Ludovic Courtès <ludo@gnu.org> writes:

>> --- a/doc/guix.texi
>> +++ b/doc/guix.texi
>> @@ -2438,6 +2438,12 @@ Read a list of store file names from the standard input, one per line,
>>  and write on the standard output the subset of these files missing from
>>  the store.
>>  
>> +@item --export-docker-image=@var{directory}
>> +@cindex docker, export
>> +Recursively export the specified store directory as a Docker image in
>> +tar archive format.  The generated archive can be loaded by Docker using
>> +@command{docker load}.
>
> Maybe “as a Docker image in tar archive format, as specified in
> @uref{http://…, version 1.0 of the Foo Bar Spec}.”

Okay.

> I would be in favor of --format=FMT, where FMT can be one of “nar” or
> “docker”.  Maybe there’ll be others in the future.  WDYT?

Sounds good.

> The paragraph that says “Archives are stored in the “normalized archive”
> or “nar” format,“ should be updated.
>
> Also, it seems that ‘-f docker’ would always imply ’-r’, right?  That’s
> reasonable but would be worth mentioning.

Okay.

>> +(define (hexencode bv)
>> +  "Return the hexadecimal representation of the bytevector BV."
>> +  (format #f "~{~2,'0x~}" (bytevector->u8-list bv)))
>
> Maybe use ‘bytevector->base16-string’ from (guix utils) instead.

Ah, didn’t know about this one.

>> +(define spec-version "1.0")
>
> Please add the URL to said spec as a comment.

I added a clarifying comment (because confusingly this is NOT the
version of the Docker image spec).

>> +;; TODO: heroically copied from guix/script/pull.scm
>> +(define (temporary-directory)
>
> Alternatively, there’s ‘call-with-temporary-directory’ in (guix utils).
> :-)

Neat!

>> +          (and (zero? (apply system* "tar" "-cf" "layer.tar"
>> +                             (cons "../bin" items)))
>> +               (delete-file "../bin"))))
>
> This reminds me we should steal this code of Mark’s sometime:
>
>   https://github.com/spk121/guile100/blob/master/code/tar2.scm

Yes, this would be nice.

Attached is a new patch with all requested changes and a couple of fixes
(generated images now have proper names and tags).

~~ Ricardo