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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/>. 

21 

22"""Configuration control.""" 

23 

24__all__ = ("Config", "ConfigSubset") 

25 

26import collections 

27import copy 

28import logging 

29import pprint 

30import os 

31import yaml 

32import sys 

33from yaml.representer import Representer 

34import io 

35from typing import Sequence, Optional, ClassVar 

36 

37try: 

38 import boto3 

39except ImportError: 

40 boto3 = None 

41 

42import lsst.utils 

43from lsst.utils import doImport 

44from .location import ButlerURI 

45from .s3utils import getS3Client 

46 

47yaml.add_representer(collections.defaultdict, Representer.represent_dict) 

48 

49 

50# Config module logger 

51log = logging.getLogger(__name__) 

52 

53# PATH-like environment variable to use for defaults. 

54CONFIG_PATH = "DAF_BUTLER_CONFIG_PATH" 

55 

56 

57class Loader(yaml.CSafeLoader): 

58 """YAML Loader that supports file include directives 

59 

60 Uses ``!include`` directive in a YAML file to point to another 

61 YAML file to be included. The path in the include directive is relative 

62 to the file containing that directive. 

63 

64 storageClasses: !include storageClasses.yaml 

65 

66 Examples 

67 -------- 

68 >>> with open("document.yaml", "r") as f: 

69 data = yaml.load(f, Loader=Loader) 

70 

71 Notes 

72 ----- 

73 See https://davidchall.github.io/yaml-includes.html 

74 """ 

75 

76 def __init__(self, stream): 

77 super().__init__(stream) 

78 self._root = ButlerURI(stream.name) 

79 Loader.add_constructor("!include", Loader.include) 

80 

81 def include(self, node): 

82 if isinstance(node, yaml.ScalarNode): 

83 return self.extractFile(self.construct_scalar(node)) 

84 

85 elif isinstance(node, yaml.SequenceNode): 

86 result = [] 

87 for filename in self.construct_sequence(node): 

88 result.append(self.extractFile(filename)) 

89 return result 

90 

91 elif isinstance(node, yaml.MappingNode): 

92 result = {} 

93 for k, v in self.construct_mapping(node).items(): 

94 result[k] = self.extractFile(v) 

95 return result 

96 

97 else: 

98 print("Error:: unrecognised node type in !include statement", file=sys.stderr) 

99 raise yaml.constructor.ConstructorError 

100 

101 def extractFile(self, filename): 

102 fileuri = copy.copy(self._root) 

103 fileuri.updateFile(filename) 

104 log.debug("Opening YAML file via !include: %s", fileuri) 

105 

106 if not fileuri.scheme or fileuri.scheme == "file": 

107 with open(fileuri.ospath, "r") as f: 

108 return yaml.load(f, Loader) 

109 elif fileuri.scheme == "s3": 

110 if boto3 is None: 

111 raise ModuleNotFoundError("Could not find boto3. Are you sure it is installed?") 

112 s3 = getS3Client() 

113 try: 

114 response = s3.get_object(Bucket=fileuri.netloc, Key=fileuri.relativeToPathRoot) 

115 except (s3.exceptions.NoSuchKey, s3.exceptions.NoSuchBucket) as err: 

116 raise FileNotFoundError(f'No such file or directory: {fileuri}') from err 

117 

118 # boto3 response is a `StreamingBody`, but not a valid Python 

119 # IOStream. Loader will raise an error that the stream has no name. 

120 # The name is used to resolve the "!include" filename location to 

121 # download. A hackish solution is to name it explicitly. 

122 response["Body"].name = fileuri.geturl() 

123 return yaml.load(response["Body"], Loader) 

124 

125 

126class Config(collections.abc.MutableMapping): 

127 r"""Implements a datatype that is used by `Butler` for configuration 

128 parameters. 

129 

130 It is essentially a `dict` with key/value pairs, including nested dicts 

131 (as values). In fact, it can be initialized with a `dict`. 

132 This is explained next: 

133 

134 Config extends the `dict` api so that hierarchical values may be accessed 

135 with delimited notation or as a tuple. If a string is given the delimiter 

136 is picked up from the first character in that string. For example, 

137 ``foo.getValue(".a.b.c")``, ``foo["a"]["b"]["c"]``, ``foo["a", "b", "c"]``, 

138 ``foo[".a.b.c"]``, and ``foo["/a/b/c"]`` all achieve the same outcome. 

139 If the first character is alphanumeric, no delimiter will be used. 

140 ``foo["a.b.c"]`` will be a single key ``a.b.c`` as will ``foo[":a.b.c"]``. 

141 Unicode characters can be used as the delimiter for distinctiveness if 

142 required. 

143 

144 If a key in the hierarchy starts with a non-alphanumeric character care 

145 should be used to ensure that either the tuple interface is used or 

146 a distinct delimiter is always given in string form. 

147 

148 Finally, the delimiter can be escaped if it is part of a key and also 

149 has to be used as a delimiter. For example, ``foo[r".a.b\.c"]`` results in 

150 a two element hierarchy of ``a`` and ``b.c``. For hard-coded strings it is 

151 always better to use a different delimiter in these cases. 

