LSST Applications  21.0.0+04719a4bac,21.0.0-1-ga51b5d4+f5e6047307,21.0.0-11-g2b59f77+a9c1acf22d,21.0.0-11-ga42c5b2+86977b0b17,21.0.0-12-gf4ce030+76814010d2,21.0.0-13-g1721dae+760e7a6536,21.0.0-13-g3a573fe+768d78a30a,21.0.0-15-g5a7caf0+f21cbc5713,21.0.0-16-g0fb55c1+b60e2d390c,21.0.0-19-g4cded4ca+71a93a33c0,21.0.0-2-g103fe59+bb20972958,21.0.0-2-g45278ab+04719a4bac,21.0.0-2-g5242d73+3ad5d60fb1,21.0.0-2-g7f82c8f+8babb168e8,21.0.0-2-g8f08a60+06509c8b61,21.0.0-2-g8faa9b5+616205b9df,21.0.0-2-ga326454+8babb168e8,21.0.0-2-gde069b7+5e4aea9c2f,21.0.0-2-gecfae73+1d3a86e577,21.0.0-2-gfc62afb+3ad5d60fb1,21.0.0-25-g1d57be3cd+e73869a214,21.0.0-3-g357aad2+ed88757d29,21.0.0-3-g4a4ce7f+3ad5d60fb1,21.0.0-3-g4be5c26+3ad5d60fb1,21.0.0-3-g65f322c+e0b24896a3,21.0.0-3-g7d9da8d+616205b9df,21.0.0-3-ge02ed75+a9c1acf22d,21.0.0-4-g591bb35+a9c1acf22d,21.0.0-4-g65b4814+b60e2d390c,21.0.0-4-gccdca77+0de219a2bc,21.0.0-4-ge8a399c+6c55c39e83,21.0.0-5-gd00fb1e+05fce91b99,21.0.0-6-gc675373+3ad5d60fb1,21.0.0-64-g1122c245+4fb2b8f86e,21.0.0-7-g04766d7+cd19d05db2,21.0.0-7-gdf92d54+04719a4bac,21.0.0-8-g5674e7b+d1bd76f71f,master-gac4afde19b+a9c1acf22d,w.2021.13
LSST Data Management Base Package
storage.py
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1 #!/usr/bin/env python
2 
3 #
4 # LSST Data Management System
5 # Copyright 2016 LSST Corporation.
6 #
7 # This product includes software developed by the
8 # LSST Project (http://www.lsst.org/).
9 #
10 # This program is free software: you can redistribute it and/or modify
11 # it under the terms of the GNU General Public License as published by
12 # the Free Software Foundation, either version 3 of the License, or
13 # (at your option) any later version.
14 #
15 # This program is distributed in the hope that it will be useful,
16 # but WITHOUT ANY WARRANTY; without even the implied warranty of
17 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 # GNU General Public License for more details.
19 #
20 # You should have received a copy of the LSST License Statement and
21 # the GNU General Public License along with this program. If not,
22 # see <http://www.lsstcorp.org/LegalNotices/>.
23 #
24 
25 import urllib.parse
26 from . import NoRepositroyAtRoot
27 
28 
29 class Storage:
30  """Base class for storages"""
31 
32  storages = {}
33 
34  def __init__(self):
35  self.repositoryCfgsrepositoryCfgs = {}
36 
37  @staticmethod
38  def registerStorageClass(scheme, cls):
39  """Register derived classes for lookup by URI scheme.
40 
41  A scheme is a name that describes the form a resource at the beginning of a URI
42  e.g. 'http' indicates HTML and related code, such as is found in http://www.lsst.org
43 
44  The only currently supported schemes are:
45  * 'file' where the portion of the URI after the // indicates an absolute locaiton on disk.
46  for example: file:/my_repository_folder/
47  * '' (no scheme) where the entire string is a relative path on the local system
48  for example "my_repository_folder" will indicate a folder in the current working directory with the
49  same name.
50 
51  See documentation for the urlparse python library for more information.
52 
53  .. warning::
54 
55  Storage is 'wet paint' and very likely to change during factorization of Butler back end and
56  storage formats (DM-6225). Use of it in production code other than via the 'old butler' API is
57  strongly discouraged.
