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1 # -*- coding: iso-8859-1 -*-
2 # vim: set ft=python ts=3 sw=3 expandtab:
3 # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
4 #
5 # C E D A R
6 # S O L U T I O N S "Software done right."
7 # S O F T W A R E
8 #
9 # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
10 #
11 # Copyright (c) 2007 Kenneth J. Pronovici.
12 # All rights reserved.
13 #
14 # This program is free software; you can redistribute it and/or
15 # modify it under the terms of the GNU General Public License,
16 # Version 2, as published by the Free Software Foundation.
17 #
18 # This program is distributed in the hope that it will be useful,
19 # but WITHOUT ANY WARRANTY; without even the implied warranty of
20 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
21 #
22 # Copies of the GNU General Public License are available from
23 # the Free Software Foundation website, http://www.gnu.org/.
24 #
25 # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
26 #
27 # Author : Kenneth J. Pronovici <pronovic@ieee.org>
28 # Language : Python (>= 2.3)
29 # Project : Cedar Backup, release 2
30 # Revision : $Id: util.py 747 2007-03-25 19:42:43Z pronovic $
31 # Purpose : Implements action-related utilities
32 #
33 # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
34
35 ########################################################################
36 # Module documentation
37 ########################################################################
38
39 """
40 Implements action-related utilities
41 @sort: findDailyDirs
42 @author: Kenneth J. Pronovici <pronovic@ieee.org>
43 """
44
45
46 ########################################################################
47 # Imported modules
48 ########################################################################
49
50 # System modules
51 import os
52 import time
53 import tempfile
54 import logging
55
56 # Cedar Backup modules
57 from CedarBackup2.filesystem import FilesystemList
58 from CedarBackup2.util import changeOwnership
59 from CedarBackup2.util import deviceMounted
60 from CedarBackup2.writers.util import readMediaLabel
61 from CedarBackup2.writers.cdwriter import CdWriter
62 from CedarBackup2.writers.dvdwriter import DvdWriter
63 from CedarBackup2.writers.cdwriter import MEDIA_CDR_74, MEDIA_CDR_80, MEDIA_CDRW_74, MEDIA_CDRW_80
64 from CedarBackup2.writers.dvdwriter import MEDIA_DVDPLUSR, MEDIA_DVDPLUSRW
65 from CedarBackup2.config import DEFAULT_MEDIA_TYPE, DEFAULT_DEVICE_TYPE, REWRITABLE_MEDIA_TYPES
66 from CedarBackup2.actions.constants import INDICATOR_PATTERN
67
68
69 ########################################################################
70 # Module-wide constants and variables
71 ########################################################################
72
73 logger = logging.getLogger("CedarBackup2.log.actions.util")
74 MEDIA_LABEL_PREFIX = "CEDAR BACKUP"
75
76
77 ########################################################################
78 # Public utility functions
79 ########################################################################
80
81 ###########################
82 # findDailyDirs() function
83 ###########################
84
86 """
87 Returns a list of all daily staging directories that do not contain
88 the indicated indicator file.
89
90 @param stagingDir: Configured staging directory (config.targetDir)
91
92 @return: List of absolute paths to daily staging directories.
93 """
94 results = FilesystemList()
95 yearDirs = FilesystemList()
96 yearDirs.excludeFiles = True
97 yearDirs.excludeLinks = True
98 yearDirs.addDirContents(path=stagingDir, recursive=False, addSelf=False)
99 for yearDir in yearDirs:
100 monthDirs = FilesystemList()
101 monthDirs.excludeFiles = True
102 monthDirs.excludeLinks = True
103 monthDirs.addDirContents(path=yearDir, recursive=False, addSelf=False)
104 for monthDir in monthDirs:
105 dailyDirs = FilesystemList()
106 dailyDirs.excludeFiles = True
107 dailyDirs.excludeLinks = True
108 dailyDirs.addDirContents(path=monthDir, recursive=False, addSelf=False)
109 for dailyDir in dailyDirs:
110 if os.path.exists(os.path.join(dailyDir, indicatorFile)):
111 logger.debug("Skipping directory [%s]; contains %s." % (dailyDir, indicatorFile))
112 else:
113 logger.debug("Adding [%s] to list of daily directories." % dailyDir)
114 results.append(dailyDir) # just put it in the list, no fancy operations
115 return results
116
117
118 ###########################
119 # createWriter() function
120 ###########################
121
123 """
124 Creates a writer object based on current configuration.
125
126 This function creates and returns a writer based on configuration. This is
127 done to abstract action functionality from knowing what kind of writer is in
128 use. Since all writers implement the same interface, there's no need for
129 actions to care which one they're working with.
