text: """AMQP Connections."""
  # Copyright (C) 2007-2008 Barry Pederson <bp@barryp.org>
  #
  # This library is free software; you can redistribute it and/or
  # modify it under the terms of the GNU Lesser General Public
  # License as published by the Free Software Foundation; either
  # version 2.1 of the License, or (at your option) any later version.
  #
  # This library is distributed in the hope that it will be useful,
  # but WITHOUT ANY WARRANTY; without even the implied warranty of
  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  # Lesser General Public License for more details.
  #
  # You should have received a copy of the GNU Lesser General Public
  # License along with this library; if not, write to the Free Software
  # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
  from __future__ import absolute_import, unicode_literals
  
  import logging
  import socket
  import uuid
  import warnings
  
  from vine import ensure_promise
  
  from . import __version__
  from . import sasl
  from . import spec
  from .abstract_channel import AbstractChannel
  from .channel import Channel
  from .exceptions import (
      AMQPDeprecationWarning, ChannelError, ResourceError,
      ConnectionForced, ConnectionError, error_for_code,
      RecoverableConnectionError, RecoverableChannelError,
  )
  from .five import array, items, monotonic, range, values, string
  from .method_framing import frame_handler, frame_writer
  from .transport import Transport
  
  try:
      from ssl import SSLError
  except ImportError:  # pragma: no cover
      class SSLError(Exception):  # noqa
          pass
  
  W_FORCE_CONNECT = """\
  The .{attr} attribute on the connection was accessed before
  the connection was established.  This is supported for now, but will
  be deprecated in amqp 2.2.0.
  
  Since amqp 2.0 you have to explicitly call Connection.connect()
  before using the connection.
  """
  
  START_DEBUG_FMT = """
  Start from server, version: %d.%d, properties: %s, mechanisms: %s, locales: %s
  """.strip()
  
  __all__ = ['Connection']
  
  AMQP_LOGGER = logging.getLogger('amqp')
  
  #: Default map for :attr:`Connection.library_properties`
  LIBRARY_PROPERTIES = {
      'product': 'py-amqp',
      'product_version': __version__,
  }
  
  #: Default map for :attr:`Connection.negotiate_capabilities`
  NEGOTIATE_CAPABILITIES = {
      'consumer_cancel_notify': True,
      'connection.blocked': True,
      'authentication_failure_close': True,
  }
  
  
  class Connection(AbstractChannel):
      """AMQP Connection.
  
      The connection class provides methods for a client to establish a
      network connection to a server, and for both peers to operate the
      connection thereafter.
  
      GRAMMAR::
  
          connection          = open-connection *use-connection close-connection
          open-connection     = C:protocol-header
                                S:START C:START-OK
                                *challenge
                                S:TUNE C:TUNE-OK
                                C:OPEN S:OPEN-OK
          challenge           = S:SECURE C:SECURE-OK
          use-connection      = *channel
          close-connection    = C:CLOSE S:CLOSE-OK
                              / S:CLOSE C:CLOSE-OK
      Create a connection to the specified host, which should be
      a 'host[:port]', such as 'localhost', or '1.2.3.4:5672'
      (defaults to 'localhost', if a port is not specified then
      5672 is used)
  
      Authentication can be controlled by passing one or more
      `amqp.sasl.SASL` instances as the `authentication` parameter, or
      by using the userid and password parameters (for AMQPLAIN and PLAIN).
  
      The 'ssl' parameter may be simply True/False, or for Python >= 2.6
      a dictionary of options to pass to ssl.wrap_socket() such as
      requiring certain certificates.
  
      The "socket_settings" parameter is a dictionary defining tcp
      settings which will be applied as socket options.
      """
  
      Channel = Channel
  
      #: Mapping of protocol extensions to enable.
      #: The server will report these in server_properties[capabilities],
      #: and if a key in this map is present the client will tell the
      #: server to either enable or disable the capability depending
      #: on the value set in this map.
      #: For example with:
      #:     negotiate_capabilities = {
      #:         'consumer_cancel_notify': True,
      #:     }
      #: The client will enable this capability if the server reports
      #: support for it, but if the value is False the client will
      #: disable the capability.
      negotiate_capabilities = NEGOTIATE_CAPABILITIES
  
      #: These are sent to the server to announce what features
      #: we support, type of client etc.
      library_properties = LIBRARY_PROPERTIES
  
      #: Final heartbeat interval value (in float seconds) after negotiation
      heartbeat = None
  
      #: Original heartbeat interval value proposed by client.
      client_heartbeat = None
  
