OpenStack library for messaging
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# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# All Rights Reserved.
# Copyright 2013 Red Hat, Inc.
# Copyright (c) 2012 Rackspace Hosting
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
__all__ = [
import logging
from debtcollector import removals
from oslo_config import cfg
import six
from six.moves.urllib import parse
from stevedore import driver
from oslo_messaging._i18n import _LW
from oslo_messaging import exceptions
LOG = logging.getLogger(__name__)
_transport_opts = [
help='The network address and optional user credentials for '
'connecting to the messaging backend, in URL format. The '
'expected format is:\n\n'
'Example: rabbit://rabbitmq:password@\n\n'
'For full details on the fields in the URL see the '
'documentation of oslo_messaging.TransportURL at '
deprecated_reason="Replaced by [DEFAULT]/transport_url",
help='The messaging driver to use, defaults to rabbit. Other '
'drivers include amqp and zmq.'),
help='The default exchange under which topics are scoped. May '
'be overridden by an exchange name specified in the '
'transport_url option.'),
def set_transport_defaults(control_exchange):
"""Set defaults for messaging transport configuration options.
:param control_exchange: the default exchange under which topics are scoped
:type control_exchange: str
class Transport(object):
"""A messaging transport.
This is a mostly opaque handle for an underlying messaging transport
RPCs and Notifications may use separate messaging systems that utilize
different drivers, access permissions, message delivery, etc. To ensure
the correct messaging functionality, the corresponding method should be
used to construct a Transport object from transport configuration
gleaned from the user's configuration and, optionally, a transport URL.
The factory method for RPC Transport objects::
def get_rpc_transport(conf, url=None,
If a transport URL is supplied as a parameter, any transport configuration
contained in it takes precedence. If no transport URL is supplied, but
there is a transport URL supplied in the user's configuration then that
URL will take the place of the URL parameter.
The factory method for Notification Transport objects::
def get_notification_transport(conf, url=None,
If no transport URL is provided, the URL in the notifications section of
the config file will be used. If that URL is also absent, the same
transport as specified in the user's default section will be used.
The Transport has a single 'conf' property which is the cfg.ConfigOpts
instance used to construct the transport object.
def __init__(self, driver):
self.conf = driver.conf
self._driver = driver
def _require_driver_features(self, requeue=False):
def _send(self, target, ctxt, message, wait_for_reply=None, timeout=None,
call_monitor_timeout=None, retry=None):
if not target.topic:
raise exceptions.InvalidTarget('A topic is required to send',
return self._driver.send(target, ctxt, message,
def _send_notification(self, target, ctxt, message, version, retry=None):
if not target.topic:
raise exceptions.InvalidTarget('A topic is required to send',
self._driver.send_notification(target, ctxt, message, version,
def _listen(self, target, batch_size, batch_timeout):
if not (target.topic and target.server):
raise exceptions.InvalidTarget('A server\'s target must have '
'topic and server names specified',
return self._driver.listen(target, batch_size,
def _listen_for_notifications(self, targets_and_priorities, pool,
batch_size, batch_timeout):
for target, priority in targets_and_priorities:
if not target.topic:
raise exceptions.InvalidTarget('A target must have '
'topic specified',
return self._driver.listen_for_notifications(
targets_and_priorities, pool, batch_size, batch_timeout
def cleanup(self):
"""Release all resources associated with this transport."""
class RPCTransport(Transport):
"""Transport object for RPC."""
def __init__(self, driver):
super(RPCTransport, self).__init__(driver)
class NotificationTransport(Transport):
"""Transport object for notifications."""
def __init__(self, driver):
super(NotificationTransport, self).__init__(driver)
class InvalidTransportURL(exceptions.MessagingException):
"""Raised if transport URL is invalid."""
def __init__(self, url, msg):
super(InvalidTransportURL, self).__init__(msg)
self.url = url
class DriverLoadFailure(exceptions.MessagingException):
"""Raised if a transport driver can't be loaded."""
def __init__(self, driver, ex):
msg = 'Failed to load transport driver "%s": %s' % (driver, ex)
super(DriverLoadFailure, self).__init__(msg)
self.driver = driver
self.ex = ex
def _get_transport(conf, url=None, allowed_remote_exmods=None,
allowed_remote_exmods = allowed_remote_exmods or []
if not isinstance(url, TransportURL):
url = TransportURL.parse(conf, url)
kwargs = dict(default_exchange=conf.control_exchange,
mgr = driver.DriverManager('oslo.messaging.drivers',
invoke_args=[conf, url],
except RuntimeError as ex:
raise DriverLoadFailure(url.transport, ex)
return transport_cls(mgr.driver)
message='use get_rpc_transport or get_notification_transport'
def get_transport(conf, url=None, allowed_remote_exmods=None):
"""A factory method for Transport objects.
