var url = "http://www.inmon.com/tutorials2/customers.xml";
var rootdir = "/var/www/html/customers/";
var height = 200;
var width = 400;

// get customer data
var customersString = readurl(url);
var customers = new XML(customersString);

var network = Network.current();

// create list of customer interfaces
var ifs = new Array();
for each (var customer in customers..customer) {  
  for each (var port in customer..port) {
    network.path = port.@agent + ">" + port.@ifName;
    var ifId = network.interfaceId();
    if(ifId) ifs.push(ifId);
  }
}

// query for trends on each customer interface
var query = Query.trend(
  "historycounters",
  "time,interface,rate(ifinoctets),rate(ifoutoctets)",
  "interface=" + ifs,
  "yesterday",
  5);
var table = query.run();

// split results by customer
var trends = new Array();
var pvt = table.pivotTime(0,1,2);
for(var j = 1; j < pvt.ncols; j++) {
  var t = new Table();
  t.start = table.start;
  t.end = table.end;
  t.addColumn("Time","time",pvt.column(0));
  t.addColumn("In","double",pvt.column(j));
  t.scaleColumn(1,8);
  trends[pvt.cnames[j]] = t;
}
pvt = table.pivotTime(0,1,3);
for(var j = 1; j < pvt.ncols; j++) {
  var t = trends[pvt.cnames[j]];
  t.addColumn("Out","double",pvt.column(j));
}

// create charts for each customer
for each (var customer in customers..customer) {  
  var n = 1;
  for each (var port in customer..port) {
    network.path = port.@agent + ">" + port.@ifName;
    var ifId = network.interfaceId();
    if(ifId) {
      var t = trends[ifId];
      var chart = Chart.multiSeries(
           "trend", "Interface:" + n++,
           t, "Time", 0, "Bits per Second", [1,2]); 
      chart.height = height;
      chart.width = width;
      write(
        rootdir + customer.@id + "/" 
        + port.@agent + "-" + port.@ifName + ".png",
        chart);      
    }
    else println(
       "cannot find interface, agent=" + port.@agent 
       + " ifName=" + port.@ifName);
  }
}