Re: [BuildStream] Introduce a docker sandbox

[Jürg Billeter <j bitron ch>]

Hi,

On Wed, 2018-10-31 at 23:36 +0900, Tristan Van Berkom via BuildStream-
list wrote:
> If the goal here is to have the capability of doing cross platform
> development without remote execution (or alternatively, with remote
> execution but without workers which run on the target execution
> environment natively), and if Docker can help to achieve this, then I
> think this should probably be implemented as a detail of BuildBox.
>
> This will probably be complicated to implement whether it is in
> BuildStream or BuildBox, but at least in BuildBox it is closer to
> other related sandboxing details, and so presumably more manageable
> and easier to ensure correctness across execution environments.

This makes sense to me as well, in line with the BuildBox goal to
support other platforms and sandboxing mechanisms.

That said, right now FUSE is still a hard requirement for BuildBox.
I.e., there is no fallback with hardlinks yet. This would likely have
to be implemented as prerequisite for actual Docker support. On the
plus side, we can hopefully use Docker's overlay support to prevent
cache corruption (as replacement for SafeHardlinks pyfuse).

This assumes the plan is to run Docker without an extra base image.
Another option could be to run BuildBox with FUSE and Bubblewrap in a
container (controlled by BuildBox on the host) to keep the benefit from
FUSE on-demand staging.

Jürg