9f58e2c3fe
This patch allows to quickly create a listener to receive
notification messages.
Example of the api:
class Endpoint(object):
def warn(self, ctxt, publisher_id, event_type, payload):
do_something(payload)
target = messaging.Target(topic='notifications', exchange='cinder')
listener = notify.get_notification_listener(transport, [target],
[Endpoint()],
executor,
serializer)
Implements blueprint notification-subscriber-server
Change-Id: I434bc487c382a2048670df726d9bebd640150bb9
424 lines
14 KiB
Python
424 lines
14 KiB
Python
|
|
# 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
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# 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__ = [
|
|
'DriverLoadFailure',
|
|
'InvalidTransportURL',
|
|
'Transport',
|
|
'TransportHost',
|
|
'TransportURL',
|
|
'get_transport',
|
|
'set_transport_defaults',
|
|
]
|
|
|
|
from oslo.config import cfg
|
|
import six
|
|
from stevedore import driver
|
|
|
|
from oslo.messaging import exceptions
|
|
from oslo.messaging.openstack.common.py3kcompat import urlutils
|
|
|
|
|
|
_transport_opts = [
|
|
cfg.StrOpt('transport_url',
|
|
default=None,
|
|
help='A URL representing the messaging driver to use and its '
|
|
'full configuration. If not set, we fall back to the '
|
|
'rpc_backend option and driver specific configuration.'),
|
|
cfg.StrOpt('rpc_backend',
|
|
default='rabbit',
|
|
help='The messaging driver to use, defaults to rabbit. Other '
|
|
'drivers include qpid and zmq.'),
|
|
cfg.StrOpt('control_exchange',
|
|
default='openstack',
|
|
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
|
|
"""
|
|
cfg.set_defaults(_transport_opts,
|
|
control_exchange=control_exchange)
|
|
|
|
|
|
class Transport(object):
|
|
|
|
"""A messaging transport.
|
|
|
|
This is a mostly opaque handle for an underlying messaging transport
|
|
driver.
|
|
|
|
It 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 _send(self, target, ctxt, message, wait_for_reply=None, timeout=None):
|
|
if not target.topic:
|
|
raise exceptions.InvalidTarget('A topic is required to send',
|
|
target)
|
|
return self._driver.send(target, ctxt, message,
|
|
wait_for_reply=wait_for_reply,
|
|
timeout=timeout)
|
|
|
|
def _send_notification(self, target, ctxt, message, version):
|
|
if not target.topic:
|
|
raise exceptions.InvalidTarget('A topic is required to send',
|
|
target)
|
|
self._driver.send_notification(target, ctxt, message, version)
|
|
|
|
def _listen(self, target):
|
|
if not (target.topic and target.server):
|
|
raise exceptions.InvalidTarget('A server\'s target must have '
|
|
'topic and server names specified',
|
|
target)
|
|
return self._driver.listen(target)
|
|
|
|
def _listen_for_notifications(self, targets_and_priorities):
|
|
for target, priority in targets_and_priorities:
|
|
if not target.topic:
|
|
raise exceptions.InvalidTarget('A target must have '
|
|
'topic specified',
|
|
target)
|
|
return self._driver.listen_for_notifications(targets_and_priorities)
|
|
|
|
def cleanup(self):
|
|
"""Release all resources associated with this transport."""
|
|
self._driver.cleanup()
|
|
|
|
|
|
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=[], aliases=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::
|
|
|
|
rabbit://me:passwd@host:5672/virtual_host
|
|
|
|
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
|
|
:type url: str or TransportURL
|
|
:param allowed_remote_exmods: a list of modules which a client using this
|
|
transport will deserialize remote exceptions
|
|
from
|
|
:type allowed_remote_exmods: list
|
|
:param aliases: A map of transport alias to transport name
|
|
:type aliases: dict
|
|
"""
|
|
conf.register_opts(_transport_opts)
|
|
|
|
if not isinstance(url, TransportURL):
|
|
url = url or conf.transport_url
|
|
parsed = TransportURL.parse(conf, url, aliases)
|
|
if not parsed.transport:
|
|
raise InvalidTransportURL(url, 'No scheme specified in "%s"' % url)
|
|
url = parsed
|
|
|
|
kwargs = dict(default_exchange=conf.control_exchange,
|
|
allowed_remote_exmods=allowed_remote_exmods)
|
|
|
|
try:
|
|
mgr = driver.DriverManager('oslo.messaging.drivers',
|
|
url.transport,
|
|
invoke_on_load=True,
|
|
invoke_args=[conf, url],
|
|
invoke_kwds=kwargs)
|
|
except RuntimeError as ex:
|
|
raise DriverLoadFailure(url.transport, ex)
|
|
|
|
return Transport(mgr.driver)
|
|
|
|
|
|
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 __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::
|
|
|
|
transport://user:pass@host1:port[,hostN:portN]/virtual_host
|
|
|
|
i.e. the scheme selects the transport driver, you may include multiple
|
|
hosts in netloc and the path part is a "virtual host" partition path.
