capability to point to local postgres db

:

standalone/settings.py

@@ -87,6 +87,15 @@ else:
         }
     }
 
+# Session storage — DB-backed by default. Set SESSION_ENGINE=signed_cookies when
+# pointing DB_ENGINE at a database whose user has read-only access, since the
+# default engine writes a row to django_session on every login.
+SESSION_ENGINE = (
+    "django.contrib.sessions.backends.signed_cookies"
+    if os.environ.get("SESSION_ENGINE") == "signed_cookies"
+    else "django.contrib.sessions.backends.db"
+)
+
 # Password validation
 AUTH_PASSWORD_VALIDATORS = [
     {"NAME": "django.contrib.auth.password_validation.UserAttributeSimilarityValidator"},

standalone/wsgi.py

@@ -7,3 +7,15 @@ from django.core.wsgi import get_wsgi_application
 os.environ.setdefault("DJANGO_SETTINGS_MODULE", "standalone.settings")
 
 application = get_wsgi_application()
+
+# Read-only deployments (SESSION_ENGINE=signed_cookies) point at a database
+# whose user has no write access. Django writes to auth_user.last_login on
+# every successful login by default, which would error out against such a
+# user and break login entirely — so skip that write here.
+from django.conf import settings  # noqa: E402
+
+if settings.SESSION_ENGINE == "django.contrib.sessions.backends.signed_cookies":
+    from django.contrib.auth.models import update_last_login
+    from django.contrib.auth.signals import user_logged_in
+
+    user_logged_in.disconnect(update_last_login, dispatch_uid="update_last_login")