Coverage for python / lsst / daf / butler / registry / _config.py: 41%

1# This file is part of daf_butler. 

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 software is dual licensed under the GNU General Public License and also 

10# under a 3-clause BSD license. Recipients may choose which of these licenses 

11# to use; please see the files gpl-3.0.txt and/or bsd_license.txt, 

12# respectively. If you choose the GPL option then the following text applies 

13# (but note that there is still no warranty even if you opt for BSD instead): 

14# 

15# This program is free software: you can redistribute it and/or modify 

16# it under the terms of the GNU General Public License as published by 

17# the Free Software Foundation, either version 3 of the License, or 

18# (at your option) any later version. 

19# 

20# This program is distributed in the hope that it will be useful, 

21# but WITHOUT ANY WARRANTY; without even the implied warranty of 

22# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

23# GNU General Public License for more details. 

24# 

25# You should have received a copy of the GNU General Public License 

26# along with this program. If not, see <http://www.gnu.org/licenses/>. 

27 

28from __future__ import annotations 

29 

30__all__ = ("RegistryConfig",) 

31 

32from typing import TYPE_CHECKING 

33 

34from lsst.utils import doImportType 

35 

36from .._config import ConfigSubset 

37from ..repo_relocation import replaceRoot 

38from .connectionString import ConnectionStringFactory 

39from .interfaces import Database 

40 

41if TYPE_CHECKING: 

42 import sqlalchemy 

43 

44 from lsst.resources import ResourcePathExpression 

45 

46 

47class RegistryConfig(ConfigSubset): 

48 """Configuration specific to a butler Registry.""" 

49 

50 component = "registry" 

51 requiredKeys = ("db",) 

52 defaultConfigFile = "registry.yaml" 

53 

54 def getDialect(self) -> str: 

55 """Parse the ``db`` key of the config and returns the database dialect. 

56 

57 Returns 

58 ------- 

59 dialect : `str` 

60 Dialect found in the connection string. 

61 """ 

62 conStr = ConnectionStringFactory.fromConfig(self) 

63 return conStr.get_backend_name() 

64 

65 def getDatabaseClass(self) -> type[Database]: 

66 """Return the `Database` class targeted by configuration values. 

67 

68 The appropriate class is determined by parsing the ``db`` key to 

69 extract the dialect, and then looking that up under the ``engines`` key 

70 of the registry config. 

71 """ 

72 dialect = self.getDialect() 

73 if dialect not in self["engines"]: 

74 raise ValueError(f"Connection string dialect has no known aliases. Received: {dialect}") 

75 databaseClassName = self["engines", dialect] 

76 databaseClass = doImportType(databaseClassName) 

77 if not issubclass(databaseClass, Database): 

78 raise TypeError(f"Imported database class {databaseClassName} is not a Database") 

79 return databaseClass 

80 

81 def makeDefaultDatabaseUri(self, root: str) -> str | None: 

82 """Return a default 'db' URI for the registry configured here that is 

83 appropriate for a new empty repository with the given root. 

84 

85 Parameters 

86 ---------- 

87 root : `str` 

88 Filesystem path to the root of the data repository. 

89 

90 Returns 

91 ------- 

92 uri : `str` 

93 URI usable as the 'db' string in a `RegistryConfig`. 

94 """ 

95 DatabaseClass = self.getDatabaseClass() 

96 return DatabaseClass.makeDefaultUri(root) 

97 

98 def replaceRoot(self, root: ResourcePathExpression | None) -> None: 

99 """Replace any occurrences of `BUTLER_ROOT_TAG` in the connection 

100 with the given root directory. 

101 

102 Parameters 

103 ---------- 

104 root : `lsst.resources.ResourcePathExpression`, or `None` 

105 String to substitute for `BUTLER_ROOT_TAG`. Passing `None` here is 

106 allowed only as a convenient way to raise an exception 

107 (`ValueError`). 

108 

109 Raises 

110 ------ 

111 ValueError 

112 Raised if ``root`` is not set but a value is required. 

113 """ 

114 self["db"] = replaceRoot(self["db"], root) 

115 

116 @property 

117 def connectionString(self) -> sqlalchemy.engine.url.URL: 

118 """Return the connection string to the underlying database 

119 (`sqlalchemy.engine.url.URL`). 

120 """ 

121 return ConnectionStringFactory.fromConfig(self) 

122 

123 @property 

124 def areTemporaryTablesAllowed(self) -> bool: 

125 """Return `True` if the database allows creating temporary tables for 

126 read operations; `False` otherwise. 

127 

128 By default this is `True`, because there is a performance penalty 

129 for some queries if temporary tables cannot be used. 

130 

131 This should be set to `False` when using a Postgres hot standby using 

132 physical replication or an AlloyDB read pool, since these backends 

133 do not support temporary tables. 

134 """ 

135 key = "temporary_tables" 

136 value = self.get(key) 

137 if value is None: 

138 return True 

139 elif isinstance(value, bool): 

140 return value 

141 

142 raise ValueError(f"Unexpected value '{value}' for '{key}' in registry configuration")