Pause snapshots

[ygerlach]

This adds the ability to pause scheduled snapshots (those started with --scripted).
To do this, i added an option to the timeshift.json, that can contain a string with a boot_id or a timestamp.
When a snapshot is to be created, these values are checked and the snapshot might be skipped.

Here a screenshot of the ui:

unpause is only available, if snapshots are currently paused.

Fixes: #295

[DJCrashdummy]

just my 2 cents: as "unpause" is only available if snapshots are paused, i would suggest to put it on top of the list... therefore it jumps right into your eyes (if present) and you don't have to go down the whole list.
perhaps even place "pause until shutdown" at the first place after "unpause" as it might be the most used option.

[mtwebster]

typo 'snpashots'

[ygerlach]

just my 2 cents: as "unpause" is only available if snapshots are paused, i would suggest to put it on top of the list... therefore it jumps right into your eyes (if present) and you don't have to go down the whole list. perhaps even place "pause until shutdown" at the first place after "unpause" as it might be the most used option.

I have now reordered the entrys. "Unpause" is always visible, but gray when currently not paused. (See screenshot)

I am not sure if i like it that the "ordering" of the entrys is not a bit "messed up". But that might be just me.
As it is now:

• pause time 0
• pause time infinite
• pause time 30 min
• pause time 4h
• ...

[DJCrashdummy]

stupid question: what happens if a snapshot is prohibited because of a pause?
is it simply completely skipped or does it take place after Timeshift is unpaused?
-> i'm asking because if someone only has monthly snapshots active, and even if just one gets skipped completely because he paused Thimeshift for a short period of time to be on the safe side... it punches quite a hole in the backup strategy.

[ygerlach]

stupid question: what happens if a snapshot is prohibited because of a pause? is it simply completely skipped or does it take place after Timeshift is unpaused? -> i'm asking because if someone only has monthly snapshots active, and even if just one gets skipped completely because he paused Thimeshift for a short period of time to be on the safe side... it punches quite a hole in the backup strategy.

The snapshots are delayed until the snapshots are unpaused. Thats what timeshift does anyways. It has some moments (once every hour or something), when it checks if it needs to do a snapshot and if it doesnt need one (or its paused) it just terminates. As soon as the next check is triggered it continues to create snapshots. The same way it would if the computer was off during the planned once-a-month snapshot.