Coverage for python/lsst/daf/butler/registry/interfaces/_opaque.py: 88%
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6# See the COPYRIGHT file at the top-level directory of this distribution
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15# This program is free software: you can redistribute it and/or modify
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28"""Interfaces for the objects that manage opaque (logical) tables within a
29`Registry`.
30"""
32from __future__ import annotations
34__all__ = ["OpaqueTableStorageManager", "OpaqueTableStorage"]
36from abc import ABC, abstractmethod
37from collections.abc import Iterable, Iterator, Mapping
38from typing import TYPE_CHECKING, Any
40from ...ddl import TableSpec
41from ._database import Database, StaticTablesContext
42from ._versioning import VersionedExtension, VersionTuple
44if TYPE_CHECKING:
45 from ...datastore import DatastoreTransaction
48class OpaqueTableStorage(ABC):
49 """An interface that manages the records associated with a particular
50 opaque table in a `Registry`.
52 Parameters
53 ----------
54 name : `str`
55 Name of the opaque table.
56 """
58 def __init__(self, name: str):
59 self.name = name
61 @abstractmethod
62 def insert(self, *data: dict, transaction: DatastoreTransaction | None = None) -> None:
63 """Insert records into the table.
65 Parameters
66 ----------
67 *data
68 Each additional positional argument is a dictionary that represents
69 a single row to be added.
70 transaction : `DatastoreTransaction`, optional
71 Transaction object that can be used to enable an explicit rollback
72 of the insert to be registered. Can be ignored if rollback is
73 handled via a different mechanism, such as by a database. Can be
74 `None` if no external transaction is available.
75 """
76 raise NotImplementedError()
78 @abstractmethod
79 def ensure(self, *data: dict, transaction: DatastoreTransaction | None = None) -> None:
80 """Insert records into the table, skipping rows that already exist.
82 Parameters
83 ----------
84 *data
85 Each additional positional argument is a dictionary that represents
86 a single row to be added.
87 transaction : `DatastoreTransaction`, optional
88 Transaction object that can be used to enable an explicit rollback
89 of the insert to be registered. Can be ignored if rollback is
90 handled via a different mechanism, such as by a database. Can be
91 `None` if no external transaction is available.
92 """
93 raise NotImplementedError()
95 @abstractmethod
96 def replace(self, *data: dict, transaction: DatastoreTransaction | None = None) -> None:
97 """Insert records into the table, replacing if previously existing
98 but different.
100 Parameters
101 ----------
102 *data
103 Each additional positional argument is a dictionary that represents
104 a single row to be added.
105 transaction : `DatastoreTransaction`, optional
106 Transaction object that can be used to enable an explicit rollback
107 of the insert to be registered. Can be ignored if rollback is
108 handled via a different mechanism, such as by a database. Can be
109 `None` if no external transaction is available.
110 """
111 raise NotImplementedError()
113 @abstractmethod
114 def fetch(self, **where: Any) -> Iterator[Mapping[Any, Any]]:
115 """Retrieve records from an opaque table.
117 Parameters
118 ----------
119 **where
120 Additional keyword arguments are interpreted as equality
121 constraints that restrict the returned rows (combined with AND);
122 keyword arguments are column names and values are the values they
123 must have.
125 Yields
126 ------
127 row : `dict`
128 A dictionary representing a single result row.
129 """
130 raise NotImplementedError()
132 @abstractmethod
133 def delete(self, columns: Iterable[str], *rows: dict) -> None:
134 """Remove records from an opaque table.
136 Parameters
137 ----------
138 columns : `~collections.abc.Iterable` of `str`
139 The names of columns that will be used to constrain the rows to
140 be deleted; these will be combined via ``AND`` to form the
141 ``WHERE`` clause of the delete query.
142 *rows
143 Positional arguments are the keys of rows to be deleted, as
144 dictionaries mapping column name to value. The keys in all
145 dictionaries must be exactly the names in ``columns``.
146 """
147 raise NotImplementedError()
149 name: str
150 """The name of the logical table this instance manages (`str`).
