Docker Support

Steps to reproduce:

1. pulp-admin docker repo create --repo-id=synctest --feed=https://registry-1.docker.io --upstream-name=busybox --tags=latest

2) sync repo

[ipanova@ina pulp_docker]$ pulp-admin docker repo list

--------------------------------------------------------------------
Docker Repositories
--------------------------------------------------------------------

Id: synctest
Display Name: None
Description: None
Content Unit Counts:
Docker Blob: 17
Docker Manifest: 9
Docker Manifest List: 1
Docker Tag: 2

3) remove 1 manifest list by specifying its digest

pulp-admin -vv docker repo remove manifest-list --repo-id synctest --str-eq='digest=sha256:cb63aa0641a885f54de20f61d152187419e8f6b159ed11a251a09d115fdff9bd'

4) observe that number of docker manifests did not change, that means manifests where not purged as they should been

[ipanova@ina pulp_docker]$ pulp-admin docker repo list

--------------------------------------------------------------------
Docker Repositories
--------------------------------------------------------------------

Id: synctest
Display Name: None
Description: None
Content Unit Counts:
Docker Blob: 17
Docker Manifest: 9
Docker Manifest List: 0
Docker Tag: 1

Expected behaviour:

4) observe that number of docker manifest decreased, because unlinked manifests were removed with manifest list removal

[ipanova@ina pulp_docker]$ pulp-admin docker repo list

--------------------------------------------------------------------
Docker Repositories
--------------------------------------------------------------------

Id: synctest
Display Name: None
Description: None
Content Unit Counts:
Docker Blob: 2
Docker Manifest: 1
Docker Manifest List: 0
Docker Tag: 1