feat(CLI): improved nested stack diff

packages/@aws-cdk/cloudformation-diff/lib/diff-template.ts

@@ -54,7 +54,7 @@ export function fullDiff(
  normalize(newTemplate);
  const theDiff = diffTemplate(currentTemplate, newTemplate);
  if (changeSet) {
- filterFalsePositivies(theDiff, changeSet);
+ filterFalsePositives(theDiff, changeSet);
  addImportInformation(theDiff, changeSet);
  }
  if (isImport) {
@@ -64,7 +64,7 @@ export function fullDiff(
  return theDiff;
 }
 
-function diffTemplate(
+export function diffTemplate(
  currentTemplate: { [key: string]: any },
  newTemplate: { [key: string]: any },
 ): types.TemplateDiff {
@@ -235,7 +235,7 @@ function addImportInformation(diff: types.TemplateDiff, changeSet?: CloudFormati
  }
 }
 
-function filterFalsePositivies(diff: types.TemplateDiff, changeSet: CloudFormation.DescribeChangeSetOutput) {
+function filterFalsePositives(diff: types.TemplateDiff, changeSet: CloudFormation.DescribeChangeSetOutput) {
  const replacements = findResourceReplacements(changeSet);
  diff.resources.forEachDifference((logicalId: string, change: types.ResourceDifference) => {
  if (change.resourceType.includes('AWS::Serverless')) {

packages/@aws-cdk/cloudformation-diff/lib/format.ts

@@ -30,7 +30,7 @@ export interface FormatStream extends NodeJS.WritableStream {
 export function formatDifferences(
  stream: FormatStream,
  templateDiff: TemplateDiff,
- logicalToPathMap: { [logicalId: string]: string } = { },
+ logicalToPathMap: { [logicalId: string]: string } = {},
  context: number = 3) {
  const formatter = new Formatter(stream, logicalToPathMap, templateDiff, context);
 
@@ -59,7 +59,7 @@ export function formatDifferences(
 export function formatSecurityChanges(
  stream: NodeJS.WritableStream,
  templateDiff: TemplateDiff,
- logicalToPathMap: {[logicalId: string]: string} = {},
+ logicalToPathMap: { [logicalId: string]: string } = {},
  context?: number) {
  const formatter = new Formatter(stream, logicalToPathMap, templateDiff, context);
 
@@ -254,7 +254,7 @@ class Formatter {
  const oldStr = JSON.stringify(oldObject, null, 2);
  const newStr = JSON.stringify(newObject, null, 2);
  const diff = _diffStrings(oldStr, newStr, this.context);
- for (let i = 0 ; i < diff.length ; i++) {
+ for (let i = 0; i < diff.length; i++) {
  this.print('%s %s %s', linePrefix, i === 0 ? '└─' : ' ', diff[i]);
  }
  } else {
@@ -466,7 +466,7 @@ function _diffStrings(oldStr: string, newStr: string, context: number): string[]
  function _findIndent(lines: string[]): number {
  let indent = Number.MAX_SAFE_INTEGER;
  for (const line of lines) {
- for (let i = 1 ; i < line.length ; i++) {
+ for (let i = 1; i < line.length; i++) {
  if (line.charAt(i) !== ' ') {
  indent = indent > i - 1 ? i - 1 : indent;
  break;

