Package CedarBackup2 :: Package tools :: Module span
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Source Code for Module CedarBackup2.tools.span

  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) 2007-2008,2010 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 (>= 2.7) 
 29  # Project  : Cedar Backup, release 2 
 30  # Purpose  : Spans staged data among multiple discs 
 31  # 
 32  # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
 33   
 34  ######################################################################## 
 35  # Notes 
 36  ######################################################################## 
 37   
 38  """ 
 39  Spans staged data among multiple discs 
 40   
 41  This is the Cedar Backup span tool.  It is intended for use by people who stage 
 42  more data than can fit on a single disc.  It allows a user to split staged data 
 43  among more than one disc.  It can't be an extension because it requires user 
 44  input when switching media. 
 45   
 46  Most configuration is taken from the Cedar Backup configuration file, 
 47  specifically the store section.  A few pieces of configuration are taken 
 48  directly from the user. 
 49   
 50  @author: Kenneth J. Pronovici <pronovic@ieee.org> 
 51  """ 
 52   
 53  ######################################################################## 
 54  # Imported modules and constants 
 55  ######################################################################## 
 56   
 57  # System modules 
 58  import sys 
 59  import os 
 60  import logging 
 61  import tempfile 
 62   
 63  # Cedar Backup modules 
 64  from CedarBackup2.release import AUTHOR, EMAIL, VERSION, DATE, COPYRIGHT 
 65  from CedarBackup2.util import displayBytes, convertSize, mount, unmount 
 66  from CedarBackup2.util import UNIT_SECTORS, UNIT_BYTES 
 67  from CedarBackup2.config import Config 
 68  from CedarBackup2.filesystem import BackupFileList, compareDigestMaps, normalizeDir 
 69  from CedarBackup2.cli import Options, setupLogging, setupPathResolver 
 70  from CedarBackup2.cli import DEFAULT_CONFIG, DEFAULT_LOGFILE, DEFAULT_OWNERSHIP, DEFAULT_MODE 
 71  from CedarBackup2.actions.constants import STORE_INDICATOR 
 72  from CedarBackup2.actions.util import createWriter 
 73  from CedarBackup2.actions.store import writeIndicatorFile 
 74  from CedarBackup2.actions.util import findDailyDirs 
 75  from CedarBackup2.util import Diagnostics 
 76   
 77   
 78  ######################################################################## 
 79  # Module-wide constants and variables 
 80  ######################################################################## 
 81   
 82  logger = logging.getLogger("CedarBackup2.log.tools.span") 
 83   
 84   
 85  ####################################################################### 
 86  # SpanOptions class 
 87  ####################################################################### 
 88   
89 -class SpanOptions(Options):
90 91 """ 92 Tool-specific command-line options. 93 94 Most of the cback command-line options are exactly what we need here -- 95 logfile path, permissions, verbosity, etc. However, we need to make a few 96 tweaks since we don't accept any actions. 97 98 Also, a few extra command line options that we accept are really ignored 99 underneath. I just don't care about that for a tool like this. 100 """ 101
102 - def validate(self):
103 """ 104 Validates command-line options represented by the object. 105 There are no validations here, because we don't use any actions. 106 @raise ValueError: If one of the validations fails. 107 """ 108 pass
109 110 111 ####################################################################### 112 # Public functions 113 ####################################################################### 114 115 ################# 116 # cli() function 117 ################# 118
119 -def cli():
