[CRIU] CRIU and GO

[Adrian Reber]

On Wed, Oct 03, 2018 at 08:03:30AM -0700, Andrei Vagin wrote:
> On Wed, Oct 03, 2018 at 08:12:04AM +0200, Adrian Reber wrote:
> > On Tue, Oct 02, 2018 at 07:18:21PM -0700, Andrei Vagin wrote:
> > > On Tue, Oct 02, 2018 at 08:17:01AM +0200, Adrian Reber wrote:
> > > > Hello Andrei,
> > > > 
> > > > I am currently trying to add checkpoint/restore support to podman:
> > > > 
> > > > https://github.com/containers/libpod/pull/469
> > > > 
> > > > and I hope it will soon be merged. As I need at least CRIU 3.11 for
> > > > podman I would like to include a version check into podman.
> > > > 
> > > > As we already have a version check in GO in runc I was first looking at
> > > > the runc code but then I remembered the Pavel's CRIU go interface in
> > > > lib/go/.
> > > > 
> > > > So for podman I tried to vendor-in github.com/checkpoint-restore/criu
> > > > and started to wonder if we might want to have an independent GO
> > > > binding, because right now most of the vendor-in'd code is C code and
> > > > tests and not much GO code.
> > > 
> > > Is it impossible to vendor only github.com/checkpoint-restore/criu/lib/go/src/criu?
> > 
> > Hmm, the tool used to manage the vendoring (vndr) keeps all the .c files
> > around. If manually managing the vendor tree it would probably be
> > possible, but using the tool it is not. But I hardly have any
> > experience how to manage a GO project. Right now I get:
> > 
> > $ du -hs vendor/github.com/checkpoint-restore/criu
> > 5.8M	vendor/github.com/checkpoint-restore/criu
> > 
> > It just seems easier to detect the CRIU GO bindings if they would be a
> > separate repository, especially as it probably can live with a
> > completely different and much slower release schedule. Most changes
> > to CRIU are not necessarily necessary in the GO bindings. Right now the
> > GO code is buried in a lot of C code which the vndr tool does not delete
> > as it could be a cgo file.
> > 
> > > > So instead of including 'github.com/checkpoint-restore/criu/lib/go/src/criu'
> > > > we could have something like 'github.com/checkpoint-restore/go-criu' ?
> > > > 
> > > > What do you say? Would it make sense to have an independent go binding
> > > > for CRIU? Once it works we could start to also use it in runc...
> > 
> > The main idea was to have a canonical location for the go bindings which
> > is easy to detect and switch runc to using it once it exists. I would
> > like to use it in podman right now and the vendor/github.com tree is
> > around 20MB of which 5MB is CRIU. It basically is only a tool problem
> > (vndr), but it probably is more difficult to change the tool, then
> > provide CRIU go bindings separately.
> 
> Ok. All these sound reasonable. I don't have objections about a new repo.

OK, let me prepare something and I will post it here for review.

		Adrian