152 

153 Note that adding a multi-level key implicitly creates any nesting levels 

154 that do not exist, but removing multi-level keys does not automatically 

155 remove empty nesting levels. As a result: 

156 

157 >>> c = Config() 

158 >>> c[".a.b"] = 1 

159 >>> del c[".a.b"] 

160 >>> c["a"] 

161 Config({'a': {}}) 

162 

163 Storage formats supported: 

164 

165 - yaml: read and write is supported. 

166 

167 

168 Parameters 

169 ---------- 

170 other : `str` or `Config` or `dict` 

171 Other source of configuration, can be: 

172 

173 - (`str`) Treated as a path to a config file on disk. Must end with 

174 ".yaml". 

175 - (`Config`) Copies the other Config's values into this one. 

176 - (`dict`) Copies the values from the dict into this Config. 

177 

178 If `None` is provided an empty `Config` will be created. 

179 """ 

180 

181 _D: ClassVar[str] = "→" 

182 """Default internal delimiter to use for components in the hierarchy when 

183 constructing keys for external use (see `Config.names()`).""" 

184 

185 includeKey: ClassVar[str] = "includeConfigs" 

186 """Key used to indicate that another config should be included at this 

187 part of the hierarchy.""" 

188 

189 def __init__(self, other=None): 

190 self._data = {} 

191 self.configFile = None 

192 

193 if other is None: 

194 return 

195 

196 if isinstance(other, Config): 

197 self._data = copy.deepcopy(other._data) 

198 self.configFile = other.configFile 

199 elif isinstance(other, collections.abc.Mapping): 

200 self.update(other) 

201 elif isinstance(other, str): 

202 # if other is a string, assume it is a file path. 

203 self.__initFromFile(other) 

204 self._processExplicitIncludes() 

205 else: 

206 # if the config specified by other could not be recognized raise 

207 # a runtime error. 

208 raise RuntimeError("A Config could not be loaded from other:%s" % other) 

209 

210 def ppprint(self): 

211 """helper function for debugging, prints a config out in a readable 

212 way in the debugger. 

213 

214 use: pdb> print(myConfigObject.ppprint()) 

215 

216 Returns 

217 ------- 

218 s : `str` 

219 A prettyprint formatted string representing the config 

220 """ 

221 return pprint.pformat(self._data, indent=2, width=1) 

222 

223 def __repr__(self): 

224 return f"{type(self).__name__}({self._data!r})" 

225 

226 def __str__(self): 

227 return self.ppprint() 

228 

229 def __len__(self): 

230 return len(self._data) 

231 

232 def __iter__(self): 

233 return iter(self._data) 

234 

235 def copy(self): 

236 return type(self)(self) 

237 

238 def __initFromFile(self, path): 

239 """Load a file from a path or an URI. 

240 

241 Parameters 

242 ---------- 

243 path : `str` 

244 Path or an URI to a persisted config file. 

245 """ 

246 uri = ButlerURI(path) 

247 if uri.path.endswith("yaml"): 

248 if uri.scheme == "s3": 

249 self.__initFromS3YamlFile(uri.geturl()) 

250 else: 

251 self.__initFromYamlFile(uri.ospath) 

252 else: 

253 raise RuntimeError("Unhandled config file type:%s" % uri) 

254 self.configFile = str(path) 

255 

256 def __initFromS3YamlFile(self, url): 

257 """Load a file at a given S3 Bucket uri and attempts to load it from 

258 yaml. 

259 

260 Parameters 

261 ---------- 

262 path : `str` 

263 To a persisted config file. 

264 """ 

265 if boto3 is None: 

266 raise ModuleNotFoundError("boto3 not found." 

267 "Are you sure it is installed?") 

268 

269 uri = ButlerURI(url) 

270 s3 = getS3Client() 

271 try: 

272 response = s3.get_object(Bucket=uri.netloc, Key=uri.relativeToPathRoot) 

273 except (s3.exceptions.NoSuchKey, s3.exceptions.NoSuchBucket) as err: 

274 raise FileNotFoundError(f"No such file or directory: {uri}") from err 

275 

276 # boto3 response is a `StreamingBody`, but not a valid Python IOStream. 

277 # Loader will raise an error that the stream has no name. A hackish 

278 # solution is to name it explicitly. 

279 response["Body"].name = url 

280 self.__initFromYaml(response["Body"]) 

281 response["Body"].close() 

282 

283 def __initFromYamlFile(self, path): 

284 """Opens a file at a given path and attempts to load it in from yaml. 

285 

286 Parameters 

287 ---------- 

288 path : `str` 

289 To a persisted config file in YAML format. 

290 """ 

291 log.debug("Opening YAML config file: %s", path) 

292 with open(path, "r") as f: 

293 self.__initFromYaml(f) 

294 

295 def __initFromYaml(self, stream): 

296 """Loads a YAML config from any readable stream that contains one. 

297 

298 Parameters 

299 ---------- 

300 stream 

301 To a persisted config file in YAML format. 

302 

303 Raises 

304 ------ 

305 yaml.YAMLError 

306 If there is an error loading the file. 

307 """ 

308 content = yaml.load(stream, Loader=Loader) 

309 if content is None: 

310 content = {} 

311 self._data = content 

312 return self 

313 

314 def _processExplicitIncludes(self): 

315 """Scan through the configuration searching for the special 

316 includeConfigs directive and process the includes.""" 