120 """ 121 Implements the command-line interface for the C{cback-span} script. 122 123 Essentially, this is the "main routine" for the cback-span script. It does 124 all of the argument processing for the script, and then also implements the 125 tool functionality. 126 127 This function looks pretty similiar to C{CedarBackup2.cli.cli()}. It's not 128 easy to refactor this code to make it reusable and also readable, so I've 129 decided to just live with the duplication. 130 131 A different error code is returned for each type of failure: 132 133 - C{1}: The Python interpreter version is < 2.7 134 - C{2}: Error processing command-line arguments 135 - C{3}: Error configuring logging 136 - C{4}: Error parsing indicated configuration file 137 - C{5}: Backup was interrupted with a CTRL-C or similar 138 - C{6}: Error executing other parts of the script 139 140 @note: This script uses print rather than logging to the INFO level, because 141 it is interactive. Underlying Cedar Backup functionality uses the logging 142 mechanism exclusively. 143 144 @return: Error code as described above. 145 """ 146 try: 147 if map(int, [sys.version_info[0], sys.version_info[1]]) < [2, 7]: 148 sys.stderr.write("Python 2 version 2.7 or greater required.\n") 149 return 1 150 except: 151 # sys.version_info isn't available before 2.0 152 sys.stderr.write("Python 2 version 2.7 or greater required.\n") 153 return 1 154 155 try: 156 options = SpanOptions(argumentList=sys.argv[1:]) 157 except Exception, e: 158 _usage() 159 sys.stderr.write(" *** Error: %s\n" % e) 160 return 2 161 162 if options.help: 163 _usage() 164 return 0 165 if options.version: 166 _version() 167 return 0 168 if options.diagnostics: 169 _diagnostics() 170 return 0 171 172 if options.stacktrace: 173 logfile = setupLogging(options) 174 else: 175 try: 176 logfile = setupLogging(options) 177 except Exception as e: 178 sys.stderr.write("Error setting up logging: %s\n" % e) 179 return 3 180 181 logger.info("Cedar Backup 'span' utility run started.") 182 logger.info("Options were [%s]", options) 183 logger.info("Logfile is [%s]", logfile) 184 185 if options.config is None: 186 logger.debug("Using default configuration file.") 187 configPath = DEFAULT_CONFIG 188 else: 189 logger.debug("Using user-supplied configuration file.") 190 configPath = options.config 191 192 try: 193 logger.info("Configuration path is [%s]", configPath) 194 config = Config(xmlPath=configPath) 195 setupPathResolver(config) 196 except Exception, e: 197 logger.error("Error reading or handling configuration: %s", e) 198 logger.info("Cedar Backup 'span' utility run completed with status 4.") 199 return 4 200 201 if options.stacktrace: 202 _executeAction(options, config) 203 else: 204 try: 205 _executeAction(options, config) 206 except KeyboardInterrupt: 207 logger.error("Backup interrupted.") 208 logger.info("Cedar Backup 'span' utility run completed with status 5.") 209 return 5 210 except Exception, e: 211 logger.error("Error executing backup: %s", e) 212 logger.info("Cedar Backup 'span' utility run completed with status 6.") 213 return 6 214 215 logger.info("Cedar Backup 'span' utility run completed with status 0.") 216 return 0
217 218 219 ####################################################################### 220 # Utility functions 221 ####################################################################### 222 223 #################### 224 # _usage() function 225 #################### 226
227 -def _usage(fd=sys.stderr):
