Don't cache files globally

src/pretix/base/services/cart.py

@@ -670,15 +670,15 @@ class CartManager:
         self._check_max_cart_size()
         self._calculate_expiry()
 
-        with self.event.lock() as now_dt:
-            with transaction.atomic():
-                self.now_dt = now_dt
-                self._extend_expiry_of_valid_existing_positions()
-                err = self._delete_out_of_timeframe()
-                err = self.extend_expired_positions() or err
-                err = self._perform_operations() or err
-            if err:
-                raise CartError(err)
+        # with self.event.lock() as now_dt:
+        with transaction.atomic():
+            self.now_dt = now()
+            self._extend_expiry_of_valid_existing_positions()
+            err = self._delete_out_of_timeframe()
+            err = self.extend_expired_positions() or err
+            err = self._perform_operations() or err
+        if err:
+            raise CartError(err)
 
 
 def update_tax_rates(event: Event, cart_id: str, invoice_address: InvoiceAddress):

src/pretix/base/services/orders.py

@@ -597,16 +597,16 @@ def _perform_order(event: str, payment_provider: str, position_ids: List[str],
         except InvoiceAddress.DoesNotExist:
             pass
 
-    with event.lock() as now_dt:
-        positions = list(CartPosition.objects.filter(
-            id__in=position_ids).select_related('item', 'variation', 'subevent'))
-        if len(positions) == 0:
-            raise OrderError(error_messages['empty'])
-        if len(position_ids) != len(positions):
-            raise OrderError(error_messages['internal'])
-        _check_positions(event, now_dt, positions, address=addr)
-        order = _create_order(event, email, positions, now_dt, pprov,
-                              locale=locale, address=addr, meta_info=meta_info, sales_channel=sales_channel)
+    # with event.lock() as now_dt:
+    now_dt = now()
+    positions = list(CartPosition.objects.filter(id__in=position_ids).select_related('item', 'variation', 'subevent'))
+    if len(positions) == 0:
+        raise OrderError(error_messages['empty'])
+    if len(position_ids) != len(positions):
+        raise OrderError(error_messages['internal'])
+    _check_positions(event, now_dt, positions, address=addr)
+    order = _create_order(event, email, positions, now_dt, pprov,
+                          locale=locale, address=addr, meta_info=meta_info, sales_channel=sales_channel)
 
     invoice = order.invoices.last()  # Might be generated by plugin already
     if event.settings.get('invoice_generate') == 'True' and invoice_qualified(order):

src/pretix/settings.py

@@ -179,6 +179,10 @@ METRICS_PASSPHRASE = config.get('metrics', 'passphrase', fallback="")
 CACHES = {
     'default': {
         'BACKEND': 'pretix.helpers.cache.CustomDummyCache',
+    },
+    'file': {
+        'BACKEND': 'django.core.cache.backends.filebased.FileBasedCache',
+        'LOCATION': '/tmp/django_cache',
     }
 }
 REAL_CACHE_USED = False
@@ -489,6 +493,8 @@ COMPRESS_PRECOMPILERS = (
 
 COMPRESS_ENABLED = COMPRESS_OFFLINE = not debug_fallback
 
+COMPRESS_CACHE_BACKEND = 'file'
+
 COMPRESS_CSS_FILTERS = (
     # CssAbsoluteFilter is incredibly slow, especially when dealing with our _flags.scss
     # However, we don't need it if we consequently use the static() function in Sass