purge sitetree cache on change

- matches our caching between dev/prod
- adds signal to purge sitetree caches on change

Note: we _should_ migrate to redis for caching, it wasn't around when we first added it

Author: ewdurbin

Makefile

@@ -17,11 +17,14 @@ default: help
 .state/db-migrated:
 	# Call migrate target
 	make migrate 
+	docker compose run --rm web ./manage.py createcachetable
 
 	# Mark the state so we don't rebuild this needlessly.
 	mkdir -p .state && touch .state/db-migrated
 
 .state/db-initialized: .state/docker-build-web .state/db-migrated
+	# Ensure cache table
+	docker compose run --rm web ./manage.py createcachetable
 	# Load all fixtures
 	docker compose run --rm web ./manage.py loaddata fixtures/*.json
 

pydotorg/apps.py

@@ -0,0 +1,8 @@
+from django.apps import AppConfig
+
+
+class PyDotOrgConfig(AppConfig):
+    name = "pydotorg"
+
+    def ready(self):
+        import pydotorg.signals  # noqa: F401

pydotorg/settings/base.py

@@ -208,6 +208,7 @@
     'django_countries',
     'sorl.thumbnail',
 
+    'pydotorg',
     'banners',
     'blogs',
     'boxes',

pydotorg/settings/local.py

@@ -64,8 +64,8 @@
 
 CACHES = {
     'default': {
-        'BACKEND': 'django.core.cache.backends.locmem.LocMemCache',
-        'LOCATION': 'pythondotorg-local-cache',
+        'BACKEND': 'django.core.cache.backends.db.DatabaseCache',
+        'LOCATION': 'django_cache_table',
     }
 }
 

pydotorg/signals.py

@@ -0,0 +1,14 @@
+from django.db.models.signals import m2m_changed, post_delete, post_save
+from django.dispatch import receiver
+
+from sitetree.models import Tree, TreeItem
+from sitetree.sitetreeapp import get_sitetree
+
+@receiver(post_save, sender=Tree)
+@receiver(post_save, sender=TreeItem)
+@receiver(post_delete, sender=TreeItem)
+@receiver(m2m_changed, sender=TreeItem.access_permissions)
+def purge_sitetree_cache(sender, instance, **kwargs):
+    cache_ = get_sitetree().cache
+    cache_.empty()
+    cache_.reset()