317 

318 # Search paths for config files 

319 searchPaths = [os.path.curdir] 

320 if self.configFile is not None: 

321 searchPaths.append(os.path.abspath(os.path.dirname(self.configFile))) 

322 

323 # Ensure we know what delimiter to use 

324 names = self.nameTuples() 

325 for path in names: 

326 if path[-1] == self.includeKey: 

327 

328 log.debug("Processing file include directive at %s", self._D + self._D.join(path)) 

329 basePath = path[:-1] 

330 

331 # Extract the includes and then delete them from the config 

332 includes = self[path] 

333 del self[path] 

334 

335 # Be consistent and convert to a list 

336 if not isinstance(includes, list): 

337 includes = [includes] 

338 

339 # Read each file assuming it is a reference to a file 

340 # The file can be relative to config file or cwd 

341 # ConfigSubset search paths are not used 

342 # At some point these might be URIs which we will have to 

343 # assume resolve explicitly 

344 subConfigs = [] 

345 for fileName in includes: 

346 # Expand any shell variables 

347 fileName = os.path.expandvars(fileName) 

348 found = None 

349 if os.path.isabs(fileName): 

350 found = fileName 

351 else: 

352 for dir in searchPaths: 

353 filePath = os.path.join(dir, fileName) 

354 if os.path.exists(filePath): 

355 found = os.path.normpath(os.path.abspath(filePath)) 

356 break 

357 if not found: 

358 raise RuntimeError(f"Unable to find referenced include file: {fileName}") 

359 

360 # Read the referenced Config as a Config 

361 subConfigs.append(type(self)(found)) 

362 

363 # Now we need to merge these sub configs with the current 

364 # information that was present in this node in the config 

365 # tree with precedence given to the explicit values 

366 newConfig = subConfigs.pop(0) 

367 for sc in subConfigs: 

368 newConfig.update(sc) 

369 

370 # Explicit values take precedence 

371 if not basePath: 

372 # This is an include at the root config 

373 newConfig.update(self) 

374 # Replace the current config 

375 self._data = newConfig._data 

376 else: 

377 newConfig.update(self[basePath]) 

378 # And reattach to the base config 

379 self[basePath] = newConfig 

380 

381 @staticmethod 

382 def _splitIntoKeys(key): 

383 r"""Split the argument for get/set/in into a hierarchical list. 

384 

385 Parameters 

386 ---------- 

387 key : `str` or iterable 

388 Argument given to get/set/in. If an iterable is provided it will 

389 be converted to a list. If the first character of the string 

390 is not an alphanumeric character then it will be used as the 

391 delimiter for the purposes of splitting the remainder of the 

392 string. If the delimiter is also in one of the keys then it 

393 can be escaped using ``\``. There is no default delimiter. 

394 

395 Returns 

396 ------- 

397 keys : `list` 

398 Hierarchical keys as a `list`. 

399 """ 

400 if isinstance(key, str): 

401 if not key[0].isalnum(): 

402 d = key[0] 

403 key = key[1:] 

404 else: 

405 return [key, ] 

406 escaped = f"\\{d}" 

407 temp = None 

408 if escaped in key: 

409 # Complain at the attempt to escape the escape 

410 doubled = fr"\{escaped}" 

411 if doubled in key: 

412 raise ValueError(f"Escaping an escaped delimiter ({doubled} in {key})" 

413 " is not yet supported.") 

414 # Replace with a character that won't be in the string 

415 temp = "\r" 

416 if temp in key or d == temp: 

417 raise ValueError(f"Can not use character {temp!r} in hierarchical key or as" 

418 " delimiter if escaping the delimiter") 

419 key = key.replace(escaped, temp) 

420 hierarchy = key.split(d) 

421 if temp: 

422 hierarchy = [h.replace(temp, d) for h in hierarchy] 

423 return hierarchy 

424 elif isinstance(key, collections.abc.Iterable): 

425 return list(key) 

426 else: 

427 # Not sure what this is so try it anyway 

428 return [key, ] 

429 

430 def _getKeyHierarchy(self, name): 

431 """Retrieve the key hierarchy for accessing the Config 

432 

433 Parameters 

434 ---------- 

435 name : `str` or `tuple` 

436 Delimited string or `tuple` of hierarchical keys. 

437 

438 Returns 

439 ------- 

440 hierarchy : `list` of `str` 

441 Hierarchy to use as a `list`. If the name is available directly 

442 as a key in the Config it will be used regardless of the presence 

443 of any nominal delimiter. 

444 """ 

445 if name in self._data: 

446 keys = [name, ] 

447 else: 

448 keys = self._splitIntoKeys(name) 

449 return keys 

450 

451 def _findInHierarchy(self, keys, create=False): 

452 """Look for hierarchy of keys in Config 

453 

454 Parameters 

455 ---------- 

456 keys : `list` or `tuple` 

457 Keys to search in hierarchy. 

458 create : `bool`, optional 

459 If `True`, if a part of the hierarchy does not exist, insert an 

460 empty `dict` into the hierarchy. 

