1. 技术文章
  2. How Do You Test the Android 6.0 Full-Backup Behavior?

How Do You Test the Android 6.0 Full-Backup Behavior?

由 跟風遠走 提交于 2019-11-29 20:56:02
MH.

After having discussed and tested various scenarios (refer to comments below the question), I've decided to combine and write up those results into an answer. In reality, this doesn't actually solve the problem presented, but it will answer the question of "How do you successfuly use the command-line tools (or anything else) to test the Android 6.0 backup and restore behavior?" It will do so in the form of a step-by-step guide outlining what worked for me and how I overcame the various snags I encounted along the way.

Here goes. If you haven't gone through the training on "Configuring Auto Backup for Apps" yet, I'd suggest you do that first. It documents the auto-backup feature and already does a very decent job of documenting the various steps.

Let's start at the beginning: we need an app to test with! Just like CommonsWare, I simply used Android Studio to create a new project with an Empty activity. Make sure you set API 23 as target SDK. Open up the auto-generated MainActivity and add some code into onCreate() to persist a value into the shared preferences (or just copy the code snippet from the question):

PreferenceManager
  .getDefaultSharedPreferences(this)
  .edit()
  .putBoolean("foo", true)
  .apply();

Build, deploy and run the app. This should trigger foo to be persisted, and will result in an xml file being created on disk. Confirm this with:

adb shell run-as <package_name> ls -al shared_prefs

My test app's packge is com.example.mh.backuptest (which is what I'll use in the example commands from here on), so my command is: 

adb shell run-as com.example.mh.backuptest ls -al shared_prefs

You should see a single line of output listing all files in the shared_prefs folder, which should be only one:

com.example.mh.backuptest_preferences.xml

This means the preference file was successfully created and foo was written to it. If you like, you can inspect the file's contents to confirm this.

Now, back to testing auto-backup. First, make sure you're opted in to automatic app backups. On your Android 6.0 device, go to:

Settings > Backup & reset > Back up my data > On

After that, turn on verbose logging for the backup transport and backup xml parser so that we can see what's happening:

adb shell setprop log.tag.GmsBackupTransport VERBOSE
adb shell setprop log.tag.BackupXmlParserLogging VERBOSE

Then, initialise the backup manager:

adb shell bmgr run

This should generate quite a bit of output in logcat. You should see at least something similar to this:

D/AndroidRuntime: Calling main entry com.android.commands.bmgr.Bmgr
V/BackupManagerService: Scheduling immediate backup pass
V/BackupManagerService: Running a backup pass
V/BackupManagerService: clearing pending backups
V/PerformBackupTask: Beginning backup of 1 targets
D/PerformBackupTask: invokeAgentForBackup on @pm@
I/BackupRestoreController: Getting widget state for user: 0
D/PerformBackupTask: starting key/value backup of BackupRequest{pkg=com.google.android.googlequicksearchbox}
D/BackupManagerService: awaiting agent for ApplicationInfo{9f9289c com.google.android.googlequicksearchbox}
D/BackupManagerService: agentConnected pkg=com.google.android.googlequicksearchbox agent=android.os.BinderProxy@dcdbafd
I/BackupManagerService: got agent android.app.IBackupAgent$Stub$Proxy@c3fe3f2
D/PerformBackupTask: invokeAgentForBackup on com.google.android.googlequicksearchbox
D/BackupHelperDispatcher: handling existing helper 'L' com.android.launcher3.LauncherBackupHelper@7e2dcc3
V/LauncherBackupHelper: lastBackupTime = 1448612678367
W/LauncherBackupHelper: empty intent on application favorite: 223
I/BackupRestoreController: Getting widget state for user: 0
V/GmsBackupTransport: starting new backup session
V/GmsBackupTransport: starting performBackup for com.google.android.googlequicksearchbox
V/GmsBackupTransport: performBackup done for com.google.android.googlequicksearchbox
V/GmsBackupTransport: sending request: 101667 bytes
I/GmsBackupTransport: Http Response Code : 200
V/GmsBackupTransport: backup finished for com.google.android.googlequicksearchbox
I/BackupManagerService: Backup pass finished.

Don't worry if your output contains a lot more. I intentionally removed lines not relevant to backing up. I've only only pasted in the output for when a single app is getting backed up; you will probably see a lot more entries the first time you run this command.

