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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.
#
# 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.
"""helper methods that provide boilerplate socket I/O and Connection
processing.
"""
__all__ = [
"read_socket_input",
"write_socket_output"
]
import errno
import logging
import socket
from pyngus.connection import Connection
LOG = logging.getLogger(__name__)
def read_socket_input(connection, socket_obj):
"""Read from the network layer and processes all data read. Can
support both blocking and non-blocking sockets.
Returns the number of input bytes processed, or EOS if input processing
is done. Any exceptions raised by the socket are re-raised.
"""
count = connection.needs_input
if count <= 0:
return count # 0 or EOS
while True:
try:
sock_data = socket_obj.recv(count)
break
except socket.timeout as e:
LOG.debug("Socket timeout exception %s", str(e))
raise # caller must handle
except socket.error as e:
LOG.debug("Socket error exception %s", str(e))
err = e.errno
if err in [errno.EAGAIN,
errno.EWOULDBLOCK,
errno.EINTR]:
# try again later
return 0
# otherwise, unrecoverable, caller must handle
raise
except Exception as e: # beats me... assume fatal
LOG.debug("unknown socket exception %s", str(e))
raise # caller must handle
if len(sock_data) > 0:
count = connection.process_input(sock_data)
else:
LOG.debug("Socket closed")
count = Connection.EOS
connection.close_input()
connection.close_output()
LOG.debug("Socket recv %s bytes", count)
return count
def write_socket_output(connection, socket_obj):
"""Write data to the network layer. Can support both blocking and
non-blocking sockets.
Returns the number of output bytes sent, or EOS if output processing
is done. Any exceptions raised by the socket are re-raised.
"""
count = connection.has_output
if count <= 0:
return count # 0 or EOS
data = connection.output_data()
if not data:
# error - has_output > 0, but no data?
return Connection.EOS
while True:
try:
count = socket_obj.send(data)
break
except socket.timeout as e:
LOG.debug("Socket timeout exception %s", str(e))
raise # caller must handle
except socket.error as e:
LOG.debug("Socket error exception %s", str(e))
err = e.errno
if err in [errno.EAGAIN,
errno.EWOULDBLOCK,
errno.EINTR]:
# try again later
return 0
# else assume fatal let caller handle it:
raise
except Exception as e: # beats me... assume fatal
LOG.debug("unknown socket exception %s", str(e))
raise
if count > 0:
LOG.debug("Socket sent %s bytes", count)
connection.output_written(count)
elif data:
LOG.debug("Socket closed")
count = Connection.EOS
connection.close_output()
connection.close_input()
return count
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