461 

462 Returns 

463 ------- 

464 hierarchy : `list` 

465 List of the value corresponding to each key in the supplied 

466 hierarchy. Only keys that exist in the hierarchy will have 

467 a value. 

468 complete : `bool` 

469 `True` if the full hierarchy exists and the final element 

470 in ``hierarchy`` is the value of relevant value. 

471 """ 

472 d = self._data 

473 

474 def checkNextItem(k, d, create): 

475 """See if k is in d and if it is return the new child""" 

476 nextVal = None 

477 isThere = False 

478 if d is None: 

479 # We have gone past the end of the hierarchy 

480 pass 

481 elif isinstance(d, collections.abc.Sequence): 

482 # Check sequence first because for lists 

483 # __contains__ checks whether value is found in list 

484 # not whether the index exists in list. When we traverse 

485 # the hierarchy we are interested in the index. 

486 try: 

487 nextVal = d[int(k)] 

488 isThere = True 

489 except IndexError: 

490 pass 

491 except ValueError: 

492 isThere = k in d 

493 elif k in d: 

494 nextVal = d[k] 

495 isThere = True 

496 elif create: 

497 d[k] = {} 

498 nextVal = d[k] 

499 isThere = True 

500 return nextVal, isThere 

501 

502 hierarchy = [] 

503 complete = True 

504 for k in keys: 

505 d, isThere = checkNextItem(k, d, create) 

506 if isThere: 

507 hierarchy.append(d) 

508 else: 

509 complete = False 

510 break 

511 

512 return hierarchy, complete 

513 

514 def __getitem__(self, name): 

515 # Override the split for the simple case where there is an exact 

516 # match. This allows `Config.items()` to work via a simple 

517 # __iter__ implementation that returns top level keys of 

518 # self._data. 

519 keys = self._getKeyHierarchy(name) 

520 

521 hierarchy, complete = self._findInHierarchy(keys) 

522 if not complete: 

523 raise KeyError(f"{name} not found") 

524 data = hierarchy[-1] 

525 

526 if isinstance(data, collections.abc.Mapping): 

527 data = Config(data) 

528 # Ensure that child configs inherit the parent internal delimiter 

529 if self._D != Config._D: 

530 data._D = self._D 

531 return data 

532 

533 def __setitem__(self, name, value): 

534 keys = self._getKeyHierarchy(name) 

535 last = keys.pop() 

536 if isinstance(value, Config): 

537 value = copy.deepcopy(value._data) 

538 

539 hierarchy, complete = self._findInHierarchy(keys, create=True) 

540 if hierarchy: 

541 data = hierarchy[-1] 

542 else: 

543 data = self._data 

544 

545 try: 

546 data[last] = value 

547 except TypeError: 

548 data[int(last)] = value 

549 

550 def __contains__(self, key): 

551 keys = self._getKeyHierarchy(key) 

552 hierarchy, complete = self._findInHierarchy(keys) 

553 return complete 

554 

555 def __delitem__(self, key): 

556 keys = self._getKeyHierarchy(key) 

557 last = keys.pop() 

558 hierarchy, complete = self._findInHierarchy(keys) 

559 if complete: 

560 if hierarchy: 

561 data = hierarchy[-1] 

562 else: 

563 data = self._data 

564 del data[last] 

565 else: 

566 raise KeyError(f"{key} not found in Config") 

567 

568 def update(self, other): 

569 """Like dict.update, but will add or modify keys in nested dicts, 

570 instead of overwriting the nested dict entirely. 

571 

572 For example, for the given code: 

573 foo = {"a": {"b": 1}} 

574 foo.update({"a": {"c": 2}}) 

575 

576 Parameters 

577 ---------- 

578 other : `dict` or `Config` 

579 Source of configuration: 

580 

581 - If foo is a dict, then after the update foo == {"a": {"c": 2}} 

582 - But if foo is a Config, then after the update 

583 foo == {"a": {"b": 1, "c": 2}} 

584 """ 

585 def doUpdate(d, u): 

586 if not isinstance(u, collections.abc.Mapping) or \ 

587 not isinstance(d, collections.abc.Mapping): 

588 raise RuntimeError("Only call update with Mapping, not {}".format(type(d))) 

589 for k, v in u.items(): 

590 if isinstance(v, collections.abc.Mapping): 

591 d[k] = doUpdate(d.get(k, {}), v) 

592 else: 

593 d[k] = v 

594 return d 

595 doUpdate(self._data, other) 

596 

597 def merge(self, other): 

598 """Like Config.update, but will add keys & values from other that 

599 DO NOT EXIST in self. 

600 

601 Keys and values that already exist in self will NOT be overwritten. 

602 

603 Parameters 

604 ---------- 

605 other : `dict` or `Config` 

606 Source of configuration: 

607 """ 

608 otherCopy = copy.deepcopy(other) 

609 otherCopy.update(self) 

610 self._data = otherCopy._data 

611 

612 def nameTuples(self, topLevelOnly=False): 

613 """Get tuples representing the name hierarchies of all keys. 

614 

615 The tuples returned from this method are guaranteed to be usable 

616 to access items in the configuration object. 

