Coverage for python/lsst/dax/apdb/apdbConfigFreezer.py: 34%
24 statements
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« prev ^ index » next coverage.py v7.5.0, created at 2024-04-27 03:01 -0700
1# This file is part of dax_apdb.
2#
3# Developed for the LSST Data Management System.
4# This product includes software developed by the LSST Project
5# (http://www.lsst.org).
6# See the COPYRIGHT file at the top-level directory of this distribution
7# for details of code ownership.
8#
9# This program is free software: you can redistribute it and/or modify
10# it under the terms of the GNU General Public License as published by
11# the Free Software Foundation, either version 3 of the License, or
12# (at your option) any later version.
13#
14# This program is distributed in the hope that it will be useful,
15# but WITHOUT ANY WARRANTY; without even the implied warranty of
16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17# GNU General Public License for more details.
18#
19# You should have received a copy of the GNU General Public License
20# along with this program. If not, see <http://www.gnu.org/licenses/>.
22from __future__ import annotations
24__all__ = ["ApdbConfigFreezer"]
26import json
27from collections.abc import Iterable
28from typing import Generic, TypeVar
30from .apdb import ApdbConfig
32_Config = TypeVar("_Config", bound=ApdbConfig)
35class ApdbConfigFreezer(Generic[_Config]):
36 """Class that handles freezing of the configuration parameters, this is
37 an implementation detail for use in Apdb subclasses.
39 Parameters
40 ----------
41 field_names : `~collections.abc.Iterable` [`str`]
42 Names of configuration fields to be frozen.
43 """
45 def __init__(self, field_names: Iterable[str]):
46 self._field_names = list(field_names)
48 def to_json(self, config: ApdbConfig) -> str:
49 """Convert part of the configuration object to JSON string.
51 Parameters
52 ----------
53 config : `ApdbConfig`
54 Configuration object.
56 Returns
57 -------
58 json_str : `str`
59 JSON representation of the frozen part of the config.
60 """
61 config_dict = config.toDict()
62 json_dict = {name: config_dict[name] for name in self._field_names}
63 return json.dumps(json_dict)
65 def update(self, config: _Config, json_str: str) -> _Config:
66 """Update configuration field values from a JSON string.
68 Parameters
69 ----------
70 config : `ApdbConfig`
71 Configuration object.
72 json_str : str
73 String containing JSON representation of configuration.
75 Returns
76 -------
77 updated : `ApdbConfig`
78 Copy of the ``config`` with some fields updated from JSON object.
80 Raises
81 ------
82 TypeError
83 Raised if JSON string does not represent JSON object.
84 ValueError
85 Raised if JSON object contains key which is not present in
86 ``field_names``.
87 """
88 data = json.loads(json_str)
89 if not isinstance(data, dict):
90 raise TypeError(f"JSON string must be convertible to object: {json_str!r}")
92 new_config = type(config)(**config.toDict())
93 for key, value in data.items():
94 if key not in self._field_names:
95 raise ValueError(f"JSON object contains unknown key: {key}")
96 setattr(new_config, key, value)
98 return new_config