[Feature Request] Add runtime filter support to MilvusEmbeddingRetriever

[kukjun]

📝 Description

This PR adds runtime filter parameter support to all retriever classes (MilvusEmbeddingRetriever, MilvusSparseEmbeddingRetriever, and MilvusHybridRetriever), enabling dynamic metadata filtering at query time.

🎯 Motivation

Previously, filters could only be set during retriever initialization. This limitation prevented users from dynamically changing filter conditions at runtime, which is a common use case in production environments where filter criteria may vary per query.

• issues: [Feature Request] Add runtime filter support to MilvusEmbeddingRetriever #67
• reference pr: added pipeline dynamic filters #45

🔧 Changes

Code Changes

• MilvusEmbeddingRetriever.run(): Added optional filters parameter
• MilvusSparseEmbeddingRetriever.run(): Added optional filters parameter
• MilvusHybridRetriever.run(): Added optional filters parameter

All retrievers now support both:

1. Static filters: Set during initialization (existing behavior)
2. Runtime filters: Pass filters parameter to run() method (new feature)

Runtime filters take precedence over static filters when both are provided.

Test Coverage

Added comprehensive test coverage with test_run_using_filters() for each retriever class:

• TestMilvusEmbeddingTests.test_run_using_filters(): Tests dense embedding retrieval with runtime filters
• TestMilvusSparseEmbeddingTests.test_run_using_filters(): Tests sparse embedding retrieval with runtime filters
• TestMilvusHybridTests.test_run_using_filters(): Tests hybrid retrieval with runtime filters

📊 Example Usage

# Initialize retriever (with optional static filter)
retriever = MilvusEmbeddingRetriever(document_store)

# Apply runtime filter for specific query
filters = {"field": "category", "operator": "==", "value": "news"}
results = retriever.run(query_embedding, filters=filters)

# Different filter for next query
filters = {"field": "year", "operator": ">=", "value": 2023}
results = retriever.run(query_embedding, filters=filters)

[LuRe97]

I hope this gets merged soon, its really useful and also relatively short for that :)

[zc277584121]

/lgtm

[zc277584121]

@kukjun

seems need DCO, it means you have to append the sign-off to your commit message. Can you please check it again

[kukjun]

@zc277584121

I’ve finished it!

[zc277584121]

@kukjun merged at another PR #70