Add --dry option to the promote script.

tools/promote.py

 #!/usr/bin/env python
 #
 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 # Dart Editor promote tools.
 
 import imp
 import optparse
 import os
 import subprocess
 import sys
 import time
 import urllib
 import bots.bot_utils as bot_utils
 
 from os.path import join
 
 DART_PATH = os.path.abspath(os.path.join(__file__, '..', '..'))
+DRY_RUN = False
 
 def BuildOptions():
   usage = """usage: %prog promote [options]
   where:
     promote - Will promote builds from raw/signed locations to release
               locations.
 
     Example: Promote revision r29962 on dev channel:
         python editor/build/promote.py promote --channel=dev --revision=29962
   """
 
   result = optparse.OptionParser(usage=usage)
 
   group = optparse.OptionGroup(
       result, 'Promote', 'options used to promote code')
   group.add_option(
       '--revision', help='The svn revision to promote', action='store')
   group.add_option(
       '--channel', type='string', help='Channel to promote.', default=None)
+  group.add_option("--dry", help='Dry run', default=False, action="store_true")
   result.add_option_group(group)
 
   return result
 
 
 def main():
   parser = BuildOptions()
   (options, args) = parser.parse_args()
 
   def die(msg):
@@ skipping 16 matching lines @@
       die('You must supply a valid integer argument to --revision to promote')
 
     # Make sure options.channel is a valid
     if not options.channel:
       die('Specify --channel=be/dev/stable')
     if options.channel not in bot_utils.Channel.ALL_CHANNELS:
       die('You must supply a valid channel to --channel to promote')
   else:
     die('Invalid command specified: {0}.  See help below'.format(args[0]))
 
+  if options.dry:
+    global DRY_RUN
+    DRY_RUN = True
   if command == 'promote':
     _PromoteDartArchiveBuild(options.channel, options.revision)
 
 
 def UpdateDocs():
   try:
     print 'Updating docs'
     url = "http://api.dartlang.org/docs/releases/latest/?force_reload=true"
     f = urllib.urlopen(url)
     f.read()
@@ skipping 20 matching lines @@
             "InternalError: Sanity check failed on GS URI: %s" % gs_path)
 
     # Google cloud storage has read-after-write, read-after-update,
     # and read-after-delete consistency, but not list after delete consistency.
     # Because gsutil uses list to figure out if it should do the unix styly
     # copy to or copy into, this means that if the directory is reported as
     # still being there (after it has been deleted) gsutil will copy
     # into the directory instead of to the directory.
     def wait_for_delete_to_be_consistent_with_list(gs_path):
       while True:
+        if DRY_RUN:
+          break
         (_, _, exit_code) = Gsutil(['ls', gs_path], throw_on_error=False)
         # gsutil will exit 1 if the "directory" does not exist
         if exit_code != 0:
           break
         time.sleep(1)
 
     def remove_gs_directory(gs_path):
       safety_check_on_gs_path(gs_path, to_revision, channel)
       Gsutil(['-m', 'rm', '-R', '-f', gs_path])
       wait_for_delete_to_be_consistent_with_list(gs_path)
@@ skipping 32 matching lines @@
     from_loc = raw_namer.version_filepath(revision)
     to_loc = release_namer.version_filepath(to_revision)
     Gsutil(['cp', '-a', 'public-read', from_loc, to_loc])
 
 
   promote(revision)
   promote('latest')
 
 def Gsutil(cmd, throw_on_error=True):
   gsutilTool = join(DART_PATH, 'third_party', 'gsutil', 'gsutil')
-  return bot_utils.run([sys.executable, gsutilTool] + cmd,
-                       throw_on_error=throw_on_error)
+  command = [sys.executable, gsutilTool] + cmd
+  if DRY_RUN:
+    print "DRY runnning: %s" % command
+    return
+  return bot_utils.run(command, throw_on_error=throw_on_error)
 
 
 if __name__ == '__main__':
   sys.exit(main())