617 

618 Parameters 

619 ---------- 

620 topLevelOnly : `bool`, optional 

621 If False, the default, a full hierarchy of names is returned. 

622 If True, only the top level are returned. 

623 

624 Returns 

625 ------- 

626 names : `list` of `tuple` of `str` 

627 List of all names present in the `Config` where each element 

628 in the list is a `tuple` of strings representing the hierarchy. 

629 """ 

630 if topLevelOnly: 

631 return list((k,) for k in self) 

632 

633 def getKeysAsTuples(d, keys, base): 

634 if isinstance(d, collections.abc.Sequence): 

635 theseKeys = range(len(d)) 

636 else: 

637 theseKeys = d.keys() 

638 for key in theseKeys: 

639 val = d[key] 

640 levelKey = base + (key,) if base is not None else (key,) 

641 keys.append(levelKey) 

642 if isinstance(val, (collections.abc.Mapping, collections.abc.Sequence)) \ 

643 and not isinstance(val, str): 

644 getKeysAsTuples(val, keys, levelKey) 

645 keys = [] 

646 getKeysAsTuples(self._data, keys, None) 

647 return keys 

648 

649 def names(self, topLevelOnly=False, delimiter=None): 

650 """Get a delimited name of all the keys in the hierarchy. 

651 

652 The values returned from this method are guaranteed to be usable 

653 to access items in the configuration object. 

654 

655 Parameters 

656 ---------- 

657 topLevelOnly : `bool`, optional 

658 If False, the default, a full hierarchy of names is returned. 

659 If True, only the top level are returned. 

660 delimiter : `str`, optional 

661 Delimiter to use when forming the keys. If the delimiter is 

662 present in any of the keys, it will be escaped in the returned 

663 names. If `None` given a delimiter will be automatically provided. 

664 The delimiter can not be alphanumeric. 

665 

666 Returns 

667 ------- 

668 names : `list` of `str` 

669 List of all names present in the `Config`. 

670 

671 Notes 

672 ----- 

673 This is different than the built-in method `dict.keys`, which will 

674 return only the first level keys. 

675 

676 Raises 

677 ------ 

678 ValueError: 

679 The supplied delimiter is alphanumeric. 

680 """ 

681 if topLevelOnly: 

682 return list(self.keys()) 

683 

684 # Get all the tuples of hierarchical keys 

685 nameTuples = self.nameTuples() 

686 

687 if delimiter is not None and delimiter.isalnum(): 

688 raise ValueError(f"Supplied delimiter ({delimiter!r}) must not be alphanumeric.") 

689 

690 if delimiter is None: 

691 # Start with something, and ensure it does not need to be 

692 # escaped (it is much easier to understand if not escaped) 

693 delimiter = self._D 

694 

695 # Form big string for easy check of delimiter clash 

696 combined = "".join("".join(str(s) for s in k) for k in nameTuples) 

697 

698 # Try a delimiter and keep trying until we get something that 

699 # works. 

700 ntries = 0 

701 while delimiter in combined: 

702 log.debug(f"Delimiter '{delimiter}' could not be used. Trying another.") 

703 ntries += 1 

704 

705 if ntries > 100: 

706 raise ValueError(f"Unable to determine a delimiter for Config {self}") 

707 

708 # try another one 

709 while True: 

710 delimiter = chr(ord(delimiter)+1) 

711 if not delimiter.isalnum(): 

712 break 

713 

714 log.debug(f"Using delimiter {delimiter!r}") 

715 

716 # Form the keys, escaping the delimiter if necessary 

717 strings = [delimiter + delimiter.join(str(s).replace(delimiter, f"\\{delimiter}") for s in k) 

718 for k in nameTuples] 

719 return strings 

720 

721 def asArray(self, name): 

722 """Get a value as an array. 

723 

724 May contain one or more elements. 

725 

726 Parameters 

727 ---------- 

728 name : `str` 

729 Key to use to retrieve value. 

730 

731 Returns 

732 ------- 

733 array : `collections.abc.Sequence` 

734 The value corresponding to name, but guaranteed to be returned 

735 as a list with at least one element. If the value is a 

736 `~collections.abc.Sequence` (and not a `str`) the value itself 

737 will be returned, else the value will be the first element. 

738 """ 

739 val = self.get(name) 

740 if isinstance(val, str): 

741 val = [val] 

742 elif not isinstance(val, collections.abc.Sequence): 

743 val = [val] 

744 return val 

745 

746 def __eq__(self, other): 

747 if isinstance(other, Config): 

748 other = other._data 

749 return self._data == other 

750 

751 def __ne__(self, other): 

752 if isinstance(other, Config): 

753 other = other._data 

754 return self._data != other 

755 

756 ####### 

757 # i/o # 

758 

759 def dump(self, output): 

760 """Writes the config to a yaml stream. 

761 

762 Parameters 

763 ---------- 

764 output 

765 The YAML stream to use for output. 

766 """ 

767 yaml.safe_dump(self._data, output, default_flow_style=False) 

768 

769 def dumpToUri(self, uri, updateFile=True, defaultFileName="butler.yaml", 

770 overwrite=True): 

771 """Writes the config to location pointed to by given URI. 

