"""Base class extended by connection adapters. This extends the
connection.Connection class to encapsulate connection behavior but still
isolate socket and low level communication.
"""
import errno
import logging
import socket
import ssl
import pika.compat
import pika.tcp_socket_opts
from pika import __version__
from pika import connection
from pika.compat import SOCKET_ERROR
from pika.compat import SOL_TCP
LOGGER = logging.getLogger(__name__)
class BaseConnection(connection.Connection):
"""BaseConnection class that should be extended by connection adapters"""
# Use epoll's constants to keep life easy
READ = 0x0001
WRITE = 0x0004
ERROR = 0x0008
ERRORS_TO_ABORT = [
errno.EBADF, errno.ECONNABORTED, errno.EPIPE, errno.ETIMEDOUT
]
ERRORS_TO_IGNORE = [errno.EWOULDBLOCK, errno.EAGAIN, errno.EINTR]
DO_HANDSHAKE = True
WARN_ABOUT_IOLOOP = False
def __init__(self,
parameters=None,
on_open_callback=None,
on_open_error_callback=None,
on_close_callback=None,
ioloop=None,
stop_ioloop_on_close=True):
"""Create a new instance of the Connection object.
:param pika.connection.Parameters parameters: Connection parameters
:param method on_open_callback: Method to call on connection open
:param method on_open_error_callback: Called if the connection can't
be established: on_open_error_callback(connection, str|exception)
:param method on_close_callback: Called when the connection is closed:
on_close_callback(connection, reason_code, reason_text)
:param object ioloop: IOLoop object to use
:param bool stop_ioloop_on_close: Call ioloop.stop() if disconnected
:raises: RuntimeError
:raises: ValueError
"""
if parameters and not isinstance(parameters, connection.Parameters):
raise ValueError(
'Expected instance of Parameters, not %r' % (parameters,))
# Let the developer know we could not import SSL
if parameters and parameters.ssl and not ssl:
raise RuntimeError("SSL specified but it is not available")
self.base_events = self.READ | self.ERROR
self.event_state = self.base_events
self.ioloop = ioloop
self.socket = None
self.stop_ioloop_on_close = stop_ioloop_on_close
self.write_buffer = None
super(BaseConnection,
self).__init__(parameters, on_open_callback,
on_open_error_callback, on_close_callback)
def __repr__(self):
def get_socket_repr(sock):
"""Return socket info suitable for use in repr"""
if sock is None:
return None
sockname = None
peername = None
try:
sockname = sock.getsockname()
except SOCKET_ERROR:
# closed?
pass
else:
try:
peername = sock.getpeername()
except SOCKET_ERROR:
# not connected?
pass
return '%s->%s' % (sockname, peername)
return ('<%s %s socket=%s params=%s>' %
(self.__class__.__name__,
self._STATE_NAMES[self.connection_state],
get_socket_repr(self.socket), self.params))
def add_timeout(self, deadline, callback_method):
"""Add the callback_method to the IOLoop timer to fire after deadline
seconds. Returns a handle to the timeout
:param int deadline: The number of seconds to wait to call callback
:param method callback_method: The callback method
:rtype: str
"""
return self.ioloop.add_timeout(deadline, callback_method)
def close(self, reply_code=200, reply_text='Normal shutdown'):
"""Disconnect from RabbitMQ. If there are any open channels, it will
attempt to close them prior to fully disconnecting. Channels which
have active consumers will attempt to send a Basic.Cancel to RabbitMQ
to cleanly stop the delivery of messages prior to closing the channel.
:param int reply_code: The code number for the close
:param str reply_text: The text reason for the close
"""
try:
super(BaseConnection, self).close(reply_code, reply_text)
finally:
if self.is_closed:
self._handle_ioloop_stop()
def remove_timeout(self, timeout_id):
"""Remove the timeout from the IOLoop by the ID returned from
add_timeout.
:rtype: str
"""
self.ioloop.remove_timeout(timeout_id)
def add_callback_threadsafe(self, callback):
"""Requests a call to the given function as soon as possible in the
context of this connection's IOLoop thread.
NOTE: This is the only thread-safe method offered by the connection. All
other manipulations of the connection must be performed from the
connection's thread.
For example, a thread may request a call to the
`channel.basic_ack` method of a connection that is running in a
different thread via
```
connection.add_callback_threadsafe(
functools.partial(channel.basic_ack, delivery_tag=...))
