[CRIU] rewriting images via criu (or crit?)

[Tycho Andersen]

On Mon, Oct 27, 2014 at 05:10:33PM +0200, Ruslan Kuprieiev wrote:
> Hi all,
> 
> I was recently thinking about converting/modifying images and i want to
> share some of my thoughts.
> For now I see 4 main ways:
> 
> 1) Use existing patch set for crit written in python.
> Pros:
>     1. Already works.
>     2. Python project is easy to support.
>     3. Adding xpath-like language for modifying images should be easy in
> Python.
>     4. All needed dependencies are available in (any?) repo.
> Cons:
>     1. Performance(maybe we could use Cython to make it better?).
> 
> 2) Rewrite crit in C
> Pros:
>     1. Performance.
> Cons:
>     1. C project is hard to support.
>     3. Adding xpath-like language for modifying images is not as easy as in
> Python.
>     4. Requires protobuf-c-text, which is quite new and isn't available in
> repos.
> 
> 3) Add crit functionality to criu ("criu convert", "criu modify").
> Pros:
>     1. Performance
>     2. Allows us to reuse a bunch of existing code.
>     3. Having such tool shipped along with "criu show" looks like a nice
> feature.
>     4. We can easily teach criu how to use images in text format, which
> seems
>         quite handy.
> Cons:
>     1. criu is already complex enough and adding more stuff might be too
> much,
>         especially xpath-like language engine.
>     2. Hard to support.
>     3. Requires protobuf-c-text, which is quite new and isn't available in
> repos.
>     4. Requires heavy patching to existing code.
> 
> 4) Use 1), but for _high-speed_ image modification use criu plugins and
> hooks
>     to modify images on restore.
> Pros:
>     1. Performance.
>     2. No heavy patching.
> Cons:
>     Can't see any.
> 
> I prefer 4) because it seems like a good compromise.
> What do you guys think?

Does that mean we'd need to expose all the protobuf headers? Will
users then need to link against libprotobuf?

Tycho