ad475ee927
This change implements a collector which does an HTTP GET via python requests to fetch the metadata. It should work with any GET-able URL, however it is designed to work with Swift TempURLs. Swift objects are not consistent, so the Last-Modified header is checked for each poll and metadata is not fetched if the last modified is not newer than the previous successful poll. This collector will be enabled for OS::Nova::Server software_config_transport: POLL_TEMP_URL which is available in the Juno release of Heat. Using POLL_TEMP_URL will result in no metadata polling load on heat, which has historically been an issue with tripleo scalability. Change-Id: I22155c22bdcc3c81a5e945ca5436a8f29f196528
94 lines
2.8 KiB
Python
94 lines
2.8 KiB
Python
# Copyright (c) 2013 Hewlett-Packard Development Company, L.P.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain 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,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import calendar
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import json
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import time
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from oslo.config import cfg
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from os_collect_config import common
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from os_collect_config import exc
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from os_collect_config.openstack.common import log
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CONF = cfg.CONF
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logger = log.getLogger(__name__)
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opts = [
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cfg.StrOpt('metadata-url',
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help='URL to query for metadata'),
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]
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name = 'request'
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class Collector(object):
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def __init__(self, requests_impl=common.requests):
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self._requests_impl = requests_impl
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self._session = requests_impl.Session()
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self.last_modified = None
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def check_fetch_content(self, headers):
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'''Raises RequestMetadataNotAvailable if metadata should not be
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fetched.
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'''
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# no last-modified header, so fetch
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lm = headers.get('last-modified')
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if not lm:
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return
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last_modified = calendar.timegm(
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time.strptime(lm, '%a, %d %b %Y %H:%M:%S %Z'))
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# first run, so fetch
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if not self.last_modified:
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return last_modified
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if last_modified < self.last_modified:
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logger.warn(
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'Last-Modified is older than previous collection')
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if last_modified <= self.last_modified:
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raise exc.RequestMetadataNotAvailable
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return last_modified
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def collect(self):
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if CONF.request.metadata_url is None:
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logger.warn('No metadata_url configured.')
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raise exc.RequestMetadataNotConfigured
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url = CONF.request.metadata_url
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final_content = {}
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try:
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head = self._session.head(url)
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last_modified = self.check_fetch_content(head.headers)
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content = self._session.get(url)
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content.raise_for_status()
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self.last_modified = last_modified
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except self._requests_impl.exceptions.RequestException as e:
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logger.warn(e)
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raise exc.RequestMetadataNotAvailable
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try:
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value = json.loads(content.text)
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except ValueError as e:
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logger.warn(
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'Failed to parse as json. (%s)' % e)
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raise exc.RequestMetadataNotAvailable
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final_content.update(value)
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return [('request', final_content)]
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