MM-58281 Allow client metrics to be floats and round timestamps (#27027)

* MM-58281 Allow client metrics to be floats and round timestamps

* MM-58281 Fix report version

* Ensure reports can contain a single timestamp

* Round timestamps in unit tests

webapp/channels/src/utils/performance_telemetry/reporter.test.ts

@@ -52,23 +52,23 @@ describe('PerformanceReporter', () => {
         expect(sendBeacon.mock.calls[0][0]).toEqual(siteUrl + '/api/v4/client_perf');
         const report = JSON.parse(sendBeacon.mock.calls[0][1]);
         expect(report).toMatchObject({
-            start: performance.timeOrigin + testMarkA.startTime,
-            end: performance.timeOrigin + testMarkB.startTime,
+            start: Math.round(performance.timeOrigin + testMarkA.startTime),
+            end: Math.round(performance.timeOrigin + testMarkB.startTime),
             histograms: [
                 {
                     metric: 'testMeasureA',
                     value: testMarkB.startTime - testMarkA.startTime,
-                    timestamp: performance.timeOrigin + testMarkA.startTime,
+                    timestamp: Math.round(performance.timeOrigin + testMarkA.startTime),
                 },
                 {
                     metric: 'testMeasureB',
                     value: testMarkC.startTime - testMarkA.startTime,
-                    timestamp: performance.timeOrigin + testMarkA.startTime,
+                    timestamp: Math.round(performance.timeOrigin + testMarkA.startTime),
                 },
                 {
                     metric: 'testMeasureC',
                     value: testMarkC.startTime - testMarkB.startTime,
-                    timestamp: performance.timeOrigin + testMarkB.startTime,
+                    timestamp: Math.round(performance.timeOrigin + testMarkB.startTime),
                 },
             ],
         });
@@ -94,7 +94,7 @@ describe('PerformanceReporter', () => {
 
         expect(reporter.handleObservations).toHaveBeenCalled();
 
-        const timestamp = performance.timeOrigin + performance.now();
+        const timestamp = Math.round(performance.timeOrigin + performance.now());
 
         await waitForReport();
 

webapp/channels/src/utils/performance_telemetry/reporter.ts

@@ -17,13 +17,28 @@ import type {PlatformLabel, UserAgentLabel} from './platform_detection';
 import {getPlatformLabel, getUserAgentLabel} from './platform_detection';
 
 type PerformanceReportMeasure = {
+
+    /**
+     * metric is the name of a counter or histogram metric which must match a MetricType constant as defined in
+     * model/metrics.go on the server.
+     */
     metric: string;
+
+    /**
+     * value is the floating point value of the metric. It's often a millisecond duration, but it's meaning depends
+     * on which metric this is.
+     */
     value: number;
+
+    /**
+     * timestamp is an integer value representing when the metric was measured as a millisecond value. Some browsers
+     * use floating point numbers for performance timestamps, so we need to make sure to round this.
+     */
     timestamp: number;
 }
 
 type PerformanceReport = {
-    version: '1.0';
+    version: '0.1.0';
 
     labels: {
         platform: PlatformLabel;
@@ -126,7 +141,7 @@ export default class PerformanceReporter {
         this.histogramMeasures.push({
             metric: entry.name,
             value: entry.duration,
-            timestamp: performance.timeOrigin + entry.startTime,
+            timestamp: Math.round(performance.timeOrigin + entry.startTime),
         });
     }
 
@@ -151,7 +166,7 @@ export default class PerformanceReporter {
         this.histogramMeasures.push({
             metric: metric.name,
             value: metric.value,
-            timestamp: performance.timeOrigin + performance.now(),
+            timestamp: Math.round(performance.timeOrigin + performance.now()),
         });
     }
 
@@ -212,7 +227,7 @@ export default class PerformanceReporter {
         const counterMeasures = this.countersToMeasures(now, counters);
 
         return {
-            version: '1.0',
+            version: '0.1.0',
 
             labels: {
                 platform: this.platformLabel,
@@ -252,7 +267,7 @@ export default class PerformanceReporter {
             counterMeasures.push({
                 metric: name,
                 value,
-                timestamp: now,
+                timestamp: Math.round(now),
             });
         }