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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) 2007,2010 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 (>= 2.5)
29 # Project : Cedar Backup, release 2
30 # Revision : $Id: util.py 1006 2010-07-07 21:03:57Z 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 refreshMediaDelay = config.store.refreshMediaDelay
151 deviceType = _getDeviceType(config)
152 mediaType = _getMediaType(config)
153 if deviceMounted(devicePath):
154 raise IOError("Device [%s] is currently mounted." % (devicePath))
155 if deviceType == "cdwriter":
156 return CdWriter(devicePath, deviceScsiId, driveSpeed, mediaType, noEject, refreshMediaDelay)
157 elif deviceType == "dvdwriter":
158 return DvdWriter(devicePath, deviceScsiId, driveSpeed, mediaType, noEject, refreshMediaDelay)
159 else:
160 raise ValueError("Device type [%s] is invalid." % deviceType)
161
162
163 ################################
164 # writeIndicatorFile() function
165 ################################
166
168 """
169 Writes an indicator file into a target directory.
170 @param targetDir: Target directory in which to write indicator
171 @param indicatorFile: Name of the indicator file
172 @param backupUser: User that indicator file should be owned by
173 @param backupGroup: Group that indicator file should be owned by
174 @raise IOException: If there is a problem writing the indicator file
175 """
176 filename = os.path.join(targetDir, indicatorFile)
177 logger.debug("Writing indicator file [%s]." % filename)
178 try:
179 open(filename, "w").write("")
180 changeOwnership(filename, backupUser, backupGroup)
181 except Exception, e:
182 logger.error("Error writing [%s]: %s" % (filename, e))
183 raise e
184
185
186 ############################
187 # getBackupFiles() function
188 ############################
189
191 """
192 Gets a list of backup files in a target directory.
193
194 Files that match INDICATOR_PATTERN (i.e. C{"cback.store"}, C{"cback.stage"},
195 etc.) are assumed to be indicator files and are ignored.
196
197 @param targetDir: Directory to look in
198
199 @return: List of backup files in the directory
200
201 @raise ValueError: If the target directory does not exist
202 """
203 if not os.path.isdir(targetDir):
204 raise ValueError("Target directory [%s] is not a directory or does not exist." % targetDir)
205 fileList = FilesystemList()
206 fileList.excludeDirs = True
207 fileList.excludeLinks = True
208 fileList.excludeBasenamePatterns = INDICATOR_PATTERN
209 fileList.addDirContents(targetDir)
210 return fileList
211
212
213 ####################
214 # checkMediaState()
215 ####################
216
218 """
219 Checks state of the media in the backup device to confirm whether it has
220 been initialized for use with Cedar Backup.
221
222 We can tell whether the media has been initialized by looking at its media
223 label. If the media label starts with MEDIA_LABEL_PREFIX, then it has been
224 initialized.
225
226 The check varies depending on whether the media is rewritable or not. For
227 non-rewritable media, we also accept a C{None} media label, since this kind
228 of media cannot safely be initialized.
229
230 @param storeConfig: Store configuration
231
232 @raise ValueError: If media is not initialized.
233 """
234 mediaLabel = readMediaLabel(storeConfig.devicePath)
235 if storeConfig.mediaType in REWRITABLE_MEDIA_TYPES:
236 if mediaLabel is None:
237 raise ValueError("Media has not been initialized: no media label available")
238 elif not mediaLabel.startswith(MEDIA_LABEL_PREFIX):
239 raise ValueError("Media has not been initialized: unrecognized media label [%s]" % mediaLabel)
240 else:
241 if mediaLabel is None:
242 logger.info("Media has no media label; assuming OK since media is not rewritable.")
243 elif not mediaLabel.startswith(MEDIA_LABEL_PREFIX):
244 raise ValueError("Media has not been initialized: unrecognized media label [%s]" % mediaLabel)
245
246
247 #########################
248 # initializeMediaState()
249 #########################
250
252 """
253 Initializes state of the media in the backup device so Cedar Backup can
254 recognize it.
