Ensure an image source is present on the computenode

    name : string
        source url
    source_type : string
        source type (imgapi or docker)

def source_present(name, source_type='imgapi'):
    '''
    Ensure an image source is present on the computenode

    name : string
        source url
    source_type : string
        source type (imgapi or docker)
    '''
    ret = {'name': name,
           'changes': {},
           'result': None,
           'comment': ''}

    if name in __salt__['imgadm.sources']():
        # source is present
        ret['result'] = True
        ret['comment'] = 'image source {0} is present'.format(name)
    else:
        # add new source
        if __opts__['test']:
            res = {}
            ret['result'] = True
        else:
            res = __salt__['imgadm.source_add'](name, source_type)
            ret['result'] = (name in res)

        if ret['result']:
            ret['comment'] = 'image source {0} added'.format(name)
            ret['changes'][name] = 'added'
        else:
            ret['comment'] = 'image source {0} not added'.format(name)
            if 'Error' in res:
                ret['comment'] = '{0}: {1}'.format(ret['comment'], res['Error'])

    return ret