How to use the metadata parameter in retriever.get_relevant_documents()?

[AlexPascu001]

I have an ElasticSearch retriever that I am using to get different Elasticsearch Documents (chunks). Each chunk has a metadata called category that I want to use to be able to filter documents based on that category (i. e. get only the documents that have metadata.category == my_category). I saw that there is a metadata parameter in the get_relevant_documents() function, however I don't understand how I can use it along with the callbacks and whether this would be able to solve my problem by getting only some documents from elastic.

[dosubot[bot]]

Hello @AlexPascu001! I'm here to help you with any bugs, questions, or contributions you have. Let's tackle this issue together!

To filter documents based on the category metadata using the get_relevant_documents() function with an ElasticSearch retriever in LangChain, you can utilize the metadata parameter to specify your filter criteria. Here's how you can do it:

1. Structure the Metadata Filter: You need to create a filter dictionary that specifies the metadata key and the value you want to filter by. For your case, it would look like this:

   metadata_filter = {"category": "my_category"}

2. Use the Metadata Filter in the Function: Pass this filter to the get_relevant_documents() function. The function will use this filter to retrieve only the documents that match the specified category.

3. Integrate with Callbacks: If you are using callbacks, you can pass them along with the metadata filter. The callbacks parameter allows you to handle events during the retrieval process, but it doesn't directly affect the filtering logic.

Here's an example of how you might set this up:

results = retriever.get_relevant_documents(
    query="your_query",
    metadata=metadata_filter,
    callbacks=your_callbacks  # Optional: if you have any callbacks to handle events
)

This setup will retrieve documents that have the category metadata equal to my_category. The callbacks parameter is used to manage events during the retrieval process and does not interfere with the metadata filtering ^[1].

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