228 """ 229 Prints usage information for the cback script. 230 @param fd: File descriptor used to print information. 231 @note: The C{fd} is used rather than C{print} to facilitate unit testing. 232 """ 233 fd.write("\n") 234 fd.write(" Usage: cback-span [switches]\n") 235 fd.write("\n") 236 fd.write(" Cedar Backup 'span' tool.\n") 237 fd.write("\n") 238 fd.write(" This Cedar Backup utility spans staged data between multiple discs.\n") 239 fd.write(" It is a utility, not an extension, and requires user interaction.\n") 240 fd.write("\n") 241 fd.write(" The following switches are accepted, mostly to set up underlying\n") 242 fd.write(" Cedar Backup functionality:\n") 243 fd.write("\n") 244 fd.write(" -h, --help Display this usage/help listing\n") 245 fd.write(" -V, --version Display version information\n") 246 fd.write(" -b, --verbose Print verbose output as well as logging to disk\n") 247 fd.write(" -c, --config Path to config file (default: %s)\n" % DEFAULT_CONFIG) 248 fd.write(" -l, --logfile Path to logfile (default: %s)\n" % DEFAULT_LOGFILE) 249 fd.write(" -o, --owner Logfile ownership, user:group (default: %s:%s)\n" % (DEFAULT_OWNERSHIP[0], DEFAULT_OWNERSHIP[1])) 250 fd.write(" -m, --mode Octal logfile permissions mode (default: %o)\n" % DEFAULT_MODE) 251 fd.write(" -O, --output Record some sub-command (i.e. tar) output to the log\n") 252 fd.write(" -d, --debug Write debugging information to the log (implies --output)\n") 253 fd.write(" -s, --stack Dump a Python stack trace instead of swallowing exceptions\n") 254 fd.write("\n")
255 256 257 ###################### 258 # _version() function 259 ###################### 260
261 -def _version(fd=sys.stdout):
262 """ 263 Prints version information for the cback script. 264 @param fd: File descriptor used to print information. 265 @note: The C{fd} is used rather than C{print} to facilitate unit testing. 266 """ 267 fd.write("\n") 268 fd.write(" Cedar Backup 'span' tool.\n") 269 fd.write(" Included with Cedar Backup version %s, released %s.\n" % (VERSION, DATE)) 270 fd.write("\n") 271 fd.write(" Copyright (c) %s %s <%s>.\n" % (COPYRIGHT, AUTHOR, EMAIL)) 272 fd.write(" See CREDITS for a list of included code and other contributors.\n") 273 fd.write(" This is free software; there is NO warranty. See the\n") 274 fd.write(" GNU General Public License version 2 for copying conditions.\n") 275 fd.write("\n") 276 fd.write(" Use the --help option for usage information.\n") 277 fd.write("\n")
278 279 280 ########################## 281 # _diagnostics() function 282 ########################## 283
284 -def _diagnostics(fd=sys.stdout):
285 """ 286 Prints runtime diagnostics information. 287 @param fd: File descriptor used to print information. 288 @note: The C{fd} is used rather than C{print} to facilitate unit testing. 289 """ 290 fd.write("\n") 291 fd.write("Diagnostics:\n") 292 fd.write("\n") 293 Diagnostics().printDiagnostics(fd=fd, prefix=" ") 294 fd.write("\n")
295 296 297 ############################ 298 # _executeAction() function 299 ############################ 300 301 # pylint: disable=W0613
302 -def _executeAction(options, config):
303 """ 304 Implements the guts of the cback-span tool. 305 306 @param options: Program command-line options. 307 @type options: SpanOptions object. 308 309 @param config: Program configuration. 310 @type config: Config object. 311 312 @raise Exception: Under many generic error conditions 313 """ 314 print "" 315 print "================================================" 316 print " Cedar Backup 'span' tool" 317 print "================================================" 318 print "" 319 print "This the Cedar Backup span tool. It is used to split up staging" 320 print "data when that staging data does not fit onto a single disc." 321 print "" 322 print "This utility operates using Cedar Backup configuration. Configuration" 323 print "specifies which staging directory to look at and which writer device" 324 print "and media type to use." 325 print "" 326 if not _getYesNoAnswer("Continue?", default="Y"): 327 return 328 print "===" 329 330 print "" 331 print "Cedar Backup store configuration looks like this:" 332 print "" 333 print " Source Directory...: %s" % config.store.sourceDir 334 print " Media Type.........: %s" % config.store.mediaType 335 print " Device Type........: %s" % config.store.deviceType 336 print " Device Path........: %s" % config.store.devicePath 337 print " Device SCSI ID.....: %s" % config.store.deviceScsiId 338 print " Drive Speed........: %s" % config.store.driveSpeed 339 print " Check Data Flag....: %s" % config.store.checkData 340 print " No Eject Flag......: %s" % config.store.noEject 341 print "" 342 if not _getYesNoAnswer("Is this OK?", default="Y"): 343 return 344 print "===" 345 346 (writer, mediaCapacity) = _getWriter(config) 347 348 print "" 349 print "Please wait, indexing the source directory (this may take a while)..." 