130
131 Currently, the C{cdwriter} and C{dvdwriter} device types are allowed. An
132 exception will be raised if any other device type is used.
133
134 This function also checks to make sure that the device isn't mounted before
135 creating a writer object for it. Experience shows that sometimes if the
136 device is mounted, we have problems with the backup. We may as well do the
137 check here first, before instantiating the writer.
138
139 @param config: Config object.
140
141 @return: Writer that can be used to write a directory to some media.
142
143 @raise ValueError: If there is a problem getting the writer.
144 @raise IOError: If there is a problem creating the writer object.
145 """
146 devicePath = config.store.devicePath
147 deviceScsiId = config.store.deviceScsiId
148 driveSpeed = config.store.driveSpeed
149 noEject = config.store.noEject
150 deviceType = _getDeviceType(config)
151 mediaType = _getMediaType(config)
152 if deviceMounted(devicePath):
153 raise IOError("Device [%s] is currently mounted." % (devicePath))
154 if deviceType == "cdwriter":
155 return CdWriter(devicePath, deviceScsiId, driveSpeed, mediaType, noEject)
156 elif deviceType == "dvdwriter":
157 return DvdWriter(devicePath, deviceScsiId, driveSpeed, mediaType, noEject)
158 else:
159 raise ValueError("Device type [%s] is invalid." % deviceType)
160
161
162 ################################
163 # writeIndicatorFile() function
164 ################################
165
167 """
168 Writes an indicator file into a target directory.
169 @param targetDir: Target directory in which to write indicator
170 @param indicatorFile: Name of the indicator file
171 @param backupUser: User that indicator file should be owned by
172 @param backupGroup: Group that indicator file should be owned by
173 @raise IOException: If there is a problem writing the indicator file
174 """
175 filename = os.path.join(targetDir, indicatorFile)
176 logger.debug("Writing indicator file [%s]." % filename)
177 try:
178 open(filename, "w").write("")
179 changeOwnership(filename, backupUser, backupGroup)
180 except Exception, e:
181 logger.error("Error writing [%s]: %s" % (filename, e))
182 raise e
183
184
185 ############################
186 # getBackupFiles() function
187 ############################
188
190 """
191 Gets a list of backup files in a target directory.
192
193 Files that match INDICATOR_PATTERN (i.e. C{"cback.store"}, C{"cback.stage"},
194 etc.) are assumed to be indicator files and are ignored.
195
196 @param targetDir: Directory to look in
197
198 @return: List of backup files in the directory
199
200 @raise ValueError: If the target directory does not exist
201 """
202 if not os.path.isdir(targetDir):
203 raise ValueError("Target directory [%s] is not a directory or does not exist." % targetDir)
204 fileList = FilesystemList()
205 fileList.excludeDirs = True
206 fileList.excludeLinks = True
207 fileList.excludeBasenamePatterns = INDICATOR_PATTERN
208 fileList.addDirContents(targetDir)
209 return fileList
210
211
212 ####################
213 # checkMediaState()
214 ####################
215
217 """
218 Checks state of the media in the backup device to confirm whether it has
219 been initialized for use with Cedar Backup.
220
221 We can tell whether the media has been initialized by looking at its media
222 label. If the media label starts with MEDIA_LABEL_PREFIX, then it has been
223 initialized.
224
225 The check varies depending on whether the media is rewritable or not. For
226 non-rewritable media, we also accept a C{None} media label, since this kind
227 of media cannot safely be initialized.
228
229 @param storeConfig: Store configuration
230
231 @raise ValueError: If media is not initialized.
232 """
233 mediaLabel = readMediaLabel(storeConfig.devicePath)
234 if storeConfig.mediaType in REWRITABLE_MEDIA_TYPES:
235 if mediaLabel is None:
236 raise ValueError("Media has not been initialized: no media label available")
237 elif not mediaLabel.startswith(MEDIA_LABEL_PREFIX):
238 raise ValueError("Media has not been initialized: unrecognized media label [%s]" % mediaLabel)
239 else:
240 if mediaLabel is None:
241 logger.info("Media has no media label; assuming OK since media is not rewritable.")
