def get_digest_from_prefix()

in appengine/reconciletags/tag_reconciler.py [0:0]

• 14 lines of code
• 6 McCabe index (conditional complexity)

    def get_digest_from_prefix(self, repo, prefix):
        name = docker_name.Repository(repo)
        creds = docker_creds.DefaultKeychain.Resolve(name)
        transport = transport_pool.Http(httplib2.Http)

        with docker_image.FromRegistry(name, creds, transport) as img:
            digests = [d[len('sha256:'):] for d in img.manifests()]
            matches = [d for d in digests if d.startswith(prefix)]
            if len(matches) == 1:
                return matches[0]
            if len(matches) == 0:
                raise AssertionError('{0} is not a valid prefix'.format(
                                                                 prefix))
        raise AssertionError('{0} is not a unique digest prefix'.format(
                                                                 prefix))