feat(vector-io): add OpenGauss vector database provider

Implement OpenGauss vector database integration for Llama Stack with the following features:
- Add OpenGaussVectorIOAdapter for vector storage and retrieval
- Support native vector similarity search operations
- Implement connection and query management with psycopg2
- Provide configuration template for easy setup
- Add comprehensive unit tests

The implementation allows Llama Stack users to leverage OpenGauss as an
enterprise-grade vector database for RAG applications. Users can configure
their environment through a simple YAML configuration and environment variables.

llama_stack/templates/opengauss-demo/__init__.py

@@ -0,0 +1,9 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+# from .mymilvus_demo import get_distribution_template
+
+# __all__ = ["get_distribution_template"]

llama_stack/templates/opengauss-demo/build.yaml

@@ -0,0 +1,27 @@
+version: 2
+distribution_spec:
+  description: "Custom configuration using Opengauss for vector storage and metadata"
+  providers:
+    inference:
+      - remote::together-openai-compat
+    vector_io:
+      - remote::opengauss
+    agents:
+      - inline::meta-reference
+    tool_runtime:
+      - inline::rag-runtime
+    files:
+      - inline::localfs
+    telemetry:
+      - inline::meta-reference
+    safety:
+      - inline::llama-guard
+
+image_type: venv
+additional_pip_packages:
+  - psycopg2-binary>=2.9.3
+  - pgvector>=0.2.0
+  - asyncpg>=0.27.0
+# rm -rf ~/.llama/distributions/opengauss-demo
+# uv run --with llama-stack llama stack build --template opengauss-demo --image-type venv
+# uv run --env-file .env --with llama-stack llama stack run /home/gt/.llama/distributions/opengauss-demo/opengauss-demo-run.yaml

llama_stack/templates/opengauss-demo/run.yaml

@@ -0,0 +1,96 @@
+version: 2
+image_name: opengauss-demo
+apis:
+  - agents
+  - inference
+  - vector_io
+  - tool_runtime
+  - files
+  - models
+  - telemetry
+  - safety
+
+providers:
+  inference:
+    - provider_id: together
+      provider_type: remote::together
+      config:
+        api_key: ${env.TOGETHER_API_KEY}
+        url: ${env.TOGETHER_API_BASE_URL}
+    - provider_id: sentence-transformers
+      provider_type: inline::sentence-transformers
+      config: {}
+
+  vector_io:
+    - provider_id: opengauss
+      provider_type: remote::opengauss
+      config:
+        host: ${env.OPENGAUSS_HOST}
+        port: ${env.OPENGAUSS_PORT:=5432}
+        db: ${env.OPENGAUSS_DB}
+        user: ${env.OPENGAUSS_USER}
+        password: ${env.OPENGAUSS_PASSWORD}
+
+  agents:
+    - provider_id: meta-reference
+      provider_type: inline::meta-reference
+      config:
+        persistence_store:
+          type: sqlite
+          db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/opengauss-demo}/agent_store.db
+        responses_store:
+          type: sqlite
+          db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/opengauss-demo}/agent_responses.db
+        tool_store:
+          type: sqlite
+          db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/opengauss-demo}/agent_tools.db
+
+  tool_runtime:
+    - provider_id: rag-runtime
+      provider_type: inline::rag-runtime
+      config: {}
+
+  files:
+    - provider_id: localfs
+      provider_type: inline::localfs
+      config:
+        storage_dir: ${env.LOCALFS_BASE_PATH:=~/.llama/distributions/opengauss-demo/files}
+        metadata_store:
+          type: sqlite
+          db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/opengauss-demo}/files_metadata.db
+
+  telemetry:
+    - provider_id: meta-reference
+      provider_type: inline::meta-reference
+      config: {}
+
+  safety:
+    - provider_id: llama-guard
+      provider_type: inline::llama-guard
+      config: {}
+
+models:
+  - model_id: meta-llama/Llama-3.3-70B-Instruct-Turbo
+    model_type: llm
+    provider_id: together
+    provider_model_id: meta-llama/Llama-3.3-70B-Instruct-Turbo
+    metadata: {}
+
+  - model_id: all-MiniLM-L6-v2
+    model_type: embedding
+    provider_id: sentence-transformers
+    provider_model_id: all-MiniLM-L6-v2
+    metadata:
+      embedding_dimension: 384
+
+metadata_store:
+  type: sqlite
+  db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/opengauss-demo}/registry.db
+
+inference_store:
+  type: sqlite
+  db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/opengauss-demo}/inference_store.db
+
+tool_groups:
+  - toolgroup_id: builtin::rag
+    provider_id: rag-runtime