def get_objects(params):
    """
    Convert params from the "get_objects" RPC method into an Elasticsearch query.
    Retrieve a list of objects based on their upas.
    params:
        ids - list of string - Search document ids to fetch; ids are in a specific
        format for object indexes: "WS::<wsid>:<objid>"
    output:
        query - elasticsearch query for document ids specified in the params argument
    """
    return {'query': {'terms': {'_id': params['ids']}}}