packages/aws-cdk/lib/api/deployments.ts

@@ -7,7 +7,7 @@ import { CredentialsOptions, SdkForEnvironment, SdkProvider } from './aws-auth/s
 import { deployStack, DeployStackResult, destroyStack, DeploymentMethod } from './deploy-stack';
 import { EnvironmentResources, EnvironmentResourcesRegistry } from './environment-resources';
 import { HotswapMode } from './hotswap/common';
-import { loadCurrentTemplateWithNestedStacks, loadCurrentTemplate, flattenNestedStackNames, TemplateWithNestedStackCount } from './nested-stack-helpers';
+import { loadCurrentTemplateWithNestedStacks, loadCurrentTemplate, RootTemplateWithNestedStacks } from './nested-stack-helpers';
 import { CloudFormationStack, Template, ResourcesToImport, ResourceIdentifierSummaries } from './util/cloudformation';
 import { StackActivityProgress } from './util/cloudformation/stack-activity-monitor';
 import { replaceEnvPlaceholders } from './util/placeholders';
@@ -327,13 +327,9 @@ export class Deployments {
  public async readCurrentTemplateWithNestedStacks(
  rootStackArtifact: cxapi.CloudFormationStackArtifact,
  retrieveProcessedTemplate: boolean = false,
- ): Promise<TemplateWithNestedStackCount> {
+ ): Promise<RootTemplateWithNestedStacks> {
  const sdk = (await this.prepareSdkWithLookupOrDeployRole(rootStackArtifact)).stackSdk;
- const templateWithNestedStacks = await loadCurrentTemplateWithNestedStacks(rootStackArtifact, sdk, retrieveProcessedTemplate);
- return {
- deployedTemplate: templateWithNestedStacks.deployedTemplate,
- nestedStackCount: flattenNestedStackNames(templateWithNestedStacks.nestedStackNames).length,
- };
+ return loadCurrentTemplateWithNestedStacks(rootStackArtifact, sdk, retrieveProcessedTemplate);
  }
 
  public async readCurrentTemplate(stackArtifact: cxapi.CloudFormationStackArtifact): Promise<Template> {

packages/aws-cdk/lib/api/evaluate-cloudformation-template.ts

@@ -1,7 +1,7 @@
 import * as AWS from 'aws-sdk';
 import { PromiseResult } from 'aws-sdk/lib/request';
 import { ISDK } from './aws-auth';
-import { NestedStackNames } from './nested-stack-helpers';
+import { NestedStackTemplates } from './nested-stack-helpers';
 
 export interface ListStackResources {
  listStackResources(): Promise<AWS.CloudFormation.StackResourceSummary[]>;
@@ -102,7 +102,7 @@ export interface EvaluateCloudFormationTemplateProps {
  readonly partition: string;
  readonly urlSuffix: (region: string) => string;
  readonly sdk: ISDK;
- readonly nestedStackNames?: { [nestedStackLogicalId: string]: NestedStackNames };
+ readonly nestedStacks?: { [nestedStackLogicalId: string]: NestedStackTemplates };
 }
 
 export class EvaluateCloudFormationTemplate {
@@ -114,7 +114,7 @@ export class EvaluateCloudFormationTemplate {
  private readonly partition: string;
  private readonly urlSuffix: (region: string) => string;
  private readonly sdk: ISDK;
- private readonly nestedStackNames: { [nestedStackLogicalId: string]: NestedStackNames };
+ private readonly nestedStacks: { [nestedStackLogicalId: string]: NestedStackTemplates };
  private readonly stackResources: ListStackResources;
  private readonly lookupExport: LookupExport;
 
@@ -136,7 +136,7 @@ export class EvaluateCloudFormationTemplate {
  this.sdk = props.sdk;
 
  // We need names of nested stack so we can evaluate cross stack references
- this.nestedStackNames = props.nestedStackNames ?? {};
+ this.nestedStacks = props.nestedStacks ?? {};
 
  // The current resources of the Stack.
  // We need them to figure out the physical name of a resource in case it wasn't specified by the user.
@@ -163,7 +163,7 @@ export class EvaluateCloudFormationTemplate {
  partition: this.partition,
  urlSuffix: this.urlSuffix,
  sdk: this.sdk,
- nestedStackNames: this.nestedStackNames,
+ nestedStacks: this.nestedStacks,
  });
  }
 
@@ -386,17 +386,15 @@ export class EvaluateCloudFormationTemplate {
  }
 
  if (foundResource.ResourceType == 'AWS::CloudFormation::Stack' && attribute?.startsWith('Outputs.')) {
- // need to resolve attributes from another stack's Output section
- const dependantStackName = this.findNestedStack(logicalId, this.nestedStackNames);
- if (!dependantStackName) {
+ const dependantStack = this.findNestedStack(logicalId, this.nestedStacks);
+ if (!dependantStack || !dependantStack.physicalName) {
  //this is a newly created nested stack and cannot be hotswapped
  return undefined;
  }
- const dependantStackTemplate = this.template.Resources[logicalId];
  const evaluateCfnTemplate = await this.createNestedEvaluateCloudFormationTemplate(
- dependantStackName,
- dependantStackTemplate?.Properties?.NestedTemplate,
- dependantStackTemplate.newValue?.Properties?.Parameters);
+ dependantStack.physicalName,
+ dependantStack.generatedTemplate,
+ dependantStack.generatedTemplate.Parameters!);
 
