langchain/vectorstores/elastic_vector_search.py/ElasticVectorSearch/add_texts
class ElasticVectorSearch:    def add_texts(
        self,
        texts: Iterable[str],
        metadatas: Optional[List[dict]] = None,
        refresh_indices: bool = True,
        **kwargs: Any,
    ) -> List[str]:
        """Run more texts through the embeddings and add to the vectorstore.

        Args:
            texts: Iterable of strings to add to the vectorstore.
            metadatas: Optional list of metadatas associated with the texts.
            refresh_indices: bool to refresh ElasticSearch indices

        Returns:
            List of ids from adding the texts into the vectorstore.
        """
        try:
            from elasticsearch.exceptions import NotFoundError
            from elasticsearch.helpers import bulk
        except ImportError:
            raise ImportError(
                "Could not import elasticsearch python package. "
                "Please install it with `pip install elasticsearch`."
            )
        requests = []
        ids = []
        embeddings = self.embedding.embed_documents(list(texts))
        dim = len(embeddings[0])
        mapping = _default_text_mapping(dim)

        # check to see if the index already exists
        try:
            self.client.indices.get(index=self.index_name)
        except NotFoundError:
            # TODO would be nice to create index before embedding,
            # just to save expensive steps for last
            self.client.indices.create(index=self.index_name, mappings=mapping)

        for i, text in enumerate(texts):
            metadata = metadatas[i] if metadatas else {}
            _id = str(uuid.uuid4())
            request = {
                "_op_type": "index",
                "_index": self.index_name,
                "vector": embeddings[i],
                "text": text,
                "metadata": metadata,
                "_id": _id,
            }
            ids.append(_id)
            requests.append(request)
        bulk(self.client, requests)

        if refresh_indices:
            self.client.indices.refresh(index=self.index_name)
        return ids