improv(idempotency): Prevent error when AWS_LAMBDA_FUNCTION_NAME is not passed in the Idempotency Persistence Layer (#4327)

Co-authored-by: Andrea Amorosi <dreamorosi@gmail.com>

Author: sdangol

packages/idempotency/src/persistence/BasePersistenceLayer.ts

@@ -1,7 +1,7 @@
 import { createHash, type Hash } from 'node:crypto';
 import type { JSONValue } from '@aws-lambda-powertools/commons/types';
-import { LRUCache } from '@aws-lambda-powertools/commons/utils/lru-cache';
 import { getStringFromEnv } from '@aws-lambda-powertools/commons/utils/env';
+import { LRUCache } from '@aws-lambda-powertools/commons/utils/lru-cache';
 import { search } from '@aws-lambda-powertools/jmespath';
 import type { JMESPathParsingOptions } from '@aws-lambda-powertools/jmespath/types';
 import { IdempotencyRecordStatus } from '../constants.js';
@@ -39,7 +39,7 @@ abstract class BasePersistenceLayer implements BasePersistenceLayerInterface {
   public constructor() {
     this.idempotencyKeyPrefix = getStringFromEnv({
       key: 'AWS_LAMBDA_FUNCTION_NAME',
-      errorMessage: 'AWS_LAMBDA_FUNCTION_NAME environment variable is required',
+      defaultValue: '',
     });
   }
 

packages/idempotency/tests/unit/persistence/BasePersistenceLayer.test.ts

@@ -63,6 +63,27 @@ describe('Class: BasePersistenceLayer', () => {
         })
       );
     });
+
+    it('initializes with empty key prefix if AWS_LAMBDA_FUNCTION_NAME is not in the environment variable', () => {
+      // Prepare
+      vi.stubEnv('AWS_LAMBDA_FUNCTION_NAME', undefined);
+
+      // Act
+      const persistenceLayer = new PersistenceLayerTestClass();
+
+      // Assess
+      expect(persistenceLayer.idempotencyKeyPrefix).toBe('');
+      expect(persistenceLayer).toEqual(
+        expect.objectContaining({
+          configured: false,
+          expiresAfterSeconds: 3600,
+          hashFunction: 'md5',
+          payloadValidationEnabled: false,
+          throwOnNoIdempotencyKey: false,
+          useLocalCache: false,
+        })
+      );
+    });
   });
 
   describe('Method: configure', () => {