docs: 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