```
:param method callback: The callback method; must be callable.
"""
if not callable(callback):
raise TypeError(
'callback must be a callable, but got %r' % (callback,))
self.ioloop.add_callback_threadsafe(callback)
def _adapter_connect(self):
"""Connect to the RabbitMQ broker, returning True if connected.
:returns: error string or exception instance on error; None on success
"""
# Get the addresses for the socket, supporting IPv4 & IPv6
while True:
try:
addresses = self._getaddrinfo(
self.params.host, self.params.port, 0, socket.SOCK_STREAM,
socket.IPPROTO_TCP)
break
except SOCKET_ERROR as error:
if error.errno == errno.EINTR:
continue
LOGGER.critical('Could not get addresses to use: %s (%s)',
error, self.params.host)
return error
# If the socket is created and connected, continue on
error = "No socket addresses available"
for sock_addr in addresses:
error = self._create_and_connect_to_socket(sock_addr)
if not error:
# Make the socket non-blocking after the connect
self.socket.setblocking(0)
return None
self._cleanup_socket()
# Failed to connect
return error
def _adapter_disconnect(self):
"""Invoked if the connection is being told to disconnect"""
try:
self._cleanup_socket()
finally:
self._handle_ioloop_stop()
def _cleanup_socket(self):
"""Close the socket cleanly"""
if self.socket:
try:
self.socket.shutdown(socket.SHUT_RDWR)
except SOCKET_ERROR:
pass
self.socket.close()
self.socket = None
def _create_and_connect_to_socket(self, sock_addr_tuple):
"""Create socket and connect to it, using SSL if enabled.
:returns: error string on failure; None on success
"""
self.socket = self._create_tcp_connection_socket(
sock_addr_tuple[0], sock_addr_tuple[1], sock_addr_tuple[2])
self.socket.setsockopt(SOL_TCP, socket.TCP_NODELAY, 1)
self.socket.settimeout(self.params.socket_timeout)
pika.tcp_socket_opts.set_sock_opts(self.params.tcp_options, self.socket)
# Wrap socket if using SSL
if self.params.ssl:
self.socket = self._wrap_socket(self.socket)
ssl_text = " with SSL"
else:
ssl_text = ""
LOGGER.info('Pika version %s connecting to %s:%s%s',
__version__,
sock_addr_tuple[4][0],
sock_addr_tuple[4][1], ssl_text)
# Connect to the socket
try:
self.socket.connect(sock_addr_tuple[4])
except socket.timeout:
error = 'Connection to %s:%s failed: timeout' % (
sock_addr_tuple[4][0], sock_addr_tuple[4][1])
LOGGER.error(error)
return error
except SOCKET_ERROR as error:
error = 'Connection to %s:%s failed: %s' % (sock_addr_tuple[4][0],
sock_addr_tuple[4][1],
error)
LOGGER.error(error)
return error
# Handle SSL Connection Negotiation
if self.params.ssl and self.DO_HANDSHAKE:
try:
self._do_ssl_handshake()
except ssl.SSLError as error:
error = 'SSL connection to %s:%s failed: %s' % (
sock_addr_tuple[4][0], sock_addr_tuple[4][1], error)
LOGGER.error(error)
return error
# Made it this far
return None
@staticmethod
def _create_tcp_connection_socket(sock_family, sock_type, sock_proto):
""" Create TCP/IP stream socket for AMQP connection
:param int sock_family: socket family
:param int sock_type: socket type
:param int sock_proto: socket protocol number
NOTE We break this out to make it easier to patch in mock tests
"""
return socket.socket(sock_family, sock_type, sock_proto)
def _do_ssl_handshake(self):
"""Perform SSL handshaking, copied from python stdlib test_ssl.py.
"""
if not self.DO_HANDSHAKE:
return
while True:
try:
self.socket.do_handshake()
break
# TODO should be using SSLWantReadError, etc. directly
except ssl.SSLError as err:
# TODO these exc are for non-blocking sockets, but ours isn't
# at this stage, so it's not clear why we have this.
if err.args[0] == ssl.SSL_ERROR_WANT_READ:
self.event_state = self.READ
elif err.args[0] == ssl.SSL_ERROR_WANT_WRITE:
self.event_state = self.WRITE
else:
raise
self._manage_event_state()
@staticmethod
def _getaddrinfo(host, port, family, socktype, proto):
"""Wrap `socket.getaddrinfo` to make it easier to patch for unit tests
"""
return socket.getaddrinfo(host, port, family, socktype, proto)
@staticmethod
def _get_error_code(error_value):
"""Get the error code from the error_value accounting for Python
version differences.
