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76 lines
2.3 KiB
76 lines
2.3 KiB
# 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) -> str: |
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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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