def getDockerRunnerTypeAndConfigStr(dockerRunnerArg):
    """
    >>> getDockerRunnerTypeAndConfigStr('drType:drConfig')
    ('drType', 'drConfig')
    """
    idx = dockerRunnerArg.find(":")
    assert idx != -1
    drType = dockerRunnerArg[:idx]
    drConfig = dockerRunnerArg[idx + 1:]
    return (drType, drConfig)