API: Make all mutating endpoints transactional (#6430)

All of our API endpoints that do something in the system do at least two
SQL queries, one for the actual change and one for the log entry. Often
many more. We want all of this to happen in a transaction so we know an
API call was executed or not at all, not half-way.

src/pretix/api/views/checkin.py

@@ -139,6 +139,7 @@ class CheckinListViewSet(viewsets.ModelViewSet):
             )
         return qs
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.log_action(
@@ -153,6 +154,7 @@ class CheckinListViewSet(viewsets.ModelViewSet):
         ctx['event'] = self.request.event
         return ctx
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.log_action(

src/pretix/api/views/discount.py

@@ -32,6 +32,7 @@
 # distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations under the License.
 
+from django.db import transaction
 from django_filters.rest_framework import DjangoFilterBackend, FilterSet
 from django_scopes import scopes_disabled
 from rest_framework import viewsets
@@ -64,6 +65,7 @@ class DiscountViewSet(ConditionalListView, viewsets.ModelViewSet):
             'limit_sales_channels',
         )
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.log_action(
@@ -78,6 +80,7 @@ class DiscountViewSet(ConditionalListView, viewsets.ModelViewSet):
         ctx['event'] = self.request.event
         return ctx
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.log_action(
@@ -87,6 +90,7 @@ class DiscountViewSet(ConditionalListView, viewsets.ModelViewSet):
             data=self.request.data
         )
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         if not instance.allow_delete():
             raise PermissionDenied('You cannot delete this discount because it already has '

src/pretix/api/views/event.py

@@ -257,6 +257,7 @@ class EventViewSet(viewsets.ModelViewSet):
                 data=self.request.data
             )
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         copy_from = None
         if 'clone_from' in self.request.GET:
@@ -320,6 +321,7 @@ class EventViewSet(viewsets.ModelViewSet):
             data=self.request.data
         )
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         if not instance.allow_delete():
             raise PermissionDenied('The event can not be deleted as it already contains orders. Please set \'live\''
@@ -355,6 +357,7 @@ class CloneEventViewSet(viewsets.ModelViewSet):
         ctx['organizer'] = self.request.organizer
         return ctx
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         # Weird edge case: Requires settings permission on the event (to read) but also on the organizer (two write)
         perm_holder = (self.request.auth if isinstance(self.request.auth, (Device, TeamAPIToken))
@@ -513,6 +516,7 @@ class SubEventViewSet(ConditionalListView, viewsets.ModelViewSet):
         resp['X-Page-Generated'] = date
         return resp
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         original_data = self.get_serializer(instance=serializer.instance).data
         super().perform_update(serializer)
@@ -529,6 +533,7 @@ class SubEventViewSet(ConditionalListView, viewsets.ModelViewSet):
             data=self.request.data
         )
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.log_action(
@@ -538,6 +543,7 @@ class SubEventViewSet(ConditionalListView, viewsets.ModelViewSet):
             data=self.request.data
         )
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         if not instance.allow_delete():
             raise PermissionDenied('The sub-event can not be deleted as it has already been used in orders. Please set'
@@ -566,6 +572,7 @@ class TaxRuleViewSet(ConditionalListView, viewsets.ModelViewSet):
     def get_queryset(self):
         return self.request.event.tax_rules.all()
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         super().perform_update(serializer)
         serializer.instance.log_action(
@@ -575,6 +582,7 @@ class TaxRuleViewSet(ConditionalListView, viewsets.ModelViewSet):
             data=self.request.data
         )
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.log_action(
@@ -584,6 +592,7 @@ class TaxRuleViewSet(ConditionalListView, viewsets.ModelViewSet):
             data=self.request.data
         )
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         if not instance.allow_delete():
             raise PermissionDenied('This tax rule can not be deleted as it is currently in use.')
@@ -757,6 +766,7 @@ class SeatViewSet(ConditionalListView, UpdateModelMixin, viewsets.ReadOnlyModelV
         }
         return ctx
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         super().perform_update(serializer)
         serializer.instance.event.log_action(
@@ -766,6 +776,7 @@ class SeatViewSet(ConditionalListView, UpdateModelMixin, viewsets.ReadOnlyModelV
             data={"seats": [serializer.instance.pk]},
         )
 
