dockerapp: avoid multiple current ostree installs

[doanac]

Compare current against target OSTree hash and skip the install call if
the same.

Signed-off-by: Ricardo Salveti ricardo@foundries.io
Signed-off-by: Andy Doan andy@foundries.io

[pattivacek]

This looks fine, but I'm a bit confused why this even happens. Shouldn't we catch this at an earlier stage during the check for updates? If a target is already installed, we shouldn't consider it a new update, and we should toss it out.

By coincidence, I was just looking at that code yesterday and will probably make a small PR to improve some things, but it won't change the basic idea here.

[mike-sul]

Shouldn't we catch this at an earlier stage during the check for updates?

I don't think that this stage present in aktualizr-lite if you mean SotaUptaneClient::checkUpdates() what eventually calls this line

aktualizr/src/libaktualizr/primary/sotauptaneclient.cc

Line 490 in ea1f81d

} else if (current_version->filename() != target.filename()) {

, the lite doesn't use the uptane cycle.

[doanac]

I didn't realize this was specific to aklite. I don't mind keeping this out of tree if you'd rather do that

[pattivacek]

I didn't realize this was specific to aklite. I don't mind keeping this out of tree if you'd rather do that

Nah, sorry, didn't mean to imply that. I was just trying to understand why this was necessary, since we already do a similar check. I think Mike is right that this is because of the unusual nature of this package manager. It's fine for now, I think.

[doanac]

Nah, sorry, didn't mean to imply that.

You didn't imply anything. There's a cost to ever "if" in a code base, so its always worth thinking about.