Soy un poco nuevo en D3.js, y logré crear un indicador con lo que encontré en Internet. Pero no pude encontrar ningún indicador que muestre el valor actual en la parte superior de la aguja. Algo como esto :lo que quiero

Obviamente me gustaría que el valor siga la aguja. Traté de agregar el atributo "texto" a la aguja en sí, pero no funcionó.

Aquí hay un enlace codepen:http://codepen.io/kazu_codepen/pen/wGmGjv?editors=1010

Aquí está mi código js:

// data which need to be fetched

var name = "azerty";

var value = 17;


var gaugeMaxValue = 100; 

// data to calculate 
var percentValue = value / gaugeMaxValue; 

////////////////////////

var needleClient;



(function(){

var barWidth, chart, chartInset, degToRad, repaintGauge,
    height, margin, numSections, padRad, percToDeg, percToRad, 
    percent, radius, sectionIndx, svg, totalPercent, width;



  percent = percentValue;

  numSections = 1;
  sectionPerc = 1 / numSections / 2;
  padRad = 0.025;
  chartInset = 10;

  // Orientation of gauge:
  totalPercent = .75;

  el = d3.select('.chart-gauge');

  margin = {
    top: 20,
    right: 20,
    bottom: 30,
    left: 20
  };

  width = el[0][0].offsetWidth - margin.left - margin.right;
  height = width;
  radius = Math.min(width, height) / 2;
  barWidth = 40 * width / 300;



  //Utility methods 

  percToDeg = function(perc) {
    return perc * 360;
  };

  percToRad = function(perc) {
    return degToRad(percToDeg(perc));
  };

  degToRad = function(deg) {
    return deg * Math.PI / 180;
  };

  // Create SVG element
  svg = el.append('svg').attr('width', width + margin.left + margin.right).attr('height', height + margin.top + margin.bottom);

  // Add layer for the panel
  chart = svg.append('g').attr('transform', "translate(" + ((width + margin.left) / 2) + ", " + ((height + margin.top) / 2) + ")");


  chart.append('path').attr('class', "arc chart-first");
  chart.append('path').attr('class', "arc chart-second");
  chart.append('path').attr('class', "arc chart-third");


  arc3 = d3.svg.arc().outerRadius(radius - chartInset).innerRadius(radius - chartInset - barWidth)
  arc2 = d3.svg.arc().outerRadius(radius - chartInset).innerRadius(radius - chartInset - barWidth)
  arc1 = d3.svg.arc().outerRadius(radius - chartInset).innerRadius(radius - chartInset - barWidth)

  repaintGauge = function () 
  {
    perc = 0.5;
    var next_start = totalPercent;
    arcStartRad = percToRad(next_start);
    arcEndRad = arcStartRad + percToRad(perc / 3);
    next_start += perc / 3;


    arc1.startAngle(arcStartRad).endAngle(arcEndRad);

    arcStartRad = percToRad(next_start);
    arcEndRad = arcStartRad + percToRad(perc / 3);
    next_start += perc / 3;

    arc2.startAngle(arcStartRad + padRad).endAngle(arcEndRad);

    arcStartRad = percToRad(next_start);
    arcEndRad = arcStartRad + percToRad(perc / 3);

    arc3.startAngle(arcStartRad + padRad).endAngle(arcEndRad);

    chart.select(".chart-first").attr('d', arc1);
    chart.select(".chart-second").attr('d', arc2);
    chart.select(".chart-third").attr('d', arc3);


  }
/////////

    var dataset = [{metric:name, value: value}]

    var texts = svg.selectAll("text")
                .data(dataset)
                .enter();

    texts.append("text")
         .text(function(){
              return dataset[0].metric;
         })
         .attr('id', "Name")
         .attr('transform', "translate(" + ((width + margin.left) / 6) + ", " + ((height + margin.top) / 1.5) + ")")
         .attr("font-size",25)
         .style("fill", "#000000");


    texts.append("text")
         .text(function(){
            return dataset[0].value;
         })
         .attr('id', "Value")
         .attr('transform', "translate(" + ((width + margin.left) / 1.4) + ", " + ((height + margin.top) / 1.5) + ")")
         .attr("font-size",25)
         .style("fill", "#000000");




