Problem: Publications are not needed for Docker plugin

[dkliban]

Solution: Add 'repository_version' field to DockerDistribution

This patch allows users to create DockerDistributions that serve repository versions. A distribution can
be created with either a repository or repository version defined. If a repository is defined, the latest
version of that repository is always available at the distribution. If a repository version is specified,
then that repository version is always available at that distribution.

This patch updates an existing test and adds a new one. The two tests assert that a docker or podman pull
can be performed when a repository is used in a distribution and when a repository version is used.

This patch also fixes the tests to work with docker as the client.

closes: #4669
https://pulp.plan.io/issues/4669

[ipanova]

HTTP/1.1 400 Bad Request
Allow: GET, POST, DELETE, HEAD, OPTIONS
Connection: close
Content-Length: 61
Content-Type: application/json
Date: Wed, 17 Apr 2019 09:42:59 GMT
Server: gunicorn/19.9.0
Vary: Accept, Cookie
X-Frame-Options: SAMEORIGIN

{
    "publisher": [
        "Publisher must be set if repository is set."
    ]
}

(pulp) [vagrant@pulp3-source-fedora29 pulp_rpm]$ http POST http://localhost:8000/pulp/api/v3/docker-distributions/ name='baz' base_path='foo' repository=/pulp/api/v3/repositories/b8c1211c-baef-456d-829e-1db5d5189976/versions/1/
HTTP/1.1 400 Bad Request
Allow: GET, POST, DELETE, HEAD, OPTIONS
Connection: close
Content-Length: 59
Content-Type: application/json
Date: Wed, 17 Apr 2019 09:43:16 GMT
Server: gunicorn/19.9.0
Vary: Accept, Cookie
X-Frame-Options: SAMEORIGIN

{
    "repository": [
        "Invalid hyperlink - Incorrect URL match."
    ]
}

(pulp) [vagrant@pulp3-source-fedora29 pulp_rpm]$ http POST http://localhost:8000/pulp/api/v3/docker-distributions/ name='baz' base_path='foo' repository_version=/pulp/api/v3/repositories/b8c1211c-baef-456d-829e-1db5d5189976/versions/1/
HTTP/1.1 202 Accepted
Allow: GET, POST, DELETE, HEAD, OPTIONS
Connection: close
Content-Length: 67
Content-Type: application/json
Date: Wed, 17 Apr 2019 09:43:31 GMT
Server: gunicorn/19.9.0
Vary: Accept, Cookie
X-Frame-Options: SAMEORIGIN

{
    "task": "/pulp/api/v3/tasks/f312b192-1ffd-42dc-860f-164ff88b5044/"
}

[vagrant@pulp3-source-fedora29 pulp_rpm]$ http POST http://localhost:8000/pulp/api/v3/docker-distributions/ name='bazz' base_path='foo1' repository_version=/pulp/api/v3/repositories/b8c1211c-baef-456d-829e-1db5d5189976/
HTTP/1.1 202 Accepted
Allow: GET, POST, DELETE, HEAD, OPTIONS
Connection: close
Content-Length: 67
Content-Type: application/json
Date: Wed, 17 Apr 2019 09:52:06 GMT
Server: gunicorn/19.9.0
Vary: Accept, Cookie
X-Frame-Options: SAMEORIGIN

{
    "task": "/pulp/api/v3/tasks/ad492be8-b953-490e-9314-5f150ccfb946/"
}

@dkliban can you also reproduce this?

[ipanova]

@dkliban also podman pull has issues

$ podman pull localhost:8080/foo1:latest --tls-verify=False
Trying to pull docker://localhost:8080/foo1:latest...Failed
(0x1840f00,0xc000411460)
Error: error pulling image "localhost:8080/foo1:latest": Invalid image name "localhost:8080/foo1:latest", unknown transport "localhost"

[dkliban]

@ipanova The publisher validation code is coming from pulpcore. I updated the commit message to require pulp/pulpcore#93 but forgot to update the PR description. Please test again with both PRs.

[dkliban]

@ipanova When I tested earlier with docker, I ran into a problem where after the sync finished, not all ImageManifests were associated with the repository version. Then I got a 404 when trying to pull. However, after I cleaned out my DB and synced the repo again, I could not reproduce the problem and docker pull worked fine. I will try to reproduce again though.

[ipanova]

@dkliban i will re-test with pulpcore PR, sorry i did not check the commit message

[dkliban]

@ipanova I have fixed the problem with the repository_version not working. I've also added a test that checks that this works. I also updated the docs around Docker Distribution creation. I also made sure that the tests work when running on a system that only has docker installed and not podman. Please re-review.

[ipanova]

i re-tested, repo_version works as well as pull of the content with a client. thank you!