  // Split Outputs.<refName> into 'Outputs' and '<refName>' and recursively call evaluate
  return evaluateCfnTemplate.evaluateCfnExpression({ 'Fn::GetAtt': attribute.split(/\.(.*)/s) });
@@ -406,14 +404,14 @@ export class EvaluateCloudFormationTemplate {
  return this.formatResourceAttribute(foundResource, attribute);
  }
 
- private findNestedStack(logicalId: string, nestedStackNames: {
- [nestedStackLogicalId: string]: NestedStackNames;
- }): string | undefined {
- for (const [nestedStackLogicalId, { nestedChildStackNames, nestedStackPhysicalName }] of Object.entries(nestedStackNames)) {
+ private findNestedStack(logicalId: string, nestedStacks: {
+ [nestedStackLogicalId: string]: NestedStackTemplates;
+ }): NestedStackTemplates | undefined {
+ for (const nestedStackLogicalId of Object.keys(nestedStacks)) {
  if (nestedStackLogicalId === logicalId) {
- return nestedStackPhysicalName;
+ return nestedStacks[nestedStackLogicalId];
  }
- const checkInNestedChildStacks = this.findNestedStack(logicalId, nestedChildStackNames);
+ const checkInNestedChildStacks = this.findNestedStack(logicalId, nestedStacks[nestedStackLogicalId].nestedStackTemplates);
  if (checkInNestedChildStacks) return checkInNestedChildStacks;
  }
  return undefined;

packages/aws-cdk/lib/api/hotswap-deployments.ts

@@ -11,7 +11,7 @@ import { isHotswappableEcsServiceChange } from './hotswap/ecs-services';
 import { isHotswappableLambdaFunctionChange } from './hotswap/lambda-functions';
 import { skipChangeForS3DeployCustomResourcePolicy, isHotswappableS3BucketDeploymentChange } from './hotswap/s3-bucket-deployments';
 import { isHotswappableStateMachineChange } from './hotswap/stepfunctions-state-machines';
-import { loadCurrentTemplateWithNestedStacks, NestedStackNames } from './nested-stack-helpers';
+import { NestedStackTemplates, loadCurrentTemplateWithNestedStacks } from './nested-stack-helpers';
 import { CloudFormationStack } from './util/cloudformation';
 import { print } from '../logging';
 
@@ -78,12 +78,12 @@ export async function tryHotswapDeployment(
  partition: (await sdk.currentAccount()).partition,
  urlSuffix: (region) => sdk.getEndpointSuffix(region),
  sdk,
- nestedStackNames: currentTemplate.nestedStackNames,
+ nestedStacks: currentTemplate.nestedStacks,
  });
 
- const stackChanges = cfn_diff.fullDiff(currentTemplate.deployedTemplate, stackArtifact.template);
+ const stackChanges = cfn_diff.fullDiff(currentTemplate.deployedRootTemplate, stackArtifact.template);
  const { hotswappableChanges, nonHotswappableChanges } = await classifyResourceChanges(
- stackChanges, evaluateCfnTemplate, sdk, currentTemplate.nestedStackNames,
+ stackChanges, evaluateCfnTemplate, sdk, currentTemplate.nestedStacks,
  );
 
  logNonHotswappableChanges(nonHotswappableChanges, hotswapMode);
@@ -109,7 +109,7 @@ async function classifyResourceChanges(
  stackChanges: cfn_diff.TemplateDiff,
  evaluateCfnTemplate: EvaluateCloudFormationTemplate,
  sdk: ISDK,
- nestedStackNames: { [nestedStackName: string]: NestedStackNames },
+ nestedStackNames: { [nestedStackName: string]: NestedStackTemplates },
 ): Promise<ClassifiedResourceChanges> {
  const resourceDifferences = getStackResourceDifferences(stackChanges);
 
