#!/usr/bin/python
#
# Munin plugin to show the network traffic of libvirt managed virtual machines
# 
# Copyright  Guido Guenther <agx@sigxcpu.org>
#
# depends: python-libvirt, python-libxml2
#
# If you don't want to use the default uri use:
# 
# [libvirt-*]
# env.uri qemu:///system
#
# in your plugin configuration

import re, sys, os
import libvirt
import libxml2

def canon(name):
    return re.sub(r"[^a-zA-Z0-9_]", "_", name)

def print_config(uri):
    """print the plugin config, determine the domains"""

    print """graph_title Virtual Domain Network I/O
graph_vlabel Bytes rx (-)/ tx (+) per ${graph_period}
graph_category Virtual Machines
graph_info This graph shows the network I/O of the virtual machines
"""

    conn = libvirt.openReadOnly(uri)
    ids = conn.listDomainsID()
    for id in ids:
        dom = conn.lookupByID(id)
        name = dom.name()
        print "%s_rx.label %s" % (canon(name), name)
        print "%s_rx.type DERIVE" % canon(name)
        print "%s_rx.min 0" % canon(name)
        print "%s_rx.graph no" % canon(name)
        print "%s_tx.label %s" % (canon(name), name)
        print "%s_tx.type DERIVE" % canon(name)
        print "%s_tx.min 0" % canon(name)
        print "%s_tx.negative %s_rx" % (canon(name), canon(name))

def get_ifaces(dom):
    xml = dom.XMLDesc(0)
    doc = None
    try:
        doc = libxml2.parseDoc(xml)
    except:
        return []
    ctx = doc.xpathNewContext()
    ifaces = []
    try:
        ret = ctx.xpathEval("/domain/devices/interface")
        for node in ret:
            devdst = None
            for child in node.children:
                if child.name == "target":
                    devdst = child.prop("dev")
            if devdst == None:
                continue
            ifaces.append(devdst)
    finally:
        if ctx != None:
            ctx.xpathFreeContext()
        if doc != None:
            doc.freeDoc()
    return ifaces
        
def fetch_values(uri):
    conn = libvirt.openReadOnly(uri)
    ids = conn.listDomainsID()
    for id in ids:
        rd = 0
        wr = 0
        dom = conn.lookupByID(id)
        name = dom.name()
        ifaces = get_ifaces(dom)
        for iface in ifaces:
            try:
                stats = dom.interfaceStats(iface)
                rd += stats[0]
                wr += stats[4]
            except TypeError:
                print >>sys.stderr, "Cannot get ifstats for '%s' on '%s'" % (iface, name)
        print "%s_rx.value %d" % (canon(name), rd)
        print "%s_tx.value %d" % (canon(name), wr)


def main(sys):
    uri = os.getenv("uri")

    if len(sys) > 1:
        if sys[1] in [ 'autoconf', 'detect' ]:
            if libvirt.openReadOnly(uri):
                print "yes"
                return 0
            else:
                print "no"
                return 1
        elif sys[1] == 'config':
            print_config(uri)
            return 0
    fetch_values(uri)
    return 0

if __name__ == "__main__":
    sys.exit(main(sys.argv))

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