#!/usr/bin/python
# -*- coding: utf-8 -*-
# vim: set fileencoding=utf-8
#
# Munin plugin to show the network I/O per vm
#
# Copyright Maxence Dunnewind, Rodolphe Quiédeville
#
# License : GPLv3
#
# need to be run with root privilege to execute brctl
#
#
# parsed environment variables:
# vmsuffix: part of vm name to be removed
#
#%# capabilities=autoconf
#%# family=contrib

import re, os, sys
from subprocess import Popen, PIPE

def config(vm_names):
    ''' Print the plugin's config
    @param vm_names : a list of "cleaned" vms' name
    '''
    base_config = """graph_title KVM Network I/O
graph_vlabel Bytes rx(-)/tx(+) per second
graph_category KVM
graph_info This graph shows the network I/O of the virtual machines
graph_args --base 1024
    """
    print base_config
    for vm in vm_names:
        print "%s_in.label %s" % (vm, vm)
        print "%s_in.type COUNTER" % vm
        print "%s_in.min 0" % vm
        print "%s_in.draw LINE2" % vm
        print "%s_out.negative %s_in" % (vm, vm)
        print "%s_out.label %s" % (vm, vm)
        print "%s_out.type COUNTER" % vm
        print "%s_out.min 0" % vm
        print "%s_out.draw LINE2" % vm

def clean_vm_name(vm_name):
    ''' Replace all special chars
    @param vm_name : a vm's name
    @return cleaned vm's name
    '''
    # suffix part defined in conf
    suffix = os.getenv('vmsuffix')
    if suffix:
        vm_name = re.sub(suffix,'',vm_name)

    return re.sub(r"[^a-zA-Z0-9_]", "_", vm_name)
    
def fetch(vms):
    ''' Fetch values for a list of pids
    @param dictionnary {kvm_pid: cleaned vm name}
    '''
    macs = find_vms_tap()
    res = {}
    for pid in vms:
        mac = get_vm_mac(pid)
        try:
            tap = "tap%s" % macs[mac]
    	    f = open("/proc/net/dev", "r")
    	    for line in f.readlines():
    	        if tap in line:
                    line = line.split(':')[1]
	    	    print "%s_in.value %s" % (vms[pid], line.split()[0]) 
	    	    print "%s_out.value %s" % (vms[pid], line.split()[8]) 
	    	    break
	        else:
	    	    f.close()
        except:
            continue

def detect_kvm():
    ''' Check if kvm is installed
    '''
    kvm = Popen("which kvm", shell=True, stdout=PIPE)
    kvm.communicate()
    return not bool(kvm.returncode)

def find_vm_names(pids):
    '''Find and clean vm names from pids
    @return a dictionnary of {pids : cleaned vm name}
    '''
    result = {}
    for pid in pids:
        cmdline = open("/proc/%s/cmdline" % pid, "r")
        result[pid] = clean_vm_name(re.sub(r"^.*-name\x00([a-zA-Z0-9.-]*)\x00\-.*$",r"\1", cmdline.readline()))        
    return result
    
def get_vm_mac(pid):
    '''Find and clean vm names from pids
    @return the mac address for a specified pid
    '''
    cmdline = open("/proc/%s/cmdline" % pid, "r")
    mac = re.sub(r"^.*macaddr=(..:..:..:..:..:..).*$",r"\1", cmdline.readline())
    return mac

def list_pids():
    ''' Find the pid of kvm processes
    @return a list of pids from running kvm
    '''
    pid = Popen("pidof kvm", shell=True, stdout=PIPE)
    return pid.communicate()[0].split()

def find_vms_tap():
    ''' Check if kvm is installed
    @return a list of pids from running kvm
    '''
    result = {}
    kvm = Popen("brctl showmacs br0 | grep no", shell=True, stdout=PIPE)
    res = kvm.communicate()[0].split('\n')
    for line in res:
        try:
            tap = str(int(line.split()[0]) - 1)
            mac = line.split()[1]
            result[mac] = tap
        except:
            continue
    return result
    
if __name__ == "__main__":
    if len(sys.argv) > 1:
        if sys.argv[1] in ['autoconf', 'detect']:
            if detect_kvm():
                print "yes"
            else:
                print "no"
        elif sys.argv[1] == "config":
            config(find_vm_names(list_pids()).values())
        else:
            fetch(find_vm_names(list_pids()))
    else:
        fetch(find_vm_names(list_pids()))