772 

773 Currently supports 's3' and 'file' URI schemes. 

774 

775 Parameters 

776 ---------- 

777 uri: `str` or `ButlerURI` 

778 URI of location where the Config will be written. 

779 updateFile : bool, optional 

780 If True and uri does not end on a filename with extension, will 

781 append `defaultFileName` to the target uri. True by default. 

782 defaultFileName : bool, optional 

783 The file name that will be appended to target uri if updateFile is 

784 True and uri does not end on a file with an extension. 

785 overwrite : bool, optional 

786 If True the configuration will be written even if it already 

787 exists at that location. 

788 """ 

789 if isinstance(uri, str): 

790 uri = ButlerURI(uri) 

791 

792 if not uri.scheme or uri.scheme == "file": 

793 if os.path.isdir(uri.path) and updateFile: 

794 uri = ButlerURI(os.path.join(uri.ospath, defaultFileName)) 

795 self.dumpToFile(uri.ospath, overwrite=overwrite) 

796 elif uri.scheme == "s3": 

797 if not uri.dirLike and "." not in uri.basename(): 

798 uri = ButlerURI(uri.geturl(), forceDirectory=True) 

799 uri.updateFile(defaultFileName) 

800 self.dumpToS3File(uri, overwrite=overwrite) 

801 else: 

802 raise ValueError(f"Unrecognized URI scheme: {uri.scheme}") 

803 

804 def dumpToFile(self, path, *, overwrite=True): 

805 """Writes the config to a file. 

806 

807 Parameters 

808 ---------- 

809 path : `str` 

810 Path to the file to use for output. 

811 overwrite : `bool`, optional 

812 If True any existing file will be over written. 

813 

814 Notes 

815 ----- 

816 The name of the config file is stored in the Config object. 

817 

818 Raises 

819 ------ 

820 FileExistsError 

821 Raised if the file already exists but overwrite is False. 

822 """ 

823 if overwrite: 

824 mode = "w" 

825 else: 

826 mode = "x" 

827 with open(path, mode) as f: 

828 self.dump(f) 

829 self.configFile = path 

830 

831 def dumpToS3File(self, uri, *, overwrite=True): 

832 """Writes the config to a file in S3 Bucket. 

833 

834 Parameters 

835 ---------- 

836 uri : `ButlerURI` 

837 S3 URI where the configuration should be stored. 

838 overwrite : `bool`, optional 

839 If False, a check will be made to see if the key already 

840 exists. 

841 

842 Raises 

843 ------ 

844 FileExistsError 

845 Raised if the configuration already exists at this location 

846 and overwrite is set to `False`. 

847 """ 

848 if boto3 is None: 

849 raise ModuleNotFoundError("Could not find boto3. " 

850 "Are you sure it is installed?") 

851 

852 if uri.scheme != "s3": 

853 raise ValueError(f"Must provide S3 URI not {uri}") 

854 

855 s3 = getS3Client() 

856 

857 if not overwrite: 

858 from .s3utils import s3CheckFileExists 

859 if s3CheckFileExists(uri, client=s3)[0]: 

860 raise FileExistsError(f"Config already exists at {uri}") 

861 

862 bucket = uri.netloc 

863 key = uri.relativeToPathRoot 

864 

865 with io.StringIO() as stream: 

866 self.dump(stream) 

867 stream.seek(0) 

868 s3.put_object(Bucket=bucket, Key=key, Body=stream.read()) 

869 

870 @staticmethod 

871 def updateParameters(configType, config, full, toUpdate=None, toCopy=None, overwrite=True): 

872 """Generic helper function for updating specific config parameters. 

873 

874 Allows for named parameters to be set to new values in bulk, and 

875 for other values to be set by copying from a reference config. 

876 

877 Assumes that the supplied config is compatible with ``configType`` 

878 and will attach the updated values to the supplied config by 

879 looking for the related component key. It is assumed that 

880 ``config`` and ``full`` are from the same part of the 

881 configuration hierarchy. 

882 

883 Parameters 

884 ---------- 

885 configType : `ConfigSubset` 

886 Config type to use to extract relevant items from ``config``. 

887 config : `Config` 

888 A `Config` to update. Only the subset understood by 

889 the supplied `ConfigSubset` will be modified. Default values 

890 will not be inserted and the content will not be validated 

891 since mandatory keys are allowed to be missing until 

892 populated later by merging. 

893 full : `Config` 

894 A complete config with all defaults expanded that can be 

895 converted to a ``configType``. Read-only and will not be 

896 modified by this method. Values are read from here if 

897 ``toCopy`` is defined. 

898 

899 Repository-specific options that should not be obtained 

900 from defaults when Butler instances are constructed 

901 should be copied from ``full`` to ``config``. 

902 toUpdate : `dict`, optional 

903 A `dict` defining the keys to update and the new value to use. 

904 The keys and values can be any supported by `Config` 

905 assignment. 

906 toCopy : `tuple`, optional 

907 `tuple` of keys whose values should be copied from ``full`` 

908 into ``config``. 

909 overwrite : `bool`, optional 

910 If `False`, do not modify a value in ``config`` if the key 

911 already exists. Default is always to overwrite. 

