Add support for Gauge metrics. (#10)

* Add support for Gauge metrics.

* Update package-lock.json

README.md

@@ -31,9 +31,13 @@ const registry = new metrics.Registry();
 
 // Counter with metric level tags
 let c = new metrics.Counter();
-registry.addTaggedMetric("http.requests", c, {"key1":"val1"});
+registry.addTaggedMetric("request.counter", c, {"key1":"val1"});
 c.inc();
 
+// Gauge with metric level tags
+let g = new metrics.Gauge(2.2);
+registry.addTaggedMetric("request.gauge", g, {"key1":"val1"});
+
 // Histogram
 let h = new metrics.Histogram();
 registry.addTaggedMetric("request.duration", h, {"key1":"val1"});

lib/index.js

@@ -5,6 +5,7 @@ exports.Histogram = Metrics.Histogram;
 exports.Meter = Metrics.Meter;
 exports.Counter = Metrics.Counter;
 exports.Timer = Metrics.Timer;
+exports.Gauge = Metrics.Gauge;
 
 exports.deltaCounterName = Delta.deltaCounterName;
 exports.Registry = require('./registry');

lib/wavefront-direct-reporter.js

@@ -43,6 +43,10 @@ class WavefrontDirectReporter extends ScheduledReporter {
       metrics.counters.forEach(count => self.appendCounter(count, points));
     }
 
+    if (metrics.gauges.length != 0) {
+      metrics.gauges.forEach(value => self.appendGauge(value, points));
+    }
+
     if (metrics.meters.length != 0) {
       metrics.meters.forEach(meter => self.appendMeter(meter, points));
     }
@@ -128,6 +132,11 @@ class WavefrontDirectReporter extends ScheduledReporter {
     points.push(formatter.counterPoint(counter, this.prefix, '', tags));
   }
 
+  appendGauge(gauge, points) {
+    let tags = helper.tagger(this.registry.getTags(gauge.name), this.globaltags);
+    points.push(formatter.gaugePoint(gauge, this.prefix, '', tags));
+  }
+
   appendMeter(meter, points) {
     let tags = helper.tagger(this.registry.getTags(meter.name), this.globaltags);
     points.push(...formatter.meterPoints(meter, this.prefix, '', tags));

lib/wavefront-metrics-formatter.js

@@ -13,6 +13,10 @@ function counterPoint(counter, prefix, ts, tags) {
   }
 }
 
+function gaugePoint(gauge, prefix, ts, tags) {
+  return pointLine(prefix, gauge.name, '', gauge.value, ts, tags);
+}
+
 function meterPoints(meter, prefix, ts, tags) {
   let points = [];
   points.push(pointLine(prefix, meter.name, '.count', meter.count, ts, tags));
@@ -68,6 +72,7 @@ function pointLine(prefix, name, suffix, value, ts, tags) {
 
 module.exports = {
   counterPoint,
+  gaugePoint,
   meterPoints,
   timerPoints,
   histoPoints

lib/wavefront-proxy-reporter.js

@@ -69,6 +69,10 @@ class WavefrontProxyReporter extends ScheduledReporter {
       metrics.counters.forEach(count => self.reportCounter(count, timestamp));
     }
 
+    if (metrics.gauges.length != 0) {
+      metrics.gauges.forEach(value => self.reportGauge(value, timestamp));
+    }
+
     if (metrics.meters.length != 0) {
       metrics.meters.forEach(meter => self.reportMeter(meter, timestamp));
     }
@@ -104,6 +108,11 @@ class WavefrontProxyReporter extends ScheduledReporter {
     this.send(formatter.counterPoint(counter, this.prefix, timestamp, tags));
   }
 
+  reportGauge(gauge, timestamp) {
+    let tags = helper.tagger(this.registry.getTags(gauge.name), this.globaltags);
+    this.send(formatter.gaugePoint(gauge, this.prefix, timestamp, tags));
+  }
+
   reportMeter(meter, timestamp) {
     let tags = helper.tagger(this.registry.getTags(meter.name), this.globaltags);
     let points = formatter.meterPoints(meter, this.prefix, timestamp, tags);

package.json

@@ -25,6 +25,6 @@
     "mocha": "^5.2.0"
   },
   "dependencies": {
-    "metrics": "^0.1.11"
+    "metrics": "^0.1.21"
   }
 }

test/formatter.js

@@ -28,6 +28,19 @@ describe('deltaPoint', function() {
   });
 });
 
+describe('gaugePoint', function() {
+  it('Validate gauge point format', function() {
+    const gauge = new metrics.Gauge(2.2);
+    gauge.name = "requests.value";
+
+    let point = formatter.gaugePoint(gauge, 'test', '', "key1=\"val1\"");
+    expect(point).to.be.equal('test.requests.value 2.2 key1=\"val1\"');
+
+    point = formatter.gaugePoint(gauge, 'test', '1350450000', "key1=\"val1\"")
+    expect(point).to.be.equal('test.requests.value 2.2 1350450000 key1=\"val1\"');
+  });
+});
+
 describe('meterPoints', function() {
   it('Validate meter point format', function() {
     const meter = new metrics.Meter();