correctly handle non backend outputs from stack metadata (#2537)

Author: rtpascual

.changeset/real-pants-smash.md

@@ -0,0 +1,5 @@
+---
+'@aws-amplify/deployed-backend-client': patch
+---
+
+correctly handle non backend outputs from stack metadata

packages/deployed-backend-client/src/stack_metadata_output_retrieval_strategy.test.ts

@@ -532,5 +532,85 @@ void describe('StackMetadataBackendOutputRetrievalStrategy', () => {
         },
       });
     });
+
+    void it('returns expected BackendOutput without other stack metadata entries', async () => {
+      const cfnClientMock = {
+        send: mock.fn((command) => {
+          if (command instanceof GetTemplateSummaryCommand) {
+            return {
+              Metadata: JSON.stringify({
+                [authOutputKey]: {
+                  version: '1',
+                  stackOutputs: ['testName1', 'testName2'],
+                },
+                [graphqlOutputKey]: {
+                  version: '2',
+                  stackOutputs: ['thing1', 'thing2'],
+                },
+                test: 'test',
+                testArray: ['element0', 'element1'],
+                testObj: {
+                  testA: 'testA',
+                  testB: 'testB',
+                },
+              }),
+            };
+          } else if (command instanceof DescribeStacksCommand) {
+            return {
+              Stacks: [
+                {
+                  Outputs: [
+                    {
+                      OutputKey: 'testName1',
+                      OutputValue: 'testValue1',
+                    },
+                    {
+                      OutputKey: 'testName2',
+                      OutputValue: 'testValue2',
+                    },
+                    {
+                      OutputKey: 'thing1',
+                      OutputValue: 'The cat',
+                    },
+                    {
+                      OutputKey: 'thing2',
+                      OutputValue: 'in the hat',
+                    },
+                  ],
+                },
+              ],
+            };
+          }
+          assert.fail(`Unknown command ${typeof command}`);
+        }),
+      } as unknown as CloudFormationClient;
+
+      const stackNameResolverMock: MainStackNameResolver = {
+        resolveMainStackName: mock.fn(async () => 'testMainStack'),
+      };
+
+      const retrievalStrategy = new StackMetadataBackendOutputRetrievalStrategy(
+        cfnClientMock,
+        stackNameResolverMock
+      );
+
+      const output = await retrievalStrategy.fetchBackendOutput();
+      assert.deepStrictEqual(output, {
+        [authOutputKey]: {
+          version: '1',
+          payload: {
+            testName1: 'testValue1',
+            testName2: 'testValue2',
+          },
+        },
+        [graphqlOutputKey]: {
+          version: '2',
+          payload: {
+            thing1: 'The cat',
+            thing2: 'in the hat',
+          },
+        },
+      });
+    });
   });
 });

packages/deployed-backend-client/src/stack_metadata_output_retrieval_strategy.ts

@@ -9,7 +9,10 @@ import {
   BackendOutputRetrievalStrategy,
   MainStackNameResolver,
 } from '@aws-amplify/plugin-types';
-import { backendOutputStackMetadataSchema } from '@aws-amplify/backend-output-schemas';
+import {
+  BackendOutputEntryStackMetadata,
+  backendOutputStackMetadataSchema,
+} from '@aws-amplify/backend-output-schemas';
 import {
   BackendOutputClientError,
   BackendOutputClientErrorType,
@@ -87,9 +90,13 @@ export class StackMetadataBackendOutputRetrievalStrategy
       throw error;
     }
 
+    const filteredMetadataObject =
+      this.filterBackendOutputEntryStackMetadata(metadataObject);
+
     // parse and validate the metadata object
-    const backendOutputMetadata =
-      backendOutputStackMetadataSchema.parse(metadataObject);
+    const backendOutputMetadata = backendOutputStackMetadataSchema.parse(
+      filteredMetadataObject
+    );
 
     // DescribeStacks includes the template output
     const stackDescription = await this.cfnClient.send(
@@ -152,4 +159,32 @@ export class StackMetadataBackendOutputRetrievalStrategy
     });
     return result;
   };
+
+  /**
+   * Filter out stack metadata entries that do not pertain to backend outputs
+   */
+  private filterBackendOutputEntryStackMetadata<
+    T extends Record<string, unknown>
+  >(metadata: T) {
+    return Object.fromEntries(
+      Object.entries(metadata).filter(([, value]) =>
+        this.isBackendOutputEntryStackMetadata(value)
+      )
+    );
+  }
+
+  /**
+   * Type predicate to determine if stack metadata entry is like a backend output entry.
+   * Zod parsing validation will handle stricter type checking
+   */
+  private isBackendOutputEntryStackMetadata(
+    obj: unknown
+  ): obj is BackendOutputEntryStackMetadata {
+    return (
+      !!obj &&
+      typeof obj === 'object' &&
+      'version' in obj &&
+      'stackOutputs' in obj
+    );
+  }
 }