912 

913 Raises 

914 ------ 

915 ValueError 

916 Neither ``toUpdate`` not ``toCopy`` were defined. 

917 """ 

918 if toUpdate is None and toCopy is None: 

919 raise ValueError("One of toUpdate or toCopy parameters must be set.") 

920 

921 # If this is a parent configuration then we need to ensure that 

922 # the supplied config has the relevant component key in it. 

923 # If this is a parent configuration we add in the stub entry 

924 # so that the ConfigSubset constructor will do the right thing. 

925 # We check full for this since that is guaranteed to be complete. 

926 if configType.component in full and configType.component not in config: 

927 config[configType.component] = {} 

928 

929 # Extract the part of the config we wish to update 

930 localConfig = configType(config, mergeDefaults=False, validate=False) 

931 

932 if toUpdate: 

933 for key, value in toUpdate.items(): 

934 if key in localConfig and not overwrite: 

935 log.debug("Not overriding key '%s' with value '%s' in config %s", 

936 key, value, localConfig.__class__.__name__) 

937 else: 

938 localConfig[key] = value 

939 

940 if toCopy: 

941 localFullConfig = configType(full, mergeDefaults=False) 

942 for key in toCopy: 

943 if key in localConfig and not overwrite: 

944 log.debug("Not overriding key '%s' from defaults in config %s", 

945 key, localConfig.__class__.__name__) 

946 else: 

947 localConfig[key] = localFullConfig[key] 

948 

949 # Reattach to parent if this is a child config 

950 if configType.component in config: 

951 config[configType.component] = localConfig 

952 else: 

953 config.update(localConfig) 

954 

955 

956class ConfigSubset(Config): 

957 """Config representing a subset of a more general configuration. 

958 

959 Subclasses define their own component and when given a configuration 

960 that includes that component, the resulting configuration only includes 

961 the subset. For example, your config might contain ``dimensions`` if it's 

962 part of a global config and that subset will be stored. If ``dimensions`` 

963 can not be found it is assumed that the entire contents of the 

964 configuration should be used. 

965 

966 Default values are read from the environment or supplied search paths 

967 using the default configuration file name specified in the subclass. 

968 This allows a configuration class to be instantiated without any 

969 additional arguments. 

970 

971 Additional validation can be specified to check for keys that are mandatory 

972 in the configuration. 

973 

974 Parameters 

975 ---------- 

976 other : `Config` or `str` or `dict` 

977 Argument specifying the configuration information as understood 

978 by `Config` 

979 validate : `bool`, optional 

980 If `True` required keys will be checked to ensure configuration 

981 consistency. 

982 mergeDefaults : `bool`, optional 

983 If `True` defaults will be read and the supplied config will 

984 be combined with the defaults, with the supplied valiues taking 

985 precedence. 

986 searchPaths : `list` or `tuple`, optional 

987 Explicit additional paths to search for defaults. They should 

988 be supplied in priority order. These paths have higher priority 

989 than those read from the environment in 

990 `ConfigSubset.defaultSearchPaths()`. 

991 """ 

992 

993 component: ClassVar[Optional[str]] = None 

994 """Component to use from supplied config. Can be None. If specified the 

995 key is not required. Can be a full dot-separated path to a component. 

996 """ 

997 

998 requiredKeys: ClassVar[Sequence[str]] = () 

999 """Keys that are required to be specified in the configuration. 

1000 """ 

1001 

1002 defaultConfigFile: ClassVar[Optional[str]] = None 

1003 """Name of the file containing defaults for this config class. 

1004 """ 

1005 

1006 def __init__(self, other=None, validate=True, mergeDefaults=True, searchPaths=None): 

1007 

1008 # Create a blank object to receive the defaults 

1009 # Once we have the defaults we then update with the external values 

1010 super().__init__() 

1011 

1012 # Create a standard Config rather than subset 

1013 externalConfig = Config(other) 

1014 

1015 # Select the part we need from it 

1016 # To simplify the use of !include we also check for the existence of 

1017 # component.component (since the included files can themselves 

1018 # include the component name) 

1019 if self.component is not None: 

1020 doubled = (self.component, self.component) 

1021 # Must check for double depth first 

1022 if doubled in externalConfig: 

1023 externalConfig = externalConfig[doubled] 

1024 elif self.component in externalConfig: 

1025 externalConfig._data = externalConfig._data[self.component] 

1026 

1027 # Default files read to create this configuration 

1028 self.filesRead = [] 

1029 

1030 # Assume we are not looking up child configurations 

1031 containerKey = None 

1032 

1033 # Sometimes we do not want to merge with defaults. 

1034 if mergeDefaults: 

1035 

1036 # Supplied search paths have highest priority 

1037 fullSearchPath = [] 

1038 if searchPaths: 

1039 fullSearchPath.extend(searchPaths) 

1040 

1041 # Read default paths from enviroment 

1042 fullSearchPath.extend(self.defaultSearchPaths()) 

1043 

1044 # There are two places to find defaults for this particular config 

1045 # - The "defaultConfigFile" defined in the subclass 

1046 # - The class specified in the "cls" element in the config. 

1047 # Read cls after merging in case it changes. 