255
256 This is done by writing an mostly-empty image (it contains a "Cedar Backup"
257 directory) to the media with a known media label.
258
259 @note: Only rewritable media (CD-RW, DVD+RW) can be initialized. It
260 doesn't make any sense to initialize media that cannot be rewritten (CD-R,
261 DVD+R), since Cedar Backup would then not be able to use that media for a
262 backup.
263
264 @param config: Cedar Backup configuration
265
266 @raise ValueError: If media could not be initialized.
267 @raise ValueError: If the configured media type is not rewritable
268 """
269 if not config.store.mediaType in REWRITABLE_MEDIA_TYPES:
270 raise ValueError("Only rewritable media types can be initialized.")
271 mediaLabel = buildMediaLabel()
272 writer = createWriter(config)
273 writer.initializeImage(True, config.options.workingDir, mediaLabel) # always create a new disc
274 tempdir = tempfile.mkdtemp(dir=config.options.workingDir)
275 try:
276 writer.addImageEntry(tempdir, "CedarBackup")
277 writer.writeImage()
278 finally:
279 if os.path.exists(tempdir):
280 try:
281 os.rmdir(tempdir)
282 except: pass
283
284
285 ####################
286 # buildMediaLabel()
287 ####################
288
290 """
291 Builds a media label to be used on Cedar Backup media.
292 @return: Media label as a string.
293 """
294 currentDate = time.strftime("%d-%b-%Y").upper()
295 return "%s %s" % (MEDIA_LABEL_PREFIX, currentDate)
296
297
298 ########################################################################
299 # Private attribute "getter" functions
300 ########################################################################
301
302 ############################
303 # _getDeviceType() function
304 ############################
305
307 """
308 Gets the device type that should be used for storing.
309
310 Use the configured device type if not C{None}, otherwise use
311 L{config.DEFAULT_DEVICE_TYPE}.
312
313 @param config: Config object.
314 @return: Device type to be used.
315 """
316 if config.store.deviceType is None:
317 deviceType = DEFAULT_DEVICE_TYPE
318 else:
319 deviceType = config.store.deviceType
320 logger.debug("Device type is [%s]" % deviceType)
321 return deviceType
322
323
324 ###########################
325 # _getMediaType() function
326 ###########################
327
329 """
330 Gets the media type that should be used for storing.
331
332 Use the configured media type if not C{None}, otherwise use
333 C{DEFAULT_MEDIA_TYPE}.
334
335 Once we figure out what configuration value to use, we return a media type
336 value that is valid in one of the supported writers::
337
338 MEDIA_CDR_74
339 MEDIA_CDRW_74
340 MEDIA_CDR_80
341 MEDIA_CDRW_80
342 MEDIA_DVDPLUSR
343 MEDIA_DVDPLUSRW
344
345 @param config: Config object.
346
347 @return: Media type to be used as a writer media type value.
348 @raise ValueError: If the media type is not valid.
349 """
350 if config.store.mediaType is None:
351 mediaType = DEFAULT_MEDIA_TYPE
352 else:
353 mediaType = config.store.mediaType
354 if mediaType == "cdr-74":
355 logger.debug("Media type is MEDIA_CDR_74.")
356 return MEDIA_CDR_74
357 elif mediaType == "cdrw-74":
358 logger.debug("Media type is MEDIA_CDRW_74.")
359 return MEDIA_CDRW_74
360 elif mediaType == "cdr-80":
361 logger.debug("Media type is MEDIA_CDR_80.")
362 return MEDIA_CDR_80
363 elif mediaType == "cdrw-80":
364 logger.debug("Media type is MEDIA_CDRW_80.")
365 return MEDIA_CDRW_80
366 elif mediaType == "dvd+r":
367 logger.debug("Media type is MEDIA_DVDPLUSR.")
368 return MEDIA_DVDPLUSR
369 elif mediaType == "dvd+rw":
370 logger.debug("Media type is MEDIA_DVDPLUSRW.")
371 return MEDIA_DVDPLUSRW
372 else:
373 raise ValueError("Media type [%s] is not valid." % mediaType)
374
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