75 lines
2.7 KiB
Python
75 lines
2.7 KiB
Python
#
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# locality.py
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#
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# This source file is part of the FoundationDB open source project
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#
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# Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
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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 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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#
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# FoundationDB Python API
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"""Documentation for this API can be found at
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https://apple.github.io/foundationdb/api-python.html"""
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from fdb import impl as _impl
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def _get_boundary_keys(db_or_tr, begin, end):
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if isinstance(db_or_tr, _impl.Transaction):
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tr = db_or_tr.db.create_transaction()
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# This does not guarantee transactionality because of the exception handling below,
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# but it does hide latency for the new transaction's start
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tr.set_read_version(db_or_tr.get_read_version().wait())
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else:
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tr = db_or_tr.create_transaction()
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first_time = True
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while begin < end:
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try:
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lastbegin = begin
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tr.options.set_read_system_keys()
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tr.options.set_lock_aware()
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kvs = tr.snapshot.get_range(b'\xff' + b'/keyServers/' + begin, b'\xff' + b'/keyServers/' + end)
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if first_time:
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first_time = False
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yield None # trick to get the above get_range to be asynchronously dispatched before get_boundary_keys() returns.
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for kv in kvs:
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yield kv.key[13:]
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begin = kv.key[13:] + b'\x00'
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begin = end
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except _impl.FDBError as e:
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# if we get a transaction_too_old and *something* has happened, then we are no longer transactional
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if e.code == 1007 and begin != lastbegin:
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tr = tr.db.create_transaction()
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else:
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tr.on_error(e).wait()
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def get_boundary_keys(db_or_tr, begin, end):
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begin = _impl.keyToBytes(begin)
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end = _impl.keyToBytes(end)
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gen = _get_boundary_keys(db_or_tr, begin, end)
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try:
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next(gen)
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except StopIteration: # if _get_boundary_keys() never yields a value, e.g. begin > end
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return (x for x in list())
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return gen
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@_impl.transactional
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def get_addresses_for_key(tr, key):
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keyBytes = _impl.keyToBytes(key)
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return _impl.FutureStringArray(tr.capi.fdb_transaction_get_addresses_for_key(tr.tpointer, keyBytes, len(keyBytes)))
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