1048 if self.defaultConfigFile is not None: 

1049 self._updateWithConfigsFromPath(fullSearchPath, self.defaultConfigFile) 

1050 

1051 # Can have a class specification in the external config (priority) 

1052 # or from the defaults. 

1053 pytype = None 

1054 if "cls" in externalConfig: 

1055 pytype = externalConfig["cls"] 

1056 elif "cls" in self: 

1057 pytype = self["cls"] 

1058 

1059 if pytype is not None: 

1060 try: 

1061 cls = doImport(pytype) 

1062 except ImportError as e: 

1063 raise RuntimeError(f"Failed to import cls '{pytype}' for config {type(self)}") from e 

1064 defaultsFile = cls.defaultConfigFile 

1065 if defaultsFile is not None: 

1066 self._updateWithConfigsFromPath(fullSearchPath, defaultsFile) 

1067 

1068 # Get the container key in case we need it 

1069 try: 

1070 containerKey = cls.containerKey 

1071 except AttributeError: 

1072 pass 

1073 

1074 # Now update this object with the external values so that the external 

1075 # values always override the defaults 

1076 self.update(externalConfig) 

1077 

1078 # If this configuration has child configurations of the same 

1079 # config class, we need to expand those defaults as well. 

1080 

1081 if mergeDefaults and containerKey is not None and containerKey in self: 

1082 for idx, subConfig in enumerate(self[containerKey]): 

1083 self[containerKey, idx] = type(self)(other=subConfig, validate=validate, 

1084 mergeDefaults=mergeDefaults, 

1085 searchPaths=searchPaths) 

1086 

1087 if validate: 

1088 self.validate() 

1089 

1090 @classmethod 

1091 def defaultSearchPaths(cls): 

1092 """Read the environment to determine search paths to use for global 

1093 defaults. 

1094 

1095 Global defaults, at lowest priority, are found in the ``config`` 

1096 directory of the butler source tree. Additional defaults can be 

1097 defined using the environment variable ``$DAF_BUTLER_CONFIG_PATHS`` 

1098 which is a PATH-like variable where paths at the front of the list 

1099 have priority over those later. 

1100 

1101 Returns 

1102 ------- 

1103 paths : `list` 

1104 Returns a list of paths to search. The returned order is in 

1105 priority with the highest priority paths first. The butler config 

1106 directory will always be at the end of the list. 

1107 """ 

1108 # We can pick up defaults from multiple search paths 

1109 # We fill defaults by using the butler config path and then 

1110 # the config path environment variable in reverse order. 

1111 defaultsPaths = [] 

1112 

1113 if CONFIG_PATH in os.environ: 

1114 externalPaths = os.environ[CONFIG_PATH].split(os.pathsep) 

1115 defaultsPaths.extend(externalPaths) 

1116 

1117 # Find the butler configs 

1118 defaultsPaths.append(os.path.join(lsst.utils.getPackageDir("daf_butler"), "config")) 

1119 

1120 return defaultsPaths 

1121 

1122 def _updateWithConfigsFromPath(self, searchPaths, configFile): 

1123 """Search the supplied paths, merging the configuration values 

1124 

1125 The values read will override values currently stored in the object. 

1126 Every file found in the path will be read, such that the earlier 

1127 path entries have higher priority. 

1128 

1129 Parameters 

1130 ---------- 

1131 searchPaths : `list` 

1132 Paths to search for the supplied configFile. This path 

1133 is the priority order, such that files read from the 

1134 first path entry will be selected over those read from 

1135 a later path. 

1136 configFile : `str` 

1137 File to locate in path. If absolute path it will be read 

1138 directly and the search path will not be used. 

1139 """ 

1140 if os.path.isabs(configFile): 

1141 if os.path.exists(configFile): 

1142 self.filesRead.append(configFile) 

1143 self._updateWithOtherConfigFile(configFile) 

1144 else: 

1145 # Reverse order so that high priority entries 

1146 # update the object last. 

1147 for pathDir in reversed(searchPaths): 

1148 file = os.path.join(pathDir, configFile) 

1149 if os.path.exists(file): 

1150 self.filesRead.append(file) 

1151 self._updateWithOtherConfigFile(file) 

1152 

1153 def _updateWithOtherConfigFile(self, file): 

1154 """Read in some defaults and update. 

1155 

1156 Update the configuration by reading the supplied file as a config 

1157 of this class, and merging such that these values override the 

1158 current values. Contents of the external config are not validated. 

1159 

1160 Parameters 

1161 ---------- 

1162 file : `Config`, `str`, or `dict` 

1163 Entity that can be converted to a `ConfigSubset`. 

1164 """ 

1165 # Use this class to read the defaults so that subsetting can happen 

1166 # correctly. 

1167 externalConfig = type(self)(file, validate=False, mergeDefaults=False) 

1168 self.update(externalConfig) 

1169 

1170 def validate(self): 

1171 """Check that mandatory keys are present in this configuration. 

1172 

1173 Ignored if ``requiredKeys`` is empty.""" 

1174 # Validation 

1175 missing = [k for k in self.requiredKeys if k not in self._data] 

1176 if missing: 

1177 raise KeyError(f"Mandatory keys ({missing}) missing from supplied configuration for {type(self)}")