Source code for langchain.retrievers.merger_retriever

import asyncio
from typing import List

from langchain_core.callbacks import (
    AsyncCallbackManagerForRetrieverRun,
    CallbackManagerForRetrieverRun,
)
from langchain_core.documents import Document
from langchain_core.retrievers import BaseRetriever


[docs]class MergerRetriever(BaseRetriever): """Retriever that merges the results of multiple retrievers.""" retrievers: List[BaseRetriever] """A list of retrievers to merge.""" def _get_relevant_documents( self, query: str, *, run_manager: CallbackManagerForRetrieverRun, ) -> List[Document]: """ Get the relevant documents for a given query. Args: query: The query to search for. Returns: A list of relevant documents. """ # Merge the results of the retrievers. merged_documents = self.merge_documents(query, run_manager) return merged_documents async def _aget_relevant_documents( self, query: str, *, run_manager: AsyncCallbackManagerForRetrieverRun, ) -> List[Document]: """ Asynchronously get the relevant documents for a given query. Args: query: The query to search for. Returns: A list of relevant documents. """ # Merge the results of the retrievers. merged_documents = await self.amerge_documents(query, run_manager) return merged_documents
[docs] def merge_documents( self, query: str, run_manager: CallbackManagerForRetrieverRun ) -> List[Document]: """ Merge the results of the retrievers. Args: query: The query to search for. Returns: A list of merged documents. """ # Get the results of all retrievers. retriever_docs = [ retriever.get_relevant_documents( query, callbacks=run_manager.get_child("retriever_{}".format(i + 1)) ) for i, retriever in enumerate(self.retrievers) ] # Merge the results of the retrievers. merged_documents = [] max_docs = max(len(docs) for docs in retriever_docs) for i in range(max_docs): for retriever, doc in zip(self.retrievers, retriever_docs): if i < len(doc): merged_documents.append(doc[i]) return merged_documents
[docs] async def amerge_documents( self, query: str, run_manager: AsyncCallbackManagerForRetrieverRun ) -> List[Document]: """ Asynchronously merge the results of the retrievers. Args: query: The query to search for. Returns: A list of merged documents. """ # Get the results of all retrievers. retriever_docs = await asyncio.gather( *( retriever.aget_relevant_documents( query, callbacks=run_manager.get_child("retriever_{}".format(i + 1)) ) for i, retriever in enumerate(self.retrievers) ) ) # Merge the results of the retrievers. merged_documents = [] max_docs = max(len(docs) for docs in retriever_docs) for i in range(max_docs): for retriever, doc in zip(self.retrievers, retriever_docs): if i < len(doc): merged_documents.append(doc[i]) return merged_documents