ref: Differentiate between browser/other sessions

Previously in c9b3d10, the duration
was updated to be undefined when the browser SDK sent sessions to
Sentry. This patch removes that logic and instead adds a browser flag
to the Session class, which indicates if a duration should be included
or not.

Author: AbhiPrasad

packages/browser/src/sdk.ts

@@ -199,7 +199,7 @@ function startSessionTracking(): void {
     return;
   }
 
-  hub.startSession();
+  hub.startSession({ browser: true });
   hub.captureSession();
 
   // We want to create a session for every navigation as well
@@ -209,7 +209,7 @@ function startSessionTracking(): void {
       if (from === undefined || from === to) {
         return;
       }
-      hub.startSession();
+      hub.startSession({ browser: true });
       hub.captureSession();
     },
     type: 'history',

packages/hub/src/session.ts

@@ -21,13 +21,14 @@ export class Session implements SessionInterface {
   public release?: string;
   public sid: string = uuid4();
   public did?: string;
-  public timestamp: number = timestampInSeconds;
-  public started: number = timestampInSeconds;
+  public timestamp: number = timestampInSeconds();
+  public started: number = timestampInSeconds();
   public duration?: number = 0;
   public status: SessionStatus = SessionStatus.Ok;
   public environment?: string;
   public ipAddress?: string;
   public init: boolean = true;
+  public browser: boolean = false;
 
   public constructor(context?: Omit<SessionContext, 'started' | 'status'>) {
     if (context) {
@@ -48,8 +49,11 @@ export class Session implements SessionInterface {
       }
     }
 
-    this.timestamp = context.timestamp || timestampInSeconds;
+    this.timestamp = context.timestamp || timestampInSeconds();
 
+    if (context.browser) {
+      this.browser = context.browser;
+    }
     if (context.sid) {
       // Good enough uuid validation. — Kamil
       this.sid = context.sid.length === 32 ? context.sid : uuid4();
@@ -63,10 +67,18 @@ export class Session implements SessionInterface {
     if (typeof context.started === 'number') {
       this.started = context.started;
     }
-    if (typeof context.duration === 'number' || typeof context.duration === undefined) {
-      this.duration = context.duration;
+    // The session duration for browser sessions does not track a meaningful
+    // concept that can be used as a metric.
+    // Automatically captured sessions are akin to page views, and thus we
+    // discard their duration.
+    if (this.browser) {
+      this.duration = undefined;
     } else {
-      this.duration = this.timestamp - this.started;
+      if (typeof context.duration === 'number') {
+        this.duration = context.duration;
+      } else {
+        this.duration = this.timestamp - this.started;
+      }
     }
     if (context.release) {
       this.release = context.release;

packages/types/src/session.ts

@@ -50,6 +50,8 @@ export interface SessionContext {
   ipAddress?: string;
   errors?: number;
   user?: User | null;
+  // Sessions are handled differently in browser environments
+  browser?: boolean;
 }
 
 /**

packages/utils/src/time.ts

@@ -103,7 +103,7 @@ const timestampSource: TimestampSource =
 /**
  * Returns a timestamp in seconds since the UNIX epoch using the Date API.
  */
-export const dateTimestampInSeconds = dateTimestampSource.nowSeconds.bind(dateTimestampSource);
+export const dateTimestampInSeconds: () => number = dateTimestampSource.nowSeconds.bind(dateTimestampSource);
 
 /**
  * Returns a timestamp in seconds since the UNIX epoch using either the Performance or Date APIs, depending on the
@@ -116,7 +116,7 @@ export const dateTimestampInSeconds = dateTimestampSource.nowSeconds.bind(dateTi
  * skew can grow to arbitrary amounts like days, weeks or months.
  * See https://github.com/getsentry/sentry-javascript/issues/2590.
  */
-export const timestampInSeconds = timestampSource.nowSeconds.bind(timestampSource);
+export const timestampInSeconds: () => number = timestampSource.nowSeconds.bind(timestampSource);
 
 // Re-exported with an old name for backwards-compatibility.
 export const timestampWithMs = timestampInSeconds;