Add Weaviate to Vector Databases

[CShorten]

Overview

Adds Weaviate as a vector database backend to Modaic with full support for vector search, metadata filtering, and complex data types.

Core Implementation

WeaviateBackend Class

• Implements VectorDBBackend interface for local and cloud-hosted instances
• Connection via __init__(url, api_key) or from_local() factory method
• Full collection CRUD: create, drop, list, check existence
• Record operations: add, retrieve by ID
• Vector search with configurable k and metadata filtering

Data Handling

• Automatic JSON serialization/deserialization for nested objects and dicts
• Support for arrays of primitives and objects
• Proper null/None value handling
• UUID-based record identification

MQL Filter Translation

• WeaviateTranslator converts Modaic queries to Weaviate filters
• Supports logical operators (AND, OR, NOT), comparisons (==, !=, >, <, etc.), and collection operators (IN, CONTAIN, LIKE)

Type System Integration

• Maps Modaic vector types (FLOAT, FLOAT16, BFLOAT16) to Weaviate formats
• Supports HNSW, FLAT, and DYNAMIC index types
• Distance metrics: cosine, L2, dot product, euclidean
• Schema translation handles all Modaic types including optionals and nested structures

Test Coverage

• Parameterized tests for local and hosted instances
• MQL translation validation
• Collection and record CRUD operations
• Vector search with various k values and filter combinations
• Multi-vector batch search
• Null value handling (advantage over backends like Milvus Lite)
• CustomContext test model covering all supported field types

All tests pass with proper resource cleanup.

[TyTodd]

Thanks for submitting. Implementation looks great! I'm running the test cases on hosted mode and getting this error.

        results_k1 = vector_database.search(collection_name, "query", k=1)
>       assert results_k1[0][0].context == context1
               ^^^^^^^^^^^^^^^^
E       IndexError: list index out of range

tests/databases/vector_database/test_weaviate.py:325: IndexError
================================================================================================================================================================================================= warnings summary ==================================================================================================================================================================================================
tests/databases/vector_database/test_weaviate.py::test_search[hosted]
  /Users/tytodd/Desktop/Modaic/code/modaic/.venv/lib/python3.11/site-packages/weaviate/warnings.py:206: DeprecationWarning: Dep025: You are using the `vector_index_config` argument in `collection.config.create()`, which is deprecated.
              Use the `vector_config` argument instead defining `vector_index_config` as a sub-argument.
              
    warnings.warn(

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
============================================================================================================================================================================================== short test summary info ==============================================================================================================================================================================================
FAILED tests/databases/vector_database/test_weaviate.py::test_search[hosted] - IndexError: list index out of range

Are you seeing this on your end?

Other than that I think its ready to merge.