refactor: FastAPI Depends injection replacing globals, real health check, logging config

src/server/deps.py

@@ -0,0 +1,61 @@
+"""FastAPI 依赖注入 — 集中管理应用状态, 替代模块级全局变量."""
+import os
+import logging
+
+from src.core.config import load_config
+from src.core.db import VectorDB
+from src.core.embedder import create_embedder
+from src.core.ingest import DocumentIngestor
+from src.core.search import Searcher
+
+logger = logging.getLogger(__name__)
+
+
+class AppState:
+    """应用级共享状态."""
+
+    def __init__(self):
+        config_path = os.environ.get("MD_VECTOR_CONFIG", "config.yaml")
+        self.config = load_config(config_path)
+
+        data_dir = os.environ.get(
+            "MD_VECTOR_DB_DATA_DIR", self.config.chroma.persist_dir
+        )
+        self.db = VectorDB(persist_dir=data_dir)
+
+        self.embedder = create_embedder(self.config.embed)
+
+        collection = os.environ.get(
+            "MD_VECTOR_DB_COLLECTION", self.config.chroma.collection_name
+        )
+        self.searcher = Searcher(self.db, self.embedder, collection)
+        self.ingestor = DocumentIngestor(self.db, self.embedder, collection)
+
+    def is_healthy(self) -> dict:
+        """真实健康检查: 验证 ChromaDB 和 Embedder 是否可用."""
+        status = {"status": "ok", "checks": {}}
+        try:
+            count = self.searcher.collection.count()
+            status["checks"]["chromadb"] = {"status": "ok", "count": count}
+        except Exception as e:
+            status["checks"]["chromadb"] = {"status": "error", "detail": str(e)}
+            status["status"] = "degraded"
+        try:
+            dim = self.embedder.dimension
+            status["checks"]["embedder"] = {"status": "ok", "dimension": dim}
+        except Exception as e:
+            status["checks"]["embedder"] = {"status": "error", "detail": str(e)}
+            status["status"] = "degraded"
+        return status
+
+
+_state: AppState | None = None
+
+
+def get_state() -> AppState:
+    """获取应用状态单例 (懒初始化)."""
+    global _state
+    if _state is None:
+        logger.info("初始化应用状态...")
+        _state = AppState()
+    return _state