This method will construct a Transport object from transport configuration
gleaned from the user's configuration and, optionally, a transport URL.
If a transport URL is supplied as a parameter, any transport configuration
contained in it takes precedence. If no transport URL is supplied, but
there is a transport URL supplied in the user's configuration then that
URL will take the place of the URL parameter. In both cases, any
configuration not supplied in the transport URL may be taken from
individual configuration parameters in the user's configuration.
An example transport URL might be::
and can either be passed as a string or a TransportURL object.
:param conf: the user configuration
:type conf: cfg.ConfigOpts
:param url: a transport URL, see :py:class:`transport.TransportURL`
:type url: str or TransportURL
:param allowed_remote_exmods: a list of modules which a client using this
transport will deserialize remote exceptions
:type allowed_remote_exmods: list
return _get_transport(conf, url, allowed_remote_exmods,
class TransportHost(object):
"""A host element of a parsed transport URL."""
def __init__(self, hostname=None, port=None, username=None, password=None):
self.hostname = hostname
self.port = port
self.username = username
self.password = password
def __hash__(self):
return hash((self.hostname, self.port, self.username, self.password))
def __eq__(self, other):
return vars(self) == vars(other)
def __ne__(self, other):
return not self == other
def __repr__(self):
attrs = []
for a in ['hostname', 'port', 'username', 'password']:
v = getattr(self, a)
if v:
attrs.append((a, repr(v)))
values = ', '.join(['%s=%s' % i for i in attrs])
return '<TransportHost ' + values + '>'
class TransportURL(object):
"""A parsed transport URL.
Transport URLs take the form::
Specifies the transport driver to use. Typically this is `rabbit` for the
RabbitMQ broker. See the documentation for other available transport
Specifies the network location of the broker. `user` and `pass` are the
optional username and password used for authentication with the broker.
`user` and `pass` may contain any of the following ASCII characters:
* Alphabetic (a-z and A-Z)
* Numeric (0-9)
* Special characters: & = $ - _ . + ! * ( )
`user` may include at most one `@` character for compatibility with some
implementations of SASL.
All other characters in `user` and `pass` must be encoded via '%nn'
You may include multiple different network locations separated by commas.
The client will connect to any of the available locations and will
automatically fail over to another should the connection fail.
Specifies the "virtual host" within the broker. Support for virtual hosts
is specific to the message bus used.
Permits passing driver-specific options which override the corresponding
values from the configuration file.
:param conf: a ConfigOpts instance
:type conf: oslo.config.cfg.ConfigOpts
:param transport: a transport name for example 'rabbit'
:type transport: str
:param virtual_host: a virtual host path for example '/'
:type virtual_host: str
:param hosts: a list of TransportHost objects
:type hosts: list
:param query: a dictionary of URL query parameters
:type query: dict
def __init__(self, conf, transport=None, virtual_host=None, hosts=None,
self.conf = conf
self._transport = transport
self.virtual_host = virtual_host
if hosts is None:
self.hosts = []
self.hosts = hosts
if query is None:
self.query = {}
self.query = query
self._deprecation_logged = False
def transport(self):
if self._transport is None:
transport = self.conf.rpc_backend
transport = self._transport
final_transport = transport
if not self._deprecation_logged and final_transport != transport:
