Container Support

Failure shows up in tests:

_____________________ PullContentTestCase.test_pull_image ______________________
self = <pulp_docker.tests.functional.api.test_pull_content.PullContentTestCase testMethod=test_pull_image>
    def test_pull_image(self):
        """Verify that a client can pull the image from Pulp.

        1. Using the RegistryClient pull the image from Pulp.
        2. Pull the same image from remote registry.
        3. Verify both images has the same checksum.
        4. Ensure image is deleted after the test.
        """
        registry = cli.RegistryClient(self.cfg)
        registry.raise_if_unsupported(
            unittest.SkipTest, 'Test requires podman/docker'
        )

        local_url = urljoin(
            self.cfg.get_content_host_base_url(),
            self.distribution['base_path']
        )

>       registry.pull(local_url)
pulp_docker/tests/functional/api/test_pull_content.py:151: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
../../../virtualenv/python3.7.1/lib/python3.7/site-packages/pulp_smash/cli.py:965: in _dispatch_command
    result = self._client.run(cmd, sudo=True)
../../../virtualenv/python3.7.1/lib/python3.7/site-packages/pulp_smash/cli.py:257: in run
    return self.response_handler(completed_process)
../../../virtualenv/python3.7.1/lib/python3.7/site-packages/pulp_smash/cli.py:54: in code_handler
    completed_proc.check_returncode()
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
self = CompletedProcess(args=('sudo', 'podman', 'pull', 'localhost:8080/1d95b8a8-f9f6-43c2-bed2-48cb47023154'), returncode=12...b47023154": Invalid image name "localhost:8080/1d95b8a8-f9f6-43c2-bed2-48cb47023154", unknown transport "localhost"\n')
    def check_returncode(self):
        """Raise an exception if ``returncode`` is non-zero.

        Raise :class:`pulp_smash.exceptions.CalledProcessError` if
        ``returncode`` is non-zero.

        Why not raise ``subprocess.CalledProcessError``? Because stdout and
        stderr are not included when str() is called on a CalledProcessError
        object. A typical message is::

            "Command '('ls', 'foo')' returned non-zero exit status 2"

        This information is valuable. One could still make
        ``subprocess.CalledProcessError`` work by overloading ``args``:

        >>> if isinstance(args, (str, bytes)):
        ...     custom_args = (args, stdout, stderr)
        ... else:
        ...     custom_args = tuple(args) + (stdout, stderr)
        >>> subprocess.CalledProcessError(args, returncode)

        But this seems like a hack.

        In addition, it's generally good for an application to raise expected
        exceptions from its own namespace, so as to better abstract away
        dependencies.
        """
        if self.returncode != 0:
            raise exceptions.CalledProcessError(
>               self.args, self.returncode, self.stdout, self.stderr
            )
E           pulp_smash.exceptions.CalledProcessError: Command ('sudo', 'podman', 'pull', 'localhost:8080/1d95b8a8-f9f6-43c2-bed2-48cb47023154') returned non-zero exit status 125.
E           
E           stdout: 
E           
E           stderr: Trying to pull docker://localhost:8080/1d95b8a8-f9f6-43c2-bed2-48cb47023154...time="2019-03-26T17:32:04Z" level=error msg="Error pulling image ref //localhost:8080/1d95b8a8-f9f6-43c2-bed2-48cb47023154:latest: Error determining manifest MIME type for docker://localhost:8080/1d95b8a8-f9f6-43c2-bed2-48cb47023154:latest: Error reading manifest latest in localhost:8080/1d95b8a8-f9f6-43c2-bed2-48cb47023154: received unexpected HTTP status: 500 Internal Server Error" 
E           Failed
E           (0x178cce0,0xc420144720)
E           Error: error pulling image "localhost:8080/1d95b8a8-f9f6-43c2-bed2-48cb47023154": Invalid image name "localhost:8080/1d95b8a8-f9f6-43c2-bed2-48cb47023154", unknown transport "localhost"

I was able to reproduce locally:

podman pull localhost:8080/foo
Trying to pull docker://localhost:8080/foo...Failed
(0x179ec00,0xc420270320)
Error: error pulling image "localhost:8080/foo": Invalid image name "localhost:8080/foo", unknown transport "localhost"

Docker pull doesnt work either:

docker pull localhost:8080/foo
Using default tag: latest
Error response from daemon: received unexpected HTTP status: 500 Internal Server Error

FYI:

cat /etc/docker/daemon.json
{
    "insecure-registries" : ["localhost:8080"]
}

cat /etc/containers/registries.conf 
[registries.search]
registries = ["docker.io", "registry.fedoraproject.org", "quay.io", "registry.access.redhat.com", "registry.centos.org"]
[registries.insecure]
registries = ["localhost:8080"]
[registries.block]
registries = []

 http http://localhost:8000/pulp/api/v3/docker-distributions/
HTTP/1.1 200 OK
Allow: GET, POST, HEAD, OPTIONS
Connection: close
Content-Length: 394
Content-Type: application/json
Date: Tue, 26 Mar 2019 19:31:47 GMT
Server: gunicorn/19.9.0
Vary: Accept, Cookie
X-Frame-Options: SAMEORIGIN

{
    "count": 1,
    "next": null,
    "previous": null,
    "results": [
        {
            "_created": "2019-03-26T19:13:58.403236Z",
            "_href": "/pulp/api/v3/docker-distributions/e880d0f3-891b-4a90-a235-15c50df6370e/",
            "base_path": "foo",
            "content_guard": null,
            "name": "baz",
            "publication": "/pulp/api/v3/publications/6663b5f9-d8c5-4cc4-88e6-cab081e1d953/",
            "publisher": null,
            "registry_path": "localhost:8080/foo",
            "remote": null,
            "repository": null
        }
    ]
}