:rtype: int
"""
if not error_value:
return None
return error_value.errno
def _flush_outbound(self):
"""Have the state manager schedule the necessary I/O.
"""
# NOTE: We don't call _handle_write() from this context, because pika
# code was not designed to be writing to (or reading from) the socket
# from any methods, except from ioloop handler callbacks. Many methods
# in pika core and adapters do not deal gracefully with connection
# errors occurring in their context; e.g., Connection.channel (pika
# issue #659), Connection._on_connection_tune (if connection loss is
# detected in _send_connection_tune_ok, before _send_connection_open is
# called), etc., etc., etc.
self._manage_event_state()
def _handle_ioloop_stop(self):
"""Invoked when the connection is closed to determine if the IOLoop
should be stopped or not.
"""
if self.stop_ioloop_on_close and self.ioloop:
self.ioloop.stop()
elif self.WARN_ABOUT_IOLOOP:
LOGGER.warning('Connection is closed but not stopping IOLoop')
def _handle_error(self, error_value):
"""Internal error handling method. Here we expect a socket error
coming in and will handle different socket errors differently.
:param int|object error_value: The inbound error
"""
# TODO doesn't seem right: docstring defines error_value as int|object,
# but _get_error_code expects a falsie or an exception-like object
error_code = self._get_error_code(error_value)
if not error_code:
LOGGER.critical("Tried to handle an error where no error existed")
return
# Ok errors, just continue what we were doing before
if error_code in self.ERRORS_TO_IGNORE:
LOGGER.debug("Ignoring %s", error_code)
return
# Socket is no longer connected, abort
elif error_code in self.ERRORS_TO_ABORT:
LOGGER.error("Fatal Socket Error: %r", error_value)
elif self.params.ssl and isinstance(error_value, ssl.SSLError):
if error_value.args[0] == ssl.SSL_ERROR_WANT_READ:
# TODO doesn't seem right: this logic updates event state, but
# the logic at the bottom unconditionaly disconnects anyway.
self.event_state = self.READ
elif error_value.args[0] == ssl.SSL_ERROR_WANT_WRITE:
self.event_state = self.WRITE
else:
LOGGER.error("SSL Socket error: %r", error_value)
else:
# Haven't run into this one yet, log it.
LOGGER.error("Socket Error: %s", error_code)
# Disconnect from our IOLoop and let Connection know what's up
self._on_terminate(connection.InternalCloseReasons.SOCKET_ERROR,
repr(error_value))
def _handle_timeout(self):
"""Handle a socket timeout in read or write.
We don't do anything in the non-blocking handlers because we
only have the socket in a blocking state during connect."""
LOGGER.warning("Unexpected socket timeout")
def _handle_events(self, fd, events, error=None, write_only=False):
"""Handle IO/Event loop events, processing them.
:param int fd: The file descriptor for the events
:param int events: Events from the IO/Event loop
:param int error: Was an error specified; TODO none of the current
adapters appear to be able to pass the `error` arg - is it needed?
:param bool write_only: Only handle write events
"""
if not self.socket:
LOGGER.error('Received events on closed socket: %r', fd)
return
if self.socket and (events & self.WRITE):
self._handle_write()
self._manage_event_state()
if self.socket and not write_only and (events & self.READ):
self._handle_read()
if (self.socket and write_only and (events & self.READ) and
(events & self.ERROR)):
error_msg = ('BAD libc: Write-Only but Read+Error. '
'Assume socket disconnected.')
LOGGER.error(error_msg)
self._on_terminate(connection.InternalCloseReasons.SOCKET_ERROR,
error_msg)
if self.socket and (events & self.ERROR):
LOGGER.error('Error event %r, %r', events, error)
self._handle_error(error)
def _handle_read(self):
"""Read from the socket and call our on_data_available with the data."""
