feat: send id only when storage is accessible

Author: Joozty

packages/web/src/index.ts

@@ -434,10 +434,13 @@ export const SplunkRum: SplunkOtelWebType = {
       // Splunk specific attributes
       'splunk.rumVersion': VERSION,
       'splunk.scriptInstance': instanceId,
-      'browser.instance.id': BrowserInstanceService.id,
       'app': applicationName,
     };
 
+    if(BrowserInstanceService.id) {
+      resourceAttrs['browser.instance.id'] = BrowserInstanceService.id
+    }
+
     const syntheticsRunId = getSyntheticsRunId();
     if (syntheticsRunId) {
       resourceAttrs[SYNTHETICS_RUN_ID_ATTRIBUTE] = syntheticsRunId;

packages/web/src/services/BrowserInstanceService.ts

@@ -31,22 +31,29 @@ const BROWSER_INSTANCE_ID_KEY = 'browser_instance_id';
  *    This is not implemented yet as requires bigger refactoring.
  */
 export class BrowserInstanceService {
-  static _id: string | undefined = undefined;
+  // `undefined` represents the case when the storage is inaccessible.
+  static _id: string | undefined | null = null;
 
-  static get id(): string {
-    if(this._id) {
+  static get id(): string | undefined {
+    if(this._id !== null) {
       return this._id;
     }
 
 
     // Check if the ID is already stored in the session storage. It might be generated by another frame/context.
     let browserInstanceId = safelyGetSessionStorage(BROWSER_INSTANCE_ID_KEY);
-    if(!browserInstanceId) {
+    if(browserInstanceId) {
+      this._id = browserInstanceId;
+    } else if(browserInstanceId === null) {
+      // Storage is accessible but the ID is not stored yet.
       browserInstanceId = generateId(64);
+      this._id = browserInstanceId;
       safelySetSessionStorage(BROWSER_INSTANCE_ID_KEY, browserInstanceId);
+    } else {
+        // Storage is not accessible.
+        this._id = undefined;
     }
 
-    this._id = browserInstanceId;
 
     return this._id;
   }

packages/web/src/utils/storage.ts

@@ -14,15 +14,14 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-export const safelyGetSessionStorage = (key: string): string | null => {
-  let value = null;
+export const safelyGetSessionStorage = (key: string): string | null | undefined => {
   try {
-    value = window.sessionStorage.getItem(key);
+    return window.sessionStorage.getItem(key);
   } catch {
+    return undefined
     // sessionStorage not accessible probably user is in incognito-mode
     // or set "Block third-party cookies" option in browser settings
   }
-  return value;
 };
 
 export const safelySetSessionStorage = (key: string, value: string): boolean => {