feat: Unique connection tracking (#9067)

src/lib/metrics.test.ts

@@ -130,7 +130,7 @@ test('should collect metrics for requests', async () => {
 
     const metrics = await prometheusRegister.metrics();
     expect(metrics).toMatch(
-        /http_request_duration_milliseconds\{quantile="0\.99",path="somePath",method="GET",status="200",appName="undefined"\}.*1337/,
+        /http_request_duration_milliseconds\{quantile="0\.99",path="somePath",method="GET",status="200",appName="undefined",connectionId="undefined"\}.*1337/,
     );
 });
 

src/lib/metrics.ts

@@ -124,7 +124,7 @@ export function registerPrometheusMetrics(
     const requestDuration = createSummary({
         name: 'http_request_duration_milliseconds',
         help: 'App response time',
-        labelNames: ['path', 'method', 'status', 'appName'],
+        labelNames: ['path', 'method', 'status', 'appName', 'connectionId'],
         percentiles: [0.1, 0.5, 0.9, 0.95, 0.99],
         maxAgeSeconds: 600,
         ageBuckets: 5,
@@ -700,13 +700,14 @@ export function registerPrometheusMetrics(
 
     eventBus.on(
         events.REQUEST_TIME,
-        ({ path, method, time, statusCode, appName }) => {
+        ({ path, method, time, statusCode, appName, connectionId }) => {
             requestDuration
                 .labels({
                     path,
                     method,
                     status: statusCode,
                     appName,
+                    connectionId,
                 })
                 .observe(time);
         },

src/lib/middleware/response-time-metrics.ts

@@ -55,12 +55,19 @@ export function responseTimeMetrics(
         // when pathname is undefined use a fallback
         pathname = pathname ?? collapse(req.path);
         let appName: string | undefined;
+        let connectionId: string | undefined;
         if (
             !flagResolver.isEnabled('responseTimeWithAppNameKillSwitch') &&
             (instanceStatsService.getAppCountSnapshot('7d') ??
                 appNameReportingThreshold) < appNameReportingThreshold
         ) {
-            appName = req.headers['unleash-appname'] ?? req.query.appName;
+            appName =
+                req.headers['x-unleash-appname'] ??
+                req.headers['unleash-appname'] ??
+                req.query.appName;
+            if (flagResolver.isEnabled('uniqueSdkTracking')) {
+                connectionId = req.headers['x-unleash-connection-id'];
+            }
         }
 
         const timingInfo = {
@@ -69,6 +76,7 @@ export function responseTimeMetrics(
             statusCode,
             time,
             appName,
+            connectionId,
         };
         if (!res.locals.responseTimeEmitted) {
             res.locals.responseTimeEmitted = true;

src/lib/types/experimental.ts

@@ -61,7 +61,8 @@ export type IFlagKey =
     | 'etagVariant'
     | 'oidcRedirect'
     | 'deltaApi'
-    | 'newHostedAuthHandler';
+    | 'newHostedAuthHandler'
+    | 'uniqueSdkTracking';
 
 export type IFlags = Partial<{ [key in IFlagKey]: boolean | Variant }>;
 
@@ -290,6 +291,10 @@ const flags: IFlags = {
         process.env.UNLEASH_EXPERIMENTAL_NEW_HOSTED_AUTH_HANDLER,
         false,
     ),
+    uniqueSdkTracking: parseEnvVarBoolean(
+        process.env.UNLEASH_EXPERIMENTAL_UNIQUE_SDK_TRACKING,
+        false,
+    ),
 };
 
 export const defaultExperimentalOptions: IExperimentalOptions = {