otaproxy: not register atexit handler by us, instead use uvicorn's ex…

…it handler

src/ota_proxy/__init__.py

@@ -15,11 +15,7 @@
 
 from __future__ import annotations
 
-import atexit
 import logging
-from functools import partial
-
-from ota_proxy.external_cache import mount_external_cache, umount_external_cache
 
 from .cache_control_header import OTAFileCacheControl
 from .config import config
@@ -53,25 +49,14 @@ async def run_otaproxy(
 
     from . import App, OTACache
 
-    _loaded_mnt_point = None
-    if external_cache_mnt_point and (
-        _loaded_mnt_point := mount_external_cache(external_cache_mnt_point)
-    ):
-        _loaded_mnt_point = str(_loaded_mnt_point)
-
-        def _atexit(_mnt_point) -> None:
-            umount_external_cache(_mnt_point)
-
-        atexit.register(partial(_atexit, _loaded_mnt_point))
-
     _ota_cache = OTACache(
         base_dir=cache_dir,
         db_file=cache_db_f,
         cache_enabled=enable_cache,
         upper_proxy=upper_proxy,
         enable_https=enable_https,
         init_cache=init_cache,
-        external_cache_mnt_point=_loaded_mnt_point,
+        external_cache_mnt_point=external_cache_mnt_point,
     )
     _config = uvicorn.Config(
         App(_ota_cache),

src/ota_proxy/ota_cache.py

@@ -37,6 +37,7 @@
 from .config import config as cfg
 from .db import CacheMeta, check_db, init_db
 from .errors import BaseOTACacheError
+from .external_cache import mount_external_cache, umount_external_cache
 from .lru_cache_helper import LRUCacheHelper
 from .utils import read_file, url_based_hash
 
@@ -137,10 +138,16 @@ def __init__(
         )
 
         self._external_cache_data_dir = None
-        if external_cache_mnt_point and cache_enabled:
+        self._external_cache_mp = None
+        if (
+            cache_enabled
+            and external_cache_mnt_point
+            and mount_external_cache(external_cache_mnt_point)
+        ):
             logger.info(
                 f"external cache source is enabled at: {external_cache_mnt_point}"
             )
+            self._external_cache_mp = external_cache_mnt_point
             self._external_cache_data_dir = (
                 Path(external_cache_mnt_point) / cfg.EXTERNAL_CACHE_DATA_DNAME
             )
@@ -224,6 +231,9 @@ async def close(self):
                 if self._cache_enabled:
                     self._lru_helper.close()
 
+                if self._external_cache_mp:
+                    umount_external_cache(self._external_cache_mp)
+
         logger.info("shutdown ota-cache completed")
 
     def _background_check_free_space(self):