350 (dailyDirs, fileList) = _findDailyDirs(config.store.sourceDir) 351 print "===" 352 353 print "" 354 print "The following daily staging directories have not yet been written to disc:" 355 print "" 356 for dailyDir in dailyDirs: 357 print " %s" % dailyDir 358 359 totalSize = fileList.totalSize() 360 print "" 361 print "The total size of the data in these directories is %s." % displayBytes(totalSize) 362 print "" 363 if not _getYesNoAnswer("Continue?", default="Y"): 364 return 365 print "===" 366 367 print "" 368 print "Based on configuration, the capacity of your media is %s." % displayBytes(mediaCapacity) 369 370 print "" 371 print "Since estimates are not perfect and there is some uncertainly in" 372 print "media capacity calculations, it is good to have a \"cushion\"," 373 print "a percentage of capacity to set aside. The cushion reduces the" 374 print "capacity of your media, so a 1.5% cushion leaves 98.5% remaining." 375 print "" 376 cushion = _getFloat("What cushion percentage?", default=4.5) 377 print "===" 378 379 realCapacity = ((100.0 - cushion)/100.0) * mediaCapacity 380 minimumDiscs = (totalSize/realCapacity) + 1 381 print "" 382 print "The real capacity, taking into account the %.2f%% cushion, is %s." % (cushion, displayBytes(realCapacity)) 383 print "It will take at least %d disc(s) to store your %s of data." % (minimumDiscs, displayBytes(totalSize)) 384 print "" 385 if not _getYesNoAnswer("Continue?", default="Y"): 386 return 387 print "===" 388 389 happy = False 390 while not happy: 391 print "" 392 print "Which algorithm do you want to use to span your data across" 393 print "multiple discs?" 394 print "" 395 print "The following algorithms are available:" 396 print "" 397 print " first....: The \"first-fit\" algorithm" 398 print " best.....: The \"best-fit\" algorithm" 399 print " worst....: The \"worst-fit\" algorithm" 400 print " alternate: The \"alternate-fit\" algorithm" 401 print "" 402 print "If you don't like the results you will have a chance to try a" 403 print "different one later." 404 print "" 405 algorithm = _getChoiceAnswer("Which algorithm?", "worst", [ "first", "best", "worst", "alternate", ]) 406 print "===" 407 408 print "" 409 print "Please wait, generating file lists (this may take a while)..." 410 spanSet = fileList.generateSpan(capacity=realCapacity, algorithm="%s_fit" % algorithm) 411 print "===" 412 413 print "" 414 print "Using the \"%s-fit\" algorithm, Cedar Backup can split your data" % algorithm 415 print "into %d discs." % len(spanSet) 416 print "" 417 counter = 0 418 for item in spanSet: 419 counter += 1 420 print "Disc %d: %d files, %s, %.2f%% utilization" % (counter, len(item.fileList), 421 displayBytes(item.size), item.utilization) 422 print "" 423 if _getYesNoAnswer("Accept this solution?", default="Y"): 424 happy = True 425 print "===" 426 427 counter = 0 428 for spanItem in spanSet: 429 counter += 1 430 if counter == 1: 431 print "" 432 _getReturn("Please place the first disc in your backup device.\nPress return when ready.") 433 print "===" 434 else: 435 print "" 436 _getReturn("Please replace the disc in your backup device.\nPress return when ready.") 437 print "===" 438 _writeDisc(config, writer, spanItem) 439 440 _writeStoreIndicator(config, dailyDirs) 441 442 print "" 443 print "Completed writing all discs."
