add useCounterAsExemplarValue support

siimon · Mar 26, 2024 · 5fcf716 · 5fcf716
1 parent 4e514e7
commit 5fcf716
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Showing 2 changed files with 56 additions and 4 deletions.
diff --git a/lib/counter.js b/lib/counter.js
@@ -22,6 +22,8 @@ class Counter extends Metric {
 		this.defaultLabels = {};
 		this.defaultValue = 1;
 		this.defaultExemplarLabelSet = {};
+		this.useCounterValueAsExemplarValue =
+			config.useCounterValueAsExemplarValue || false;
 		if (config.enableExemplars) {
 			this.enableExemplars = true;
 			this.inc = this.incWithExemplar;
@@ -58,7 +60,7 @@ class Counter extends Metric {
 
 		setValue(this.hashMap, value, labels, hash);
 
-		return { labelHash: hash };
+		return { labelHash: hash, value: this.hashMap[hash].value };
 	}
 
 	/**
@@ -81,7 +83,11 @@ class Counter extends Metric {
 		exemplarLabels = this.defaultExemplarLabelSet,
 	} = {}) {
 		const res = this.incWithoutExemplar(labels, value);
-		this.updateExemplar(exemplarLabels, value, res.labelHash);
+		const exemplarValue = this.useCounterValueAsExemplarValue
+			? res.value
+			: value;
+
+		this.updateExemplar(exemplarLabels, exemplarValue, res.labelHash);
 	}
 
 	updateExemplar(exemplarLabels, value, hash) {

diff --git a/test/exemplarsTest.js b/test/exemplarsTest.js
@@ -213,6 +213,7 @@ describe('Exemplars', () => {
 						labelNames: ['method', 'code'],
 						enableExemplars: true,
 					});
+					const vals = (await histogramInstance.get()).values;
 
 					histogramInstance.observe({
 						value: 0.3,
@@ -227,8 +228,6 @@ describe('Exemplars', () => {
 						labels: { method: 'get', code: '200' },
 					});
 
-					const vals = (await histogramInstance.get()).values;
-
 					expect(getValuesByLabel(0.5, vals)[0].value).toEqual(2);
 					expect(
 						getValuesByLabel(0.5, vals)[0].exemplar.labelSet.traceId,
@@ -240,6 +239,53 @@ describe('Exemplars', () => {
 				});
 			});
 
+			describe('when useCounterValueAsExemplarValue is enabled', () => {
+				it('uses the counter value for the exemplar', async () => {
+					const counterInstance = new Counter({
+						name: 'counter_exemplar_value_as_counter_test',
+						help: 'help',
+						labelNames: ['method', 'code'],
+						enableExemplars: true,
+						useCounterValueAsExemplarValue: true,
+					});
+
+					counterInstance.inc({
+						labelValues: { method: 'get', code: '200' },
+						exemplarLabels: {
+							traceId: 'trace_id_test_1',
+							spanId: 'span_id_test_1',
+						},
+					});
+
+					counterInstance.inc({
+						labelValues: { method: 'get', code: '200' },
+						exemplarLabels: {
+							traceId: 'trace_id_test_2',
+							spanId: 'span_id_test_2',
+						},
+					});
+
+					counterInstance.inc({
+						labelValues: { method: 'get', code: '200' },
+						exemplarLabels: {
+							traceId: 'trace_id_test_3',
+							spanId: 'span_id_test_3',
+						},
+					});
+
+					const vals = await counterInstance.get();
+					expect(vals.values[0].value).toEqual(3);
+					expect(vals.values[0].exemplar.value).toEqual(3);
+					expect(vals.values[0].exemplar.labelSet.traceId).toEqual(
+						'trace_id_test_3',
+					);
+
+					expect(vals.values[0].exemplar.labelSet.spanId).toEqual(
+						'span_id_test_3',
+					);
+				});
+			});
+
 			function getValueByLabel(label, values, key) {
 				return values.reduce((acc, val) => {
 					if (val.labels && val.labels[key || 'le'] === label) {