正式起服务打底

app/main.py

@@ -0,0 +1,51 @@
+# app/main.py
+from fastapi import FastAPI, Header, Depends
+
+from .config import get_settings
+from .db import check_health
+
+app = FastAPI(
+    title="LLZQ Backend",
+    version="0.1.0",
+)
+
+
+def resolve_db_name(x_llzq_env: str | None = Header(default=None, alias="X-LLZQ-Env")) -> str:
+    """
+    从请求头 X-LLZQ-Env 中解析要用的 DB 名。
+    """
+    settings = get_settings()
+    return settings.resolve_db_name(x_llzq_env)
+
+
+@app.get("/api/ping")
+def ping(db_name: str = Depends(resolve_db_name)):
+    """
+    最简单调通接口：
+    - 返回当前后端环境
+    - 返回实际连接的 DB 名
+    - 简单做一个 DB 健康检查
+    """
+    settings = get_settings()
+    ok = False
+    error_msg = None
+
+    try:
+        ok = check_health(db_name)
+    except Exception as e:
+        error_msg = str(e)
+
+    return {
+        "ok": ok,
+        "app_env": settings.app_env,
+        "db": db_name,
+        "error": error_msg,
+    }
+
+
+@app.get("/api/healthz")
+def healthz():
+    """
+    给 Nginx / 监控用的探活接口，不查 DB。
+    """
+    return {"status": "ok"}