      #: Original heartbeat interval proposed by server.
      server_heartbeat = None
  
      #: Time of last heartbeat sent (in monotonic time, if available).
      last_heartbeat_sent = 0
  
      #: Time of last heartbeat received (in monotonic time, if available).
      last_heartbeat_received = 0
  
      #: Number of successful writes to socket.
      bytes_sent = 0
  
      #: Number of successful reads from socket.
      bytes_recv = 0
  
      #: Number of bytes sent to socket at the last heartbeat check.
      prev_sent = None
  
      #: Number of bytes received from socket at the last heartbeat check.
      prev_recv = None
  
      _METHODS = {
          spec.method(spec.Connection.Start, 'ooFSS'),
          spec.method(spec.Connection.OpenOk),
          spec.method(spec.Connection.Secure, 's'),
          spec.method(spec.Connection.Tune, 'BlB'),
          spec.method(spec.Connection.Close, 'BsBB'),
          spec.method(spec.Connection.Blocked),
          spec.method(spec.Connection.Unblocked),
          spec.method(spec.Connection.CloseOk),
      }
      _METHODS = {m.method_sig: m for m in _METHODS}
  
      connection_errors = (
          ConnectionError,
          socket.error,
          IOError,
          OSError,
      )
      channel_errors = (ChannelError,)
      recoverable_connection_errors = (
          RecoverableConnectionError,
          socket.error,
          IOError,
          OSError,
      )
      recoverable_channel_errors = (
          RecoverableChannelError,
      )
  
      def __init__(self, host='localhost:5672', userid='guest', password='guest',
                   login_method=None, login_response=None,
                   authentication=(),
                   virtual_host='/', locale='en_US', client_properties=None,
                   ssl=False, connect_timeout=None, channel_max=None,
                   frame_max=None, heartbeat=0, on_open=None, on_blocked=None,
                   on_unblocked=None, confirm_publish=False,
                   on_tune_ok=None, read_timeout=None, write_timeout=None,
                   socket_settings=None, frame_handler=frame_handler,
                   frame_writer=frame_writer, **kwargs):
          self._connection_id = uuid.uuid4().hex
          channel_max = channel_max or 65535
          frame_max = frame_max or 131072
          if authentication:
              if isinstance(authentication, sasl.SASL):
                  authentication = (authentication,)
              self.authentication = authentication
          elif login_method is not None and login_response is not None:
              self.authentication = (sasl.RAW(login_method, login_response),)
          elif userid is not None and password is not None:
              self.authentication = (sasl.GSSAPI(userid, fail_soft=True),
                                     sasl.AMQPLAIN(userid, password),
                                     sasl.PLAIN(userid, password))
          else:
              raise ValueError("Must supply authentication or userid/password")
  
          self.client_properties = dict(
              self.library_properties, **client_properties or {}
          )
          self.locale = locale
          self.host = host
          self.virtual_host = virtual_host
          self.on_tune_ok = ensure_promise(on_tune_ok)
  
          self.frame_handler_cls = frame_handler
          self.frame_writer_cls = frame_writer
  
          self._handshake_complete = False
  
          self.channels = {}
          # The connection object itself is treated as channel 0
          super(Connection, self).__init__(self, 0)
  
          self._frame_writer = None
          self._on_inbound_frame = None
          self._transport = None
  
          # Properties set in the Tune method
          self.channel_max = channel_max
          self.frame_max = frame_max
          self.client_heartbeat = heartbeat
  
          self.confirm_publish = confirm_publish
          self.ssl = ssl
          self.read_timeout = read_timeout
          self.write_timeout = write_timeout
          self.socket_settings = socket_settings
  
          # Callbacks
          self.on_blocked = on_blocked
          self.on_unblocked = on_unblocked
          self.on_open = ensure_promise(on_open)
  
          self._avail_channel_ids = array('H', range(self.channel_max, 0, -1))
  
