fix(sessions): Correctly compute session duration

Closes #3615

* Update the @sentry/browser client to not send durations when capturing
  sessions.

* Leverage timestampInSeconds from @sentry/utils instead of Date.now()
  to make sure that durations are correctly reported to Sentry.

Author: AbhiPrasad

packages/browser/src/client.ts

@@ -1,4 +1,4 @@
-import { BaseClient, Scope, SDK_VERSION } from '@sentry/core';
+import { BaseClient, Scope, SDK_VERSION, Session } from '@sentry/core';
 import { Event, EventHint } from '@sentry/types';
 import { getGlobalObject, logger } from '@sentry/utils';
 
@@ -57,6 +57,15 @@ export class BrowserClient extends BaseClient<BrowserBackend, BrowserOptions> {
     });
   }
 
+  /**
+   * @inheritDoc
+   */
+  public captureSession(session: Session): void {
+    // Make sure session duration is not sent
+    session.duration = undefined;
+    super.captureSession(session);
+  }
+
   /**
    * @inheritDoc
    */

packages/core/src/index.ts

@@ -13,7 +13,7 @@ export {
   setUser,
   withScope,
 } from '@sentry/minimal';
-export { addGlobalEventProcessor, getCurrentHub, getHubFromCarrier, Hub, makeMain, Scope } from '@sentry/hub';
+export { addGlobalEventProcessor, getCurrentHub, getHubFromCarrier, Hub, makeMain, Scope, Session } from '@sentry/hub';
 export { API } from './api';
 export { BaseClient } from './baseclient';
 export { BackendClass, BaseBackend } from './basebackend';

packages/hub/src/session.ts

@@ -8,7 +8,7 @@ import {
   SessionStatus,
   Transport,
 } from '@sentry/types';
-import { dropUndefinedKeys, logger, uuid4 } from '@sentry/utils';
+import { dropUndefinedKeys, logger, timestampInSeconds, uuid4 } from '@sentry/utils';
 
 import { getCurrentHub } from './hub';
 
@@ -21,9 +21,9 @@ export class Session implements SessionInterface {
   public release?: string;
   public sid: string = uuid4();
   public did?: string;
-  public timestamp: number = Date.now();
-  public started: number = Date.now();
-  public duration: number = 0;
+  public timestamp: number = timestampInSeconds;
+  public started: number = timestampInSeconds;
+  public duration?: number = 0;
   public status: SessionStatus = SessionStatus.Ok;
   public environment?: string;
   public ipAddress?: string;
@@ -48,7 +48,7 @@ export class Session implements SessionInterface {
       }
     }
 
-    this.timestamp = context.timestamp || Date.now();
+    this.timestamp = context.timestamp || timestampInSeconds;
 
     if (context.sid) {
       // Good enough uuid validation. — Kamil
@@ -63,7 +63,7 @@ export class Session implements SessionInterface {
     if (typeof context.started === 'number') {
       this.started = context.started;
     }
-    if (typeof context.duration === 'number') {
+    if (typeof context.duration === 'number' || typeof context.duration === undefined) {
       this.duration = context.duration;
     } else {
       this.duration = this.timestamp - this.started;
@@ -104,9 +104,9 @@ export class Session implements SessionInterface {
     init: boolean;
     sid: string;
     did?: string;
-    timestamp: string;
-    started: string;
-    duration: number;
+    timestamp: number;
+    started: number;
+    duration?: number;
     status: SessionStatus;
     errors: number;
     attrs?: {
@@ -119,8 +119,8 @@ export class Session implements SessionInterface {
     return dropUndefinedKeys({
       sid: `${this.sid}`,
       init: this.init,
-      started: new Date(this.started).toISOString(),
-      timestamp: new Date(this.timestamp).toISOString(),
+      started: this.started,
+      timestamp: this.timestamp,
       status: this.status,
       errors: this.errors,
       did: typeof this.did === 'number' || typeof this.did === 'string' ? `${this.did}` : undefined,

packages/types/src/session.ts

@@ -15,9 +15,9 @@ export interface Session extends SessionContext {
     init: boolean;
     sid: string;
     did?: string;
-    timestamp: string;
-    started: string;
-    duration: number;
+    timestamp: number;
+    started: number;
+    duration?: number;
     status: SessionStatus;
     errors: number;
     attrs?: {