snapd layout feature not supported

[Ondrej Kubik]

snapd landed new feature "layout" which needs to be supported by snapcraft

layout allows file system overlay, it is defined in snapcraft.yaml
Such a definition triggers error from snapcraft build
Issues while validating snapcraft.yaml: Additional properties are not allowed ('layout' was unexpected)

[Kyle Fazzari (kyrofa)]

Thanks ondra! Can you please include the snapd version for when this was introduced? Or is it still master?

[Ondrej Kubik (ondrak)]

layout has been now for some time in edge channel.
I verified functionality with 2.31.1+git607.a15e601~ubuntu16.04.1

[Gerry Boland (gerboland)]

I've also verified it with snapd in the edge channel (same rev as Ondrej). It is an extremely useful feature, allows me remove LD_PRELOAD shims which redirect file access, which was causing problems with some software.

[Gustavo Niemeyer (niemeyer)]

Please note that on the first release this feature will be blocked behind a feature flag that needs to be enabled in snapd itself by doing:

$ snap set core experimental.layouts=true

Snaps that use that feature will also be blocked for manual review in the store.

Both of those measures aim at giving us some more time of stabilization before we promise the feature as ready for use and with the usual syntax stability guarantees. That was deemed appropriate for this case due to the underlying complexity involved in getting it to work.

[Ondrej Kubik (ondrak)]

Gustavo that is fine, and indeed we should be careful when landing layouts.
I believe snapcraft allowing actual snap building is something which should happen in parallel, rather then start implementation once layouts land in stable

[Sergio Schvezov (sergiusens)]

This should probably go with the passthrough feature.

[Kyle Fazzari (kyrofa)]

Support added in this PR: https://github.com/snapcore/snapcraft/pull/2336

[Kyle Fazzari (kyrofa)]

Nevermind, this PR: https://github.com/snapcore/snapcraft/pull/2338