If instead you see something along the lines of:

GmsBackupTransport: Scotty transfer exception. null
PFTBT   : Error -1002 backing up com.example.mh.backuptest

Or:

GmsBackupTransport: Rejecting full data backup. user has not seen up to date legal text

Make sure you have opted in to automatic app backups (see above). If you have and you're still seeing these messages - which happened for me too - try toggling the setting a few times and rebooting the device. Still no luck? I've been there... Remove the Google account from the device, reboot, re-add it and opt in again. Others have reported that a factory reset works too, but that seems a little overboard to me. :)

If you got this far, then it's time to ensure our test app gets backed up! To force a backup, run:

adb shell bmgr fullbackup com.example.mh.backuptest

This will kill your app if it's still running - don't worry, that's normal. You should see quite some output from the backup transport:

D/AndroidRuntime: Calling main entry com.android.commands.bmgr.Bmgr
D/BackupManagerService: fullTransportBackup()
I/PFTBT: Initiating full-data transport backup of com.example.mh.backuptest
V/GmsBackupTransport: create full backup for : com.example.mh.backuptest
V/GmsBackupTransport: Start scotty uploading.
D/BackupManagerService: Binding to full backup agent : com.example.mh.backuptest
I/ActivityManager: Start proc 22032:com.example.mh.backuptest/u0a491 for backup android/FullBackupAgent
D/BackupManagerService: awaiting agent for ApplicationInfo{dd359cd com.example.mh.backuptest}
V/GmsBackupTransport: [READ]
V/GmsBackupTransport: [READ] wait for avaible data.
BackupManagerService: agentConnected pkg=com.example.mh.backuptest agent=android.os.BinderProxy@9e7e282
I/BackupManagerService: got agent android.app.IBackupAgent$Stub$Proxy@14b3d93
V/BackupXmlParserLogging: android:fullBackupContent - "true"
I/BackupRestoreController: Getting widget state for user: 0
I/file_backup_helper:    Name: apps/com.example.mh.backuptest/_manifest
V/GmsBackupTransport: [PUSH] Push 512 bytes into pipe.
V/GmsBackupTransport: [PUSH] signal data available.
V/GmsBackupTransport: [PUSH] Wait for data been processed.
V/GmsBackupTransport: [READ] Read 256 bytes data.
V/GmsBackupTransport: [READ]
V/GmsBackupTransport: [READ] Read 256 bytes data.
V/GmsBackupTransport: [READ] signal data processed.
V/GmsBackupTransport: [READ]
V/GmsBackupTransport: [READ] wait for avaible data.
V/GmsBackupTransport: [PUSH] Push 2048 bytes into pipe.
V/GmsBackupTransport: [PUSH] signal data available.
V/GmsBackupTransport: [PUSH] Wait for data been processed.
V/GmsBackupTransport: [READ] Read 256 bytes data.
V/GmsBackupTransport: [READ]
V/GmsBackupTransport: [READ] Read 256 bytes data.
V/GmsBackupTransport: [READ]
V/GmsBackupTransport: [READ] Read 256 bytes data.
V/GmsBackupTransport: [READ]
V/GmsBackupTransport: [READ] Read 256 bytes data.
V/GmsBackupTransport: [READ]
V/GmsBackupTransport: [READ] Read 256 bytes data.
V/GmsBackupTransport: [READ]
V/GmsBackupTransport: [READ] Read 256 bytes data.
V/GmsBackupTransport: [READ]
V/GmsBackupTransport: [READ] Read 256 bytes data.
V/GmsBackupTransport: [READ]
V/GmsBackupTransport: [READ] Read 256 bytes data.
V/GmsBackupTransport: [READ] signal data processed.
V/GmsBackupTransport: [READ]
V/GmsBackupTransport: [READ] wait for avaible data.
D/BackupManagerService: Calling doFullBackup() on com.example.mh.backuptest
I/file_backup_helper:    Name: apps/com.example.mh.backuptest/sp/com.example.mh.backuptest_preferences.xml
V/GmsBackupTransport: [PUSH] Push 512 bytes into pipe.
V/GmsBackupTransport: [PUSH] signal data available.
V/GmsBackupTransport: [PUSH] Wait for data been processed.
V/GmsBackupTransport: [READ] Read 256 bytes data.
V/GmsBackupTransport: [READ]
V/GmsBackupTransport: [READ] Read 256 bytes data.
V/GmsBackupTransport: [READ] signal data processed.
V/GmsBackupTransport: [READ]
V/GmsBackupTransport: [READ] wait for avaible data.
V/GmsBackupTransport: [PUSH] Push 512 bytes into pipe.
V/GmsBackupTransport: [PUSH] signal data available.
V/GmsBackupTransport: [PUSH] Wait for data been processed.
V/GmsBackupTransport: [READ] Read 256 bytes data.
V/GmsBackupTransport: [READ]
V/GmsBackupTransport: [READ] Read 256 bytes data.
V/GmsBackupTransport: [READ] signal data processed.
V/GmsBackupTransport: [READ]
V/GmsBackupTransport: [READ] wait for avaible data.
V/GmsBackupTransport: [FINISH] signal no more data.
I/Process: Sending signal. PID: 22032 SIG: 9
I/ActivityManager: Process com.example.mh.backuptest (pid 22032) has died
V/GmsBackupTransport: Scotty response: res=200 raw=3584 up=1047
I/PFTBT: Transport suggested backoff=0
I/PFTBT: Full backup completed.
D/BackupManagerService: Done with full transport backup.

