dl/lib/logger/metrics/GaugeMetric.js

DreamLab Libs

var AbstractMetric = require('./AbstractMetric.js').AbstractMetric;

var GaugeMetric = function () {
    AbstractMetric.apply(this, arguments);

    this._min = null;
    this._max = null;
    this._sum = 0;
    this._count = 0;
};

GaugeMetric.prototype = Object.create(AbstractMetric.prototype);

GaugeMetric.prototype.update = function (value) {
    if (!this._min || value < this._min) {
        this._min = value;
    }

    if (!this._max || value > this._max) {
        this._max = value;
    }

    this._sum += value;
    this._count++;

    return this;
};

GaugeMetric.prototype._dumpValue = function (count, min, max, sum) {
    if (count === 1) {
        max = sum = min;
    }

    return {
        'min': min,
        'max': max,
        'sum': sum,
        'count': count
    }
};

GaugeMetric.prototype.dump = function () {
    return [{
        'key': this._name,
        'value': this._dumpValue(this._count, this._min, this._max, this._sum)
    }];
};

exports.GaugeMetric = GaugeMetric;