Coverage for python/lsst/daf/butler/registry/opaque.py: 32%

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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 

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/>. 

21from __future__ import annotations 

22 

23"""The default concrete implementations of the classes that manage 

24opaque tables for `Registry`. 

25""" 

26 

27__all__ = ["ByNameOpaqueTableStorage", "ByNameOpaqueTableStorageManager"] 

28 

29import itertools 

30from typing import Any, ClassVar, Dict, Iterable, Iterator, List, Optional 

31 

32import sqlalchemy 

33 

34from ..core.ddl import FieldSpec, TableSpec 

35from .interfaces import ( 

36 Database, 

37 OpaqueTableStorage, 

38 OpaqueTableStorageManager, 

39 StaticTablesContext, 

40 VersionTuple, 

41) 

42 

43# This has to be updated on every schema change 

44_VERSION = VersionTuple(0, 2, 0) 

45 

46 

47class ByNameOpaqueTableStorage(OpaqueTableStorage): 

48 """An implementation of `OpaqueTableStorage` that simply creates a true 

49 table for each different named opaque logical table. 

50 

51 A `ByNameOpaqueTableStorageManager` instance should always be used to 

52 construct and manage instances of this class. 

53 

54 Parameters 

55 ---------- 

56 db : `Database` 

57 Database engine interface for the namespace in which this table lives. 

58 name : `str` 

59 Name of the logical table (also used as the name of the actual table). 

60 table : `sqlalchemy.schema.Table` 

61 SQLAlchemy representation of the table, which must have already been 

62 created in the namespace managed by ``db`` (this is the responsibility 

63 of `ByNameOpaqueTableStorageManager`). 

64 """ 

65 

66 def __init__(self, *, db: Database, name: str, table: sqlalchemy.schema.Table): 

67 super().__init__(name=name) 

68 self._db = db 

69 self._table = table 

70 

71 def insert(self, *data: dict) -> None: 

72 # Docstring inherited from OpaqueTableStorage. 

73 self._db.insert(self._table, *data) 

74 

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

76 # Docstring inherited from OpaqueTableStorage. 

77 

78 def _batch_in_clause( 

79 column: sqlalchemy.schema.Column, values: Iterable[Any] 

80 ) -> Iterator[sqlalchemy.sql.expression.ClauseElement]: 

81 """Split one long IN clause into a series of shorter ones.""" 

82 in_limit = 1000 

83 # We have to remove possible duplicates from values; and in many 

84 # cases it should be helpful to order the items in the clause. 

85 values = sorted(set(values)) 

86 for iposn in range(0, len(values), in_limit): 

87 in_clause = column.in_(values[iposn : iposn + in_limit]) 

88 yield in_clause 

89 

90 def _batch_in_clauses(**where: Any) -> Iterator[sqlalchemy.sql.expression.ClauseElement]: 

91 """Generate a sequence of WHERE clauses with a limited number of 

92 items in IN clauses. 

93 """ 

94 batches: List[Iterable[Any]] = [] 

95 for k, v in where.items(): 

96 column = self._table.columns[k] 

97 if isinstance(v, (list, tuple, set)): 

98 batches.append(_batch_in_clause(column, v)) 

99 else: 

100 # single "batch" for a regular eq operator 

101 batches.append([column == v]) 

102 

103 for clauses in itertools.product(*batches): 

104 yield sqlalchemy.sql.and_(*clauses) 

105 

106 sql = self._table.select() 

107 if where: 

108 # Split long IN clauses into shorter batches 

109 for clause in _batch_in_clauses(**where): 

110 sql_where = sql.where(clause) 

111 for row in self._db.query(sql_where): 

112 yield row._asdict() 

113 else: 

114 for row in self._db.query(sql): 

115 yield row._asdict() 

116 

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

118 # Docstring inherited from OpaqueTableStorage. 

119 self._db.delete(self._table, columns, *rows) 

120 

121 

122class ByNameOpaqueTableStorageManager(OpaqueTableStorageManager): 

123 """An implementation of `OpaqueTableStorageManager` that simply creates a 

124 true table for each different named opaque logical table. 

125 

126 Instances of this class should generally be constructed via the 

127 `initialize` class method instead of invoking ``__init__`` directly. 

128 

129 Parameters 

130 ---------- 

131 db : `Database` 

132 Database engine interface for the namespace in which this table lives. 

133 metaTable : `sqlalchemy.schema.Table` 

134 SQLAlchemy representation of the table that records which opaque 

135 logical tables exist. 

136 """ 

137 

138 def __init__(self, db: Database, metaTable: sqlalchemy.schema.Table): 

139 self._db = db 

140 self._metaTable = metaTable 

141 self._storage: Dict[str, OpaqueTableStorage] = {} 

142 

143 _META_TABLE_NAME: ClassVar[str] = "opaque_meta" 

144 

145 _META_TABLE_SPEC: ClassVar[TableSpec] = TableSpec( 

146 fields=[ 

147 FieldSpec("table_name", dtype=sqlalchemy.String, length=128, primaryKey=True), 

148 ], 

149 ) 

150 

151 @classmethod 

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

153 # Docstring inherited from OpaqueTableStorageManager. 

154 metaTable = context.addTable(cls._META_TABLE_NAME, cls._META_TABLE_SPEC) 

155 return cls(db=db, metaTable=metaTable) 

156 

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

158 # Docstring inherited from OpaqueTableStorageManager. 

159 return self._storage.get(name) 

160 

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

162 # Docstring inherited from OpaqueTableStorageManager. 

163 result = self._storage.get(name) 

164 if result is None: 

165 # Create the table itself. If it already exists but wasn't in 

166 # the dict because it was added by another client since this one 

167 # was initialized, that's fine. 

168 table = self._db.ensureTableExists(name, spec) 

169 # Add a row to the meta table so we can find this table in the 

170 # future. Also okay if that already exists, so we use sync. 

171 self._db.sync(self._metaTable, keys={"table_name": name}) 

172 result = ByNameOpaqueTableStorage(name=name, table=table, db=self._db) 

173 self._storage[name] = result 

174 return result 

175 

176 @classmethod 

177 def currentVersion(cls) -> Optional[VersionTuple]: 

178 # Docstring inherited from VersionedExtension. 

179 return _VERSION 

180 

181 def schemaDigest(self) -> Optional[str]: 

182 # Docstring inherited from VersionedExtension. 

183 return self._defaultSchemaDigest([self._metaTable], self._db.dialect)