Use Python's own lru_cache if available

python/nav/alertengine/base.py

@@ -23,7 +23,6 @@
 from datetime import datetime, timedelta
 
 from django.db import transaction, reset_queries
-from django.utils.lru_cache import lru_cache
 
 from nav.models.profiles import (
     Account,
@@ -36,6 +35,11 @@
 )
 from nav.models.event import AlertQueue
 
+try:  # Django >= 3
+    from functools import lru_cache
+except ImportError:
+    from django.utils.lru_cache import lru_cache
+
 
 _logger = logging.getLogger(__name__)
 

python/nav/metrics/lookup.py

@@ -17,10 +17,14 @@
 
 import re
 
-from django.utils.lru_cache import lru_cache
 from six import iteritems
+
 from nav.models.manage import Netbox, Interface, Prefix, Sensor
 
+try:  # Django >= 3
+    from functools import lru_cache
+except ImportError:
+    from django.utils.lru_cache import lru_cache
 
 __all__ = ['reverses', 'lookup']
 _reverse_handlers = []

python/nav/web/ipdevinfo/host_information.py

@@ -17,11 +17,15 @@
 
 
 import IPy
-from django.utils.lru_cache import lru_cache
 from nav import asyncdns
 
 from nav.util import is_valid_ip
 
+try:  # Django >= 3
+    from functools import lru_cache
+except ImportError:
+    from django.utils.lru_cache import lru_cache
+
 
 def address_sorter(addr_tuple):
     """Return ip object from tuple"""