444 445 446 ############################ 447 # _findDailyDirs() function 448 ############################ 449
450 -def _findDailyDirs(stagingDir):
451 """ 452 Returns a list of all daily staging directories that have not yet been 453 stored. 454 455 The store indicator file C{cback.store} will be written to a daily staging 456 directory once that directory is written to disc. So, this function looks 457 at each daily staging directory within the configured staging directory, and 458 returns a list of those which do not contain the indicator file. 459 460 Returned is a tuple containing two items: a list of daily staging 461 directories, and a BackupFileList containing all files among those staging 462 directories. 463 464 @param stagingDir: Configured staging directory 465 466 @return: Tuple (staging dirs, backup file list) 467 """ 468 results = findDailyDirs(stagingDir, STORE_INDICATOR) 469 fileList = BackupFileList() 470 for item in results: 471 fileList.addDirContents(item) 472 return (results, fileList)
473 474 475 ################################## 476 # _writeStoreIndicator() function 477 ################################## 478
479 -def _writeStoreIndicator(config, dailyDirs):
480 """ 481 Writes a store indicator file into daily directories. 482 483 @param config: Config object. 484 @param dailyDirs: List of daily directories 485 """ 486 for dailyDir in dailyDirs: 487 writeIndicatorFile(dailyDir, STORE_INDICATOR, 488 config.options.backupUser, 489 config.options.backupGroup)
490 491 492 ######################## 493 # _getWriter() function 494 ######################## 495
496 -def _getWriter(config):
497 """ 498 Gets a writer and media capacity from store configuration. 499 Returned is a writer and a media capacity in bytes. 500 @param config: Cedar Backup configuration 501 @return: Tuple of (writer, mediaCapacity) 502 """ 503 writer = createWriter(config) 504 mediaCapacity = convertSize(writer.media.capacity, UNIT_SECTORS, UNIT_BYTES) 505 return (writer, mediaCapacity)
506 507 508 ######################## 509 # _writeDisc() function 510 ######################## 511
512 -def _writeDisc(config, writer, spanItem):
513 """ 514 Writes a span item to disc. 515 @param config: Cedar Backup configuration 516 @param writer: Writer to use 517 @param spanItem: Span item to write 518 """ 519 print "" 520 _discInitializeImage(config, writer, spanItem) 521 _discWriteImage(config, writer) 522 _discConsistencyCheck(config, writer, spanItem) 523 print "Write process is complete." 524 print "==="
525
526 -def _discInitializeImage(config, writer, spanItem):
527 """ 528 Initialize an ISO image for a span item. 529 @param config: Cedar Backup configuration 530 @param writer: Writer to use 531 @param spanItem: Span item to write 532 """ 533 complete = False 534 while not complete: 535 try: 536 print "Initializing image..." 537 writer.initializeImage(newDisc=True, tmpdir=config.options.workingDir) 538 for path in spanItem.fileList: 539 graftPoint = os.path.dirname(path.replace(config.store.sourceDir, "", 1)) 540 writer.addImageEntry(path, graftPoint) 541 complete = True 542 except KeyboardInterrupt, e: 543 raise e 544 except Exception, e: 545 logger.error("Failed to initialize image: %s", e) 546 if not _getYesNoAnswer("Retry initialization step?", default="Y"): 547 raise e 548 print "Ok, attempting retry." 549 print "===" 550 print "Completed initializing image."
551 552 # pylint: disable=W0613
553 -def _discWriteImage(config, writer):
554 """ 555 Writes a ISO image for a span item. 556 @param config: Cedar Backup configuration 557 @param writer: Writer to use 558 """ 559 complete = False 560 while not complete: 561 try: 562 print "Writing image to disc..." 563 writer.writeImage() 564 complete = True 565 except KeyboardInterrupt, e: 566 raise e 567 except Exception, e: 568 logger.error("Failed to write image: %s", e) 569 if not _getYesNoAnswer("Retry this step?", default="Y"): 570 raise e 571 print "Ok, attempting retry." 572 _getReturn("Please replace media if needed.\nPress return when ready.") 573 print "===" 574 print "Completed writing image."
575
576 -def _discConsistencyCheck(config, writer, spanItem):
577 """ 578 Run a consistency check on an ISO image for a span item. 579 @param config: Cedar Backup configuration 580 @param writer: Writer to use 581 @param spanItem: Span item to write 582 """ 583 if config.store.checkData: 584 complete = False 585 while not complete: 586 try: 587 print "Running consistency check..." 588 _consistencyCheck(config, spanItem.fileList) 589 complete = True 590 except KeyboardInterrupt, e: 591 raise e 592 except Exception, e: 593 logger.error("Consistency check failed: %s", e) 594 if not _getYesNoAnswer("Retry the consistency check?", default="Y"): 595 raise e 596 if _getYesNoAnswer("Rewrite the disc first?", default="N"): 597 print "Ok, attempting retry." 598 _getReturn("Please replace the disc in your backup device.\nPress return when ready.") 599 print "===" 600 _discWriteImage(config, writer) 601 else: 602 print "Ok, attempting retry." 603 print "===" 604 print "Completed consistency check."