With our test app backed up, let's see if it in fact restores data too. First, let's remove the preference file that our test app created and that is part of the default auto backup:

adb shell run-as com.example.mh.backuptest rm shared_prefs/com.example.mh.backuptest_preferences.xml

Confirm that the file is no longer there:

adb shell run-as com.example.mh.backuptest ls -al shared_prefs

If the command executes without any output, it means there were no files in the shared_prefs folder and that you successfully deleted the prefs.

Now, trigger a restore for our test app:

adb shell bmgr restore com.example.mh.backuptest

Again, backup transport will generate quite some output:

V/BackupManagerService: beginRestoreSession: pkg=com.example.mh.backuptest transport=null
V/RestoreSession: restorePackage pkg=com.example.mh.backuptest obs=android.app.backup.IRestoreObserver$Stub$Proxy@23829fa
V/RestoreSession: restorePackage pkg=com.example.mh.backuptest token=31eda3bdfd5fddb7
D/BackupManagerService: MSG_RUN_RESTORE observer=android.app.backup.IRestoreObserver$Stub$Proxy@23829fa
V/GmsBackupTransport: New restore session, 2 apps
V/GmsBackupTransport: sending request: 471 bytes
I/GmsBackupTransport: Http Response Code : 200
V/GmsBackupTransport: @pm@: 109 keys
I/GmsBackupTransport: Current restore package : PackageInfo{195d280 @pm@}
V/GmsBackupTransport: A key/value pairs restore
D/BackupManagerService: initiateOneRestore packageName=@pm@
I/GmsBackupTransport: Current restore package : PackageInfo{1edd0b9 com.example.mh.backuptest}
V/GmsBackupTransport: A full restore : https://www.googleapis.com/drive/v2/files/XXXXXXXXXXXXXXXXXXXXXXXXXXXX?alt=media&sources=ANDROID_BACKUP
I/BackupManagerService: Next restore package: RestoreDescription{com.example.mh.backuptest : STREAM}
V/GmsBackupTransport: Read first chunk for com.example.mh.backuptest
V/GmsBackupTransport: Create http connection for com.example.mh.backuptest
I/GmsBackupTransport: Drive download http response status : 200
V/GmsBackupTransport: ContentLength is 3584
V/GmsBackupTransport: Downloaded: 808 / 3584 bytes
V/GmsBackupTransport: Read 808 Bytes
V/GmsBackupTransport: Read next chunk for com.example.mh.backuptest
V/GmsBackupTransport: Downloaded: 2197 / 3584 bytes
V/GmsBackupTransport: Read 1389 Bytes
I/RestoreEngine: Sig + version match; taking data
V/GmsBackupTransport: Read next chunk for com.example.mh.backuptest
V/GmsBackupTransport: Downloaded: 3584 / 3584 bytes
V/GmsBackupTransport: Read 1387 Bytes
V/GmsBackupTransport: Read next chunk for com.example.mh.backuptest
V/GmsBackupTransport: Read -1 Bytes
D/RestoreEngine: Need to launch agent for com.example.mh.backuptest
D/RestoreEngine: Clearing app data preparatory to full restore
I/ActivityManager: Force stopping com.example.mh.backuptest appid=10491 user=0: clear data
V/GmsBackupTransport: Reach end of http content -- NO MORE DATA
D/PackageBroadcastService: Received broadcast action=android.intent.action.PACKAGE_DATA_CLEARED and uri=com.example.mh.backuptest
D/AccountUtils: Clearing selected account for com.example.mh.backuptest
I/LocationSettingsChecker: Removing dialog suppression flag for package com.example.mh.backuptest
I/Icing: doRemovePackageData com.example.mh.backuptest
I/ActivityManager: Start proc 22708:com.example.mh.backuptest/u0a491 for backup android/FullBackupAgent
D/BackupManagerService: awaiting agent for ApplicationInfo{dd359cd com.example.mh.backuptest}
D/BackupManagerService: agentConnected pkg=com.example.mh.backuptest agent=android.os.BinderProxy@7875d75
I/BackupManagerService: got agent android.app.IBackupAgent$Stub$Proxy@9aa10a
D/VoldConnector: SND -> {14 volume mkdirs /storage/emulated/0/Android/data/com.example.mh.backuptest/files/}
D/VoldConnector: RCV <- {200 14 Command succeeded}
V/BackupXmlParserLogging: android:fullBackupContent - "true"
V/BackupManagerService: No more packages; finishing restore
V/GmsBackupTransport: restore finished
D/RestoreSession: endRestoreSession
I/BackupRestoreController: restoreFinished for 0
I/BackupManagerService: Restore complete.

