fix(mail): add periodic cleanup timers and proper shutdown handling for bounce manager and delivery queue; avoid mutating maps during iteration and prune stale rate-limiter stats to prevent memory growth

ts/mail/delivery/classes.delivery.queue.ts

@@ -78,6 +78,7 @@ export class UnifiedDeliveryQueue extends EventEmitter {
   private options: Required<IQueueOptions>;
   private queue: Map<string, IQueueItem> = new Map();
   private checkTimer?: NodeJS.Timeout;
+  private cleanupTimer?: NodeJS.Timeout;
   private stats: IQueueStats;
   private processing: boolean = false;
   private totalProcessed: number = 0;
@@ -158,8 +159,19 @@ export class UnifiedDeliveryQueue extends EventEmitter {
     if (this.checkTimer) {
       clearInterval(this.checkTimer);
     }
-    
+
     this.checkTimer = setInterval(() => this.processQueue(), this.options.checkInterval);
+
+    // Start periodic cleanup of delivered/failed items (every 30 minutes)
+    if (this.cleanupTimer) {
+      clearInterval(this.cleanupTimer);
+    }
+    this.cleanupTimer = setInterval(() => {
+      this.cleanupOldItems(24 * 60 * 60 * 1000).catch((err) => {
+        logger.log('error', `Auto-cleanup failed: ${err.message}`);
+      });
+    }, 30 * 60 * 1000);
+
     this.processing = true;
     this.stats.processingActive = true;
     this.emit('processingStarted');
@@ -174,7 +186,11 @@ export class UnifiedDeliveryQueue extends EventEmitter {
       clearInterval(this.checkTimer);
       this.checkTimer = undefined;
     }
-    
+    if (this.cleanupTimer) {
+      clearInterval(this.cleanupTimer);
+      this.cleanupTimer = undefined;
+    }
+
     this.processing = false;
     this.stats.processingActive = false;
     this.emit('processingStopped');
@@ -590,19 +606,24 @@ export class UnifiedDeliveryQueue extends EventEmitter {
    */
   public async cleanupOldItems(maxAge: number = 7 * 24 * 60 * 60 * 1000): Promise<number> {
     const cutoff = new Date(Date.now() - maxAge);
-    let removedCount = 0;
-    
-    // Find old items
+
+    // Collect IDs first to avoid modifying the Map during iteration
+    const idsToRemove: string[] = [];
     for (const item of this.queue.values()) {
       if (['delivered', 'failed'].includes(item.status) && item.updatedAt < cutoff) {
-        // Remove item
-        await this.removeItem(item.id);
-        removedCount++;
+        idsToRemove.push(item.id);
       }
     }
-    
-    logger.log('info', `Cleaned up ${removedCount} old items`);
-    return removedCount;
+
+    // Remove collected items
+    for (const id of idsToRemove) {
+      await this.removeItem(id);
+    }
+
+    if (idsToRemove.length > 0) {
+      logger.log('info', `Cleaned up ${idsToRemove.length} old items from delivery queue`);
+    }
+    return idsToRemove.length;
   }
   
   /**
@@ -611,15 +632,9 @@ export class UnifiedDeliveryQueue extends EventEmitter {
   public async shutdown(): Promise<void> {
     logger.log('info', 'Shutting down UnifiedDeliveryQueue');
     
-    // Stop processing
+    // Stop processing (clears both check and cleanup timers)
     this.stopProcessing();
     
-    // Clear the check timer to prevent memory leaks
-    if (this.checkTimer) {
-      clearInterval(this.checkTimer);
-      this.checkTimer = undefined;
-    }
-    
     // If using disk storage, make sure all items are persisted
     if (this.options.storageType === 'disk') {
       const pendingWrites: Promise<void>[] = [];