605 606 607 ############################### 608 # _consistencyCheck() function 609 ############################### 610
611 -def _consistencyCheck(config, fileList):
612 """ 613 Runs a consistency check against media in the backup device. 614 615 The function mounts the device at a temporary mount point in the working 616 directory, and then compares the passed-in file list's digest map with the 617 one generated from the disc. The two lists should be identical. 618 619 If no exceptions are thrown, there were no problems with the consistency 620 check. 621 622 @warning: The implementation of this function is very UNIX-specific. 623 624 @param config: Config object. 625 @param fileList: BackupFileList whose contents to check against 626 627 @raise ValueError: If the check fails 628 @raise IOError: If there is a problem working with the media. 629 """ 630 logger.debug("Running consistency check.") 631 mountPoint = tempfile.mkdtemp(dir=config.options.workingDir) 632 try: 633 mount(config.store.devicePath, mountPoint, "iso9660") 634 discList = BackupFileList() 635 discList.addDirContents(mountPoint) 636 sourceList = BackupFileList() 637 sourceList.extend(fileList) 638 discListDigest = discList.generateDigestMap(stripPrefix=normalizeDir(mountPoint)) 639 sourceListDigest = sourceList.generateDigestMap(stripPrefix=normalizeDir(config.store.sourceDir)) 640 compareDigestMaps(sourceListDigest, discListDigest, verbose=True) 641 logger.info("Consistency check completed. No problems found.") 642 finally: 643 unmount(mountPoint, True, 5, 1) # try 5 times, and remove mount point when done
644 645 646 ######################################################################### 647 # User interface utilities 648 ######################################################################## 649
650 -def _getYesNoAnswer(prompt, default):
651 """ 652 Get a yes/no answer from the user. 653 The default will be placed at the end of the prompt. 654 A "Y" or "y" is considered yes, anything else no. 655 A blank (empty) response results in the default. 656 @param prompt: Prompt to show. 657 @param default: Default to set if the result is blank 658 @return: Boolean true/false corresponding to Y/N 659 """ 660 if default == "Y": 661 prompt = "%s [Y/n]: " % prompt 662 else: 663 prompt = "%s [y/N]: " % prompt 664 answer = raw_input(prompt) 665 if answer in [ None, "", ]: 666 answer = default 667 if answer[0] in [ "Y", "y", ]: 668 return True 669 else: 670 return False
671
672 -def _getChoiceAnswer(prompt, default, validChoices):
673 """ 674 Get a particular choice from the user. 675 The default will be placed at the end of the prompt. 676 The function loops until getting a valid choice. 677 A blank (empty) response results in the default. 678 @param prompt: Prompt to show. 679 @param default: Default to set if the result is None or blank. 680 @param validChoices: List of valid choices (strings) 681 @return: Valid choice from user. 682 """ 683 prompt = "%s [%s]: " % (prompt, default) 684 answer = raw_input(prompt) 685 if answer in [ None, "", ]: 686 answer = default 687 while answer not in validChoices: 688 print "Choice must be one of %s" % validChoices 689 answer = raw_input(prompt) 690 return answer
691
692 -def _getFloat(prompt, default):
693 """ 694 Get a floating point number from the user. 695 The default will be placed at the end of the prompt. 696 The function loops until getting a valid floating point number. 697 A blank (empty) response results in the default. 698 @param prompt: Prompt to show. 699 @param default: Default to set if the result is None or blank. 700 @return: Floating point number from user 701 """ 702 prompt = "%s [%.2f]: " % (prompt, default) 703 while True: 704 answer = raw_input(prompt) 705 if answer in [ None, "" ]: 706 return default 707 else: 708 try: 709 return float(answer) 710 except ValueError: 711 print "Enter a floating point number."
712
713 -def _getReturn(prompt):
714 """ 715 Get a return key from the user. 716 @param prompt: Prompt to show. 717 """ 718 raw_input(prompt)
719 720 721 ######################################################################### 722 # Main routine 723 ######################################################################## 724 725 if __name__ == "__main__": 726 sys.exit(cli()) 727