#
# 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 logging
import socket
import struct
from .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']
logger = logging.getLogger(__name__)
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[:2]
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():
try:
frame = yield trans.readFrame()
except TTransportException as e:
if e.type == TTransportException.END_OF_FILE:
break
else:
raise
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)