    texts.append("text")
        .text(function(){
            return 0;
        })
        .attr('id', 'scale0')
        .attr('transform', "translate(" + ((width + margin.left) / 100 ) + ", " + ((height + margin.top) / 2) + ")")
        .attr("font-size", 15)
        .style("fill", "#000000");

    texts.append("text")
        .text(function(){
            return gaugeMaxValue/2;
        })
        .attr('id', 'scale10')
        .attr('transform', "translate(" + ((width + margin.left) / 2.15 ) + ", " + ((height + margin.top) / 30) + ")")
        .attr("font-size", 15)
        .style("fill", "#000000");


    texts.append("text")
        .text(function(){
            return gaugeMaxValue;
        })
        .attr('id', 'scale20')
        .attr('transform', "translate(" + ((width + margin.left) / 1.03 ) + ", " + ((height + margin.top) / 2) + ")")
        .attr("font-size", 15)
        .style("fill", "#000000");

  var Needle = (function() {

    //Helper function that returns the `d` value for moving the needle
    var recalcPointerPos = function(perc) {
      var centerX, centerY, leftX, leftY, rightX, rightY, thetaRad, topX, topY;
      thetaRad = percToRad(perc / 2);
      centerX = 0;
      centerY = 0;
      topX = centerX - this.len * Math.cos(thetaRad);
      topY = centerY - this.len * Math.sin(thetaRad);
      leftX = centerX - this.radius * Math.cos(thetaRad - Math.PI / 2);
      leftY = centerY - this.radius * Math.sin(thetaRad - Math.PI / 2);
      rightX = centerX - this.radius * Math.cos(thetaRad + Math.PI / 2);
      rightY = centerY - this.radius * Math.sin(thetaRad + Math.PI / 2);
      return "M " + leftX + " " + leftY + " L " + topX + " " + topY + " L " + rightX + " " + rightY;
    };

    function Needle(el) {
      this.el = el;
      this.len = width / 2.5;
      this.radius = this.len / 8;
    }

    Needle.prototype.render = function() {
      this.el.append('circle').attr('class', 'needle-center').attr('cx', 0).attr('cy', 0).attr('r', this.radius);

        ///////
        /**
        *
        * I tried to add text here
        *
        */
        ///////

      return this.el.append('path').attr('class', 'needle').attr('id', 'client-needle').attr('d', recalcPointerPos.call(this, 0));


    };

    Needle.prototype.moveTo = function(perc) {
      var self,
          oldValue = this.perc || 0;

      this.perc = perc;
      self = this;

      // Reset pointer position
      this.el.transition().delay(100).ease('quad').duration(200).select('.needle').tween('reset-progress', function() {
        return function(percentOfPercent) {
          var progress = (1 - percentOfPercent) * oldValue;

          repaintGauge(progress);
          return d3.select(this).attr('d', recalcPointerPos.call(self, progress));
        };
      });

      this.el.transition().delay(300).ease('bounce').duration(1500).select('.needle').tween('progress', function() {
        return function(percentOfPercent) {
          var progress = percentOfPercent * perc;

          repaintGauge(progress);
          return d3.select(this).attr('d', recalcPointerPos.call(self, progress));
        };
      });

    };


    return Needle;

  })();



  needle = new Needle(chart);
  needle.render();
  needle.moveTo(percent);   

})();

Y aquí está mi código html:

<!DOCTYPE html>
<html>
    <head>
        <script src="http://d3js.org/d3.v3.min.js" charset="utf-8"></script>
        <style type="text/css" src="gauge.css">
            .chart-gauge
            {
              width: 400px;
              margin: 100px auto  
             } 
            .chart-first
            {
                fill: #9FBD35;
            }
            .chart-second
            {
                fill: #F2BA3A;
            }
            .chart-third
            {
                fill: #FB3033;
            }

            .needle, .needle-center
            {
                fill: #000000;
            }
            .text {
                color: "#112864";
                font-size: 16px;
            }


            svg {
              font: 10px sans-serif;
            }


        </style>

    </head>
    <body>


        <div class="chart-gauge"></div>



        <script type="text/javascript" src="./gaugeClient.js"></script>
        <script type="text/javascript" src="./labels.js"></script>
        <script src="https://d3js.org/d3.v3.min.js" charset="utf-8"></script>
    </body>

</html>

Si alguien puede ayudar, me he pasado unos días intentándolo sin éxito. Gracias.