fix(plugin-meetings): add retry mechanism to fetching clusters

packages/@webex/plugin-meetings/src/reachability/index.ts

@@ -114,6 +114,32 @@ export default class Reachability extends EventsScope {
     this.clusterReachability = {};
   }
 
+  /**
+   * Fetches the list of media clusters from the backend
+   * @param {boolean} isRetry
+   * @private
+   * @returns {Promise<{clusters: ClusterList, joinCookie: any}>}
+   */
+  async getClusters(isRetry = false): Promise<{clusters: ClusterList; joinCookie: any}> {
+    try {
+      const {clusters, joinCookie} = await this.reachabilityRequest.getClusters(
+        MeetingUtil.getIpVersion(this.webex)
+      );
+
+      return {clusters, joinCookie};
+    } catch (error) {
+      if (isRetry) {
+        throw new Error('Failed to get clusters list');
+      }
+
+      LoggerProxy.logger.error(
+        `Reachability:index#getClusters --> Failed with error: ${error}, retrying...`
+      );
+
+      return this.getClusters(true);
+    }
+  }
+
   /**
    * Gets a list of media clusters from the backend and performs reachability checks on all the clusters
    * @returns {Promise<ReachabilityResults>} reachability results
@@ -123,9 +149,7 @@ export default class Reachability extends EventsScope {
   public async gatherReachability(): Promise<ReachabilityResults> {
     // Fetch clusters and measure latency
     try {
-      const {clusters, joinCookie} = await this.reachabilityRequest.getClusters(
-        MeetingUtil.getIpVersion(this.webex)
-      );
+      const {clusters, joinCookie} = await this.getClusters();
 
       // @ts-ignore
       await this.webex.boundedStorage.put(

packages/@webex/plugin-meetings/test/unit/spec/reachability/index.ts

@@ -7,7 +7,7 @@ import Reachability, {
   ReachabilityResults,
   ReachabilityResultsForBackend,
 } from '@webex/plugin-meetings/src/reachability/';
-import { ClusterNode } from '../../../../src/reachability/request';
+import {ClusterNode} from '../../../../src/reachability/request';
 import MeetingUtil from '@webex/plugin-meetings/src/meeting/util';
 import * as ClusterReachabilityModule from '@webex/plugin-meetings/src/reachability/clusterReachability';
 import Metrics from '@webex/plugin-meetings/src/metrics';
@@ -145,7 +145,6 @@ describe('isAnyPublicClusterReachable', () => {
   });
 });
 
-
 describe('isWebexMediaBackendUnreachable', () => {
   let webex;
 
@@ -1466,6 +1465,70 @@ describe('gatherReachability', () => {
       xtls: [], // empty list because TLS is disabled in config
     });
   });
+
+  it('retry of getClusters is succesfull', async () => {
+    webex.config.meetings.experimental = {
+      enableTcpReachability: true,
+      enableTlsReachability: false,
+    };
+
+    const getClustersResult = {
+      clusters: {
+        'cluster name': {
+          udp: ['testUDP1', 'testUDP2'],
+          tcp: ['testTCP1', 'testTCP2'],
+          xtls: ['testXTLS1', 'testXTLS2'],
+          isVideoMesh: false,
+        },
+      },
+      joinCookie: {id: 'id'},
+    };
+
+    const reachability = new Reachability(webex);
+
+    let getClustersCallCount = 0;
+
+    reachability.reachabilityRequest.getClusters = sinon.stub().callsFake(() => {
+      getClustersCallCount++;
+
+      if (getClustersCallCount == 1) {
+        throw new Error('fake error');
+      }
+
+      return getClustersResult;
+    });
+
+    const promise = reachability.gatherReachability();
+
+    await simulateTimeout();
+    await promise;
+
+    assert.equal(getClustersCallCount, 2);
+
+    assert.calledOnce(clusterReachabilityCtorStub);
+  });
+
+  it('two failed calls to getClusters', async () => {
+    const reachability = new Reachability(webex);
+
+    let getClustersCallCount = 0;
+
+    reachability.reachabilityRequest.getClusters = sinon.stub().callsFake(() => {
+      getClustersCallCount++;
+
+      throw new Error('fake error');
+    });
+
+    const promise = reachability.gatherReachability();
+
+    await simulateTimeout();
+
+    await promise;
+
+    assert.equal(getClustersCallCount, 2);
+
+    assert.neverCalledWith(clusterReachabilityCtorStub);
+  });
 });
 
 describe('getReachabilityResults', () => {