69 lines
2.2 KiB
Python
69 lines
2.2 KiB
Python
# (C) Copyright 2017 SUSE LLC
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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 multiprocessing
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from oslo_config import cfg
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from oslo_log import log
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from monasca_persister.repositories.cassandra import connection_util
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LOG = log.getLogger(__name__)
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conf = cfg.CONF
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class TokenRangeQueryManager(object):
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def __init__(self, cql, result_handler, process_count=None):
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if process_count:
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self._process_count = process_count
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else:
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self._process_count = multiprocessing.cpu_count()
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self._pool = multiprocessing.Pool(processes=self._process_count, initializer=self._setup,
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initargs=(cql, result_handler,))
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@classmethod
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def _setup(cls, cql, result_handler):
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cls.cluster = connection_util.create_cluster()
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cls.session = connection_util.create_session(cls.cluster)
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cls.prepared = cls.session.prepare(cql)
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cls.result_handler = result_handler
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def close_pool(self):
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self._pool.close()
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self._pool.join()
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def query(self, token_ring):
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range_size = len(token_ring) / self._process_count + 1
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start_index = 0
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params = []
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while start_index < len(token_ring):
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end_index = start_index + range_size - 1
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if end_index >= len(token_ring):
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end_index = len(token_ring) - 1
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params.append((token_ring[start_index].value, token_ring[end_index].value))
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start_index = end_index + 1
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self._pool.map(execute_query_token_range, params, 1)
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def execute_query_token_range(token_range):
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results = TokenRangeQueryManager.session.execute(
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TokenRangeQueryManager.prepared.bind(token_range))
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TokenRangeQueryManager.result_handler(results)
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