fix(integ-test): limit api response to avoid 4k limit

packages/@aws-cdk/integ-tests/lib/assertions/api-call-base.ts

@@ -60,6 +60,8 @@ export interface IApiCall extends IConstruct {
    * Assert that the ExpectedResult is equal
    * to the result of the AwsApiCall at the given path.
    *
+   * Providing a path will filter the output of the initial API call.
+   *
    * For example the SQS.receiveMessage api response would look
    * like:
    *

packages/@aws-cdk/integ-tests/lib/assertions/private/deploy-assert.ts

@@ -58,11 +58,12 @@ export class DeployAssert extends Construct implements IDeployAssert {
     Object.defineProperty(this, DEPLOY_ASSERT_SYMBOL, { value: true });
   }
 
-  public awsApiCall(service: string, api: string, parameters?: any): IApiCall {
+  public awsApiCall(service: string, api: string, parameters?: any, outputPaths?: string[]): IApiCall {
     return new AwsApiCall(this.scope, `AwsApiCall${service}${api}`, {
       api,
       service,
       parameters,
+      outputPaths,
     });
   }
 

packages/@aws-cdk/integ-tests/lib/assertions/providers/lambda-handler/sdk.ts

@@ -52,12 +52,28 @@ export class AwsApiCallHandler extends CustomResourceHandler<AwsApiCallRequest,
       ...flatten(respond),
     };
 
-    const resp = request.flattenResponse === 'true' ? flatData : respond;
+    let resp: AwsApiCallResult | { [key: string]: string } = respond;
+    if (request.outputPaths) {
+      resp = filterKeys(flatData, request.outputPaths!);
+    } else if (request.flattenResponse === 'true') {
+      resp = flatData;
+    }
     console.log(`Returning result ${JSON.stringify(resp)}`);
     return resp;
   }
 }
 
+function filterKeys(object: object, searchStrings: string[]): { [key: string]: string } {
+  return Object.entries(object).reduce((filteredObject: { [key: string]: string }, [key, value]) => {
+    for (const searchString of searchStrings) {
+      if (key.startsWith(`apiCallResponse.${searchString}`)) {
+        filteredObject[key] = value;
+      }
+    }
+    return filteredObject;
+  }, {});
+}
+
 function isJsonString(value: string): any {
   try {
     return JSON.parse(value);

packages/@aws-cdk/integ-tests/lib/assertions/providers/lambda-handler/types.ts

@@ -42,6 +42,16 @@ export interface AwsApiCallRequest {
    * @default 'false'
    */
   readonly flattenResponse?: string;
+
+  /**
+   * Restrict the data returned by the API call to specific paths in
+   * the API response. Use this to limit the data returned by the custom
+   * resource if working with API calls that could potentially result in custom
+   * response objects exceeding the hard limit of 4096 bytes.
+   *
+   * @default - return all data
+   */
+  readonly outputPaths?: string[];
 }
 
 /**

packages/@aws-cdk/integ-tests/lib/assertions/sdk.ts

@@ -25,6 +25,16 @@ export interface AwsApiCallOptions {
    * @default - no parameters
    */
   readonly parameters?: any;
+
+  /**
+   * Restrict the data returned by the API call to specific paths in
+   * the API response. Use this to limit the data returned by the custom
+   * resource if working with API calls that could potentially result in custom
+   * response objects exceeding the hard limit of 4096 bytes.
+   *
+   * @default - return all data
+   */
+  readonly outputPaths?: string[];
 }
 
 /**
@@ -59,6 +69,7 @@ export class AwsApiCall extends ApiCallBase {
   private readonly name: string;
 
   private _assertAtPath?: string;
+  private _outputPaths?: string[];
   private readonly api: string;
   private readonly service: string;
 
