Coverage for python/lsst/daf/butler/registry/interfaces/_opaque.py: 78%
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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
23"""Interfaces for the objects that manage opaque (logical) tables within a
24`Registry`.
25"""
27__all__ = ["OpaqueTableStorageManager", "OpaqueTableStorage"]
29from abc import ABC, abstractmethod
30from collections.abc import Iterable, Iterator, Mapping
31from typing import TYPE_CHECKING, Any
33from ...core.ddl import TableSpec
34from ._database import Database, StaticTablesContext
35from ._versioning import VersionedExtension, VersionTuple
37if TYPE_CHECKING:
38 from ...core.datastore import DatastoreTransaction
41class OpaqueTableStorage(ABC):
42 """An interface that manages the records associated with a particular
43 opaque table in a `Registry`.
45 Parameters
46 ----------
47 name : `str`
48 Name of the opaque table.
49 """
51 def __init__(self, name: str):
52 self.name = name
54 @abstractmethod
55 def insert(self, *data: dict, transaction: DatastoreTransaction | None = None) -> None:
56 """Insert records into the table
58 Parameters
59 ----------
60 *data
61 Each additional positional argument is a dictionary that represents
62 a single row to be added.
63 transaction : `DatastoreTransaction`, optional
64 Transaction object that can be used to enable an explicit rollback
65 of the insert to be registered. Can be ignored if rollback is
66 handled via a different mechanism, such as by a database. Can be
67 `None` if no external transaction is available.
68 """
69 raise NotImplementedError()
71 @abstractmethod
72 def fetch(self, **where: Any) -> Iterator[Mapping[Any, Any]]:
73 """Retrieve records from an opaque table.
75 Parameters
76 ----------
77 **where
78 Additional keyword arguments are interpreted as equality
79 constraints that restrict the returned rows (combined with AND);
80 keyword arguments are column names and values are the values they
81 must have.
83 Yields
84 ------
85 row : `dict`
86 A dictionary representing a single result row.
87 """
88 raise NotImplementedError()
90 @abstractmethod
91 def delete(self, columns: Iterable[str], *rows: dict) -> None:
92 """Remove records from an opaque table.
94 Parameters
95 ----------
96 columns: `~collections.abc.Iterable` of `str`
97 The names of columns that will be used to constrain the rows to
98 be deleted; these will be combined via ``AND`` to form the
99 ``WHERE`` clause of the delete query.
100 *rows
101 Positional arguments are the keys of rows to be deleted, as
102 dictionaries mapping column name to value. The keys in all
103 dictionaries must be exactly the names in ``columns``.
104 """
105 raise NotImplementedError()
107 name: str
108 """The name of the logical table this instance manages (`str`).
109 """
112class OpaqueTableStorageManager(VersionedExtension):
113 """An interface that manages the opaque tables in a `Registry`.
115 `OpaqueTableStorageManager` primarily serves as a container and factory for
116 `OpaqueTableStorage` instances, which each provide access to the records
117 for a different (logical) opaque table.
119 Notes
120 -----
121 Opaque tables are primarily used by `Datastore` instances to manage their
122 internal data in the same database that hold the `Registry`, but are not
123 limited to this.
125 While an opaque table in a multi-layer `Registry` may in fact be the union
126 of multiple tables in different layers, we expect this to be rare, as
127 `Registry` layers will typically correspond to different leaf `Datastore`
128 instances (each with their own opaque table) in a `ChainedDatastore`.
129 """
131 def __init__(self, *, registry_schema_version: VersionTuple | None = None):
132 super().__init__(registry_schema_version=registry_schema_version)
134 @classmethod
135 @abstractmethod
136 def initialize(
137 cls, db: Database, context: StaticTablesContext, registry_schema_version: VersionTuple | None = None
138 ) -> OpaqueTableStorageManager:
139 """Construct an instance of the manager.
141 Parameters
142 ----------
143 db : `Database`
144 Interface to the underlying database engine and namespace.
145 context : `StaticTablesContext`
146 Context object obtained from `Database.declareStaticTables`; used
147 to declare any tables that should always be present in a layer
148 implemented with this manager.
149 registry_schema_version : `VersionTuple` or `None`
150 Schema version of this extension as defined in registry.
152 Returns
153 -------
154 manager : `OpaqueTableStorageManager`
155 An instance of a concrete `OpaqueTableStorageManager` subclass.
156 """
157 raise NotImplementedError()
159 def __getitem__(self, name: str) -> OpaqueTableStorage:
160 """Interface to `get` that raises `LookupError` instead of returning
161 `None` on failure.
162 """
163 r = self.get(name)
164 if r is None:
165 raise LookupError(f"No logical table with name '{name}' found.")
166 return r
168 @abstractmethod
169 def get(self, name: str) -> OpaqueTableStorage | None:
170 """Return an object that provides access to the records associated with
171 an opaque logical table.
173 Parameters
174 ----------
175 name : `str`
176 Name of the logical table.
178 Returns
179 -------
180 records : `OpaqueTableStorage` or `None`
181 The object representing the records for the given table in this
182 layer, or `None` if there are no records for that table in this
183 layer.
185 Notes
186 -----
187 Opaque tables must be registered with the layer (see `register`) by
188 the same client before they can safely be retrieved with `get`.
189 Unlike most other manager classes, the set of opaque tables cannot be
190 obtained from an existing data repository.
191 """
192 raise NotImplementedError()
194 @abstractmethod
195 def register(self, name: str, spec: TableSpec) -> OpaqueTableStorage:
196 """Ensure that this layer can hold records for the given opaque logical
197 table, creating new tables as necessary.
199 Parameters
200 ----------
201 name : `str`
202 Name of the logical table.
203 spec : `TableSpec`
204 Schema specification for the table to be created.
206 Returns
207 -------
208 records : `OpaqueTableStorage`
209 The object representing the records for the given element in this
210 layer.
212 Notes
213 -----
214 This operation may not be invoked within a transaction context block.
215 """
216 raise NotImplementedError()