+    @transaction.atomic()
     def bulk_change_blocked(self, blocked):
         s = SeatBulkBlockInputSerializer(
             data=self.request.data,

src/pretix/api/views/exporters.py

@@ -23,6 +23,7 @@ from datetime import timedelta
 
 from celery.result import AsyncResult
 from django.conf import settings
+from django.db import transaction
 from django.http import Http404
 from django.shortcuts import get_object_or_404
 from django.utils.functional import cached_property
@@ -227,6 +228,7 @@ class ScheduledEventExportViewSet(ScheduledExportersViewSet):
             qs = self.request.event.scheduled_exports
         return qs.select_related("owner")
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         if not self.request.user.is_authenticated:
             raise PermissionDenied('Creation of exports requires user-specific API access.')
@@ -257,6 +259,7 @@ class ScheduledEventExportViewSet(ScheduledExportersViewSet):
         ))
         return {e.identifier: e for e in exporters}
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         if not self.request.user.is_authenticated or self.request.user != serializer.instance.owner:
             # This is to prevent a possible privilege escalation where user A creates a scheduled export and
@@ -282,6 +285,7 @@ class ScheduledEventExportViewSet(ScheduledExportersViewSet):
             data=self.request.data
         )
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         self.request.event.log_action(
             'pretix.event.export.schedule.deleted',
@@ -309,6 +313,7 @@ class ScheduledOrganizerExportViewSet(ScheduledExportersViewSet):
             qs = self.request.organizer.scheduled_exports
         return qs.select_related("owner")
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         if not self.request.user.is_authenticated:
             raise PermissionDenied('Creation of exports requires user-specific API access.')
@@ -339,6 +344,7 @@ class ScheduledOrganizerExportViewSet(ScheduledExportersViewSet):
         ))
         return {e.identifier: e for e in exporters}
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         if not self.request.user.is_authenticated or self.request.user != serializer.instance.owner:
             # This is to prevent a possible privilege escalation where user A creates a scheduled export and
@@ -389,6 +395,7 @@ class ScheduledOrganizerExportViewSet(ScheduledExportersViewSet):
             data=self.request.data
         )
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         self.request.organizer.log_action(
             'pretix.organizer.export.schedule.deleted',

src/pretix/api/views/item.py

@@ -33,6 +33,7 @@
 # License for the specific language governing permissions and limitations under the License.
 
 import django_filters
+from django.db import transaction
 from django.db.models import Q
 from django.shortcuts import get_object_or_404
 from django.utils.functional import cached_property
@@ -109,6 +110,7 @@ class ItemViewSet(ConditionalListView, viewsets.ModelViewSet):
             'limit_sales_channels', 'variations__limit_sales_channels', 'program_times'
         ).all()
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.log_action(
@@ -123,6 +125,7 @@ class ItemViewSet(ConditionalListView, viewsets.ModelViewSet):
         ctx['event'] = self.request.event
         return ctx
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         original_data = self.get_serializer(instance=serializer.instance).data
 
