feat(metrics): add histogram to metrics for logger

src/logger.js

@@ -23,6 +23,7 @@ import type {
   Payload,
   MetricPayloadCounter,
   MetricPayloadGauge,
+  MetricPayloadHistogram,
 } from "./types";
 
 export type LoggerOptions = {|
@@ -58,6 +59,7 @@ export type LoggerType = {|
   metric: LogMetric,
   metricCounter: (payload: MetricPayloadCounter) => LoggerType,
   metricGauge: (payload: MetricPayloadGauge) => LoggerType,
+  metricHistogram: (payload: MetricPayloadHistogram) => LoggerType,
 
   flush: () => ZalgoPromise<void>,
   immediateFlush: () => ZalgoPromise<void>,
@@ -331,6 +333,16 @@ export function Logger({
     });
   }
 
+  function metricHistogram(metricPayload: MetricPayloadHistogram): LoggerType {
+    return metric({
+      metricNamespace: metricPayload.namespace,
+      metricEventName: metricPayload.event,
+      metricValue: metricPayload.value,
+      metricType: "histogram",
+      dimensions: metricPayload.dimensions,
+    });
+  }
+
   function setTransport(newTransport: Transport): LoggerType {
     transport = newTransport;
     return logger; // eslint-disable-line no-use-before-define
@@ -391,6 +403,7 @@ export function Logger({
     metric,
     metricCounter,
     metricGauge,
+    metricHistogram,
     flush,
     immediateFlush,
     addPayloadBuilder,

src/logger.test.js

@@ -372,6 +372,49 @@ describe("metricGauge", () => {
   });
 });
 
+describe("metricHistogram", () => {
+  test("adds metrics of histogram type", () => {
+    const testLogger = initLogger();
+
+    testLogger.metricHistogram({
+      namespace: "namespace",
+      event: "load",
+      value: 100,
+      dimensions: {
+        one: "1",
+      },
+    });
+
+    expect(getLoggerBuffer(testLogger).metrics[0]).toEqual({
+      metricNamespace: "namespace",
+      metricEventName: "load",
+      metricValue: 100,
+      metricType: "histogram",
+      dimensions: {
+        one: "1",
+      },
+    });
+  });
+
+  test("uses metric namespace prefix", () => {
+    const testLogger = initLogger({
+      metricNamespacePrefix: "prefix",
+    });
+
+    testLogger.metricHistogram({
+      namespace: "namespace",
+      event: "load",
+      value: 100,
+    });
+
+    expect(getLoggerBuffer(testLogger).metrics[0]).toEqual(
+      expect.objectContaining({
+        metricNamespace: "prefix.namespace",
+      })
+    );
+  });
+});
+
 describe("addMetricDimensionBuilder", () => {
   test("adds dimensions from builder", () => {
     const testLogger = initLogger();

src/types.js

@@ -6,7 +6,7 @@ export type MetricPayload = {|
   metricNamespace: string, // the name of the metric that's used for charting / finding in signalFx
   metricEventName: string, // assigned to event_name dimension in signalFx
   metricValue?: number, // in most cases this will be 1 if we want to count 1 instance of an event happening.
-  metricType?: "counter" | "gauge", // We support these types of metrics. Defaults to counter.
+  metricType?: "counter" | "gauge" | "histogram", // We support these types of metrics. Defaults to counter.
   /**
    * For proper usage & best practices guidance around dimensions please read: -------------------->
    * - https://engineering.paypalcorp.com/confluence/pages/viewpage.action?pageId=981633893
@@ -38,3 +38,15 @@ export type MetricPayloadGauge = {|
    */
   dimensions?: { [string]: mixed },
 |};
+
+export type MetricPayloadHistogram = {|
+  namespace: string, // the name of the metric that's used for charting / finding in signalFx
+  event: string, // assigned to event_name dimension in signalFx
+  value: number, // in most cases this will be 1 if we want to count 1 instance of an event happening.
+  /**
+   * For proper usage & best practices guidance around dimensions please read: -------------------->
+   * - https://engineering.paypalcorp.com/confluence/pages/viewpage.action?pageId=981633893
+   * - https://engineering.paypalcorp.com/confluence/display/Checkout/Checkout+Observability+Overview
+   */
+  dimensions?: { [string]: mixed },
+|};