[Response Ops][Alerting Adding isTrackedAlert function to alerts cl…

…ient (#179253)

## Summary

Allows rule executors to determine whether an alert is tracked from a
previous execution.

Co-authored-by: Maryam Saeidi <maryam.saeidi@elastic.co>

x-pack/plugins/alerting/server/alerts_client/alerts_client.test.ts

@@ -2702,6 +2702,7 @@ describe('Alerts Client', () => {
 
           expect(keys(publicAlertsClient)).toEqual([
             'report',
+            'isTrackedAlert',
             'setAlertData',
             'getAlertLimitValue',
             'setAlertLimitReached',
@@ -2781,6 +2782,22 @@ describe('Alerts Client', () => {
           expect(recoveredAlert.hit).toBeUndefined();
         });
       });
+
+      describe('isTrackedAlert()', () => {
+        test('should return true if alert was active in a previous execution, false otherwise', async () => {
+          const alertsClient = new AlertsClient<{}, {}, {}, 'default', 'recovered'>(
+            alertsClientParams
+          );
+
+          await alertsClient.initializeExecution({
+            ...defaultExecutionOpts,
+            activeAlertsFromState: { '1': trackedAlert1Raw, '2': trackedAlert2Raw },
+          });
+          expect(alertsClient.isTrackedAlert('1')).toBe(true);
+          expect(alertsClient.isTrackedAlert('2')).toBe(true);
+          expect(alertsClient.isTrackedAlert('3')).toBe(false);
+        });
+      });
     });
   }
 });

x-pack/plugins/alerting/server/alerts_client/alerts_client.ts

@@ -277,6 +277,10 @@ export class AlertsClient<
     }
   }
 
+  public isTrackedAlert(id: string) {
+    return this.legacyAlertsClient.isTrackedAlert(id);
+  }
+
   public hasReachedAlertLimit(): boolean {
     return this.legacyAlertsClient.hasReachedAlertLimit();
   }
@@ -745,6 +749,7 @@ export class AlertsClient<
           WithoutReservedActionGroups<ActionGroupIds, RecoveryActionGroupId>
         >
       ) => this.report(alert),
+      isTrackedAlert: (id: string) => this.isTrackedAlert(id),
       setAlertData: (
         alert: UpdateableAlert<AlertData, LegacyState, LegacyContext, RecoveryActionGroupId>
       ) => this.setAlertData(alert),

x-pack/plugins/alerting/server/alerts_client/legacy_alerts_client.test.ts

@@ -307,4 +307,16 @@ describe('Legacy Alerts Client', () => {
       '2': new Alert<AlertInstanceContext, AlertInstanceContext>('2', testAlert2),
     });
   });
+
+  test('isTrackedAlert() should return true if alert was active in a previous execution, false otherwise', async () => {
+    const alertsClient = new LegacyAlertsClient({
+      logger,
+      ruleType,
+    });
+
+    await alertsClient.initializeExecution(defaultExecutionOpts);
+    expect(alertsClient.isTrackedAlert('1')).toBe(true);
+    expect(alertsClient.isTrackedAlert('2')).toBe(true);
+    expect(alertsClient.isTrackedAlert('3')).toBe(false);
+  });
 });

x-pack/plugins/alerting/server/alerts_client/legacy_alerts_client.ts

@@ -137,6 +137,10 @@ export class LegacyAlertsClient<
     return this.alertFactory?.get(id);
   }
 
+  public isTrackedAlert(id: string) {
+    return !!this.trackedAlerts.active[id];
+  }
+
   public processAlerts({
     notifyOnActionGroupChange,
     flappingSettings,

x-pack/plugins/alerting/server/alerts_client/types.ts

@@ -84,6 +84,7 @@ export interface IAlertsClient<
     alertIds: string[];
     maintenanceWindowIds: string[];
   } | null>;
+  isTrackedAlert(id: string): boolean;
   getSummarizedAlerts?(params: GetSummarizedAlertsParams): Promise<SummarizedAlerts>;
   getAlertsToSerialize(): {
     alertsToReturn: Record<string, RawAlertInstance>;
@@ -152,6 +153,7 @@ export interface PublicAlertsClient<
   report(
     alert: ReportedAlert<AlertData, State, Context, ActionGroupIds>
   ): ReportedAlertData<AlertData>;
+  isTrackedAlert(id: string): boolean;
   setAlertData(alert: UpdateableAlert<AlertData, State, Context, ActionGroupIds>): void;
   getAlertLimitValue: () => number;
   setAlertLimitReached: (reached: boolean) => void;