@@ -139,6 +142,7 @@ class ItemViewSet(ConditionalListView, viewsets.ModelViewSet):
             data=self.request.data
         )
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         if not instance.allow_delete():
             raise PermissionDenied('This item cannot be deleted because it has already been ordered '
@@ -183,6 +187,7 @@ class ItemVariationViewSet(viewsets.ModelViewSet):
         ctx['event'] = self.request.event
         return ctx
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         item = self.item
         if not item.has_variations:
@@ -197,6 +202,7 @@ class ItemVariationViewSet(viewsets.ModelViewSet):
                              {'value': serializer.instance.value})
         )
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.item.log_action(
@@ -207,6 +213,7 @@ class ItemVariationViewSet(viewsets.ModelViewSet):
                              {'value': serializer.instance.value})
         )
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         if not instance.allow_delete():
             raise PermissionDenied('This variation cannot be deleted because it has already been ordered '
@@ -249,6 +256,7 @@ class ItemBundleViewSet(viewsets.ModelViewSet):
         ctx['item'] = self.item
         return ctx
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         item = get_object_or_404(Item, pk=self.kwargs['item'], event=self.request.event)
         serializer.save(base_item=item)
@@ -259,6 +267,7 @@ class ItemBundleViewSet(viewsets.ModelViewSet):
             data=merge_dicts(self.request.data, {'id': serializer.instance.pk})
         )
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.base_item.log_action(
@@ -268,6 +277,7 @@ class ItemBundleViewSet(viewsets.ModelViewSet):
             data=merge_dicts(self.request.data, {'id': serializer.instance.pk})
         )
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         super().perform_destroy(instance)
         instance.base_item.log_action(
@@ -303,6 +313,7 @@ class ItemProgramTimeViewSet(viewsets.ModelViewSet):
         ctx['item'] = self.item
         return ctx
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         item = get_object_or_404(Item, pk=self.kwargs['item'], event=self.request.event)
         serializer.save(item=item)
@@ -313,6 +324,7 @@ class ItemProgramTimeViewSet(viewsets.ModelViewSet):
             data=merge_dicts(self.request.data, {'id': serializer.instance.pk})
         )
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.item.log_action(
@@ -322,6 +334,7 @@ class ItemProgramTimeViewSet(viewsets.ModelViewSet):
             data=merge_dicts(self.request.data, {'id': serializer.instance.pk})
         )
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         super().perform_destroy(instance)
         instance.item.log_action(
@@ -354,6 +367,7 @@ class ItemAddOnViewSet(viewsets.ModelViewSet):
         ctx['item'] = self.item
         return ctx
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         item = self.item
         category = get_object_or_404(ItemCategory, pk=self.request.data['addon_category'])
@@ -365,6 +379,7 @@ class ItemAddOnViewSet(viewsets.ModelViewSet):
             data=merge_dicts(self.request.data, {'ORDER': serializer.instance.position}, {'id': serializer.instance.pk})
         )
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.base_item.log_action(
@@ -374,6 +389,7 @@ class ItemAddOnViewSet(viewsets.ModelViewSet):
             data=merge_dicts(self.request.data, {'ORDER': serializer.instance.position}, {'id': serializer.instance.pk})
         )
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         super().perform_destroy(instance)
         instance.base_item.log_action(
@@ -403,6 +419,7 @@ class ItemCategoryViewSet(ConditionalListView, viewsets.ModelViewSet):
     def get_queryset(self):
         return self.request.event.categories.all()
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.log_action(
@@ -417,6 +434,7 @@ class ItemCategoryViewSet(ConditionalListView, viewsets.ModelViewSet):
         ctx['event'] = self.request.event
         return ctx
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.log_action(
@@ -426,6 +444,7 @@ class ItemCategoryViewSet(ConditionalListView, viewsets.ModelViewSet):
             data=self.request.data
         )
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         for item in instance.items.all():
             item.category = None
@@ -458,6 +477,7 @@ class QuestionViewSet(ConditionalListView, viewsets.ModelViewSet):
     def get_queryset(self):
         return self.request.event.questions.prefetch_related('options').all()
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.log_action(
@@ -472,6 +492,7 @@ class QuestionViewSet(ConditionalListView, viewsets.ModelViewSet):
         ctx['event'] = self.request.event
         return ctx
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.log_action(
@@ -481,6 +502,7 @@ class QuestionViewSet(ConditionalListView, viewsets.ModelViewSet):
             data=self.request.data
         )
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         instance.log_action(
             'pretix.event.question.deleted',
@@ -509,6 +531,7 @@ class QuestionOptionViewSet(viewsets.ModelViewSet):
         ctx['question'] = get_object_or_404(Question, pk=self.kwargs['question'], event=self.request.event)
         return ctx
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         q = get_object_or_404(Question, pk=self.kwargs['question'], event=self.request.event)
         serializer.save(question=q)
@@ -519,6 +542,7 @@ class QuestionOptionViewSet(viewsets.ModelViewSet):
             data=merge_dicts(self.request.data, {'ORDER': serializer.instance.position}, {'id': serializer.instance.pk})
         )
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.question.log_action(
@@ -528,6 +552,7 @@ class QuestionOptionViewSet(viewsets.ModelViewSet):
             data=merge_dicts(self.request.data, {'ORDER': serializer.instance.position}, {'id': serializer.instance.pk})
         )
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         instance.question.log_action(
             'pretix.event.question.option.deleted',
@@ -586,6 +611,7 @@ class QuotaViewSet(ConditionalListView, viewsets.ModelViewSet):
         serializer = self.get_serializer(page, many=True)
         return self.get_paginated_response(serializer.data)
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.log_action(
@@ -608,6 +634,7 @@ class QuotaViewSet(ConditionalListView, viewsets.ModelViewSet):
         ctx['request'] = self.request
         return ctx
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         original_data = self.get_serializer(instance=serializer.instance).data
 