58 
59  Parameters
60  ----------
61  scheme : str
62  Name of the `scheme` the class is being registered for, which appears at the beginning of a URI.
63  cls : class object
64  A class object that should be used for a given scheme.
65  """
66  if scheme in Storage.storages:
67  raise RuntimeError("Scheme '%s' already registered:%s" % (scheme, Storage.storages[scheme]))
68  Storage.storages[scheme] = cls
69 
70  def getRepositoryCfg(self, uri):
71  """Get a RepositoryCfg from a location specified by uri.
72 
73  If a cfg is found then it is cached by the uri, so that multiple lookups
74  are not performed on storages that might be remote.
75 
76  RepositoryCfgs are not supposed to change once they are created so this
77  should not lead to stale data.
78  """
79  cfg = self.repositoryCfgsrepositoryCfgs.get(uri, None)
80  if cfg:
81  return cfg
82  parseRes = urllib.parse.urlparse(uri)
83  if parseRes.scheme in Storage.storages:
84  cfg = Storage.storages[parseRes.scheme].getRepositoryCfg(uri)
85  if cfg:
86  self.repositoryCfgsrepositoryCfgs[uri] = cfg
87  else:
88  raise RuntimeError("No storage registered for scheme %s" % parseRes.scheme)
89  return cfg
90 
91  @staticmethod
92  def putRepositoryCfg(cfg, uri):
93  """Write a RepositoryCfg object to a location described by uri"""
94  ret = None
95  parseRes = urllib.parse.urlparse(uri)
96  if parseRes.scheme in Storage.storages:
97  ret = Storage.storages[parseRes.scheme].putRepositoryCfg(cfg, uri)
98  else:
99  raise RuntimeError("No storage registered for scheme %s" % parseRes.scheme)
100  return ret
101 
102  @staticmethod
103  def getMapperClass(uri):
104  """Get a mapper class cfg value from location described by uri.
105 
106  Note that in legacy repositories the mapper may be specified by a file called _mapper at the uri
107  location, and in newer repositories the mapper would be specified by a RepositoryCfg stored at the uri
108  location.
109 
110  .. warning::
111 
112  Storage is 'wet paint' and very likely to change during factorization of Butler back end and
113  storage formats (DM-6225). Use of it in production code other than via the 'old butler' API is
114  strongly discouraged.
115 
116  """
117  ret = None
118  parseRes = urllib.parse.urlparse(uri)
119  if parseRes.scheme in Storage.storages:
120  ret = Storage.storages[parseRes.scheme].getMapperClass(uri)
121  else:
122  raise RuntimeError("No storage registered for scheme %s" % parseRes.scheme)
123  return ret
124 
125  @staticmethod
126  def makeFromURI(uri, create=True):
127  '''Instantiate a StorageInterface sublcass from a URI.
128 
129  .. warning::
130 
131  Storage is 'wet paint' and very likely to change during factorization of Butler back end and
132  storage formats (DM-6225). Use of it in production code other than via the 'old butler' API is
133  strongly discouraged.
134 
135  Parameters
136  ----------
137  uri : string
138  The uri to the root location of a repository.
139  create : bool, optional
140  If True The StorageInterface subclass should create a new
141  repository at the root location. If False then a new repository
142  will not be created.
143 
144  Returns
145  -------
146  A Storage subclass instance, or if create is False and a repository
147  does not exist at the root location then returns None.
148 
149  Raises
150  ------
151  RuntimeError
152  When a StorageInterface subclass does not exist for the scheme
153  indicated by the uri.
154  '''
155  ret = None
156  parseRes = urllib.parse.urlparse(uri)
157  if parseRes.scheme in Storage.storages:
158  theClass = Storage.storages[parseRes.scheme]
159  try:
160  ret = theClass(uri=uri, create=create)
161  except NoRepositroyAtRoot:
162  pass
163  else:
164  raise RuntimeError("No storage registered for scheme %s" % parseRes.scheme)
165  return ret
166 
167  @staticmethod
168  def isPosix(uri):
169  """Test if a URI is for a local filesystem storage.
