Improve commit message generation for deploy_sdk.

sky/tools/deploy_sdk.py

 #!/usr/bin/env python
 # Copyright 2015 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.
 
 import argparse
 from datetime import datetime
 import logging
 import os
 import shutil
@@ skipping 186 matching lines @@
     if args.fake_pub_get_into:
         packages_dir = os.path.abspath(args.fake_pub_get_into)
         ensure_dir_exists(packages_dir)
         make_relative_symlink(sdk_path('packages/mojo/lib'),
             os.path.join(packages_dir, 'mojo'))
         make_relative_symlink(sdk_path('packages/sky/lib'),
             os.path.join(packages_dir, 'sky'))
 
     if should_commit:
         # Kinda a hack to make a prettier build dir for the commit:
-        rel_build_dir = os.path.join(os.path.split(build_dir)[-2:])
+        script_path = os.path.relpath(os.path.abspath(__file__), SRC_ROOT)
+        rel_build_dir = os.path.relpath(build_dir, SRC_ROOT)
+        revision = git_revision()
+        commit_url = "https://github.com/domokit/mojo/commit/%s" % revision
+        pattern = """Autogenerated from %s
+Using %s and build output from %s.
+"""
+        commit_message = pattern % (commit_url, script_path, rel_build_dir)
         subprocess.check_call(['git', 'add', '.'], cwd=sdk_root)
         subprocess.check_call([
             'git', 'commit',
-            '-m', '%s from %s' % (rel_build_dir, git_revision())
+            '-m', commit_message
             ], cwd=sdk_root)
 
     time_delta = datetime.now() - start_time
     print 'SDK built at %s in %ss' % (sdk_root, time_delta.total_seconds())
 
 
 if __name__ == '__main__':
     main()