Cwa-app-android: Device stops sending beacons

[michaelwingender]

I have accidentally found out that there seem to be devices that stop sending beacons. I was playing around with RamBLE and saw only one device sending out beacons for exposure notification. There were devices where I expected to see beacons. Asking the people they confirmed that they both have the app installed. Checking the status on the devices both were showing activated state. After finding out which device was not sending beacons by checking RSSI, "Risikoermittlung" was deactivated and activated again. Immediately the device start sending beacons. So the mechanism seems not be very reliable. The device was Nokia 6.1 with latest available updates. You should implement some mechanism, which gives the user the possibility to see whether his device is working correctly or not. It should not be necessary for normal user to ask some "cracks" with "hacker apps" to confirm correct functionality of their device. According to some entries in Caschys blog there seem to be other users with similar issues. They claim that they have installed the app on four devices but they only see beacons for two devices. Therefore they think RamBLE is not able to identify devices with installed CWA.

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Internal Tracking ID: EXPOSUREAPP-1933

[tkowark]

Thanks for reporting this issue, @michaelwingender

Just as a hunch, this could be somewhat related to https://github.com/corona-warn-app/cwa-app-android/issues/858 but further investigations would be needed to clarify.

Regardless of the underlying root cause (which we most likely cannot fix from within the app, but it requires an OS level fix), would the following _mitigation_ be sufficient from your point of view?:

• As soon as any change in the system disables the exposure logging, a notification outside the app should be created to make the user aware of that fact

If this notification then reappears frequently due to some OS bug, at least it is clear where the root cause resides...

The general idea of providing more feedback about whether the app works as expected is captured in this wishlist item: https://github.com/corona-warn-app/cwa-wishlist/issues/5

[michaelwingender]

In my opinion you should have:

1. Notification within the App that everything is working normally. This should include also exposure logging. Currently it doesn't.

2. If it is recognised that exposure logging was disabled/is not working and this did not happen manually but instead while running in background, exposure logging should start automatically again. In my opinion there should be no recognisable message if this happens only once or twice. This will only cause confusion for most of the users. You can put it into some logging, which must be manually opened.

3. If exposure logging was disabled for several times since a particular event (maybe device reboot?) there should be an option to report this fact, along with device information. This could be a button in the app which appears in case restart happend too often. This should be a manual process, but the user should be informed that app is not working correctly on the device. Maybe in this case an information outside the app should be thrown which tells the user something like "Your exposure logging is not working correctly. If you want to provide information about your device to fix this issue, please open the app and hit the report button." This should be collected centrally, so you can find out if this is related to particular device series (report bug to vendor) or if it is spread over all android devices (report bug to Google). If this is not suitable there should be at least some recognisable information for the user and some recommendations what he or she can do. However reporting of OS bugs should not be task of the user.

[doak]

Just as a hunch, this could be somewhat related to #858 but further investigations would be needed to clarify.

@tkowark, you have linked to the very same issue ;)