chore: import upstream snapshot with attribution

apps/sim/lib/core/storage/index.ts

@@ -0,0 +1,8 @@
+export {
+  getStorageMethod,
+  isDatabaseStorage,
+  isRedisStorage,
+  requireRedis,
+  resetStorageMethod,
+  type StorageMethod,
+} from './storage'

apps/sim/lib/core/storage/storage.ts

@@ -0,0 +1,79 @@
+import { createLogger } from '@sim/logger'
+import { getRedisClient } from '@/lib/core/config/redis'
+
+const logger = createLogger('Storage')
+
+export type StorageMethod = 'redis' | 'database'
+
+let cachedStorageMethod: StorageMethod | null = null
+
+/**
+ * Determine the storage method once based on configuration.
+ * This decision is made at first call and cached for the lifetime of the process.
+ *
+ * - If REDIS_URL is configured and client initializes → 'redis'
+ * - If REDIS_URL is not configured → 'database'
+ *
+ * Transient failures do NOT change the storage method.
+ * If Redis is configured but fails, operations will fail (not fallback to DB).
+ */
+export function getStorageMethod(): StorageMethod {
+  if (cachedStorageMethod) {
+    return cachedStorageMethod
+  }
+
+  const redis = getRedisClient()
+
+  if (redis) {
+    cachedStorageMethod = 'redis'
+    logger.info('Storage method: Redis')
+  } else {
+    cachedStorageMethod = 'database'
+    logger.info('Storage method: PostgreSQL')
+  }
+
+  return cachedStorageMethod
+}
+
+/**
+ * Check if Redis is the configured storage method.
+ * Use this for conditional logic that depends on storage type.
+ */
+export function isRedisStorage(): boolean {
+  return getStorageMethod() === 'redis'
+}
+
+/**
+ * Check if database is the configured storage method.
+ */
+export function isDatabaseStorage(): boolean {
+  return getStorageMethod() === 'database'
+}
+
+/**
+ * Get Redis client, but only if Redis is the configured storage method.
+ * Throws if Redis is configured but client is unavailable.
+ *
+ * Use this instead of getRedisClient() directly when you need to ensure
+ * consistency with the storage method decision.
+ */
+export function requireRedis() {
+  if (!isRedisStorage()) {
+    throw new Error('Redis storage not configured')
+  }
+
+  const redis = getRedisClient()
+  if (!redis) {
+    throw new Error('Redis client unavailable')
+  }
+
+  return redis
+}
+
+/**
+ * Reset the cached storage method.
+ * Only use for testing purposes.
+ */
+export function resetStorageMethod(): void {
+  cachedStorageMethod = null
+}