Docker Support

v1 repositories have repository tags and v2 repositories have manifests. Nothing identifies whether a given repository is v1 or v2, so the plan is to loop over all the tags in a repo and publish them as v1 content, and then to loop over the manifests in a repo and publish them as v2 content. This does mean that a repository can have v1 and v2 content at the same time, and that the content won't necessarily be the same. However, it advantageous because it keeps the design simpler.

It was also noted that v2 content can be published by Pulp in a format that is acceptable to the docker client so we will do that as part of this effort as well.

I've attached a couple of scripts that help you quickly go from a Vagrant up in a master checkout of all Pulp repositories to a running Docker v2 against Pulp 2.6. To use them, I recommend putting them in your pulp_docker folder on the host and then:

0) vagrant up
1) Make some coffee
2) vagrant ssh
3) workon pulp_docker
4) time ./setup_v2.sh
5) Drink said coffee (step 4 takes about 4 minutes on my spinny disk computerbox)
6) Profit
6a) You can now run pulp-admin docker repo sync run --repo-id v1_busybox to make sure v1 publish still works
6b) You can now run pulp-admin docker repo sync run --repo-id v2_registry to test your new v2 publish code

https://github.com/pulp/pulp_docker/pull/85/

Applied in changeset 4d3a7dd9bb9e3862fc019decbb20cd9a46464a92.

This story is not fully complete, as there is one step left to solve. We need some way to inject the Docker-Content-Digest header into the Manifest GET handler, as described at https://github.com/docker/distribution/blob/release/2.0/docs/spec/api.md#get-manifest . Without that header, Pulp cannot sync from itself and I suspect that the Docker client will not work with Pulp either.

I was planning to use htaccess files to add the Docker-Content-Digest headers. I'm not completely sure this will work, but I believe it has a good chance of solving the problem. If this works, we can have the Distributor create an htaccess file when publishing the manifests.

I filed a story about figuring out how to serve the Manifest's digest header, so we can call this work "done".

I'm gonna pulp-smash this mammajamma.

Verified by pulp-smash.