95 lines
3.1 KiB
Python
95 lines
3.1 KiB
Python
# -*- encoding: utf-8 -*-
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#
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# Copyright © 2012 New Dream Network, LLC (DreamHost)
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#
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# Author: Doug Hellmann <doug.hellmann@dreamhost.com>
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""Compute the signature of a metering message.
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"""
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import hashlib
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import hmac
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import uuid
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from ceilometer.openstack.common import cfg
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METER_OPTS = [
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cfg.StrOpt('metering_secret',
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default='change this or be hacked',
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help='Secret value for signing metering messages',
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),
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cfg.StrOpt('metering_topic',
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default='metering',
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help='the topic ceilometer uses for metering messages',
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),
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]
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cfg.CONF.register_opts(METER_OPTS)
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def recursive_keypairs(d):
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"""Generator that produces sequence of keypairs for nested dictionaries.
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"""
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for name, value in sorted(d.iteritems()):
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if isinstance(value, dict):
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for subname, subvalue in recursive_keypairs(value):
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yield ('%s:%s' % (name, subname), subvalue)
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else:
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yield name, value
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def compute_signature(message):
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"""Return the signature for a message dictionary.
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"""
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digest_maker = hmac.new(cfg.CONF.metering_secret, '', hashlib.sha256)
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for name, value in recursive_keypairs(message):
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if name == 'message_signature':
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# Skip any existing signature value, which would not have
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# been part of the original message.
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continue
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digest_maker.update(name)
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digest_maker.update(unicode(value).encode('utf-8'))
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return digest_maker.hexdigest()
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def verify_signature(message):
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"""Check the signature in the message against the value computed
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from the rest of the contents.
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"""
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old_sig = message.get('message_signature')
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new_sig = compute_signature(message)
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return new_sig == old_sig
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def meter_message_from_counter(counter):
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"""Make a metering message ready to be published or stored.
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Returns a dictionary containing a metering message
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for a notification message and a Counter instance.
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"""
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msg = {'source': counter.source,
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'counter_name': counter.name,
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'counter_type': counter.type,
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'counter_volume': counter.volume,
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'user_id': counter.user_id,
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'project_id': counter.project_id,
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'resource_id': counter.resource_id,
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'timestamp': counter.timestamp,
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'counter_duration': counter.duration,
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'resource_metadata': counter.resource_metadata,
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'message_id': str(uuid.uuid1()),
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}
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msg['message_signature'] = compute_signature(msg)
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return msg
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