feat(server): add workbench API, DSH planner worker and RAG pipeline

server/app/rag/backend.py

@@ -0,0 +1,78 @@
+"""Vector backend configuration.
+
+Default is ``disabled`` for lightweight local startup. Install optional local
+RAG dependencies and set RAG_VECTOR_BACKEND=chroma to restore local vectors.
+"""
+from __future__ import annotations
+
+import importlib.util
+import json
+import os
+from pathlib import Path
+from ..config import DATA_DIR
+
+
+def settings():
+    path = DATA_DIR / 'rag-backend.json'
+    try:
+        config = json.loads(path.read_text(encoding='utf-8'))
+        if not isinstance(config, dict):
+            raise ValueError('知识索引配置必须是对象')
+    except FileNotFoundError:
+        config = {}
+    value = os.environ.get('RAG_VECTOR_BACKEND', config.get('backend', 'disabled'))
+    backend_name = str(value or 'disabled').strip().lower()
+    if backend_name not in {'disabled', 'chroma', 'qdrant'}:
+        raise ValueError('知识索引后端配置无效')
+    return {**config, 'backend': backend_name}
+
+
+def configured_backend() -> str:
+    return settings()['backend']
+
+
+def local_chroma_available() -> bool:
+    return importlib.util.find_spec('chromadb') is not None
+
+
+def effective_backend() -> str:
+    """Return the backend that can actually run in this installation."""
+    value = configured_backend()
+    if value == 'chroma' and not local_chroma_available():
+        return 'disabled'
+    return value
+
+
+def is_disabled() -> bool:
+    return effective_backend() == 'disabled'
+
+
+def is_qdrant():
+    return effective_backend() == 'qdrant'
+
+
+def qdrant_settings():
+    config = settings()
+    url = str(os.environ.get('QDRANT_URL', config.get('url', ''))).rstrip('/')
+    if not url.startswith(('http://', 'https://')):
+        raise ValueError('请配置 Qdrant 服务地址')
+    key = os.environ.get('QDRANT_API_KEY', '')
+    if not key and config.get('api_key_file'):
+        key = Path(config['api_key_file']).read_text(encoding='utf-8').strip()
+    if not key:
+        raise ValueError('请配置 Qdrant API 密钥')
+    prefix = str(config.get('collection_prefix', 'yawan_'))
+    if not prefix or not all(c.isalnum() or c in '_-' for c in prefix):
+        raise ValueError('Qdrant 知识库命名空间无效')
+    return url, key, prefix
+
+
+def namespace():
+    value = effective_backend()
+    if value == 'qdrant':
+        config = settings()
+        return json.dumps(['qdrant', str(os.environ.get('QDRANT_URL', config.get('url', ''))).rstrip('/'),
+                           str(config.get('collection_prefix', 'yawan_'))], separators=(',', ':'))
+    if value == 'disabled':
+        return 'disabled'
+    return 'chroma' if local_chroma_available() else 'chroma-missing'