          # Properties set in the Start method
          self.version_major = 0
          self.version_minor = 0
          self.server_properties = {}
          self.mechanisms = []
          self.locales = []
  
          self.connect_timeout = connect_timeout
  
      def __enter__(self):
          self.connect()
          return self
  
      def __exit__(self, *eargs):
          self.close()
  
      def then(self, on_success, on_error=None):
          return self.on_open.then(on_success, on_error)
  
      def _setup_listeners(self):
          self._callbacks.update({
              spec.Connection.Start: self._on_start,
              spec.Connection.OpenOk: self._on_open_ok,
              spec.Connection.Secure: self._on_secure,
              spec.Connection.Tune: self._on_tune,
              spec.Connection.Close: self._on_close,
              spec.Connection.Blocked: self._on_blocked,
              spec.Connection.Unblocked: self._on_unblocked,
              spec.Connection.CloseOk: self._on_close_ok,
          })
  
      def connect(self, callback=None):
          # Let the transport.py module setup the actual
          # socket connection to the broker.
          #
          if self.connected:
              return callback() if callback else None
          self.transport = self.Transport(
              self.host, self.connect_timeout, self.ssl,
              self.read_timeout, self.write_timeout,
              socket_settings=self.socket_settings,
          )
          self.transport.connect()
          self.on_inbound_frame = self.frame_handler_cls(
              self, self.on_inbound_method)
          self.frame_writer = self.frame_writer_cls(self, self.transport)
  
          while not self._handshake_complete:
              self.drain_events(timeout=self.connect_timeout)
  
      def _warn_force_connect(self, attr):
          warnings.warn(AMQPDeprecationWarning(
              W_FORCE_CONNECT.format(attr=attr)))
  
      @property
      def transport(self):
          if self._transport is None:
              self._warn_force_connect('transport')
              self.connect()
          return self._transport
  
      @transport.setter
      def transport(self, transport):
          self._transport = transport
  
      @property
      def on_inbound_frame(self):
          if self._on_inbound_frame is None:
              self._warn_force_connect('on_inbound_frame')
              self.connect()
          return self._on_inbound_frame
  
      @on_inbound_frame.setter
      def on_inbound_frame(self, on_inbound_frame):
          self._on_inbound_frame = on_inbound_frame
  
      @property
      def frame_writer(self):
          if self._frame_writer is None:
              self._warn_force_connect('frame_writer')
              self.connect()
          return self._frame_writer
  
      @frame_writer.setter
      def frame_writer(self, frame_writer):
          self._frame_writer = frame_writer
  
      def _on_start(self, version_major, version_minor, server_properties,
                    mechanisms, locales, argsig='FsSs'):
          client_properties = self.client_properties
          self.version_major = version_major
          self.version_minor = version_minor
          self.server_properties = server_properties
          if isinstance(mechanisms, string):
              mechanisms = mechanisms.encode('utf-8')
          self.mechanisms = mechanisms.split(b' ')
          self.locales = locales.split(' ')
          AMQP_LOGGER.debug(
              START_DEBUG_FMT,
              self.version_major, self.version_minor,
              self.server_properties, self.mechanisms, self.locales,
          )
  
          # Negotiate protocol extensions (capabilities)
          scap = server_properties.get('capabilities') or {}
          cap = client_properties.setdefault('capabilities', {})
          cap.update({
              wanted_cap: enable_cap
              for wanted_cap, enable_cap in items(self.negotiate_capabilities)
              if scap.get(wanted_cap)
          })
          if not cap:
              # no capabilities, server may not react well to having
              # this key present in client_properties, so we remove it.
              client_properties.pop('capabilities', None)
  
          for authentication in self.authentication:
              if authentication.mechanism in self.mechanisms:
                  login_response = authentication.start(self)
                  if login_response is not NotImplemented:
                      break
          else:
              raise ConnectionError(
                  "Couldn't find appropriate auth mechanism "
                  "(can offer: {0}; available: {1})".format(
                      b", ".join(m.mechanism
                                 for m in self.authentication
                                 if m.mechanism).decode(),
                      b", ".join(self.mechanisms).decode()))
  
          self.send_method(
              spec.Connection.StartOk, argsig,
              (client_properties, authentication.mechanism,
               login_response, self.locale),
          )
  
      def _on_secure(self, challenge):
          pass
  
      def _on_tune(self, channel_max, frame_max, server_heartbeat, argsig='BlB'):
          client_heartbeat = self.client_heartbeat or 0
          self.channel_max = channel_max or self.channel_max
          self.frame_max = frame_max or self.frame_max
          self.server_heartbeat = server_heartbeat or 0
  
          # negotiate the heartbeat interval to the smaller of the
          # specified values
          if self.server_heartbeat == 0 or client_heartbeat == 0:
              self.heartbeat = max(self.server_heartbeat, client_heartbeat)
          else:
              self.heartbeat = min(self.server_heartbeat, client_heartbeat)
  