try:
while True:
try:
if self.params.ssl:
data = self.socket.read(self._buffer_size)
else:
data = self.socket.recv(self._buffer_size)
break
except SOCKET_ERROR as error:
if error.errno == errno.EINTR:
continue
else:
raise
except socket.timeout:
self._handle_timeout()
return 0
except ssl.SSLError as error:
if error.args[0] == ssl.SSL_ERROR_WANT_READ:
# ssl wants more data but there is nothing currently
# available in the socket, wait for it to become readable.
return 0
return self._handle_error(error)
except SOCKET_ERROR as error:
if error.errno in (errno.EAGAIN, errno.EWOULDBLOCK):
return 0
return self._handle_error(error)
# Empty data, should disconnect
if not data or data == 0:
LOGGER.error('Read empty data, calling disconnect')
return self._on_terminate(
connection.InternalCloseReasons.SOCKET_ERROR, "EOF")
# Pass the data into our top level frame dispatching method
self._on_data_available(data)
return len(data)
def _handle_write(self):
"""Try and write as much as we can, if we get blocked requeue
what's left"""
total_bytes_sent = 0
try:
while self.outbound_buffer:
frame = self.outbound_buffer.popleft()
while True:
try:
num_bytes_sent = self.socket.send(frame)
break
except SOCKET_ERROR as error:
if error.errno == errno.EINTR:
continue
else:
raise
total_bytes_sent += num_bytes_sent
if num_bytes_sent < len(frame):
LOGGER.debug("Partial write, requeing remaining data")
self.outbound_buffer.appendleft(frame[num_bytes_sent:])
break
except socket.timeout:
# Will only come here if the socket is blocking
LOGGER.debug("socket timeout, requeuing frame")
self.outbound_buffer.appendleft(frame)
self._handle_timeout()
except ssl.SSLError as error:
if error.args[0] == ssl.SSL_ERROR_WANT_WRITE:
# In Python 3.5+, SSLSocket.send raises this if the socket is
# not currently able to write. Handle this just like an
# EWOULDBLOCK socket error.
LOGGER.debug("Would block, requeuing frame")
self.outbound_buffer.appendleft(frame)
else:
return self._handle_error(error)
except SOCKET_ERROR as error:
if error.errno in (errno.EAGAIN, errno.EWOULDBLOCK):
LOGGER.debug("Would block, requeuing frame")
self.outbound_buffer.appendleft(frame)
else:
return self._handle_error(error)
return total_bytes_sent
def _init_connection_state(self):
"""Initialize or reset all of our internal state variables for a given
connection. If we disconnect and reconnect, all of our state needs to
be wiped.
"""
super(BaseConnection, self)._init_connection_state()
self.base_events = self.READ | self.ERROR
self.event_state = self.base_events
self.socket = None
def _manage_event_state(self):
"""Manage the bitmask for reading/writing/error which is used by the
io/event handler to specify when there is an event such as a read or
write.
"""
if self.outbound_buffer:
if not self.event_state & self.WRITE:
self.event_state |= self.WRITE
self.ioloop.update_handler(self.socket.fileno(),
self.event_state)
elif self.event_state & self.WRITE:
self.event_state = self.base_events
self.ioloop.update_handler(self.socket.fileno(), self.event_state)
def _wrap_socket(self, sock):
"""Wrap the socket for connecting over SSL. This allows the user to use
a dict for the usual SSL options or an SSLOptions object for more
advanced control.
:rtype: ssl.SSLSocket
"""
ssl_options = self.params.ssl_options or {}
# our wrapped return sock
ssl_sock = None
if isinstance(ssl_options, connection.SSLOptions):
context = ssl.SSLContext(ssl_options.ssl_version)
context.verify_mode = ssl_options.verify_mode
if ssl_options.certfile is not None:
context.load_cert_chain(
certfile=ssl_options.certfile,
keyfile=ssl_options.keyfile,
password=ssl_options.key_password)
# only one of either cafile or capath have to defined
if ssl_options.cafile is not None or ssl_options.capath is not None:
context.load_verify_locations(
cafile=ssl_options.cafile,
capath=ssl_options.capath,
cadata=ssl_options.cadata)
if ssl_options.ciphers is not None:
context.set_ciphers(ssl_options.ciphers)
ssl_sock = context.wrap_socket(
sock,
server_side=ssl_options.server_side,
do_handshake_on_connect=ssl_options.do_handshake_on_connect,
suppress_ragged_eofs=ssl_options.suppress_ragged_eofs,
server_hostname=ssl_options.server_hostname)
else:
ssl_sock = ssl.wrap_socket(
sock, do_handshake_on_connect=self.DO_HANDSHAKE, **ssl_options)
return ssl_sock