Init metrics to zero

CHANGELOG.md

@@ -6,6 +6,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/) and this p
 ## [Unreleased]
 ### Breaking
 ### Added
+- Metrics should be initialized to 0 when there are no labels
 ### Changed
 
 ## [10.0.0] - 2017-07-04

lib/counter.js

@@ -67,6 +67,10 @@ class Counter {
 
 		this.labelNames = config.labelNames || [];
 
+		if (this.labelNames.length === 0) {
+			this.hashMap = createValue({}, 0);
+		}
+
 		this.help = config.help;
 
 		config.registers.forEach(registryInstance =>

lib/gauge.js

@@ -65,6 +65,9 @@ class Gauge {
 		this.name = config.name;
 		this.labelNames = config.labelNames || [];
 		this.hashMap = {};
+		if (this.labelNames.length === 0) {
+			this.hashMap = createValue({}, 0, {});
+		}
 		this.help = config.help;
 
 		config.registers.forEach(registryInstance =>

lib/histogram.js

@@ -79,6 +79,15 @@ class Histogram {
 		this.hashMap = {};
 		this.labelNames = config.labelNames || [];
 
+		if (this.labelNames.length === 0) {
+			this.hashMap = {
+				[hashObject({})]: createBaseValues(
+					{},
+					Object.assign({}, this.bucketValues)
+				)
+			};
+		}
+
 		config.registers.forEach(registryInstance =>
 			registryInstance.registerMetric(this)
 		);

lib/summary.js

@@ -70,6 +70,17 @@ class Summary {
 		this.hashMap = {};
 		this.labelNames = config.labelNames || [];
 
+		if (this.labelNames.length === 0) {
+			this.hashMap = {
+				[hashObject({})]: {
+					labels: {},
+					td: new TDigest(),
+					count: 0,
+					sum: 0
+				}
+			};
+		}
+
 		config.registers.forEach(registryInstance =>
 			registryInstance.registerMetric(this)
 		);

test/__snapshots__/registerTest.js.snap

@@ -0,0 +1,56 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`register should not output all initialized metrics at value 0 if labels 1`] = `
+"# HELP counter help
+# TYPE counter counter
+
+# HELP gauge help
+# TYPE gauge gauge
+
+# HELP histogram help
+# TYPE histogram histogram
+
+# HELP summary help
+# TYPE summary summary
+"
+`;
+
+exports[`register should output all initialized metrics at value 0 1`] = `
+"# HELP counter help
+# TYPE counter counter
+counter 0
+
+# HELP gauge help
+# TYPE gauge gauge
+gauge 0
+
+# HELP histogram help
+# TYPE histogram histogram
+histogram_bucket{le=\\"0.005\\"} 0
+histogram_bucket{le=\\"0.01\\"} 0
+histogram_bucket{le=\\"0.025\\"} 0
+histogram_bucket{le=\\"0.05\\"} 0
+histogram_bucket{le=\\"0.1\\"} 0
+histogram_bucket{le=\\"0.25\\"} 0
+histogram_bucket{le=\\"0.5\\"} 0
+histogram_bucket{le=\\"1\\"} 0
+histogram_bucket{le=\\"2.5\\"} 0
+histogram_bucket{le=\\"5\\"} 0
+histogram_bucket{le=\\"10\\"} 0
+histogram_bucket{le=\\"+Inf\\"} 0
+histogram_sum 0
+histogram_count 0
+
+# HELP summary help
+# TYPE summary summary
+summary{quantile=\\"0.01\\"} 0
+summary{quantile=\\"0.05\\"} 0
+summary{quantile=\\"0.5\\"} 0
+summary{quantile=\\"0.9\\"} 0
+summary{quantile=\\"0.95\\"} 0
+summary{quantile=\\"0.99\\"} 0
+summary{quantile=\\"0.999\\"} 0
+summary_sum 0
+summary_count 0
+"
+`;

test/counterTest.js

@@ -143,6 +143,11 @@ describe('counter', () => {
 			instance.inc(0);
 			expect(instance.get().values[0].value).toEqual(0);
 		});
+		it('should init counter to 0', () => {
+			const values = instance.get().values;
+			expect(values).toHaveLength(1);
+			expect(values[0].value).toEqual(0);
+		});
 
 		describe('labels', () => {
 			beforeEach(() => {

test/gaugeTest.js

@@ -203,6 +203,14 @@ describe('gauge', () => {
 				expect(fn).toThrowError(Error);
 			});
 
+			it('should init to 0', () => {
+				instance = new Gauge({
+					name: 'init_gauge',
+					help: 'somehelp'
+				});
+				expectValue(0);
+			});
+
 			describe('with labels', () => {
 				beforeEach(() => {
 					instance = new Gauge({

test/histogramTest.js

@@ -352,6 +352,12 @@ describe('histogram', () => {
 				expect(valuePair.value).toEqual(undefined);
 			});
 
+			it('should init to 0', () => {
+				instance.get().values.forEach(bucket => {
+					expect(bucket.value).toEqual(0);
+				});
+			});
+
 			describe('labels', () => {
 				beforeEach(() => {
 					instance = new Histogram({

test/registerTest.js

@@ -2,6 +2,10 @@
 
 describe('register', () => {
 	const register = require('../index').register;
+	const Counter = require('../index').Counter;
+	const Gauge = require('../index').Gauge;
+	const Histogram = require('../index').Histogram;
+	const Summary = require('../index').Summary;
 
 	beforeEach(() => {
 		register.clear();
@@ -101,6 +105,24 @@ describe('register', () => {
 		);
 	});
 
+	it('should output all initialized metrics at value 0', () => {
+		new Counter({ name: 'counter', help: 'help' });
+		new Gauge({ name: 'gauge', help: 'help' });
+		new Histogram({ name: 'histogram', help: 'help' });
+		new Summary({ name: 'summary', help: 'help' });
+
+		expect(register.metrics()).toMatchSnapshot();
+	});
+
+	it('should not output all initialized metrics at value 0 if labels', () => {
+		new Counter({ name: 'counter', help: 'help', labelNames: ['label'] });
+		new Gauge({ name: 'gauge', help: 'help', labelNames: ['label'] });
+		new Histogram({ name: 'histogram', help: 'help', labelNames: ['label'] });
+		new Summary({ name: 'summary', help: 'help', labelNames: ['label'] });
+
+		expect(register.metrics()).toMatchSnapshot();
+	});
+
 	describe('should escape', () => {
 		let escapedResult;
 		beforeEach(() => {

test/summaryTest.js

@@ -130,6 +130,12 @@ describe('summary', () => {
 				expect(instance.get().values[2].value).toEqual(0);
 			});
 
+			it('should init to 0', () => {
+				instance.get().values.forEach(percentile => {
+					expect(percentile.value).toEqual(0);
+				});
+			});
+
 			describe('labels', () => {
 				beforeEach(() => {
 					globalRegistry.clear();