@@ -225,12 +225,12 @@ function filterDict<T>(dict: { [key: string]: T }, func: (t: T) => boolean): { [
 async function findNestedHotswappableChanges(
  logicalId: string,
  change: cfn_diff.ResourceDifference,
- nestedStackNames: { [nestedStackName: string]: NestedStackNames },
+ nestedStackTemplates: { [nestedStackName: string]: NestedStackTemplates },
  evaluateCfnTemplate: EvaluateCloudFormationTemplate,
  sdk: ISDK,
 ): Promise<ClassifiedResourceChanges> {
- const nestedStackName = nestedStackNames[logicalId].nestedStackPhysicalName;
- if (!nestedStackName) {
+ const nestedStack = nestedStackTemplates[logicalId];
+ if (!nestedStack.physicalName) {
  return {
  hotswappableChanges: [],
  nonHotswappableChanges: [{
@@ -244,14 +244,14 @@ async function findNestedHotswappableChanges(
  }
 
  const evaluateNestedCfnTemplate = await evaluateCfnTemplate.createNestedEvaluateCloudFormationTemplate(
- nestedStackName, change.newValue?.Properties?.NestedTemplate, change.newValue?.Properties?.Parameters,
+ nestedStack.physicalName, nestedStack.generatedTemplate, change.newValue?.Properties?.Parameters,
  );
 
  const nestedDiff = cfn_diff.fullDiff(
- change.oldValue?.Properties?.NestedTemplate, change.newValue?.Properties?.NestedTemplate,
+ nestedStackTemplates[logicalId].deployedTemplate, nestedStackTemplates[logicalId].generatedTemplate,
  );
 
- return classifyResourceChanges(nestedDiff, evaluateNestedCfnTemplate, sdk, nestedStackNames[logicalId].nestedChildStackNames);
+ return classifyResourceChanges(nestedDiff, evaluateNestedCfnTemplate, sdk, nestedStackTemplates[logicalId].nestedStackTemplates);
 }
 
 /** Returns 'true' if a pair of changes is for the same resource. */

packages/aws-cdk/lib/api/nested-stack-helpers.ts

@@ -5,59 +5,38 @@ import { ISDK } from './aws-auth';
 import { LazyListStackResources, ListStackResources } from './evaluate-cloudformation-template';
 import { CloudFormationStack, Template } from './util/cloudformation';
 
-export interface TemplateWithNestedStackNames {
+export interface NestedStackTemplates {
+ readonly physicalName: string | undefined;
  readonly deployedTemplate: Template;
- readonly nestedStackNames: { [nestedStackLogicalId: string]: NestedStackNames };
+ readonly generatedTemplate: Template;
+ readonly nestedStackTemplates: { [nestedStackLogicalId: string]: NestedStackTemplates};
 }
 
-export interface NestedStackNames {
- readonly nestedStackPhysicalName: string | undefined;
- readonly nestedChildStackNames: { [logicalId: string]: NestedStackNames };
-}
-
-export interface TemplateWithNestedStackCount {
- readonly deployedTemplate: Template;
- readonly nestedStackCount: number;
+export interface RootTemplateWithNestedStacks {
+ readonly deployedRootTemplate: Template;
+ readonly nestedStacks: { [nestedStackLogicalId: string]: NestedStackTemplates };
 }
 
 /**
- * Reads the currently deployed template from CloudFormation and adds a
- * property, `NestedTemplate`, to any nested stacks that appear in either
- * the deployed template or the newly synthesized template. `NestedTemplate`
- * is populated with contents of the nested template by mutating the
- * `template` property of `rootStackArtifact`. This is done for all
- * nested stack resources to arbitrary depths.
+ * Reads the currently deployed template and all of its nested stack templates from CloudFormation.
  */
 export async function loadCurrentTemplateWithNestedStacks(
  rootStackArtifact: cxapi.CloudFormationStackArtifact, sdk: ISDK,
  retrieveProcessedTemplate: boolean = false,
-): Promise<TemplateWithNestedStackNames> {
- const deployedTemplate = await loadCurrentTemplate(rootStackArtifact, sdk, retrieveProcessedTemplate);
- const nestedStackNames = await addNestedTemplatesToGeneratedAndDeployedStacks(rootStackArtifact, sdk, {
+): Promise<RootTemplateWithNestedStacks> {
+ const deployedRootTemplate = await loadCurrentTemplate(rootStackArtifact, sdk, retrieveProcessedTemplate);
+ const nestedStacks = await loadNestedStacks(rootStackArtifact, sdk, {
  generatedTemplate: rootStackArtifact.template,
- deployedTemplate: deployedTemplate,
+ deployedTemplate: deployedRootTemplate,
  deployedStackName: rootStackArtifact.stackName,
  });
 
