android: Make buildbot able to use a custom manifest.

buildbot/buildbot_run.py

Index: buildbot/buildbot_run.py
diff --git a/buildbot/buildbot_run.py b/buildbot/buildbot_run.py
index b20a424de53ee49fc087666a23729b76c8391a75..2d301d6fa9bd68f135d16800ad42f5ddee0ad6b3 100755
--- a/buildbot/buildbot_run.py
+++ b/buildbot/buildbot_run.py
@@ -7,6 +7,7 @@
 """Argument-less script to select what to run on the buildbots."""
 
 
+import filecmp
 import os
 import shutil
 import subprocess
@@ -82,27 +83,48 @@ def PrepareAndroidTree():
     print '@@@BUILD_STEP Clobber Android checkout@@@'
     shutil.rmtree(ANDROID_DIR)
 
-  # The release of Android we use is static, so there's no need to do anything
-  # if the directory already exists.
-  if os.path.isdir(ANDROID_DIR):
+  # (Re)create the directory so that the following steps will succeed.
+  if not os.path.isdir(ANDROID_DIR):
+    os.mkdir(ANDROID_DIR)
+
+  # We use a manifest from the gyp project listing pinned revisions of AOSP to
+  # use, to ensure that we test against a stable target. This needs to be
+  # updated to pick up new build system changes sometimes, so we must test if
+  # it has changed.
+  manifest_filename = 'aosp_manifest.xml'
+  gyp_manifest = os.path.join(BUILDBOT_DIR, manifest_filename)
+  android_manifest = os.path.join(ANDROID_DIR, '.repo', 'manifests',
+                                  manifest_filename)
+  manifest_is_current = (os.path.isfile(android_manifest) and
+                         filecmp.cmp(gyp_manifest, android_manifest))
+  if not manifest_is_current:
+    # It's safe to repeat these steps, so just do them again to make sure we are
+    # in a good state.
+    print '@@@BUILD_STEP Initialize Android checkout@@@'
+    CallSubProcess(['git', 'config', '--global', 'user.name', 'trybot'])

[jbudorick, 2014/08/22 05:10:48]

Ha, I think I wound up trying to upload a CL as "trybot" because of this.

[Primiano Tucci (use gerrit), 2014/08/22 11:18:16]

Actually turns out that we don't need this at all using just a small trick (see
the change in  CallSubProcess). If either stdin or stdout are not tty, repo will
not bother checking for git config.

+    CallSubProcess(['git', 'config', '--global',
+                    'user.email', 'chrome-bot@google.com'])
+    CallSubProcess(['git', 'config', '--global', 'color.ui', 'false'])
+    CallSubProcess(
+        ['repo', 'init',
+         '-u', 'https://android.googlesource.com/platform/manifest',
+         '-b', 'master',
+         '-g', 'all,-notdefault,-device,-darwin,-mips,-x86'],
+        cwd=ANDROID_DIR)
+    shutil.copy(gyp_manifest, android_manifest)
+
+    print '@@@BUILD_STEP Sync Android@@@'
+    CallSubProcess(['repo', 'sync', '-j4', '-m', manifest_filename],
+                   cwd=ANDROID_DIR)
+
+  # If we already built the system image successfully and didn't sync to a new
+  # version of the source, skip running the build again as it's expensive even
+  # when there's nothing to do.
+  system_img = os.path.join(ANDROID_DIR, 'out', 'target', 'product', 'generic',
+                            'system.img')
+  if manifest_is_current and os.path.isfile(system_img):
     return
 
-  print '@@@BUILD_STEP Initialize Android checkout@@@'
-  os.mkdir(ANDROID_DIR)
-  CallSubProcess(['git', 'config', '--global', 'user.name', 'trybot'])
-  CallSubProcess(['git', 'config', '--global',
-                  'user.email', 'chrome-bot@google.com'])
-  CallSubProcess(['git', 'config', '--global', 'color.ui', 'false'])
-  CallSubProcess(
-      ['repo', 'init',
-       '-u', 'https://android.googlesource.com/platform/manifest',
-       '-b', 'android-4.2.1_r1',
-       '-g', 'all,-notdefault,-device,-darwin,-mips,-x86'],
-      cwd=ANDROID_DIR)
-
-  print '@@@BUILD_STEP Sync Android@@@'
-  CallSubProcess(['repo', 'sync', '-j4'], cwd=ANDROID_DIR)
-
   print '@@@BUILD_STEP Build Android@@@'
   CallSubProcess(
       ['/bin/bash',
@@ -113,14 +135,28 @@ def PrepareAndroidTree():
 def StartAndroidEmulator():
   """Start an android emulator from the built android tree."""
   print '@@@BUILD_STEP Start Android emulator@@@'
-  android_host_bin = '$ANDROID_HOST_OUT/bin'
+
+  CallSubProcess(['/bin/bash', '-c',
+      '%s && adb kill-server ' % _ANDROID_SETUP],
+      cwd=ANDROID_DIR)
+
+  # If taskset is available, use it to force adbd to run only on one core, as,

[jbudorick, 2014/08/22 05:10:48]

yay adb

[Primiano Tucci (use gerrit), 2014/08/22 11:18:16]

Amazing, isn't it?

+  # sadly, it improves its reliability (see crbug.com/268450).
+  adbd_wrapper = ''
+  with open(os.devnull, 'w') as devnull_fd:
+    if subprocess.call(['which', 'taskset'], stdout=devnull_fd) == 0:
+      adbd_wrapper = 'taskset -c 0'
+  CallSubProcess(['/bin/bash', '-c',
+      '%s && %s adb start-server ' % (_ANDROID_SETUP, adbd_wrapper)],
+      cwd=ANDROID_DIR)
+
   subprocess.Popen(
       ['/bin/bash', '-c',
-       '%s && %s/emulator -no-window' % (_ANDROID_SETUP, android_host_bin)],
+       '%s && emulator -no-window' % _ANDROID_SETUP],

[jbudorick, 2014/08/22 05:10:48]

I think I asked this on torne's review, but is this now in the path? Was this
because emulator became a prebuilt?

[Primiano Tucci (use gerrit), 2014/08/22 11:18:16]

Correct. envsetup / lunch make it so that the correct (w.r.t. lunch
configuration) emulator prebuilt is in the PATH.

       cwd=ANDROID_DIR)
   CallSubProcess(
       ['/bin/bash', '-c',
-       '%s && %s/adb wait-for-device' % (_ANDROID_SETUP, android_host_bin)],
+       '%s && adb wait-for-device' % _ANDROID_SETUP],
       cwd=ANDROID_DIR)