'Get the ID of a repository
:param  repository_name: The unique name of the repository
:type   repository_name: ``str``
:return: The repository ID
:rtype: ``str``'

def ex_get_repository_id(self, repository_name):

    request = {'repositoryNames': [repository_name]}
    list_response = self.ecr_connection.request(ROOT, method='POST', data=json.dumps(request), headers=self._get_ecr_headers('DescribeRepositories')).object
    repository_id = list_response['repositories'][0]['registryId']
    return repository_id
