"""AMQPStorm Connection."""
from __future__ import annotations
import logging
import threading
import time
from types import TracebackType
from typing import TYPE_CHECKING
from typing import Any
from pamqp import exceptions as pamqp_exception
from pamqp import frame as pamqp_frame
from pamqp import header as pamqp_header
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 IO
if TYPE_CHECKING:
import socket as _socket
from pamqp.base import Frame
LOGGER = logging.getLogger(__name__)
DEFAULT_HEARTBEAT_TIMEOUT = 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='ca_certificate.pem'),
'server_hostname': 'rmq.eandersson.net',
'check_hostname': True,
'verify_mode': ssl.CERT_REQUIRED,
}
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 timeout
: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 str poller: Either "select" or "poll". If you encounter file descriptor errors, consider switching to "poll".
:param str locale: Locale used during connection negotiation. Defaults to "en_US".
:param bool lazy: Lazy initialize the connection
:raises AMQPConnectionError: Raises if the connection
encountered an error.
"""
__slots__ = [
'heartbeat', 'parameters', '_channel0', '_channels', '_io'
]
[docs]
def __init__(
self,
hostname: str,
username: str,
password: str,
port: int = 5672,
**kwargs: Any,
) -> None:
super().__init__()
self.lock = threading.RLock()
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_TIMEOUT),
'timeout': kwargs.get('timeout', DEFAULT_SOCKET_TIMEOUT),
'ssl': kwargs.get('ssl', False),
'ssl_options': kwargs.get('ssl_options', {}),
'client_properties': kwargs.get('client_properties', {}),
'poller': kwargs.get('poller', 'select'),
'locale': kwargs.get('locale', 'en_US'),
}
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: dict[int, Channel] = {}
self._last_channel_id: int | None = None
self._user_closed: bool = False
self.heartbeat = Heartbeat(self.parameters['heartbeat'],
self._channel0.send_heartbeat)
if not kwargs.get('lazy', False):
self.open()
def __enter__(self) -> Connection:
return self
def __exit__(
self,
exception_type: type[BaseException] | None,
exception_value: BaseException | None,
_: TracebackType | None,
) -> None:
if exception_type:
message = 'Closing connection due to an unhandled exception: %s'
LOGGER.warning(message, exception_value)
self.close()
@property
def channels(self) -> dict[int, Channel]:
"""Returns a dictionary of the Channels currently available.
:rtype: dict
"""
return self._channels
@property
def fileno(self) -> int | None:
"""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) -> bool:
"""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) -> int:
"""Returns the maximum allowed channels for the connection.
:rtype: int
"""
return self._channel0.max_allowed_channels
@property
def max_frame_size(self) -> int:
"""Returns the maximum allowed frame size for the connection.
:rtype: int
"""
return self._channel0.max_frame_size
@property
def server_properties(self) -> dict[str, Any]:
"""Returns the RabbitMQ Server Properties.
:rtype: dict
"""
return self._channel0.server_properties
@property
def socket(self) -> _socket.socket | None:
"""Returns an instance of the Socket used by the Connection.
:rtype: socket.socket
"""
return self._io.socket
[docs]
def channel(self, rpc_timeout: float = 60, lazy: bool = False) -> Channel:
"""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('connection closed')
with self.lock:
channel_id = self._get_next_available_channel_id()
channel = Channel(channel_id, self, rpc_timeout)
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) -> None:
"""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 closed')
self.exceptions.append(why)
self.set_state(self.CLOSED)
self.close()
raise self.exceptions[0]
[docs]
def close(self) -> None:
"""Close the Connection.
:raises AMQPConnectionError: Raises if the connection
encountered an error.
:return:
"""
LOGGER.debug('Connection Closing')
self._user_closed = True
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) -> None:
"""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._user_closed = False
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: int, frame_out: Frame) -> None:
"""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: int, frames_out: list[Frame]) -> None:
"""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 = b''.join(
pamqp_frame.marshal(single_frame, channel_id)
for single_frame in frames_out
)
self.heartbeat.register_write()
self._io.write_to_socket(data_out)
def _close_remaining_channels(self) -> None:
"""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) -> int:
"""Returns the next available channel id.
:raises AMQPConnectionError: Raises if there is no available channel.
:rtype: int
"""
for channel_id in range(self._last_channel_id or 1,
self.max_allowed_channels + 1):
if channel_id in self._channels:
channel = self._channels[channel_id]
if channel.current_state != Channel.CLOSED:
continue
del self._channels[channel_id]
self._last_channel_id = channel_id
return channel_id
if self._last_channel_id:
self._last_channel_id = None
return self._get_next_available_channel_id()
raise AMQPConnectionError(
f'reached the maximum number of channels {self.max_allowed_channels}'
)
def _handle_amqp_frame(
self, data_in: bytes,
) -> tuple[bytes, int | None, Any]:
"""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 pamqp_exception.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: bytes) -> bytes:
"""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: int) -> None:
"""Remove 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) -> None:
"""Send a RabbitMQ Handshake.
:return:
"""
self._io.write_to_socket(pamqp_header.ProtocolHeader().marshal())
def _validate_parameters(self) -> None:
"""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: int = Stateful.OPEN, rpc_timeout: float = 30,
) -> None:
"""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.monotonic()
while self.current_state != state:
self.check_for_errors()
if time.monotonic() - start_time > rpc_timeout:
raise AMQPConnectionError('connection timed out')
time.sleep(IDLE_WAIT)