131 test modules sat next to the code they test; instances alone had
51 of them beside views.py and utils.py. They move into a
tests/ package per app, and the JavaScript checks into
webvirtcloud/tests/js. Each non-empty tests.py becomes tests/test_views.py;
the empty generated stubs are removed.
Imports of the app's own modules become absolute, paths built from
__file__ go one level up, the live helper is instances.tests.livetest,
and coverage omits */tests/*. The suite discovers the same 960 tests as
before.
The overview read the host's info four times, now once (12 libvirt calls).
A connection object keeps it next to the capabilities, and the VM page and
VM stats take it from there; the VM page's cached_reads block holds only
the VM's own data. Free memory is still read each time.
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.
Measured on a VM with two disks, a CD-ROM and a NIC: 70 libvirt calls per
page, now 43. Within the page's cached_reads block the VM's state, the
host's info and domain capabilities, and each disk path's volume are read
once; the running and the persistent disk lists share a path's volume.
The ISO list takes the active pools in one call instead of looking each up
by name; it still refreshes them, so an image copied in by hand shows up.
The opt-in DRBD status waits at most 10 s for the compute's ssh, then
leaves the status unknown instead of holding the page.
The VM page's getters read the domain XML on their own: one load made
86 libvirt calls for a real VM, 29 of them for the same three XML
documents (live, live with secrets, persistent) and 6 for the host
capabilities. Each call is a round trip to the host.
wvmInstance.cached_reads() is a block in which _XMLDesc (per flags
value) and get_cap_xml are read from libvirt once; it ends with the
block, even on an error, does not nest, and _defineXML drops it.
Outside a block every read goes to libvirt as before. Only the VM page
view, which does not change the VM, uses it, around its rendering.
Views that change the VM keep reading fresh XML: most changes (devices,
QoS, memory) do not go through _defineXML, and several views read,
change and define more than once in one request.
Measured on the test host: 86 -> 55 calls (XMLDesc 29 -> 3,
getCapabilities 6 -> 1) for one VM, 82 -> 54 for another; the page took
0.23-0.25 s before, 0.14-0.15 s after. The HTML of both pages is
identical before and after (CSRF tokens aside). A test renders the page
on libvirt's test driver through the real getters: 25 XML reads before,
one per kind now.