If everything looks like above, let's check if our preference file is back where it should be:

adb shell run-as com.example.mh.backuptest ls -al shared_prefs

The output should be what you saw the very first time you ran the command (in the early stages of this rather long story). If so, it's time for congratulations! You've managed to successfully backup and restore your app using Google's Auto Backup for Apps!

Happy? Then let's do one more test! Uninstall the app:

adb uninstall com.example.mh.backuptest

Even though we see 'Success', confirm that it's gone:

adb shell run-as com.example.mh.backuptest

Expected output:

run-as: Package 'com.example.mh.backuptest' is unknown

Now, install the app again (but don't start it):

adb install backuptest.apk

Have a look at logcat:

V/BackupManagerService: restoreAtInstall pkg=com.example.mh.backuptest token=3 restoreSet=31eda3bdfd5fddb7
D/BackupManagerService: MSG_RUN_RESTORE observer=null
V/GmsBackupTransport: New restore session, 2 apps
V/GmsBackupTransport: sending request: 471 bytes
I/GmsBackupTransport: Http Response Code : 200
V/GmsBackupTransport: @pm@: 109 keys
I/GmsBackupTransport: Current restore package : PackageInfo{2981234 @pm@}
V/GmsBackupTransport: A key/value pairs restore
D/BackupManagerService: initiateOneRestore packageName=@pm@
I/GmsBackupTransport: Current restore package : PackageInfo{883c85d com.example.mh.backuptest}
V/GmsBackupTransport: A full restore : https://www.googleapis.com/drive/v2/files/XXXXXXXXXXXXXXXXXXXXXXXXXXXX?alt=media&sources=ANDROID_BACKUP
I/BackupManagerService: Next restore package: RestoreDescription{com.example.mh.backuptest : STREAM}
V/GmsBackupTransport: Read first chunk for com.example.mh.backuptest
V/GmsBackupTransport: Create http connection for com.example.mh.backuptest
I/GmsBackupTransport: Drive download http response status : 200
V/GmsBackupTransport: ContentLength is 3584
V/GmsBackupTransport: Downloaded: 808 / 3584 bytes
V/GmsBackupTransport: Read 808 Bytes
V/GmsBackupTransport: Read next chunk for com.example.mh.backuptest
V/GmsBackupTransport: Downloaded: 2197 / 3584 bytes
V/GmsBackupTransport: Read 1389 Bytes
I/RestoreEngine: Sig + version match; taking data
V/GmsBackupTransport: Read next chunk for com.example.mh.backuptest
V/GmsBackupTransport: Downloaded: 3584 / 3584 bytes
V/GmsBackupTransport: Read 1387 Bytes
V/GmsBackupTransport: Read next chunk for com.example.mh.backuptest
V/GmsBackupTransport: Read -1 Bytes
D/RestoreEngine: Need to launch agent for com.example.mh.backuptest
D/RestoreEngine: Clearing app data preparatory to full restore
I/ActivityManager: Force stopping com.example.mh.backuptest appid=10493 user=0: clear data
V/GmsBackupTransport: Reach end of http content -- NO MORE DATA
D/PackageBroadcastService: Received broadcast action=android.intent.action.PACKAGE_DATA_CLEARED and uri=com.example.mh.backuptest
D/AccountUtils: Clearing selected account for com.example.mh.backuptest
I/LocationSettingsChecker: Removing dialog suppression flag for package com.example.mh.backuptest
I/Icing: doRemovePackageData com.example.mh.backuptest
I/ActivityManager: Start proc 31545:com.example.mh.backuptest/u0a493 for backup android/FullBackupAgent
D/BackupManagerService: awaiting agent for ApplicationInfo{a84d42d com.example.mh.backuptest}
D/BackupManagerService: agentConnected pkg=com.example.mh.backuptest agent=android.os.BinderProxy@b023d62
I/BackupManagerService: got agent android.app.IBackupAgent$Stub$Proxy@a742ef3
D/VoldConnector: SND -> {17 volume mkdirs /storage/emulated/0/Android/data/com.example.mh.backuptest/files/}
D/VoldConnector: RCV <- {200 17 Command succeeded}
V/BackupXmlParserLogging: android:fullBackupContent - "true"
D/BackupManagerService: Restore complete, killing host process of com.example.mh.backuptest
V/BackupManagerService: No more packages; finishing restore
I/Process: Sending signal. PID: 31545 SIG: 9
V/GmsBackupTransport: restore finished
I/BackupRestoreController: restoreFinished for 0
I/BackupManagerService: Restore complete.