# NOTE(sileht): The first step is deprecate this one cycle.
# To ensure deployer have updated they configuration during Ocata
# Then in P we will deprecate aliases kwargs of TransportURL() and
# get_transport() for consuming application
LOG.warning('legacy "rpc_backend" is deprecated, '
'"%(legacy_transport)s" must be replaced by '
'"%(final_transport)s"' % {
'legacy_transport': transport,
'final_transport': final_transport})
self._deprecation_logged = True
return final_transport
def transport(self, value):
self._transport = value
def __hash__(self):
return hash((tuple(self.hosts), self.transport, self.virtual_host))
def __eq__(self, other):
return (self.transport == other.transport and
self.virtual_host == other.virtual_host and
self.hosts == other.hosts)
def __ne__(self, other):
return not self == other
def __repr__(self):
attrs = []
for a in ['transport', 'virtual_host', 'hosts']:
v = getattr(self, a)
if v:
attrs.append((a, repr(v)))
values = ', '.join(['%s=%s' % i for i in attrs])
return '<TransportURL ' + values + '>'
def __str__(self):
netlocs = []
for host in self.hosts:
username = host.username
password = host.password
hostname = host.hostname
port = host.port
# Starting place for the network location
netloc = ''
# Build the username and password portion of the transport URL
if username is not None or password is not None:
if username is not None:
netloc += parse.quote(username, '')
if password is not None:
netloc += ':%s' % parse.quote(password, '')
netloc += '@'
# Build the network location portion of the transport URL
if hostname:
if ':' in hostname:
netloc += '[%s]' % hostname
netloc += hostname
if port is not None:
netloc += ':%d' % port
# Assemble the transport URL
url = '%s://%s/' % (self.transport, ','.join(netlocs))
if self.virtual_host:
url += parse.quote(self.virtual_host)
if self.query:
url += '?' + parse.urlencode(self.query, doseq=True)
return url
def parse(cls, conf, url=None):
"""Parse a URL as defined by :py:class:`TransportURL` and return a
TransportURL object.
Assuming a URL takes the form of::
then parse the URL and return a TransportURL object.
Netloc is parsed following the sequence bellow:
* It is first split by ',' in order to support multiple hosts
* All hosts should be specified with username/password or not
at the same time. In case of lack of specification, username and
password will be omitted::
{"username": "user", "password": "pass", "host": "host1:port1"},
{"host": "host2:port2"}
If the url is not provided conf.transport_url is parsed instead.
:param conf: a ConfigOpts instance
:type conf: oslo.config.cfg.ConfigOpts
:param url: The URL to parse
:type url: str
:returns: A TransportURL
if not url:
url = url or conf.transport_url
if not url:
return cls(conf)
if not isinstance(url, six.string_types):
raise InvalidTransportURL(url, 'Wrong URL type')
url = parse.urlparse(url)
if not url.scheme:
raise InvalidTransportURL(url.geturl(), 'No scheme specified')
transport = url.scheme
query = {}
if url.query:
for key, values in parse.parse_qs(url.query).items():
query[key] = ','.join(values)
virtual_host = None
if url.path.startswith('/'):
virtual_host = parse.unquote(url.path[1:])
hosts_with_credentials = []
hosts_without_credentials = []
hosts = []
for host in url.netloc.split(','):
if not host:
hostname = host
username = password = port = None
if '@' in host:
username, hostname = host.rsplit('@', 1)
if ':' in username:
username, password = username.split(':', 1)
password = parse.unquote(password)
username = parse.unquote(username)
if not hostname:
hostname = None
elif hostname.startswith('['):
# Find the closing ']' and extract the hostname
host_end = hostname.find(']')
if host_end < 0:
# NOTE(Vek): Identical to what Python 2.7's
# urlparse.urlparse() raises in this case
raise ValueError('Invalid IPv6 URL')
port_text = hostname[host_end:]
hostname = hostname[1:host_end]
# Now we need the port; this is compliant with how urlparse
# parses the port data
port = None
if ':' in port_text:
port = port_text.split(':', 1)[1]
elif ':' in hostname:
hostname, port = hostname.split(':', 1)
if port == "":
port = None
if port is not None:
port = int(port)
if username is None or password is None:
if (len(hosts_with_credentials) > 0 and
len(hosts_without_credentials) > 0):
LOG.warning(_LW("All hosts must be set with username/password or "
"not at the same time. Hosts with credentials "
"are: %(hosts_with_credentials)s. Hosts without "
"credentials are %(hosts_without_credentials)s."),
{'hosts_with_credentials': hosts_with_credentials,
return cls(conf, transport, virtual_host, hosts, query)