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webvirtcloud/instances/test_quota_lock.py
catborise 51dedb7b8f fix(instances): disk edits keep their XML; changes lock per VM
Disk edits:
- edit_disk built a new <disk> from the form and replaced the old one,
  losing what the form does not show (e.g. encryption and virtio
  driver options); a bus change detached and re-attached the disk.
  The disk of the persistent definition is now edited in place and the
  domain defined once; a bus change picks a free device name and drops
  the old address and virtio-only options. Pending persistent changes of
  a running VM are kept.
- Clone omits empty disk devices, refuses a disk without a supported
  source and destination, and checks the name before allocating storage.

Locks:
- Every VM change held its compute's exclusive lock, so one slow
  operation blocked all VMs on that compute. A VM change now holds its
  own VM lock plus a shared compute lock; reconciliation, migration and
  cloning hold the compute exclusively (two clones of different VMs
  must not pass the name check together).
- Quota-checked changes of one user (CPU, memory and disk resize,
  clone) run one at a time under a per-user lock, also across computes,
  so concurrent requests cannot all pass the check against the old
  allocation. It is the outermost lock; superusers, who have no quota,
  skip it.
- A busy lock answers 409 to the API and a message in the web UI. API
  power and destroy actions return the view's error instead of success.
2026-10-04 01:08:11 +03:00

62 lines
2.5 KiB
Python

import threading
import time
from unittest.mock import patch
from accounts.models import UserInstance
from computes.models import Compute
from django.contrib.auth import get_user_model
from django.db import connection
from django.test import Client, TransactionTestCase, override_settings
from django.urls import reverse
from instances.models import Instance
QUOTA_CPUS = 4
# Sessions and messages in cookies: concurrent writes to the in-memory test
# database would fail for reasons unrelated to the quota race.
@override_settings(
SESSION_ENGINE="django.contrib.sessions.backends.signed_cookies",
MESSAGE_STORAGE="django.contrib.messages.storage.cookie.CookieStorage",
)
class QuotaRaceTestCase(TransactionTestCase):
"""Two concurrent resizes of one user's VMs must not both pass the quota."""
def setUp(self):
self.user = get_user_model().objects.create_user("quota_user", password="pw")
compute = Compute.objects.create(name="quota-compute", hostname="127.0.0.1", login="", password="", type=4)
self.vms = [
Instance.objects.create(compute=compute, name=f"quota-vm-{i}", uuid=f"1111111{i}-2222-3333-4444-555555555555")
for i in range(2)
]
for vm in self.vms:
UserInstance.objects.create(user=self.user, instance=vm, is_change=True)
self.allocated = 2 # two VMs with one vCPU each
def fake_quota(self, user, instance, cpu, memory, disk):
seen = self.allocated
time.sleep(0.3) # widen the window between the check and the change
return "cpu" if seen + cpu > QUOTA_CPUS else ""
def fake_resize(self, cur_vcpu, vcpu):
self.allocated += int(vcpu) - 1
def resize(self, vm):
client = Client()
client.force_login(self.user)
client.post(reverse("instances:resizevm_cpu", args=[vm.id]), {"vcpu": 3, "cur_vcpu": 3})
connection.close()
def test_second_concurrent_resize_is_refused(self):
with patch("instances.views.utils.check_user_quota", self.fake_quota), patch(
"instances.models.wvmInstance"
) as wvm:
wvm.return_value.get_vcpu.return_value = 1
wvm.return_value.resize_cpu.side_effect = self.fake_resize
threads = [threading.Thread(target=self.resize, args=(vm,)) for vm in self.vms]
for t in threads:
t.start()
for t in threads:
t.join()
self.assertEqual(wvm.return_value.resize_cpu.call_count, 1)
self.assertLessEqual(self.allocated, QUOTA_CPUS)