          # Ignore server heartbeat if client_heartbeat is disabled
          if not self.client_heartbeat:
              self.heartbeat = 0
  
          self.send_method(
              spec.Connection.TuneOk, argsig,
              (self.channel_max, self.frame_max, self.heartbeat),
              callback=self._on_tune_sent,
          )
  
      def _on_tune_sent(self, argsig='ssb'):
          self.send_method(
              spec.Connection.Open, argsig, (self.virtual_host, '', False),
          )
  
      def _on_open_ok(self):
          self._handshake_complete = True
          self.on_open(self)
  
      def Transport(self, host, connect_timeout,
                    ssl=False, read_timeout=None, write_timeout=None,
                    socket_settings=None, **kwargs):
          return Transport(
              host, connect_timeout=connect_timeout, ssl=ssl,
              read_timeout=read_timeout, write_timeout=write_timeout,
              socket_settings=socket_settings, **kwargs)
  
      @property
      def connected(self):
          return self._transport and self._transport.connected
  
      def collect(self):
          try:
              if self._transport:
                  self._transport.close()
  
              temp_list = [x for x in values(self.channels or {})
                           if x is not self]
              for ch in temp_list:
                  ch.collect()
          except socket.error:
              pass  # connection already closed on the other end
          finally:
              self._transport = self.connection = self.channels = None
  
      def _get_free_channel_id(self):
          try:
              return self._avail_channel_ids.pop()
          except IndexError:
              raise ResourceError(
                  'No free channel ids, current={0}, channel_max={1}'.format(
                      len(self.channels), self.channel_max), spec.Channel.Open)
  
      def _claim_channel_id(self, channel_id):
          try:
              return self._avail_channel_ids.remove(channel_id)
          except ValueError:
              raise ConnectionError('Channel %r already open' % (channel_id,))
  
      def channel(self, channel_id=None, callback=None):
          """Create new channel.
  
          Fetch a Channel object identified by the numeric channel_id, or
          create that object if it doesn't already exist.
          """
          if self.channels is not None:
              try:
                  return self.channels[channel_id]
              except KeyError:
                  channel = self.Channel(self, channel_id, on_open=callback)
                  channel.open()
                  return channel
          raise RecoverableConnectionError('Connection already closed.')
  
      def is_alive(self):
          raise NotImplementedError('Use AMQP heartbeats')
  
      def drain_events(self, timeout=None):
          # read until message is ready
          while not self.blocking_read(timeout):
              pass
  
      def blocking_read(self, timeout=None):
          with self.transport.having_timeout(timeout):
              frame = self.transport.read_frame()
          return self.on_inbound_frame(frame)
  
      def on_inbound_method(self, channel_id, method_sig, payload, content):
          return self.channels[channel_id].dispatch_method(
              method_sig, payload, content,
          )
  
      def close(self, reply_code=0, reply_text='', method_sig=(0, 0),
                argsig='BsBB'):
          """Request a connection close.
  
          This method indicates that the sender wants to close the
          connection. This may be due to internal conditions (e.g. a
          forced shut-down) or due to an error handling a specific
          method, i.e. an exception.  When a close is due to an
          exception, the sender provides the class and method id of the
          method which caused the exception.
  
          RULE:
  
              After sending this method any received method except the
              Close-OK method MUST be discarded.
  
          RULE:
  
              The peer sending this method MAY use a counter or timeout
              to detect failure of the other peer to respond correctly
              with the Close-OK method.
  
          RULE:
  
              When a server receives the Close method from a client it
              MUST delete all server-side resources associated with the
              client's context.  A client CANNOT reconnect to a context
              after sending or receiving a Close method.
  
          PARAMETERS:
              reply_code: short
  
                  The reply code. The AMQ reply codes are defined in AMQ
                  RFC 011.
  
              reply_text: shortstr
  
                  The localised reply text.  This text can be logged as an
                  aid to resolving issues.
  
              class_id: short
  
                  failing method class
  
                  When the close is provoked by a method exception, this
                  is the class of the method.
  
              method_id: short
  
                  failing method ID
  
                  When the close is provoked by a method exception, this
                  is the ID of the method.
          """
          if self._transport is None:
              # already closed
              return
  
          return self.send_method(
              spec.Connection.Close, argsig,
              (reply_code, reply_text, method_sig[0], method_sig[1]),
              wait=spec.Connection.CloseOk,
          )
  
      def _on_close(self, reply_code, reply_text, class_id, method_id):
          """Request a connection close.
  
          This method indicates that the sender wants to close the
          connection. This may be due to internal conditions (e.g. a
          forced shut-down) or due to an error handling a specific
          method, i.e. an exception.  When a close is due to an
          exception, the sender provides the class and method id of the
          method which caused the exception.
  
