Backup granularity, associate directories and files to applications

[cehteh]

It would be nice to have some more control over what gets backed up (and restored) including 'external' resource which may be not known to Seedvault. (This is about associated extra things to App Backups, not about backup user-storage!)

For each App have something like the Firewall UI:

1. Backup App ( o)
2. Backup App Data ( o)
   • Maximum Backed up Data size (give warnings when apps exceed this!)
   • (in future) Force backup even when App rejects it (o )
3. Backup additional Files and folders ( o)
   • [editable list of folders and filenames] (possibly with globbing/pattern matching/regex)
   • Maximum extra files directories size (give warnings when apps exceed this!)

Description

• When only (1.) is selected then the app can be reinstalled from backup, but appears as if it was freshly installed.
• With (2.) the App can be restored including its data directory (configuration) (could there even be more granularity here? config, user data, cached things). Mostly as it is today, with little more control
• Finally (3.) enables to backup data that is loosely associated with an App together with it (see examples below)

Discussion (for 3.)

Since all kinds of files and folders can be associated with any App this association needs to be loose. When backing things up all these files need to be deduplicated in case there are overlaps. Imagine one associates the DCIM folder with Camera and Gallery (bad example because this is covered by 'user storage backup' but bear with it). One wants to backups files from this folder either when new photos by the Camera where taken or when one used the Gallery edit functions to modify/tag a photo. Still one would want that things don't appear multiple times in the backup itself and bloat it.

Examples (for 3.)

• Osmand lets one create the bulk storage for maps elsewhere
• Termux can export a backup with the termux-backup command elsewhere
• Orgzly can use different locations for importing/syncing its notes
• Some Programs that disallow Backups for security reasons. Often these Applications have their own backup/restore capability and let a user select some directory on the filesystem where it shall be created.
  • For some common/known Apps may have a curated list of such storage locations to back up (defaults still editable by the user)

[grote]

It sounds like you are suggesting two new features here: The ability to decide per app if if should get backed up and the ability to back up more files than the backup API is giving us. Usually it is best to limit one ticket to one feature.