Move the exception handler to registry_api.py

The exception handler should be closer to APIView classes where it is
actually being used. At the same time, this resolves the circular import
errors caused by the recent extraction of the get_content_data method.

closes #1561

CHANGES/1561.bugfix

@@ -0,0 +1 @@
+Resolved circular import errors raised when using pulp-container as a library.

pulp_container/app/exceptions.py

@@ -1,19 +1,4 @@
-from rest_framework import status, views
-from rest_framework.exceptions import (
-    AuthenticationFailed,
-    NotAuthenticated,
-    NotFound,
-    ParseError,
-)
-
-
-def unauthorized_exception_handler(exc, context):
-    response = views.exception_handler(exc, context)
-
-    if isinstance(exc, (AuthenticationFailed, NotAuthenticated)):
-        response.status_code = status.HTTP_401_UNAUTHORIZED
-
-    return response
+from rest_framework.exceptions import NotFound, ParseError
 
 
 class RepositoryNotFound(NotFound):

pulp_container/app/registry_api.py

@@ -43,7 +43,8 @@
 from rest_framework.serializers import ModelSerializer
 from rest_framework.settings import api_settings
 from rest_framework.viewsets import ViewSet
-from rest_framework.views import APIView
+from rest_framework.views import APIView, exception_handler
+from rest_framework.status import HTTP_401_UNAUTHORIZED
 
 from pulp_container.app import models, serializers
 from pulp_container.app.authorization import AuthorizationService
@@ -53,7 +54,6 @@
     RegistryApiCache,
 )
 from pulp_container.app.exceptions import (
-    unauthorized_exception_handler,
     InvalidRequest,
     RepositoryNotFound,
     RepositoryInvalid,
@@ -417,6 +417,15 @@ def get_exception_handler(self):
         return unauthorized_exception_handler
 
 
+def unauthorized_exception_handler(exc, context):
+    response = exception_handler(exc, context)
+
+    if isinstance(exc, (AuthenticationFailed, NotAuthenticated)):
+        response.status_code = HTTP_401_UNAUTHORIZED
+
+    return response
+
+
 class VersionView(ContainerRegistryApiMixin, APIView):
     """
     Handles requests to the /v2/ endpoint.