Add Ability to interrupt snapshot

[simonsmiley]

I started my intitial backup and realized it contained tons of files that I don't need a backup of.
I could not find any way of stopping a snapshot other than killing the processes...

[Germar]

This is already reported in #195 but I'll keep this open because pause is more difficult to implement.

[norgoe]

I have not tried this myself, but I thought backintime is using rsync.
Pausing should be a matter of sendng a TSTP or STOP signal to rsync.
A CONT signal should resume the paused rsync.
And if this fails a second rsync call with --partial should continue the operation where it left when paused / aborted.

[Germar]

Jepp, thats right (except --partial, that would be needed in first run to prevent partial transferred files from being transferred again). But there are some steps that need to be done before I can implement this. For example BIT starts all processes with os.system() and has no control over it after launch. I need to change this to subprocess.Popen().

[Coshibu]

I second this. Would be great to have the option to just cancel a backup.

[caco3]

This is a feature I also miss.
Also, if you delete a backup, the GUI freezes for a while without showing any progress/status information.

[Germar]

GUI freeze is fixed in 1.1.10

[simgunz]

Are there any progress on this feature? It happens so often that I need to stop a backup.

[Germar]

Jepp. I changed almost all external processes to subprocess.Popen(). So the basis for this feature is done.

[simgunz]

Good to hear that! Thanks for your work.

[caco3]

+1
@Germar: Thank you very much for your work!