Coverage for python/lsst/obs/base/gen2to3/repoWalker/scanner.py : 39%

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1# This file is part of obs_base.
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"""Interfaces and common code for recursively scanning directories for Gen2
22dataset files.
24The `PathElementHandler` ABC is defined here instead of ``handlers.py`` for
25dependency reasons: `DirectoryScanner` uses the ABC, while its concrete
26implementations use `DirectorySCanner`.
27"""
28from __future__ import annotations
30__all__ = ["PathElementHandler", "DirectoryScanner"]
32from abc import ABC, abstractmethod
33import bisect
34import os
35from typing import (
36 Callable,
37 Iterator,
38 List,
39 Mapping,
40 Optional,
41 Tuple,
42)
44from lsst.log import Log
45from lsst.daf.butler import (
46 DataCoordinate,
47 DatasetType,
48 FileDataset,
49)
52class PathElementHandler(ABC):
53 """An interface for objects that handle a single path element (directory or
54 file) in a Gen2 data repository.
56 Handlers are added to a `DirectoryScanner` instance, which then calls them
57 until one succeeds when it processes each element in a directory.
58 """
59 def __init__(self):
60 self.lastDataId2 = {}
62 __slots__ = ("lastDataId2", "log")
64 @abstractmethod
65 def isForFiles(self) -> bool:
66 """Report what kind of path element this object handlers.
68 Returns
69 -------
70 Return `True` if this handler is for file entries, or `False` if it
71 is for directories.
72 """
73 raise NotImplementedError()
75 @abstractmethod
76 def __call__(self, path: str, name: str,
77 datasets: Mapping[DatasetType, Mapping[Optional[str], List[FileDataset]]], *,
78 predicate: Callable[[DataCoordinate], bool]) -> bool:
79 """Apply the handler to a file path.
81 Parameters
82 ----------
83 path : `str`
84 Full path of the file or directory.
85 name : `str`
86 Local name of the file or directory within its parent directory.
87 datasets : `dict` [`DatasetType`, `dict` ]
88 Dictionary that found datasets should be added to. Nested dicts
89 are keyed by either `None` (for most datasets) or a `str`
90 "CALIBDATE" for calibration datasets.
91 predicate : `~collections.abc.Callable`
92 A callable taking a single `DataCoordinate` argument and returning
93 `bool`, indicating whether that (Gen3) data ID represents one
94 that should be included in the scan.'
96 Returns
97 -------
98 matched : `bool`
99 `True` if this handler was a match for the given path and no other
100 handlers need to be tried on it, `False` otherwise.
101 """
102 raise NotImplementedError()
104 @property
105 @abstractmethod
106 def rank(self) -> int:
107 """Return a rough indication of how flexible this handler is in terms
108 of the path element names it can match.
110 Handlers that match a constant path element should always return zero.
111 """
112 raise NotImplementedError()
114 def translate(self, dataId2: dict, *, partial: bool = False
115 ) -> Tuple[Optional[DataCoordinate], Optional[str]]:
116 """Translate the given data ID from Gen2 to Gen3.
118 The default implementation returns `None`. Subclasses that are able
119 to translate data IDs should override this method.
121 Parameters
122 ----------
123 dataId2 : `dict`
124 Gen2 data ID.
125 partial : `bool`, optional
126 If `True` (`False` is default) this is a partial data ID for some
127 dataset, and missing keys are expected.
129 Returns
130 -------
131 dataId3 : `lsst.daf.butler.DataCoordinate` or `None`
132 A Gen3 data ID, or `None` if this handler cannot translate data
133 IDs.
134 calibDate : `str` or `None`
135 A Gen2 calibration "CALIBDATE" value, or `None` if there was no
136 such value in the template.
137 """
138 return None, None
140 def __lt__(self, other: PathElementHandler):
141 """Handlers are sorted by rank to reduce the possibility that more
142 flexible handlers will have a chance to match something they shouldn't.
143 """
144 return self.rank < other.rank
146 lastDataId2: dict
147 """The Gen2 data ID obtained by processing parent levels in the directory
148 tree.
150 This attribute should be reset by calling code whenever a new parent
151 directory is entered, before invoking `__call__`.
152 """
154 log: Log
155 """A logger to use for all diagnostic messages (`lsst.log.Log`).
157 This attribute is set on a handler in `DirectoryScanner.add`; this avoids
158 needing to forward one through all subclass constructors.
159 """
162class DirectoryScanner:
163 """An object that uses `PathElementHandler` instances to process the files
164 and subdirectories in a directory tree.
166 Parameters
167 ----------
168 log : `Log`, optional
169 Log to use to report warnings and debug information.
170 """
171 def __init__(self, log: Optional[Log] = None):
172 self._files = []
173 self._subdirectories = []
174 if log is None:
175 log = Log.getLogger("obs.base.gen2to3.walker")
176 self.log = log
178 __slots__ = ("_files", "_subdirectories", "log")
180 def add(self, handler: PathElementHandler):
181 """Add a new handler to the scanner.
183 Parameters
184 ----------
185 handler : `PathElementHandler`
186 The handler to be added.
187 """
188 handler.log = self.log
189 if handler.isForFiles():
190 bisect.insort(self._files, handler)
191 else:
192 bisect.insort(self._subdirectories, handler)
194 def __iter__(self) -> Iterator[PathElementHandler]:
195 """Iterate over all handlers.
196 """
197 yield from self._files
198 yield from self._subdirectories
200 def scan(self, path: str, datasets: Mapping[DatasetType, Mapping[Optional[str], List[FileDataset]]], *,
201 predicate: Callable[[DataCoordinate], bool]):
202 """Process a directory.
204 Parameters
205 ----------
206 path : `str`
207 Full path to the directory to be processed.
208 datasets : `dict` [`DatasetType`, `list` ]
209 Dictionary that found datasets should be added to. Nested lists
210 elements are tuples of `FileDataset` and an optional "CALIBDATE"
211 `str` value (for calibration datasets only).
212 predicate : `~collections.abc.Callable`
213 A callable taking a single `DataCoordinate` argument and returning
214 `bool`, indicating whether that (Gen3) data ID represents one
215 that should be included in the scan.
216 """
217 unrecognized = []
218 for entry in os.scandir(path):
219 if entry.is_file():
220 handlers = self._files
221 elif entry.is_dir():
222 handlers = self._subdirectories
223 else:
224 continue
225 for handler in handlers:
226 if handler(entry.path, entry.name, datasets, predicate=predicate):
227 break
228 else:
229 unrecognized.append(entry.name)
230 if unrecognized:
231 self.log.warn("Skipped unrecognized entries in %s: %s", path, unrecognized)