"""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