151 """
154class OpaqueTableStorageManager(VersionedExtension):
155 """An interface that manages the opaque tables in a `Registry`.
157 `OpaqueTableStorageManager` primarily serves as a container and factory for
158 `OpaqueTableStorage` instances, which each provide access to the records
159 for a different (logical) opaque table.
161 Parameters
162 ----------
163 registry_schema_version : `VersionTuple` or `None`, optional
164 Version of registry schema.
166 Notes
167 -----
168 Opaque tables are primarily used by `Datastore` instances to manage their
169 internal data in the same database that hold the `Registry`, but are not
170 limited to this.
172 While an opaque table in a multi-layer `Registry` may in fact be the union
173 of multiple tables in different layers, we expect this to be rare, as
174 `Registry` layers will typically correspond to different leaf `Datastore`
175 instances (each with their own opaque table) in a `ChainedDatastore`.
176 """
178 def __init__(self, *, registry_schema_version: VersionTuple | None = None):
179 super().__init__(registry_schema_version=registry_schema_version)
181 @classmethod
182 @abstractmethod
183 def initialize(
184 cls, db: Database, context: StaticTablesContext, registry_schema_version: VersionTuple | None = None
185 ) -> OpaqueTableStorageManager:
186 """Construct an instance of the manager.
188 Parameters
189 ----------
190 db : `Database`
191 Interface to the underlying database engine and namespace.
192 context : `StaticTablesContext`
193 Context object obtained from `Database.declareStaticTables`; used
194 to declare any tables that should always be present in a layer
195 implemented with this manager.
196 registry_schema_version : `VersionTuple` or `None`
197 Schema version of this extension as defined in registry.
199 Returns
200 -------
201 manager : `OpaqueTableStorageManager`
202 An instance of a concrete `OpaqueTableStorageManager` subclass.
203 """
204 raise NotImplementedError()
206 def __getitem__(self, name: str) -> OpaqueTableStorage:
207 """Interface to `get` that raises `LookupError` instead of returning
208 `None` on failure.
209 """
210 r = self.get(name)
211 if r is None:
212 raise LookupError(f"No logical table with name '{name}' found.")
213 return r
215 @abstractmethod
216 def get(self, name: str) -> OpaqueTableStorage | None:
217 """Return an object that provides access to the records associated with
218 an opaque logical table.
220 Parameters
221 ----------
222 name : `str`
223 Name of the logical table.
225 Returns
226 -------
227 records : `OpaqueTableStorage` or `None`
228 The object representing the records for the given table in this
229 layer, or `None` if there are no records for that table in this
230 layer.
232 Notes
233 -----
234 Opaque tables must be registered with the layer (see `register`) by
235 the same client before they can safely be retrieved with `get`.
236 Unlike most other manager classes, the set of opaque tables cannot be
237 obtained from an existing data repository.
238 """
239 raise NotImplementedError()
241 @abstractmethod
242 def register(self, name: str, spec: TableSpec) -> OpaqueTableStorage:
243 """Ensure that this layer can hold records for the given opaque logical
244 table, creating new tables as necessary.
246 Parameters
247 ----------
248 name : `str`
249 Name of the logical table.
250 spec : `TableSpec`
251 Schema specification for the table to be created.
253 Returns
254 -------
255 records : `OpaqueTableStorage`
256 The object representing the records for the given element in this
257 layer.
259 Notes
260 -----
261 This operation may not be invoked within a transaction context block.
262 """
263 raise NotImplementedError()
265 @abstractmethod
266 def clone(self, db: Database) -> OpaqueTableStorageManager:
267 """Make an independent copy of this manager instance bound to a new
268 `Database` instance.
270 Parameters
271 ----------
272 db : `Database`
273 New `Database` object to use when instantiating the manager.
275 Returns
276 -------
277 instance : `OpaqueTableStorageManager`
278 New manager instance with the same configuration as this instance,
279 but bound to a new Database object.
280 """
281 raise NotImplementedError()