Allow extra tags to be provided for tagging the manifest list

[estesp]

Provide the ability to add "tags: [ .. ]" to the input YAML with a list
of additional tags to push to the registry against the manifest list
object being pushed.

Signed-off-by: Phil Estes estesp@gmail.com

Fixes: #23

And..seems to work :)

DEBU[0009] [extra tag "1.8"] push url: https://registry-1.docker.io/v2/estesp/bbimg/manifests/1.8
DEBU[0010] [extra tag "fred"] push url: https://registry-1.docker.io/v2/estesp/bbimg/manifests/fred
DEBU[0010] [extra tag "wilma"] push url: https://registry-1.docker.io/v2/estesp/bbimg/manifests/wilma
DEBU[0011] [extra tag "1.8-alpine"] push url: https://registry-1.docker.io/v2/estesp/bbimg/manifests/1.8-alpine
DEBU[0011] [extra tag "wilson-99"] push url: https://registry-1.docker.io/v2/estesp/bbimg/manifests/wilson-99
Digest: sha256:4b1a552465dd5a332c585fb1855d8db6592add9ada7d0583b0d3c92a20d74ca7

[tianon]

Was this comment intended to sound like a cliffhanger? (feels like it ends in the middle of a sentence)

[estesp]

Building up interest sometimes takes introducing a bit of PR-style mystery around things ;) =)

Real story: saw that I forgot to type the rest, got hungry for lunch and decided I could take care of pushing an update later :)

[tianon]

I can definitely work with this, no problem!!! ❤️ ❤️ ❤️

This should give us a really dramatic speedup!

(Now I want the same thing for docker push itself! hahahaha 😇)

[estesp]

(Now I want the same thing for docker push itself! hahahaha 😇)

Not too far-fetched.. basically I would call it something like docker rtag for remote tag operation? But maybe it can fit into the docker manifest workflow? It does require the code to fetch the actual manifest being tagged (as it ends up being a POST of that JSON bytestream to a different URL (with the tag reference), but that would be dramatically less work than gathering up all the manifest details, blob mounting, etc..

[tianon]

Yeah, that'd be awesome, and it looks like @StefanScherer figured out how to make it do exactly that (docker/cli#138 (comment))! 😄

We spend a lot of time doing docker push on the official images build server, and it ends up spending way more time than it needs to re-reading layers from disk to recreate blobs that end up being identical and no-op. 😞

[funkyfuture]

it'd be great to have that feature reflected in the README.

[nitkon]

Can we add additional tags using the "manifest-tool push from-args ..." command?

[estesp]

@nitkon this would require a PR to connect a new flag (--extra-tags?) to the capability that is currently only driven by the YAML format. Would you be interested in submitting that?