load dotenv everywhere it's needed; postgresql pool pre ping

app/utils/format.py

@@ -1,4 +1,7 @@
 import os
+from dotenv import load_dotenv
+
+load_dotenv()
 
 OSS_BASE_URL = os.getenv("OSS_BASE_URL", "").rstrip("/")
 

app/utils/s3.py

@@ -1,8 +1,9 @@
 import oss2
 import httpx
 import os
-import io
-from fastapi import HTTPException
+from dotenv import load_dotenv
+
+load_dotenv()
 
 # 加载配置
 ACCESS_KEY_ID = os.getenv("S3_ACCESS_KEY_ID")