|
|
|
|
:param conf: a ConfigOpts instance
|
|
:type conf: oslo.config.cfg.ConfigOpts
|
|
:param transport: a transport name e.g. 'rabbit' or 'qpid'
|
|
:type transport: str
|
|
:param virtual_host: a virtual host path e.g. '/'
|
|
:type virtual_host: str
|
|
:param hosts: a list of TransportHost objects
|
|
:type hosts: list
|
|
:param aliases: A map of transport alias to transport name
|
|
:type aliases: dict
|
|
"""
|
|
|
|
def __init__(self, conf, transport=None, virtual_host=None, hosts=None,
|
|
aliases=None):
|
|
self.conf = conf
|
|
self.conf.register_opts(_transport_opts)
|
|
self._transport = transport
|
|
self.virtual_host = virtual_host
|
|
if hosts is None:
|
|
self.hosts = []
|
|
else:
|
|
self.hosts = hosts
|
|
if aliases is None:
|
|
self.aliases = {}
|
|
else:
|
|
self.aliases = aliases
|
|
|
|
@property
|
|
def transport(self):
|
|
if self._transport is None:
|
|
transport = self.conf.rpc_backend
|
|
else:
|
|
transport = self._transport
|
|
return self.aliases.get(transport, transport)
|
|
|
|
@transport.setter
|
|
def transport(self, value):
|
|
self._transport = value
|
|
|
|
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 += urlutils.quote(username, '')
|
|
if password is not None:
|
|
netloc += ':%s' % urlutils.quote(password, '')
|
|
netloc += '@'
|
|
|
|
# Build the network location portion of the transport URL
|
|
if hostname:
|
|
if ':' in hostname:
|
|
netloc += '[%s]' % hostname
|
|
else:
|
|
netloc += hostname
|
|
if port is not None:
|
|
netloc += ':%d' % port
|
|
|
|
netlocs.append(netloc)
|
|
|
|
# Assemble the transport URL
|
|
url = '%s://%s/' % (self.transport, ','.join(netlocs))
|
|
|
|
if self.virtual_host:
|
|
url += urlutils.quote(self.virtual_host)
|
|
|
|
return url
|
|
|
|
@classmethod
|
|
def parse(cls, conf, url, aliases=None):
|
|
"""Parse an url.
|
|
|
|
Assuming a URL takes the form of:
|
|
|
|
transport://user:pass@host1:port[,hostN:portN]/virtual_host
|
|
|
|
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
|
|
* The last parsed username and password will be propagated to the rest
|
|
of hosts specified:
|
|
|
|
user:passwd@host1:port1,host2:port2
|
|
|
|
[
|
|
{"username": "user", "password": "passwd", "host": "host1:port1"},
|
|
{"username": "user", "password": "passwd", "host": "host2:port2"}
|
|
]
|
|
|
|
* In order to avoid the above propagation, it is possible to alter the
|
|
order in which the hosts are specified or specify a set of fake
|
|
credentials using ",:@host2:port2"
|
|
|
|
user:passwd@host1:port1,:@host2:port2
|
|
|
|
[
|
|
{"username": "user", "password": "passwd", "host": "host1:port1"},
|
|
{"username": "", "password": "", "host": "host2:port2"}
|
|
]
|
|
|
|
:param conf: a ConfigOpts instance
|
|
:type conf: oslo.config.cfg.ConfigOpts
|
|
:param url: The URL to parse
|
|
:type url: str
|
|
:param aliases: A map of transport alias to transport name
|
|
:type aliases: dict
|
|
:returns: A TransportURL
|
|
"""
|
|
if not url:
|
|
return cls(conf, aliases=aliases)
|
|
|
|
if not isinstance(url, six.string_types):
|
|
raise InvalidTransportURL(url, 'Wrong URL type')
|
|
|
|
url = urlutils.urlparse(url)
|
|
|
|
# Make sure there's not a query string; that could identify
|
|
# requirements we can't comply with (e.g., ssl), so reject it if
|
|
# it's present
|
|
if '?' in url.path or url.query:
|
|
raise InvalidTransportURL(url.geturl(),
|
|
"Cannot comply with query string in "
|
|
"transport URL")
|
|
|
|
virtual_host = None
|
|
if url.path.startswith('/'):
|
|
virtual_host = url.path[1:]
|
|
|
|
hosts = []
|
|
|
|
username = password = ''
|
|
for host in url.netloc.split(','):
|
|
if not host:
|
|
continue
|
|
|
|
hostname = host
|
|
username = password = port = None
|
|
|
|
if '@' in host:
|
|
username, hostname = host.split('@', 1)
|
|
if ':' in username:
|
|
username, password = username.split(':', 1)
|
|
|
|
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 = int(port_text.split(':', 1)[1])
|
|
elif ':' in hostname:
|
|
hostname, port = hostname.split(':', 1)
|
|
port = int(port)
|
|
|
|
hosts.append(TransportHost(hostname=hostname,
|
|
port=port,
|
|
username=username,
|
|
password=password))
|
|
|
|
return cls(conf, url.scheme, virtual_host, hosts, aliases)
|