"""AMQPStorm Connection."""
import logging
import time
from time import sleep
from pamqp import exceptions as pamqp_exception
from pamqp import frame as pamqp_frame
from pamqp import header as pamqp_header
from pamqp import specification
from amqpstorm import compatibility
from amqpstorm.base import IDLE_WAIT
from amqpstorm.base import Stateful
from amqpstorm.channel import Channel
from amqpstorm.channel0 import Channel0
from amqpstorm.exception import AMQPConnectionError
from amqpstorm.exception import AMQPInvalidArgument
from amqpstorm.heartbeat import Heartbeat
from amqpstorm.io import EMPTY_BUFFER
from amqpstorm.io import IO
LOGGER = logging.getLogger(__name__)
DEFAULT_HEARTBEAT_INTERVAL = 60
DEFAULT_SOCKET_TIMEOUT = 10
DEFAULT_VIRTUAL_HOST = '/'
[docs]class Connection(Stateful):
"""RabbitMQ Connection.
e.g.
::
import amqpstorm
connection = amqpstorm.Connection('localhost', 'guest', 'guest')
Using a SSL Context:
::
import ssl
import amqpstorm
ssl_options = {
'context': ssl.create_default_context(cafile='cacert.pem'),
'server_hostname': 'rmq.eandersson.net'
}
connection = amqpstorm.Connection(
'rmq.eandersson.net', 'guest', 'guest', port=5671,
ssl=True, ssl_options=ssl_options
)
:param str hostname: Hostname
:param str username: Username
:param str password: Password
:param int port: Server port
:param str virtual_host: Virtual host
:param int heartbeat: RabbitMQ Heartbeat interval
:param int,float timeout: Socket timeout
:param bool ssl: Enable SSL
:param dict ssl_options: SSL kwargs
:param dict client_properties: None or dict of client properties
:param bool lazy: Lazy initialize the connection
:raises AMQPConnectionError: Raises if the connection
encountered an error.
"""
__slots__ = [
'heartbeat', 'parameters', '_channel0', '_channels', '_io'
]
def __init__(self, hostname, username, password, port=5672, **kwargs):
super(Connection, self).__init__()
self.parameters = {
'hostname': hostname,
'username': username,
'password': password,
'port': port,
'virtual_host': kwargs.get('virtual_host', DEFAULT_VIRTUAL_HOST),
'heartbeat': kwargs.get('heartbeat', DEFAULT_HEARTBEAT_INTERVAL),
'timeout': kwargs.get('timeout', DEFAULT_SOCKET_TIMEOUT),
'ssl': kwargs.get('ssl', False),
'ssl_options': kwargs.get('ssl_options', {}),
'client_properties': kwargs.get('client_properties', {})
}
self._validate_parameters()
self._io = IO(self.parameters, exceptions=self._exceptions,
on_read_impl=self._read_buffer)
self._channel0 = Channel0(self, self.parameters['client_properties'])
self._channels = {}
self._last_channel_id = None
self.heartbeat = Heartbeat(self.parameters['heartbeat'],
self._channel0.send_heartbeat)
if not kwargs.get('lazy', False):
self.open()
def __enter__(self):
return self
def __exit__(self, exception_type, exception_value, _):
if exception_type:
message = 'Closing connection due to an unhandled exception: %s'
LOGGER.warning(message, exception_value)
self.close()
@property
def channels(self):
"""Returns a dictionary of the Channels currently available.
:rtype: dict
"""
return self._channels
@property
def fileno(self):
"""Returns the Socket File number.
:rtype: integer,None
"""
if not self._io.socket:
return None
return self._io.socket.fileno()
@property
def is_blocked(self):
"""Is the connection currently being blocked from publishing by
the remote server.
:rtype: bool
"""
return self._channel0.is_blocked
@property
def max_allowed_channels(self):
"""Returns the maximum allowed channels for the connection.
:rtype: int
"""
return self._channel0.max_allowed_channels
@property
def max_frame_size(self):
"""Returns the maximum allowed frame size for the connection.
:rtype: int
"""
return self._channel0.max_frame_size
@property
def server_properties(self):
"""Returns the RabbitMQ Server Properties.
:rtype: dict
"""
return self._channel0.server_properties
@property
def socket(self):
"""Returns an instance of the Socket used by the Connection.
:rtype: socket.socket
"""
return self._io.socket
[docs] def channel(self, rpc_timeout=60, lazy=False):
"""Open a Channel.
:param int rpc_timeout: Timeout before we give up waiting for an RPC
response from the server.
:raises AMQPInvalidArgument: Invalid Parameters
:raises AMQPChannelError: Raises if the channel encountered an error.
:raises AMQPConnectionError: Raises if the connection
encountered an error.
:rtype: amqpstorm.Channel
"""
LOGGER.debug('Opening a new Channel')
if not compatibility.is_integer(rpc_timeout):
raise AMQPInvalidArgument('rpc_timeout should be an integer')
elif self.is_closed:
raise AMQPConnectionError('socket/connection closed')
with self.lock:
channel_id = self._get_next_available_channel_id()
channel = Channel(channel_id, self, rpc_timeout,
on_close_impl=self._cleanup_channel)
self._channels[channel_id] = channel
if not lazy:
channel.open()
LOGGER.debug('Channel #%d Opened', channel_id)
return self._channels[channel_id]
[docs] def check_for_errors(self):
"""Check Connection for errors.
:raises AMQPConnectionError: Raises if the connection
encountered an error.
:return:
"""
if not self.exceptions:
if not self.is_closed:
return
why = AMQPConnectionError('connection was closed')
self.exceptions.append(why)
self.set_state(self.CLOSED)
self.close()
raise self.exceptions[0]
[docs] def close(self):
"""Close the Connection.
