feat: Add multi-datastore support to Vertex AI Search

[10Ala10]

Summary

Enhanced Vertex AI Search functionality to support multiple datastores while maintaining full backward compatibility. Previously only supported single datastore strings, now supports both single strings and lists of datastore IDs for cross-knowledge-base search capabilities.

Key changes:

• Updated vertexai_search_datastore type from Optional[str] to Optional[Union[str, List[str]]]
• Refactored validation and tool creation logic to handle multiple datastores cleanly
• Each datastore is now added as a separate tool, enabling the model to search across multiple knowledge bases simultaneously

Type of change

• Bug fix
• New feature
• Breaking change
• Improvement
• Model update
• Other:

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Checklist

• Code complies with style guidelines
• Ran format/validation scripts (./scripts/format.sh and ./scripts/validate.sh)
• Self-review completed
• Documentation updated (comments, docstrings)
• Examples and guides: Relevant cookbook examples have been included or updated (if applicable)
• Tested in clean environment
• Tests added/updated (if applicable)

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Additional Notes

Usage Examples:

Single Datastore (Backward Compatible):

Gemini(
    vertexai_search=True,
    vertexai_search_datastore="projects/project/locations/location/collections/collection/dataStores/datastore"
)

Multiple Datastores (New Feature):

Gemini(
    vertexai_search=True,
    vertexai_search_datastore=[
        "projects/project/locations/location/collections/collection/dataStores/datastore1",
        "projects/project/locations/location/collections/collection/dataStores/datastore2",
        "projects/project/locations/location/collections/collection/dataStores/datastore3"
    ]
)

Technical Implementation:

• Each datastore becomes a separate VertexAISearch tool
• Maintains full backward compatibility with existing single datastore usage

Files Modified:

• libs/agno/agno/models/google/gemini.py: Main implementation and documentation

This enhancement enables users to leverage multiple Vertex AI Search datastores in a single agent, greatly expanding the knowledge base search capabilities while keeping the API simple and intuitive.

[dirkbrnd]

Thanks for this! Would you mind adding a cookbook example? Or even better, a test.

[10Ala10]

Yes for sure , I'll add it!