Add //tools/android/emulator/clone_avd.py

Makes it more convenient to run multiple identical emulators at the same
time.

Change-Id: Ibbab1092c751b32ebbc0f647c61823ab9f4199bd
Reviewed-on: https://chromium-review.googlesource.com/1098468
Commit-Queue: agrieve <agrieve@chromium.org>
Reviewed-by: agrieve <agrieve@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Reviewed-by: Peter Wen <wnwen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567724}

docs/android_emulator.md

@@ -37,6 +37,17 @@ Known issues:
    * Can often be fixed by editing `~/.android/avd/YOUR_DEVICE/config.ini`.
      * Look for `hw.sdCard=no` and set it to `yes`
 
+### Cloning an Image
+Running tests on two emulators is twice as fast as running on one. Rather
+than use the UI to create additional avds, you can clone an existing one via:
+
+```shell
+tools/android/emulator/clone_avd.py \
+    --source-ini ~/.android/avd/EMULATOR_ID.ini \
+    --dest-ini ~/.android/avd/EMULATOR_ID_CLONED.ini \
+    --display-name "Cloned Emulator"
+```
+
 ## Starting an Emulator from the Command Line
 Refer to: https://developer.android.com/studio/run/emulator-commandline.html.
 

tools/android/emulator/OWNERS

+agrieve@chromium.org
+wnwen@chromium.org

tools/android/emulator/clone_avd.py

+#!/usr/bin/env python
+# Copyright 2018 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.
+
+"""Clones an Android Emulator image.
+
+Create an emulator image via Android Studio and then use this script to clone
+it. Cloning an image enables you to run multiple emulators at the same time, and
+thus run tests faster.
+"""
+import argparse
+import os
+import re
+import shutil
+
+
+def main():
+  parser = argparse.ArgumentParser(description=__doc__)
+  parser.add_argument('--source-ini', required=True,
+                      help='Path to ~/.android/avd/source.ini to clone')
+  parser.add_argument('--dest-ini', required=True,
+                      help='Path to ~/.android/avd/dest.ini to create')
+  parser.add_argument('--display-name', required=True,
+                      help='Name for emulator window & Android Studio list')
+
+  args = parser.parse_args()
+
+  avd_dir = os.path.dirname(args.source_ini)
+
+  old_ini_path = args.source_ini
+  old_avd_id = os.path.basename(old_ini_path)[:-4]
+  old_avd_path = os.path.join(avd_dir, old_avd_id + '.avd')
+
+  new_ini_path = args.dest_ini
+  new_avd_id = os.path.basename(new_ini_path)[:-4]
+  new_avd_path = os.path.join(avd_dir, new_avd_id + '.avd')
+
+  if not re.match(r'\w+$', new_avd_id):
+    parser.error('--dest-ini should be alphanumeric.')
+  if not os.path.exists(old_ini_path):
+    parser.error('Path does not exist: ' + old_ini_path)
+  if not os.path.exists(old_avd_path):
+    parser.error('Path does not exist: ' + old_avd_path)
+  if os.path.exists(new_ini_path):
+    parser.error('Destination path already exists: ' + new_ini_path)
+  if os.path.exists(new_avd_path):
+    parser.error('Destination path already exists: ' + new_avd_path)
+
+  shutil.copy(old_ini_path, new_ini_path)
+  with open(new_ini_path, 'r+') as f:
+    data = f.read()
+    data = data.replace(old_avd_id + '.avd', new_avd_id + '.avd')
+    f.truncate(0)
+    f.write(data)
+
+  print 'Copying avd...'
+  shutil.copytree(old_avd_path, new_avd_path,
+                  ignore=shutil.ignore_patterns('*.lock'))
+
+  with open(os.path.join(new_avd_path, 'config.ini'), 'r+') as f:
+    data = f.read()
+    # AvdId=Android_O_26_x86
+    # avd.ini.displayname=Android O (26) x86
+    data = re.sub(r'AvdId=.+', 'AvdId=' + new_avd_id, data)
+    data = re.sub(r'avd.ini.displayname=.+',
+                  'avd.ini.displayname=' + args.display_name,
+                  data)
+    f.truncate(0)
+    f.write(data)
+
+  print 'Done!'
+
+
+if __name__ == '__main__':
+  main()