Add selection for vpnnetworkreservations

This commit is contained in:
Nico Schottelius 2020-12-09 21:20:33 +01:00
parent 7f32d05cd4
commit 074cffcbd7

23
uncloud_net/selectors.py Normal file
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from django.db.models import Count
from .models import *
@transaction.atomic
def get_suitable_pool(subnetwork_size):
"""
Find suitable pools for a certain network size.
First, filter for all pools that offer the requested subnetwork_size.
Then find those pools that are not fully exhausted:
The number of available networks in a pool is 2^(subnetwork_size-network_size.
The number of available networks in a pool is given by the number of VPNNetworkreservations.
"""
return VPNPool.objects.annotate(
num_reservations=Count('vpnnetworkreservation'),
max_reservations=2**(F('subnetwork_size')-F('network_size'))).filter(
num_reservations__lt=F('max_reservations'),
subnetwork_size=subnetwork_size)