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webvirtcloud/vrtManager/test_capabilities_once.py
catborise 9adc808d26 perf(computes): the create page reads the host's capabilities once
Measured on the create page: 751 ms and 72 libvirt calls, now 123 ms and
13. Its getters parsed the host's capabilities some 60 times, each read
from libvirt. A connection object (one per request) now reads them once,
and the domain capabilities once per emulator, arch, machine and domain
type. The VM page's cached_reads block no longer needs its own copy.
2026-10-09 15:24:03 +03:00

73 lines
2.7 KiB
Python

"""A wvmConnect reads the host's capabilities once, and its domain
capabilities once per emulator, arch, machine and domain type: the create
page's getters parse them some 60 times. An object lives for one request."""
import unittest
from django.conf import settings
if not settings.configured:
settings.configure(MAC_OUI="52:54:10")
from vrtManager.connection import wvmConnect
CAPABILITIES = """<capabilities><host><cpu><arch>x86_64</arch></cpu></host>
<guest><os_type>hvm</os_type><arch name='x86_64'><emulator>/usr/bin/qemu-kvm</emulator>
<machine>pc-q35-9.0</machine><machine canonical='pc-q35-9.0'>q35</machine><machine canonical='pc-i440fx-9.0'>pc</machine>
<domain type='qemu'/><domain type='kvm'/></arch></guest></capabilities>"""
class FakeConn:
def __init__(self):
self.reads = []
def getCapabilities(self):
self.reads.append("capabilities")
return CAPABILITIES
def getDomainCapabilities(self, emulator, arch, machine, virttype):
self.reads.append((emulator, arch, machine, virttype))
return "<domainCapabilities/>"
def connection():
conn = wvmConnect.__new__(wvmConnect) # no libvirt connection: only these calls
conn.wvm = FakeConn()
return conn
class CapabilitiesOnceTestCase(unittest.TestCase):
def test_the_capabilities_are_read_once_for_all_getters(self):
conn = connection()
for _ in range(2):
conn.get_emulator("x86_64")
conn.get_machine_types("x86_64")
conn.get_hypervisors_domain_types()
conn.get_cap_xml()
self.assertEqual(conn.wvm.reads, ["capabilities"])
def test_domain_capabilities_are_read_once_per_machine(self):
conn = connection()
for _ in range(2):
conn.get_dom_cap_xml("x86_64", "q35")
conn.get_dom_cap_xml("x86_64", "pc")
conn.get_dom_cap_xml("x86_64", "unknown") # falls back to pc
self.assertEqual(
conn.wvm.reads,
["capabilities", ("/usr/bin/qemu-kvm", "x86_64", "q35", "kvm"), ("/usr/bin/qemu-kvm", "x86_64", "pc", "kvm")],
)
def test_two_objects_do_not_share_their_reads(self):
a, b = connection(), connection()
a.get_cap_xml()
b.get_cap_xml()
self.assertEqual((a.wvm.reads, b.wvm.reads), (["capabilities"], ["capabilities"]))
def test_a_failed_read_is_not_kept(self):
conn = connection()
conn.wvm.getCapabilities = lambda: (_ for _ in ()).throw(RuntimeError("libvirt error"))
with self.assertRaises(RuntimeError):
conn.get_cap_xml()
conn.wvm = FakeConn()
conn.get_cap_xml()
self.assertEqual(conn.wvm.reads, ["capabilities"])