feat: filesystem directory backup

[a-mesin]

closes #16

Source directory of the backup is getting archived in a tar archive and compressed with gzip resulting in a .tar.gzip file at the configured destination.

Still missing:

• check if tests are needed and if yes implement them

[a-mesin]

Caveat: filename in destination config needs to have the file type .tar.gz. This will not be needed once #26 is implemented

[iabudiab]

Hey there, two questions / points:

• Why not filepath.WalkDir?
• What about symlinks? They are not followed, but the callback is still called for symlinks, if I'm not mistaken. For example, rsync -a preserve symlinks among other things. lifeboat should offer this option too.

And on the topic of rsync, maybe it can be used as an external tool if available. You know, reinventing the wheel and yada yada 😉

[a-mesin]

Hey there, two questions / points:

• Why not filepath.WalkDir?
• What about symlinks? They are not followed, but the callback is still called for symlinks, if I'm not mistaken. For example, rsync -a preserve symlinks among other things. lifeboat should offer this option too.

And on the topic of rsync, maybe it can be used as an external tool if available. You know, reinventing the wheel and yada yada 😉

Hey,

first of all thanks for having a look :)

• looks like filepath.WalkDir is indeed the better choice here as appearently it is a more performant/efficient version of filepath.Walk - thanks for pointing it out
• Symlinks are a complicated one in our use case as we want to support abitrary destinations for a backup. What happens f.e. when the file should be "backupped" into an S3 where the Symlink might point to a non-existing file? One idea could be to actually include the followed file into the final tar?

As for using rsync: the idea was to depend on as few external tools as possible so it can be used in as many environments as possible without the need for other tools.

[a-mesin]

Just checked the symlink issue: looks like resolving the symlink is quite trivial - therefore I would just add them...

[iabudiab]

Regarding the symlinks, I would do something similar to the tar utility itself, i.e. include the symlinks as soft-links in the archive. Here we have two cases:

• either the links are relative and point to some file inside the archive => they would work after unpacking
• or they are absolute and point to something outside => they would be broken after unpacking

With tar -h such links can be dereferenced