[refactor] cleaning up uncloud_net for Wireguardvpn

uncloud_net/selectors.py

@@ -1,7 +1,9 @@
-from django.db.models import Count
+from django.db import transaction
+from django.db.models import Count, F
+
+
 from .models import *
 
-@transaction.atomic
 def get_suitable_pool(subnetwork_size):
     """
     Find suitable pools for a certain network size.
@@ -21,3 +23,20 @@ def get_suitable_pool(subnetwork_size):
         max_reservations=2**(F('subnetwork_size')-F('network_size'))).filter(
             num_reservations__lt=F('max_reservations'),
             subnetwork_size=subnetwork_size)
+
+
+def allowed_vpn_network_reservation_size():
+    """
+    Find all possible sizes of subnetworks that are available.
+
+    Select all pools with free networks.
+
+    Get their subnetwork sizes, reduce to a set
+
+    """
+
+    pools = VPNPool.objects.annotate(num_reservations=Count('vpnnetworkreservation'),
+                                     max_reservations=2**(F('subnetwork_size')-F('network_size'))).filter(
+                                         num_reservations__lt=F('max_reservations'))
+
+    return set([ pool.subnetwork_size for pool in pools ])