@@ -70,6 +81,7 @@ export class AwsApiCall extends ApiCallBase {
     this.name = `${props.service}${props.api}`;
     this.api = props.api;
     this.service = props.service;
+    this._outputPaths = props.outputPaths;
 
     this.apiCallResource = new CustomResource(this, 'Default', {
       serviceToken: this.provider.serviceToken,
@@ -81,6 +93,7 @@ export class AwsApiCall extends ApiCallBase {
         stateMachineArn: Lazy.string({ produce: () => this.stateMachineArn }),
         parameters: this.provider.encode(props.parameters),
         flattenResponse: Lazy.string({ produce: () => this.flattenResponse }),
+        outputPaths: Lazy.list({ produce: () => this._outputPaths }),
         salt: Date.now().toString(),
       },
       resourceType: `${SDK_RESOURCE_TYPE_PREFIX}${this.name}`.substring(0, 60),
@@ -107,6 +120,7 @@ export class AwsApiCall extends ApiCallBase {
 
   public assertAtPath(path: string, expected: ExpectedResult): IApiCall {
     this._assertAtPath = path;
+    this._outputPaths = [path];
     this.expectedResult = expected.result;
     this.flattenResponse = 'true';
     return this;

packages/@aws-cdk/integ-tests/lib/assertions/types.ts

@@ -27,7 +27,7 @@ export interface IDeployAssert {
    *   Messages: [{ Body: 'hello' }],
    * }));
    */
-  awsApiCall(service: string, api: string, parameters?: any): IApiCall;
+  awsApiCall(service: string, api: string, parameters?: any, outputPaths?: string[]): IApiCall;
 
   /**
    * Invoke a lambda function and return the response which can be asserted

packages/@aws-cdk/integ-tests/test/assertions/providers/lambda-handler/sdk.test.ts

@@ -104,4 +104,40 @@ describe('SdkHandler', () => {
       sinon.assert.calledWith(fake, { DryRun: false });
     });
   });
+
+  test('restrict output path', async () => {
+    // GIVEN
+    const responseFake = {
+      Name: 'bucket-name',
+      Contents: [
+        {
+          Key: 'first-key',
+          ETag: 'first-key-etag',
+        },
+        {
+          Key: 'second-key',
+          ETag: 'second-key-etag',
+        },
+      ],
+    } as SDK.S3.ListObjectsOutput;
+    AWS.mock('S3', 'listObjects', sinon.fake.resolves(responseFake));
+    const handler = sdkHandler() as any;
+    const request: AwsApiCallRequest = {
+      service: 'S3',
+      api: 'listObjects',
+      parameters: {
+        Bucket: 'myBucket',
+      },
+      outputPaths: ['Name', 'Contents.0.Key'],
+    };
+
+    // WHEN
+    const response: AwsApiCallResult = await handler.processEvent(request);
+
+    // THEN
+    expect(response).toEqual({
+      'apiCallResponse.Name': 'bucket-name',
+      'apiCallResponse.Contents.0.Key': 'first-key',
+    });
+  });
 });

packages/@aws-cdk/integ-tests/test/assertions/sdk.test.ts

@@ -47,6 +47,63 @@ describe('AwsApiCall', () => {
 
   });
 
+  test('restrict output paths', () => {
+    // GIVEN
+    const app = new App();
+    const deplossert = new DeployAssert(app);
+
+    // WHEN
+    deplossert.awsApiCall('MyService', 'MyApi', {
+      param1: 'val1',
+      param2: 2,
+    }, ['path1', 'path2']);
+
+    // THEN
+    const template = Template.fromStack(deplossert.scope);
+    template.resourceCountIs('AWS::Lambda::Function', 1);
+    template.hasResourceProperties('Custom::DeployAssert@SdkCallMyServiceMyApi', {
+      service: 'MyService',
+      api: 'MyApi',
+      parameters: {
+        param1: 'val1',
+        param2: 2,
+      },
+      outputPaths: [
+        'path1',
+        'path2',
+      ],
+    });
+  });
+
+  test('assert at path', () => {
+    // GIVEN
+    const app = new App();
+    const deplossert = new DeployAssert(app);
+
+    // WHEN
+    deplossert.awsApiCall('MyService', 'MyApi', {
+      param1: 'val1',
+      param2: 2,
+    }).assertAtPath('Messages.0.Key', ExpectedResult.exact('first-key'));
+
+    // THEN
+    const template = Template.fromStack(deplossert.scope);
+    template.resourceCountIs('AWS::Lambda::Function', 1);
+    template.hasResourceProperties('Custom::DeployAssert@SdkCallMyServiceMyApi', {
+      service: 'MyService',
+      api: 'MyApi',
+      parameters: {
+        param1: 'val1',
+        param2: 2,
+      },
+      flattenResponse: 'true',
+      outputPaths: [
+        'Messages.0.Key',
+      ],
+      expected: JSON.stringify({ $Exact: 'first-key' }),
+    });
+  });
+
   test('add policy to provider', () => {
     // GIVEN
     const app = new App();