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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"""The default concrete implementation of the class that manages 

23attributes for `Registry`. 

24""" 

25 

26__all__ = ["DefaultButlerAttributeManager"] 

27 

28from typing import ( 

29 ClassVar, 

30 Iterable, 

31 Optional, 

32 Tuple, 

33) 

34 

35import sqlalchemy 

36 

37from ..core.ddl import TableSpec, FieldSpec 

38from .interfaces import ( 

39 Database, 

40 ButlerAttributeExistsError, 

41 ButlerAttributeManager, 

42 StaticTablesContext 

43) 

44 

45 

46class DefaultButlerAttributeManager(ButlerAttributeManager): 

47 """An implementation of `ButlerAttributeManager` that stores attributes 

48 in a database table. 

49 

50 Parameters 

51 ---------- 

52 db : `Database` 

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

54 table : `sqlalchemy.schema.Table` 

55 SQLAlchemy representation of the table that stores attributes. 

56 """ 

57 def __init__(self, db: Database, table: sqlalchemy.schema.Table): 

58 self._db = db 

59 self._table = table 

60 

61 _TABLE_NAME: ClassVar[str] = "butler_attributes" 

62 

63 _TABLE_SPEC: ClassVar[TableSpec] = TableSpec( 

64 fields=[ 

65 FieldSpec("name", dtype=sqlalchemy.String, length=1024, primaryKey=True), 

66 FieldSpec("value", dtype=sqlalchemy.String, length=65535, nullable=False), 

67 ], 

68 ) 

69 

70 @classmethod 

71 def initialize(cls, db: Database, context: StaticTablesContext) -> ButlerAttributeManager: 

72 # Docstring inherited from ButlerAttributeManager. 

73 table = context.addTable(cls._TABLE_NAME, cls._TABLE_SPEC) 

74 return cls(db=db, table=table) 

75 

76 def get(self, name: str, default: Optional[str] = None) -> Optional[str]: 

77 # Docstring inherited from ButlerAttributeManager. 

78 sql = sqlalchemy.sql.select([self._table.columns.value]).where( 

79 self._table.columns.name == name 

80 ) 

81 row = self._db.query(sql).fetchone() 

82 if row is not None: 

83 return row[0] 

84 return default 

85 

86 def set(self, name: str, value: str, *, force: bool = False) -> None: 

87 # Docstring inherited from ButlerAttributeManager. 

88 if not name or not value: 

89 raise ValueError("name and value cannot be empty") 

90 if force: 

91 self._db.replace(self._table, { 

92 "name": name, 

93 "value": value, 

94 }) 

95 else: 

96 try: 

97 self._db.insert(self._table, { 

98 "name": name, 

99 "value": value, 

100 }) 

101 except sqlalchemy.exc.IntegrityError as exc: 

102 raise ButlerAttributeExistsError(f"attribute {name} already exists") from exc 

103 

104 def delete(self, name: str) -> bool: 

105 # Docstring inherited from ButlerAttributeManager. 

106 numRows = self._db.delete(self._table, ["name"], {"name": name}) 

107 return numRows > 0 

108 

109 def items(self) -> Iterable[Tuple[str, str]]: 

110 # Docstring inherited from ButlerAttributeManager. 

111 sql = sqlalchemy.sql.select([ 

112 self._table.columns.name, 

113 self._table.columns.value, 

114 ]) 

115 for row in self._db.query(sql): 

116 yield row[0], row[1]