That looks promising! Did it really restore our backed up preference file when reinstalling the app?

adb shell run-as com.example.mh.backuptest ls -al shared_prefs

If you see the output that should be familiar by now, then the answer is yes!

Final notes: I've successfully tested above steps on various devices:

  • Default Android 6.0 Emulator (emulator64-x86) w/o Google Play Services
  • Genymotion Google Nexus 5X - API 23 - PREVIEW w/ Google Play Services
  • Nexus 5X (physical device) w/ Google Play Services.

If I recall correctly, without Google Play Services installed on the device, the backup manager doesn't actually go off to Google Drive (which wouldn't be surprising), but feel free to correct me on that.

Sources:

I encountered a bug in Android 6.0, where it will sometimes kill even a sticky foreground service to run doFullBackup(), and not restart it for hours. This is problematic if your app needs to run without interruption while the phone is charging (Chroma Doze is a white noise generator, so it often runs while the user is asleep):

01-22 03:01:00.303   879 25791 I PFTBT   : Initiating full-data transport backup of net.pmarks.chromadoze
01-22 03:01:00.470   879 25793 D BackupManagerService: Binding to full backup agent : net.pmarks.chromadoze
01-22 03:01:00.470   879 25793 D BackupManagerService: awaiting agent for ApplicationInfo{8ab9ee7 net.pmarks.chromadoze}
01-22 03:01:00.482   879  8822 D BackupManagerService: agentConnected pkg=net.pmarks.chromadoze agent=android.os.BinderProxy@3428a8a
01-22 03:01:00.482   879 25793 I BackupManagerService: got agent android.app.IBackupAgent$Stub$Proxy@a4738fb
01-22 03:01:00.525   879 25793 I BackupRestoreController: Getting widget state for user: 0
01-22 03:01:00.527   879 25796 D BackupManagerService: Calling doFullBackup() on net.pmarks.chromadoze
01-22 03:01:00.554   879  8821 I WindowState: WIN DEATH: Window{7b1ddb4 u0 net.pmarks.chromadoze/net.pmarks.chromadoze.ChromaDoze}
01-22 03:01:00.570   879  3721 I ActivityManager: Process net.pmarks.chromadoze (pid 18451) has died
01-22 03:01:00.570   879  3721 W ActivityManager: Scheduling restart of crashed service net.pmarks.chromadoze/.NoiseService in 13305612ms

This only affects apps with targetSdkVersion 23, but once you've published such an app, reverting to 22 is impossible: users who attempt to install the next version see (Error -504) in the Play store.

There are two solutions that I'm aware of:

  • Set android:allowBackup="false" in your manifest to disable all backups.
  • Implement an android:backupAgent, which (eventually) disables full backups and uses the old backup API instead.

However, if you have a targetSdkVersion 23 app installed without a backupAgent, adding the backupAgent doesn't actually disable full backups right away; you need to reboot the device to remove it from the queue.

To see which apps will receive a full backup, you can run the following:

$ adb shell dumpsys backup

And then look for the Full backup queue: section.

标签
android
android-6.0-marshmallow
android-backup-service
易学教程内所有资源均来自网络或用户发布的内容，如有违反法律规定的内容欢迎反馈！
该文章没有解决你所遇到的问题?点击提问,说说你的问题,让更多的人一起探讨吧!