242 elif not mediaLabel.startswith(MEDIA_LABEL_PREFIX):
243 raise ValueError("Media has not been initialized: unrecognized media label [%s]" % mediaLabel)
244
245
246 #########################
247 # initializeMediaState()
248 #########################
249
251 """
252 Initializes state of the media in the backup device so Cedar Backup can
253 recognize it.
254
255 This is done by writing an mostly-empty image (it contains a "Cedar Backup"
256 directory) to the media with a known media label.
257
258 @note: Only rewritable media (CD-RW, DVD+RW) can be initialized. It
259 doesn't make any sense to initialize media that cannot be rewritten (CD-R,
260 DVD+R), since Cedar Backup would then not be able to use that media for a
261 backup.
262
263 @param config: Cedar Backup configuration
264
265 @raise ValueError: If media could not be initialized.
266 @raise ValueError: If the configured media type is not rewritable
267 """
268 if not config.store.mediaType in REWRITABLE_MEDIA_TYPES:
269 raise ValueError("Only rewritable media types can be initialized.")
270 mediaLabel = buildMediaLabel()
271 writer = createWriter(config)
272 writer.initializeImage(True, config.options.workingDir, mediaLabel) # always create a new disc
273 tempdir = tempfile.mkdtemp(dir=config.options.workingDir)
274 try:
275 writer.addImageEntry(tempdir, "CedarBackup")
276 writer.writeImage()
277 finally:
278 if os.path.exists(tempdir):
279 try:
280 os.rmdir(tempdir)
281 except: pass
282
283
284 ####################
285 # buildMediaLabel()
286 ####################
287
289 """
290 Builds a media label to be used on Cedar Backup media.
291 @return: Media label as a string.
292 """
293 currentDate = time.strftime("%d-%b-%Y").upper()
294 return "%s %s" % (MEDIA_LABEL_PREFIX, currentDate)
295
296
297 ########################################################################
298 # Private attribute "getter" functions
299 ########################################################################
300
301 ############################
302 # _getDeviceType() function
303 ############################
304
306 """
307 Gets the device type that should be used for storing.
308
309 Use the configured device type if not C{None}, otherwise use
310 L{config.DEFAULT_DEVICE_TYPE}.
311
312 @param config: Config object.
313 @return: Device type to be used.
314 """
315 if config.store.deviceType is None:
316 deviceType = DEFAULT_DEVICE_TYPE
317 else:
318 deviceType = config.store.deviceType
319 logger.debug("Device type is [%s]" % deviceType)
320 return deviceType
321
322
323 ###########################
324 # _getMediaType() function
325 ###########################
326
328 """
329 Gets the media type that should be used for storing.
330
331 Use the configured media type if not C{None}, otherwise use
332 C{DEFAULT_MEDIA_TYPE}.
333
334 Once we figure out what configuration value to use, we return a media type
335 value that is valid in one of the supported writers::
336
337 MEDIA_CDR_74
338 MEDIA_CDRW_74
339 MEDIA_CDR_80
340 MEDIA_CDRW_80
341 MEDIA_DVDPLUSR
342 MEDIA_DVDPLUSRW
343
344 @param config: Config object.
345
346 @return: Media type to be used as a writer media type value.
347 @raise ValueError: If the media type is not valid.
348 """
349 if config.store.mediaType is None:
350 mediaType = DEFAULT_MEDIA_TYPE
351 else:
352 mediaType = config.store.mediaType
353 if mediaType == "cdr-74":
354 logger.debug("Media type is MEDIA_CDR_74.")
355 return MEDIA_CDR_74
356 elif mediaType == "cdrw-74":
357 logger.debug("Media type is MEDIA_CDRW_74.")
358 return MEDIA_CDRW_74
359 elif mediaType == "cdr-80":
360 logger.debug("Media type is MEDIA_CDR_80.")
361 return MEDIA_CDR_80
362 elif mediaType == "cdrw-80":
363 logger.debug("Media type is MEDIA_CDRW_80.")
364 return MEDIA_CDRW_80
365 elif mediaType == "dvd+r":
366 logger.debug("Media type is MEDIA_DVDPLUSR.")
367 return MEDIA_DVDPLUSR
368 elif mediaType == "dvd+rw":
369 logger.debug("Media type is MEDIA_DVDPLUSRW.")
370 return MEDIA_DVDPLUSR
371 else:
372 raise ValueError("Media type [%s] is not valid." % mediaType)
373
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