          RULE:
  
              After sending this method any received method except the
              Close-OK method MUST be discarded.
  
          RULE:
  
              The peer sending this method MAY use a counter or timeout
              to detect failure of the other peer to respond correctly
              with the Close-OK method.
  
          RULE:
  
              When a server receives the Close method from a client it
              MUST delete all server-side resources associated with the
              client's context.  A client CANNOT reconnect to a context
              after sending or receiving a Close method.
  
          PARAMETERS:
              reply_code: short
  
                  The reply code. The AMQ reply codes are defined in AMQ
                  RFC 011.
  
              reply_text: shortstr
  
                  The localised reply text.  This text can be logged as an
                  aid to resolving issues.
  
              class_id: short
  
                  failing method class
  
                  When the close is provoked by a method exception, this
                  is the class of the method.
  
              method_id: short
  
                  failing method ID
  
                  When the close is provoked by a method exception, this
                  is the ID of the method.
          """
          self._x_close_ok()
          raise error_for_code(reply_code, reply_text,
                               (class_id, method_id), ConnectionError)
  
      def _x_close_ok(self):
          """Confirm a connection close.
  
          This method confirms a Connection.Close method and tells the
          recipient that it is safe to release resources for the
          connection and close the socket.
  
          RULE:
              A peer that detects a socket closure without having
              received a Close-Ok handshake method SHOULD log the error.
          """
          self.send_method(spec.Connection.CloseOk, callback=self._on_close_ok)
  
      def _on_close_ok(self):
          """Confirm a connection close.
  
          This method confirms a Connection.Close method and tells the
          recipient that it is safe to release resources for the
          connection and close the socket.
  
          RULE:
  
              A peer that detects a socket closure without having
              received a Close-Ok handshake method SHOULD log the error.
          """
          self.collect()
  
      def _on_blocked(self):
          """Callback called when connection blocked.
  
          Notes:
              This is an RabbitMQ Extension.
          """
          reason = 'connection blocked, see broker logs'
          if self.on_blocked:
              return self.on_blocked(reason)
  
      def _on_unblocked(self):
          if self.on_unblocked:
              return self.on_unblocked()
  
      def send_heartbeat(self):
          self.frame_writer(8, 0, None, None, None)
  
      def heartbeat_tick(self, rate=2):
          """Send heartbeat packets if necessary.
  
          Raises:
              ~amqp.exceptions.ConnectionForvced: if none have been
                  received recently.
  
          Note:
              This should be called frequently, on the order of
              once per second.
  
          Keyword Arguments:
              rate (int): Previously used, but ignored now.
          """
          AMQP_LOGGER.debug('heartbeat_tick : for connection %s',
                            self._connection_id)
          if not self.heartbeat:
              return
  
          # treat actual data exchange in either direction as a heartbeat
          sent_now = self.bytes_sent
          recv_now = self.bytes_recv
          if self.prev_sent is None or self.prev_sent != sent_now:
              self.last_heartbeat_sent = monotonic()
          if self.prev_recv is None or self.prev_recv != recv_now:
              self.last_heartbeat_received = monotonic()
  
          now = monotonic()
          AMQP_LOGGER.debug(
              'heartbeat_tick : Prev sent/recv: %s/%s, '
              'now - %s/%s, monotonic - %s, '
              'last_heartbeat_sent - %s, heartbeat int. - %s '
              'for connection %s',
              self.prev_sent, self.prev_recv,
              sent_now, recv_now, now,
              self.last_heartbeat_sent,
              self.heartbeat,
              self._connection_id,
          )
  
          self.prev_sent, self.prev_recv = sent_now, recv_now
  
          # send a heartbeat if it's time to do so
          if now > self.last_heartbeat_sent + self.heartbeat:
              AMQP_LOGGER.debug(
                  'heartbeat_tick: sending heartbeat for connection %s',
                  self._connection_id)
              self.send_heartbeat()
              self.last_heartbeat_sent = monotonic()
  
          # if we've missed two intervals' heartbeats, fail; this gives the
          # server enough time to send heartbeats a little late
          if (self.last_heartbeat_received and
                  self.last_heartbeat_received + 2 *
                  self.heartbeat < monotonic()):
              raise ConnectionForced('Too many heartbeats missed')
  
      @property
      def sock(self):
          return self.transport.sock
  
      @property
      def server_capabilities(self):
          return self.server_properties.get('capabilities') or {}
  