77 lines
2.3 KiB
Python
77 lines
2.3 KiB
Python
# Copyright 2015 MongoDB, Inc.
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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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"""Tools for working with read concerns."""
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from typing import Any, Dict, Optional
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class ReadConcern:
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"""ReadConcern
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:Parameters:
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- `level`: (string) The read concern level specifies the level of
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isolation for read operations. For example, a read operation using a
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read concern level of ``majority`` will only return data that has been
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written to a majority of nodes. If the level is left unspecified, the
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server default will be used.
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.. versionadded:: 3.2
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"""
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def __init__(self, level: Optional[str] = None) -> None:
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if level is None or isinstance(level, str):
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self.__level = level
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else:
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raise TypeError("level must be a string or None.")
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@property
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def level(self) -> Optional[str]:
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"""The read concern level."""
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return self.__level
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@property
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def ok_for_legacy(self) -> bool:
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"""Return ``True`` if this read concern is compatible with
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old wire protocol versions.
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"""
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return self.level is None or self.level == "local"
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@property
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def document(self) -> Dict[str, Any]:
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"""The document representation of this read concern.
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.. note::
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:class:`ReadConcern` is immutable. Mutating the value of
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:attr:`document` does not mutate this :class:`ReadConcern`.
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"""
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doc = {}
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if self.__level:
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doc["level"] = self.level
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return doc
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def __eq__(self, other: Any) -> bool:
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if isinstance(other, ReadConcern):
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return self.document == other.document
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return NotImplemented
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def __repr__(self):
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if self.level:
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return "ReadConcern(%s)" % self.level
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return "ReadConcern()"
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DEFAULT_READ_CONCERN = ReadConcern()
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