
__all__ = ['TTornadoServer', 'TTornadoStreamTransport']
class _Lock(object):
def __init__(self):
self._waiters = deque()
def acquired(self):
return len(self._waiters) > 0
@gen.coroutine
def acquire(self):
blocker = self._waiters[-1] if self.acquired() else None
future = concurrent.Future()
self._waiters.append(future)
if blocker:
yield blocker
raise gen.Return(self._lock_context())
def release(self):
assert self.acquired(), 'Lock not aquired'
future = self._waiters.popleft()
future.set_result(None)
@contextmanager
def _lock_context(self):
try:
yield
finally:
self.release()
class TTornadoStreamTransport(TTransportBase):
"""a framed, buffered transport over a Tornado stream"""
def __init__(self, host, port, stream=None, io_loop=None):
self.host = host
self.port = port
self.io_loop = io_loop or ioloop.IOLoop.current()
self.__wbuf = BytesIO()
self._read_lock = _Lock()
# servers provide a ready-to-go stream
self.stream = stream
def with_timeout(self, timeout, future):
return gen.with_timeout(timeout, future, self.io_loop)
@gen.coroutine
def open(self, timeout=None):
logger.debug('socket connecting')
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0)
self.stream = iostream.IOStream(sock)
try:
connect = self.stream.connect((self.host, self.port))
if timeout is not None:
yield self.with_timeout(timeout, connect)
else:
yield connect
except (socket.error, IOError, ioloop.TimeoutError) as e:
message = 'could not connect to {}:{} ({})'.format(self.host, self.port, e)
raise TTransportException(
type=TTransportException.NOT_OPEN,
message=message)
raise gen.Return(self)
def set_close_callback(self, callback):
"""
Should be called only after open() returns
"""
self.stream.set_close_callback(callback)
def close(self):
# don't raise if we intend to close
self.stream.set_close_callback(None)
self.stream.close()
def read(self, _):
# The generated code for Tornado shouldn't do individual reads -- only
# frames at a time
assert False, "you're doing it wrong"
@contextmanager
def io_exception_context(self):
try:
yield
except (socket.error, IOError) as e:
raise TTransportException(
type=TTransportException.END_OF_FILE,
message=str(e))
except iostream.StreamBufferFullError as e:
raise TTransportException(
type=TTransportException.UNKNOWN,
message=str(e))
@gen.coroutine
def readFrame(self):
# IOStream processes reads one at a time
with (yield self._read_lock.acquire()):
with self.io_exception_context():
frame_header = yield self.stream.read_bytes(4)
if len(frame_header) == 0:
raise iostream.StreamClosedError('Read zero bytes from stream')
frame_length, = struct.unpack('!i', frame_header)
frame = yield self.stream.read_bytes(frame_length)
raise gen.Return(frame)
def write(self, buf):
self.__wbuf.write(buf)
def flush(self):
frame = self.__wbuf.getvalue()
# reset wbuf before write/flush to preserve state on underlying failure
frame_length = struct.pack('!i', len(frame))
self.__wbuf = BytesIO()
with self.io_exception_context():
return self.stream.write(frame_length + frame)
class TTornadoServer(tcpserver.TCPServer):
def __init__(self, processor, iprot_factory, oprot_factory=None,
*args, **kwargs):
super(TTornadoServer, self).__init__(*args, **kwargs)
self._processor = processor
self._iprot_factory = iprot_factory
self._oprot_factory = (oprot_factory if oprot_factory is not None
else iprot_factory)
@gen.coroutine
def handle_stream(self, stream, address):
host, port = address
trans = TTornadoStreamTransport(host=host, port=port, stream=stream,
io_loop=self.io_loop)
oprot = self._oprot_factory.getProtocol(trans)
try:
while not trans.stream.closed():
frame = yield trans.readFrame()
tr = TMemoryBuffer(frame)
iprot = self._iprot_factory.getProtocol(tr)
yield self._processor.process(iprot, oprot)
except Exception:
logger.exception('thrift exception in handle_stream')
trans.close()
logger.info('client disconnected %s:%d', host, port)
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