@@ -663,6 +690,7 @@ class QuotaViewSet(ConditionalListView, viewsets.ModelViewSet):
                 )
         serializer.instance.rebuild_cache()
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         instance.log_action(
             'pretix.event.quota.deleted',

src/pretix/api/views/organizer.py

@@ -394,6 +394,7 @@ class TeamViewSet(viewsets.ModelViewSet):
         )
         return inst
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         instance.log_action('pretix.team.deleted', user=self.request.user, auth=self.request.auth)
         instance.delete()
@@ -693,6 +694,7 @@ class MembershipTypeViewSet(viewsets.ModelViewSet):
         ctx['organizer'] = self.request.organizer
         return ctx
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         if not instance.allow_delete():
             raise PermissionDenied("Can only be deleted if unused.")
@@ -833,6 +835,7 @@ class SalesChannelViewSet(viewsets.ModelViewSet):
         )
         return inst
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         if not instance.allow_delete():
             raise PermissionDenied("Can only be deleted if unused.")

src/pretix/api/views/waitinglist.py

@@ -20,6 +20,7 @@
 # <https://www.gnu.org/licenses/>.
 #
 import django_filters
+from django.db import transaction
 from django_filters.rest_framework import DjangoFilterBackend, FilterSet
 from django_scopes import scopes_disabled
 from rest_framework import viewsets
@@ -62,6 +63,7 @@ class WaitingListViewSet(viewsets.ModelViewSet):
         ctx['event'] = self.request.event
         return ctx
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         serializer.save(event=self.request.event)
         serializer.instance.log_action(
@@ -70,6 +72,7 @@ class WaitingListViewSet(viewsets.ModelViewSet):
             auth=self.request.auth,
         )
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         if serializer.instance.voucher:
             raise PermissionDenied('This entry can not be changed as it has already been assigned a voucher.')
@@ -80,6 +83,7 @@ class WaitingListViewSet(viewsets.ModelViewSet):
             auth=self.request.auth,
         )
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         if instance.voucher:
             raise PermissionDenied('This entry can not be deleted as it has already been assigned a voucher.')

src/pretix/api/views/webhooks.py

@@ -20,6 +20,7 @@
 # <https://www.gnu.org/licenses/>.
 #
 import django_filters
+from django.db import transaction
 from django_filters.rest_framework import DjangoFilterBackend, FilterSet
 from rest_framework import viewsets
 
@@ -48,6 +49,7 @@ class WebHookViewSet(viewsets.ModelViewSet):
         ctx['organizer'] = self.request.organizer
         return ctx
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         inst = serializer.save(organizer=self.request.organizer)
         self.request.organizer.log_action(
@@ -57,6 +59,7 @@ class WebHookViewSet(viewsets.ModelViewSet):
             data=merge_dicts(self.request.data, {'id': inst.pk})
         )
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         inst = serializer.save(organizer=self.request.organizer)
         self.request.organizer.log_action(
@@ -67,6 +70,7 @@ class WebHookViewSet(viewsets.ModelViewSet):
         )
         return inst
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         self.request.organizer.log_action(
             'pretix.webhook.changed',

src/pretix/plugins/sendmail/api.py

@@ -20,6 +20,7 @@
 # <https://www.gnu.org/licenses/>.
 #
 from django.core.exceptions import ValidationError
+from django.db import transaction
 from django_filters.rest_framework import DjangoFilterBackend, FilterSet
 from django_scopes import scopes_disabled
 from rest_framework import viewsets
@@ -118,6 +119,7 @@ class RuleViewSet(viewsets.ModelViewSet):
     def get_queryset(self):
         return Rule.objects.filter(event=self.request.event)
 
+    @transaction.atomic()
     def perform_create(self, serializer):
         super().perform_create(serializer)
         serializer.instance.log_action(
@@ -128,6 +130,7 @@ class RuleViewSet(viewsets.ModelViewSet):
 
         )
 
+    @transaction.atomic()
     def perform_update(self, serializer):
         super().perform_update(serializer)
         serializer.instance.log_action(
@@ -137,6 +140,7 @@ class RuleViewSet(viewsets.ModelViewSet):
             data=self.request.data
         )
 
+    @transaction.atomic()
     def perform_destroy(self, instance):
         instance.log_action(
             'pretix.plugins.sendmail.rule.deleted',