170 
171  This is mostly for backward compatibility; Butler V1 repositories were only ever on the local
172  filesystem. They may exist but not have a RepositoryCfg class. This enables conditional checking for a
173  V1 Repository.
174 
175  This function treats 'file' and '' (no scheme) as posix storages, see
176  the class docstring for more details.
177 
178  Parameters
179  ----------
180  uri : string
181  URI to the root of a Repository.
182 
183  Returns
184  -------
185  Bool
186  True if the URI is associated with a posix storage, else false.
187  """
188  parseRes = urllib.parse.urlparse(uri)
189  if parseRes.scheme in ('file', ''):
190  return True
191  return False
192 
193  @staticmethod
194  def relativePath(fromUri, toUri):
195  """Get a relative path from a location to a location, if a relative path for these 2 locations exists.
196 
197  Parameters
198  ----------
199  fromPath : string
200  A URI that describes a location at which to start.
201  toPath : string
202  A URI that describes a target location.
203 
204  Returns
205  -------
206  string
207  A relative path that describes the path from fromUri to toUri, provided one exists. If a relative
208  path between the two URIs does not exist then the entire toUri path is returned.
209  """
210  fromUriParseRes = urllib.parse.urlparse(fromUri)
211  toUriParseRes = urllib.parse.urlparse(toUri)
212  if fromUriParseRes.scheme != toUriParseRes.scheme:
213  return toUri
214  storage = Storage.storages.get(fromUriParseRes.scheme, None)
215  if not storage:
216  return toUri
217  return storage.relativePath(fromUri, toUri)
218 
219  @staticmethod
220  def absolutePath(fromUri, toUri):
221  """Get an absolute path for the path from fromUri to toUri
222 
223  Parameters
224  ----------
225  fromUri : the starting location
226  Description
227  toUri : the location relative to fromUri
228  Description
229 
230  Returns
231  -------
232  string
233  URI that is absolutepath fromUri + toUri, if one exists. If toUri is absolute or if fromUri is not
234  related to toUri (e.g. are of different storage types) then toUri will be returned.
235  """
236  fromUriParseRes = urllib.parse.urlparse(fromUri)
237  toUriParseRes = urllib.parse.urlparse(toUri)
238  if fromUriParseRes.scheme != toUriParseRes.scheme:
239  return toUri
240  storage = Storage.storages.get(fromUriParseRes.scheme, None)
241  if not storage:
242  return toUri
243  return storage.absolutePath(fromUri, toUri)
244 
245  @staticmethod
246  def search(uri, path):
247  """Look for the given path in a storage root at URI; return None if it can't be found.
248 
249  If the path contains an HDU indicator (a number in brackets before the
250  dot, e.g. 'foo.fits[1]', this will be stripped when searching and so
251  will match filenames without the HDU indicator, e.g. 'foo.fits'. The
252  path returned WILL contain the indicator though, e.g. ['foo.fits[1]'].
253 
254 
255  Parameters
256  ----------
257  root : string
258  URI to the the root location to search
259  path : string
260  A filename (and optionally prefix path) to search for within root.
261 
262  Returns
263  -------
264  string or None
265  The location that was found, or None if no location was found.
266  """
267  parseRes = urllib.parse.urlparse(uri)
268  storage = Storage.storages.get(parseRes.scheme, None)
269  if storage:
270  return storage.search(uri, path)
271  return None
272 
273  @staticmethod
274  def storageExists(uri):
275  """Ask if a storage at the location described by uri exists
276 
277  Parameters
278  ----------
279  root : string
280  URI to the the root location of the storage
281 
282  Returns
283  -------
284  bool
285  True if the storage exists, false if not
286  """
287  parseRes = urllib.parse.urlparse(uri)
288  storage = Storage.storages.get(parseRes.scheme, None)
289  if storage:
290  return storage.storageExists(uri)
291  return None
def relativePath(fromUri, toUri)
Definition: storage.py:194
def registerStorageClass(scheme, cls)
Definition: storage.py:38
def absolutePath(fromUri, toUri)
Definition: storage.py:220
def makeFromURI(uri, create=True)
Definition: storage.py:126