Coverage for python/lsst/daf/butler/registry/interfaces/_opaque.py: 66%

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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 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 

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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. 

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

21from __future__ import annotations 

22 

23"""Interfaces for the objects that manage opaque (logical) tables within a 

24`Registry`. 

25""" 

26 

27__all__ = ["OpaqueTableStorageManager", "OpaqueTableStorage"] 

28 

29from abc import ABC, abstractmethod 

30from typing import TYPE_CHECKING, Any, Iterable, Iterator, Optional 

31 

32from ...core.ddl import TableSpec 

33from ._database import Database, StaticTablesContext 

34from ._versioning import VersionedExtension 

35 

36if TYPE_CHECKING: 36 ↛ 37line 36 didn't jump to line 37, because the condition on line 36 was never true

37 from ...core.datastore import DatastoreTransaction 

38 

39 

40class OpaqueTableStorage(ABC): 

41 """An interface that manages the records associated with a particular 

42 opaque table in a `Registry`. 

43 

44 Parameters 

45 ---------- 

46 name : `str` 

47 Name of the opaque table. 

48 """ 

49 

50 def __init__(self, name: str): 

51 self.name = name 

52 

53 @abstractmethod 

54 def insert(self, *data: dict, transaction: DatastoreTransaction | None = None) -> None: 

55 """Insert records into the table 

56 

57 Parameters 

58 ---------- 

59 *data 

60 Each additional positional argument is a dictionary that represents 

61 a single row to be added. 

62 transaction : `DatastoreTransaction`, optional 

63 Transaction object that can be used to enable an explicit rollback 

64 of the insert to be registered. Can be ignored if rollback is 

65 handled via a different mechanism, such as by a database. Can be 

66 `None` if no external transaction is available. 

67 """ 

68 raise NotImplementedError() 

69 

70 @abstractmethod 

71 def fetch(self, **where: Any) -> Iterator[dict]: 

72 """Retrieve records from an opaque table. 

73 

74 Parameters 

75 ---------- 

76 **where 

77 Additional keyword arguments are interpreted as equality 

78 constraints that restrict the returned rows (combined with AND); 

79 keyword arguments are column names and values are the values they 

80 must have. 

81 

82 Yields 

83 ------ 

84 row : `dict` 

85 A dictionary representing a single result row. 

86 """ 

87 raise NotImplementedError() 

88 

89 @abstractmethod 

90 def delete(self, columns: Iterable[str], *rows: dict) -> None: 

91 """Remove records from an opaque table. 

92 

93 Parameters 

94 ---------- 

95 columns: `~collections.abc.Iterable` of `str` 

96 The names of columns that will be used to constrain the rows to 

97 be deleted; these will be combined via ``AND`` to form the 

98 ``WHERE`` clause of the delete query. 

99 *rows 

100 Positional arguments are the keys of rows to be deleted, as 

101 dictionaries mapping column name to value. The keys in all 

102 dictionaries must be exactly the names in ``columns``. 

103 """ 

104 raise NotImplementedError() 

105 

106 name: str 

107 """The name of the logical table this instance manages (`str`). 

108 """ 

109 

110 

111class OpaqueTableStorageManager(VersionedExtension): 

112 """An interface that manages the opaque tables in a `Registry`. 

113 

114 `OpaqueTableStorageManager` primarily serves as a container and factory for 

115 `OpaqueTableStorage` instances, which each provide access to the records 

116 for a different (logical) opaque table. 

117 

118 Notes 

119 ----- 

120 Opaque tables are primarily used by `Datastore` instances to manage their 

121 internal data in the same database that hold the `Registry`, but are not 

122 limited to this. 

123 

124 While an opaque table in a multi-layer `Registry` may in fact be the union 

125 of multiple tables in different layers, we expect this to be rare, as 

126 `Registry` layers will typically correspond to different leaf `Datastore` 

127 instances (each with their own opaque table) in a `ChainedDatastore`. 

128 """ 

129 

130 @classmethod 

131 @abstractmethod 

132 def initialize(cls, db: Database, context: StaticTablesContext) -> OpaqueTableStorageManager: 

133 """Construct an instance of the manager. 

134 

135 Parameters 

136 ---------- 

137 db : `Database` 

138 Interface to the underlying database engine and namespace. 

139 context : `StaticTablesContext` 

140 Context object obtained from `Database.declareStaticTables`; used 

141 to declare any tables that should always be present in a layer 

142 implemented with this manager. 

143 

144 Returns 

145 ------- 

146 manager : `OpaqueTableStorageManager` 

147 An instance of a concrete `OpaqueTableStorageManager` subclass. 

148 """ 

149 raise NotImplementedError() 

150 

151 def __getitem__(self, name: str) -> OpaqueTableStorage: 

152 """Interface to `get` that raises `LookupError` instead of returning 

153 `None` on failure. 

154 """ 

155 r = self.get(name) 

156 if r is None: 

157 raise LookupError(f"No logical table with name '{name}' found.") 

158 return r 

159 

160 @abstractmethod 

161 def get(self, name: str) -> Optional[OpaqueTableStorage]: 

162 """Return an object that provides access to the records associated with 

163 an opaque logical table. 

164 

165 Parameters 

166 ---------- 

167 name : `str` 

168 Name of the logical table. 

169 

170 Returns 

171 ------- 

172 records : `OpaqueTableStorage` or `None` 

173 The object representing the records for the given table in this 

174 layer, or `None` if there are no records for that table in this 

175 layer. 

176 

177 Notes 

178 ----- 

179 Opaque tables must be registered with the layer (see `register`) by 

180 the same client before they can safely be retrieved with `get`. 

181 Unlike most other manager classes, the set of opaque tables cannot be 

182 obtained from an existing data repository. 

183 """ 

184 raise NotImplementedError() 

185 

186 @abstractmethod 

187 def register(self, name: str, spec: TableSpec) -> OpaqueTableStorage: 

188 """Ensure that this layer can hold records for the given opaque logical 

189 table, creating new tables as necessary. 

190 

191 Parameters 

192 ---------- 

193 name : `str` 

194 Name of the logical table. 

195 spec : `TableSpec` 

196 Schema specification for the table to be created. 

197 

198 Returns 

199 ------- 

200 records : `OpaqueTableStorage` 

201 The object representing the records for the given element in this 

202 layer. 

203 

204 Notes 

205 ----- 

206 This operation may not be invoked within a transaction context block. 

207 """ 

208 raise NotImplementedError()