:raises AMQPConnectionError: Raises if the connection
encountered an error.
:return:
"""
LOGGER.debug('Connection Closing')
if not self.is_closed:
self.set_state(self.CLOSING)
self.heartbeat.stop()
try:
if not self.is_closed and self.socket:
self._channel0.send_close_connection()
self._wait_for_connection_state(state=Stateful.CLOSED)
except AMQPConnectionError:
pass
finally:
self._close_remaining_channels()
self._io.close()
self.set_state(self.CLOSED)
LOGGER.debug('Connection Closed')
[docs] def open(self):
"""Open Connection.
:raises AMQPConnectionError: Raises if the connection
encountered an error.
"""
LOGGER.debug('Connection Opening')
self.set_state(self.OPENING)
self._exceptions = []
self._channels = {}
self._last_channel_id = None
self._io.open()
self._send_handshake()
self._wait_for_connection_state(state=Stateful.OPEN)
self.heartbeat.start(self._exceptions)
LOGGER.debug('Connection Opened')
def write_frame(self, channel_id, frame_out):
"""Marshal and write an outgoing pamqp frame to the Socket.
:param int channel_id: Channel ID.
:param specification.Frame frame_out: Amqp frame.
:return:
"""
frame_data = pamqp_frame.marshal(frame_out, channel_id)
self.heartbeat.register_write()
self._io.write_to_socket(frame_data)
def write_frames(self, channel_id, frames_out):
"""Marshal and write multiple outgoing pamqp frames to the Socket.
:param int channel_id: Channel ID/
:param list frames_out: Amqp frames.
:return:
"""
data_out = EMPTY_BUFFER
for single_frame in frames_out:
data_out += pamqp_frame.marshal(single_frame, channel_id)
self.heartbeat.register_write()
self._io.write_to_socket(data_out)
def _close_remaining_channels(self):
"""Forcefully close all open channels.
:return:
"""
for channel_id in list(self._channels):
self._channels[channel_id].set_state(Channel.CLOSED)
self._channels[channel_id].close()
self._cleanup_channel(channel_id)
def _get_next_available_channel_id(self):
"""Returns the next available available channel id.
:raises AMQPConnectionError: Raises if there is no available channel.
:rtype: int
"""
for index in compatibility.RANGE(self._last_channel_id or 1,
self.max_allowed_channels + 1):
if index in self._channels:
continue
self._last_channel_id = index
return index
if self._last_channel_id:
self._last_channel_id = None
return self._get_next_available_channel_id()
raise AMQPConnectionError(
'reached the maximum number of channels %d' %
self.max_allowed_channels)
def _handle_amqp_frame(self, data_in):
"""Unmarshal a single AMQP frame and return the result.
:param data_in: socket data
:return: data_in, channel_id, frame
"""
if not data_in:
return data_in, None, None
try:
byte_count, channel_id, frame_in = pamqp_frame.unmarshal(data_in)
return data_in[byte_count:], channel_id, frame_in
except pamqp_exception.UnmarshalingException:
pass
except specification.AMQPFrameError as why:
LOGGER.error('AMQPFrameError: %r', why, exc_info=True)
except ValueError as why:
LOGGER.error(why, exc_info=True)
self.exceptions.append(AMQPConnectionError(why))
return data_in, None, None
def _read_buffer(self, data_in):
"""Process the socket buffer, and direct the data to the appropriate
channel.
:rtype: bytes
"""
while data_in:
data_in, channel_id, frame_in = self._handle_amqp_frame(data_in)
if frame_in is None:
break
self.heartbeat.register_read()
if channel_id == 0:
self._channel0.on_frame(frame_in)
elif channel_id in self._channels:
self._channels[channel_id].on_frame(frame_in)
return data_in
def _cleanup_channel(self, channel_id):
"""Remove the the channel from the list of available channels.
:param int channel_id: Channel id
:return:
"""
with self.lock:
if channel_id not in self._channels:
return
del self._channels[channel_id]
def _send_handshake(self):
"""Send a RabbitMQ Handshake.
:return:
"""
self._io.write_to_socket(pamqp_header.ProtocolHeader().marshal())
def _validate_parameters(self):
"""Validate Connection Parameters.
:return:
"""
if not compatibility.is_string(self.parameters['hostname']):
raise AMQPInvalidArgument('hostname should be a string')
elif not compatibility.is_integer(self.parameters['port']):
raise AMQPInvalidArgument('port should be an integer')
elif not compatibility.is_string(self.parameters['username']):
raise AMQPInvalidArgument('username should be a string')
elif not compatibility.is_string(self.parameters['password']):
raise AMQPInvalidArgument('password should be a string')
elif not compatibility.is_string(self.parameters['virtual_host']):
raise AMQPInvalidArgument('virtual_host should be a string')
elif not isinstance(self.parameters['timeout'], (int, float)):
raise AMQPInvalidArgument('timeout should be an integer or float')
elif not compatibility.is_integer(self.parameters['heartbeat']):
raise AMQPInvalidArgument('heartbeat should be an integer')
def _wait_for_connection_state(self, state=Stateful.OPEN, rpc_timeout=30):
"""Wait for a Connection state.
:param int state: State that we expect
:raises AMQPConnectionError: Raises if we are unable to establish
a connection to RabbitMQ.
:return:
"""
start_time = time.time()
while self.current_state != state:
self.check_for_errors()
if time.time() - start_time > rpc_timeout:
raise AMQPConnectionError('Connection timed out')
sleep(IDLE_WAIT)