Fix unhandled Redis exception in the /api/server/health/ endpoint

`CustomCacheBackend` does not handle `RedisError`, so if Redis is not
responding, the backend will propagate the exception, and the endpoint will
crash with a 500 response code.

This problem has been fixed upstream in django-health-check 3.18, so just
update to the latest version and remove our custom cache backend.

The upstream version, unlike ours, doesn't handle `sqlite3.DatabaseError`,
but we're not using SQLite for caching anymore, so I don't think it matters.

changelog.d/20240131_202605_roman_bump_health_check.md

@@ -0,0 +1,4 @@
+### Fixed
+
+- Fix Redis exceptions crashing the `/api/server/health/` endpoint
+  (<https://github.com/opencv/cvat/pull/7417>)

cvat/apps/health/apps.py

@@ -3,16 +3,12 @@
 # SPDX-License-Identifier: MIT
 
 from django.apps import AppConfig
-from django.conf import settings
 
 from health_check.plugins import plugin_dir
 
 class HealthConfig(AppConfig):
     name = 'cvat.apps.health'
 
     def ready(self):
-        from .backends import OPAHealthCheck, CustomCacheBackend
+        from .backends import OPAHealthCheck
         plugin_dir.register(OPAHealthCheck)
-
-        for backend in settings.CACHES:
-            plugin_dir.register(CustomCacheBackend, backend=backend)

cvat/apps/health/backends.py

@@ -3,14 +3,11 @@
 # SPDX-License-Identifier: MIT
 
 import requests
-import sqlite3
 
 from health_check.backends import BaseHealthCheckBackend
 from health_check.exceptions import HealthCheckException
-from health_check.exceptions import ServiceReturnedUnexpectedResult, ServiceUnavailable
 
 from django.conf import settings
-from django.core.cache import CacheKeyWarning, caches
 
 from cvat.utils.http import make_requests_session
 
@@ -28,27 +25,3 @@ def check_status(self):
 
     def identifier(self):
         return self.__class__.__name__
-
-class CustomCacheBackend(BaseHealthCheckBackend):
-    def __init__(self, backend="default"):
-        super().__init__()
-        self.backend = backend
-
-    def identifier(self):
-        return f"Cache backend: {self.backend}"
-
-    def check_status(self):
-        try:
-            cache = caches[self.backend]
-
-            cache.set("djangohealtcheck_test", "itworks")
-            if not cache.get("djangohealtcheck_test") == "itworks":
-                raise ServiceUnavailable("Cache key does not match")
-        except CacheKeyWarning as e:
-            self.add_error(ServiceReturnedUnexpectedResult("Cache key warning"), e)
-        except ValueError as e:
-            self.add_error(ServiceReturnedUnexpectedResult("ValueError"), e)
-        except ConnectionError as e:
-            self.add_error(ServiceReturnedUnexpectedResult("Connection Error"), e)
-        except sqlite3.DatabaseError as e:
-            raise ServiceUnavailable("Cache error: {}".format(str(e)))

cvat/requirements/base.in

@@ -22,7 +22,7 @@ django-compressor==4.3.1
 django-cors-headers==3.5.0
 django-crum==0.7.9
 django-filter==2.4.0
-django-health-check==3.17.0
+django-health-check>=3.18.1,<4
 django-rq==2.8.1
 django-sendfile2==0.7.0
 Django~=4.2.1

cvat/requirements/base.txt

@@ -1,4 +1,4 @@
-# SHA1:97dd55235acd1b8766b6bd1227ae6d776e9d8e7a
+# SHA1:07743309d7b390659b762ca30db20ebc07ac81bc
 #
 # This file is autogenerated by pip-compile-multi
 # To update, run:
@@ -105,7 +105,7 @@ django-crum==0.7.9
     # via -r cvat/requirements/base.in
 django-filter==2.4.0
     # via -r cvat/requirements/base.in
-django-health-check==3.17.0
+django-health-check==3.18.1
     # via -r cvat/requirements/base.in
 django-rq==2.8.1
     # via -r cvat/requirements/base.in

cvat/settings/base.py

@@ -103,6 +103,7 @@ def generate_secret_key():
     'corsheaders',
     'allauth.socialaccount',
     'health_check',
+    'health_check.cache',
     'health_check.db',
     'health_check.contrib.migrations',
     'health_check.contrib.psutil',

utils/dataset_manifest/requirements.txt

@@ -1,4 +1,4 @@
-# SHA1:2c4fe23872675e963864abe27e1644f42865f712
+# SHA1:c60d1ed19f53b618c5528cd4b4fc708bc7ba404f
 #
 # This file is autogenerated by pip-compile-multi
 # To update, run: