Add wrapper for "gcl try"

Adds some validation for --bot
Review URL: https://codereview.appspot.com/7179048

git-svn-id: http://skia.googlecode.com/svn/trunk@7315 2bbb7eff-a529-9590-31e7-b0007b416f81

tools/gcl_try

@@ -0,0 +1,95 @@
+#!/usr/bin/python
+
+# Copyright (c) 2013 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+gcl_try: Submit a try request.
+
+This is a thin wrapper around "gcl try" which adds some validation.
+"""
+
+
+import argparse
+import httplib
+import json
+import os
+import subprocess
+import sys
+
+
+ALL_BUILDERS = 'all'
+SKIA_BUILD_MASTER_HOST = '70.32.156.51'
+SKIA_BUILD_MASTER_PORT = '10117'
+TRYBOT_SUFFIX = '_Trybot'
+
+
+def RetrieveTrybotList():
+  """ Retrieve the list of known trybots from the build master, stripping
+  TRYBOT_SUFFIX from the name. """
+  trybots = []
+  connection = httplib.HTTPConnection(SKIA_BUILD_MASTER_HOST,
+                                      SKIA_BUILD_MASTER_PORT)
+  httplib.HTTPConnection
+  connection.request('GET', '/json/builders')
+  response = connection.getresponse()
+  builders = json.load(response)
+  for builder in builders:
+    if builder.endswith(TRYBOT_SUFFIX):
+      trybots.append(builder[:-len(TRYBOT_SUFFIX)])
+  return trybots
+
+
+def ValidateArgs(trybots):
+  """ Parse and validate command-line arguments. If the arguments are valid,
+  returns a tuple of (<changelist name>, <list of trybots>).
+
+  trybots: A list of the known try builders.
+  """
+  parser = argparse.ArgumentParser(
+      prog=os.path.basename(__file__),
+      description='%(prog)s: Submit a try request.',
+      usage='%(prog)s [-h] <changelist> --bot <buildername> [<buildername ...]')
+  parser.add_argument('changelist', metavar='<changelist>',
+                      help='Changelist to try.')
+  parser.add_argument('--bot', metavar='<buildername>', nargs='+',
+                      help='Builder(s) on which to try the change. One of: %s'
+                               % ', '.join(trybots),
+                      choices=trybots, required=True)
+  args = parser.parse_args()
+  if args.bot == [ALL_BUILDERS]:
+    bots = trybots
+  else:
+    bots = args.bot
+  return args.changelist, bots
+
+
+def SubmitTryRequest(changelist, bots):
+  """ Submits a try request for the given changelist on the given list of
+  trybots.
+
+  changelist: string; the name of the changelist to try.
+  bots: list of trybots on which to run the try.
+  """
+  if os.name == 'nt':
+    gcl = 'gcl.bat'
+  else:
+    gcl = 'gcl'
+  cmd = [gcl, 'try', changelist, '--bot',
+         ','.join(['%s%s' % (bot, TRYBOT_SUFFIX) for bot in bots])]
+  print 'Running command: %s' % ' '.join(cmd)
+  proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+  if proc.wait() != 0:
+    raise Exception('Failed to submit try request:\n%s' % proc.communicate()[0])
+  print proc.communicate()[0]
+
+
+def main():
+  trybots = RetrieveTrybotList()
+  changelist, bots = ValidateArgs(trybots=trybots)
+  SubmitTryRequest(changelist, bots)
+
+
+if __name__ == '__main__':
+  sys.exit(main())