6:23 a.m.
On Fri, Apr 11, 2014 at 01:14:50PM +0200, Ruben Kerkhof wrote:
Hi all,
I have a few python scripts which use the libvirt api to get interface and block device
statistics.
What has been bugging me for a while now that is that there’s no high level api to get a
list of all interfaces or block devices for a vm.
The list can be retrieved from the xml with a bit of Xpath magic, but this seems to me to
break the nice abstraction layer libvirt provides.
Ideally, I don’t have to do anything with xml, and add dependencies on xml parsers to my
code.
I’ve seen examples of code doing this, for example the collectd libvirt plugin, but there
must be many others.
Can I kindly ask for such an API? Unfortunately I don’t have the skills to code this up
myself.
The libvirt-glib project provides a set of libraries including
libvirt-gconfig which intend to fill the gap you describe. They
are accessible from Python using GObject Introspection support.
The goal of libvirt-gconfig is to remove the need for apps to
know anything about XML at all.
eg,this demo program shows how to build a domain config using
the APIs. For parsing you just pass it the XML document and
then can use the various getters to access info
#!/usr/bin/python
from gi.repository import LibvirtGConfig;
domain = LibvirtGConfig.Domain.new()
domain.set_virt_type(LibvirtGConfig.DomainVirtType.KVM)
domain.set_name("foo")
domain.set_memory(1024*1024) # 1 GB
domain.set_vcpus(2)
domain.set_lifecycle(LibvirtGConfig.DomainLifecycleEvent.ON_POWEROFF,
LibvirtGConfig.DomainLifecycleAction.DESTROY)
domain.set_virt_type(LibvirtGConfig.DomainVirtType.KVM)
clock = LibvirtGConfig.DomainClock.new()
clock.set_offset(LibvirtGConfig.DomainClockOffset.UTC)
domain.set_clock(clock)
os = LibvirtGConfig.DomainOs.new()
os.set_os_type(LibvirtGConfig.DomainOsType.HVM)
os.set_arch("x86_64")
devices = [ LibvirtGConfig.DomainOsBootDevice.CDROM,
LibvirtGConfig.DomainOsBootDevice.NETWORK ]
os.set_boot_devices(devices)
domain.set_os(os)
disk = LibvirtGConfig.DomainDisk.new()
disk.set_type(LibvirtGConfig.DomainDiskType.FILE)
disk.set_guest_device_type(LibvirtGConfig.DomainDiskGuestDeviceType.DISK)
disk.set_source("/tmp/foo/bar")
disk.set_driver_name("qemu")
disk.set_driver_format(LibvirtGConfig.DomainDiskFormat.QCOW2)
disk.set_target_bus(LibvirtGConfig.DomainDiskBus.IDE)
disk.set_target_dev("hda")
domain.add_device(disk)
interface = LibvirtGConfig.DomainInterfaceNetwork.new()
interface.set_source("default")
filterref = LibvirtGConfig.DomainInterfaceFilterref.new()
filterref.set_name("clean-traffic")
parameter = LibvirtGConfig.DomainInterfaceFilterrefParameter.new()
parameter.set_name("IP")
parameter.set_value("205.23.12.40")
filterref.add_parameter(parameter)
interface.set_filterref(filterref)
domain.add_device(interface)
interface = LibvirtGConfig.DomainInterfaceUser.new()
interface.set_ifname("eth0")
interface.set_link_state(LibvirtGConfig.DomainInterfaceLinkState.UP)
interface.set_mac("00:11:22:33:44:55")
interface.set_model("foo")
domain.add_device(interface)
input = LibvirtGConfig.DomainInput.new()
input.set_device_type(LibvirtGConfig.DomainInputDeviceType.TABLET)
input.set_bus(LibvirtGConfig.DomainInputBus.USB)
domain.add_device(input)
graphics = LibvirtGConfig.DomainGraphicsSpice.new()
graphics.set_port(1234)
domain.add_device(graphics)
video = LibvirtGConfig.DomainVideo.new()
video.set_model(LibvirtGConfig.DomainVideoModel.QXL)
domain.add_device(video)
console = LibvirtGConfig.DomainConsole.new()
pty = LibvirtGConfig.DomainChardevSourcePty.new()
console.set_source(pty)
domain.add_device(console)
print domain.to_xml()
pool = LibvirtGConfig.StoragePool.new()
pool.set_pool_type(LibvirtGConfig.StoragePoolType.DIR)
pool_source = LibvirtGConfig.StoragePoolSource.new()
pool_source.set_directory("/foo/bar")
pool.set_source(pool_source)
perms = LibvirtGConfig.StoragePermissions.new()
perms.set_owner(1001)
perms.set_group(1005)
perms.set_mode(0744)
perms.set_label("virt_image_t")
pool_target = LibvirtGConfig.StoragePoolTarget.new()
pool_target.set_path("/dev/disk/by-path")
pool_target.set_permissions(perms)
pool.set_target(pool_target)
print pool.to_xml()
vol = LibvirtGConfig.StorageVol.new()
vol.set_name("my-vol")
vol.set_capacity(0xdeadbeef)
vol_target = LibvirtGConfig.StorageVolTarget.new()
vol_target.set_format("qcow2")
vol_target.set_permissions(perms)
vol.set_target(vol_target)
print vol.to_xml()
Regards,
Daniel
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