Deterministic In-Memory Caching: LRU Eviction & PM2 IPC Cache Invalidation

In a clustered Node.js environment (e.g. 4 PM2 cluster workers), updating a post in one worker leaves stale data in the remaining workers' RAM caches. Implementing **PM2 IPC (Inter-Process Communication) Broadcasts** ensures that any database write or cache purge immediately invalidates in-memory caches across all cluster workers synchronously.

1. Cluster-Wide IPC Cache Invalidation Flow

// PM2 IPC Cache Invalidation Broadcast
import pm2 from 'pm2';

export function broadcastCacheInvalidation(cacheKey) {
  // Invalidate local worker cache immediately
  CacheService.delete(cacheKey);
  
  // Broadcast invalidation event to sibling PM2 cluster workers
  if (process.send) {
    process.send({
      type: 'process:msg',
      data: { action: 'CACHE_INVALIDATE', key: cacheKey },
      topic: 'cache_sync'
    });
  }
}