  return {
- deployedTemplate,
- nestedStackNames,
+ deployedRootTemplate,
+ nestedStacks,
  };
 }
 
-export function flattenNestedStackNames(nestedStackNames: { [nestedStackLogicalId: string]: NestedStackNames }): string[] {
- const nameList = [];
- for (const key of Object.keys(nestedStackNames)) {
- nameList.push(key);
-
- if (Object.keys(nestedStackNames[key].nestedChildStackNames).length !== 0) {
- flattenNestedStacksHelper(nestedStackNames[key].nestedChildStackNames, nameList);
- }
- }
-
- return nameList;
-}
-
 /**
  * Returns the currently deployed template from CloudFormation that corresponds to `stackArtifact`.
  */
@@ -76,13 +55,13 @@ async function loadCurrentStackTemplate(
  return stack.template();
 }
 
-async function addNestedTemplatesToGeneratedAndDeployedStacks(
+async function loadNestedStacks(
  rootStackArtifact: cxapi.CloudFormationStackArtifact,
  sdk: ISDK,
  parentTemplates: StackTemplates,
-): Promise<{ [nestedStackLogicalId: string]: NestedStackNames }> {
+): Promise<{ [nestedStackLogicalId: string]: NestedStackTemplates }> {
  const listStackResources = parentTemplates.deployedStackName ? new LazyListStackResources(sdk, parentTemplates.deployedStackName) : undefined;
- const nestedStackNames: { [nestedStackLogicalId: string]: NestedStackNames } = {};
+ const nestedStacks: { [nestedStackLogicalId: string]: NestedStackTemplates } = {};
  for (const [nestedStackLogicalId, generatedNestedStackResource] of Object.entries(parentTemplates.generatedTemplate.Resources ?? {})) {
  if (!isCdkManagedNestedStack(generatedNestedStackResource)) {
  continue;
@@ -91,27 +70,19 @@ async function addNestedTemplatesToGeneratedAndDeployedStacks(
  const assetPath = generatedNestedStackResource.Metadata['aws:asset:path'];
  const nestedStackTemplates = await getNestedStackTemplates(rootStackArtifact, assetPath, nestedStackLogicalId, listStackResources, sdk);
 
- generatedNestedStackResource.Properties.NestedTemplate = nestedStackTemplates.generatedTemplate;
-
- const deployedParentTemplate = parentTemplates.deployedTemplate;
- deployedParentTemplate.Resources = deployedParentTemplate.Resources ?? {};
- const deployedNestedStackResource = deployedParentTemplate.Resources[nestedStackLogicalId] ?? {};
- deployedParentTemplate.Resources[nestedStackLogicalId] = deployedNestedStackResource;
- deployedNestedStackResource.Type = deployedNestedStackResource.Type ?? 'AWS::CloudFormation::Stack';
- deployedNestedStackResource.Properties = deployedNestedStackResource.Properties ?? {};
- deployedNestedStackResource.Properties.NestedTemplate = nestedStackTemplates.deployedTemplate;
-
- nestedStackNames[nestedStackLogicalId] = {
- nestedStackPhysicalName: nestedStackTemplates.deployedStackName,
- nestedChildStackNames: await addNestedTemplatesToGeneratedAndDeployedStacks(
+ nestedStacks[nestedStackLogicalId] = {
+ deployedTemplate: nestedStackTemplates.deployedTemplate,
+ generatedTemplate: nestedStackTemplates.generatedTemplate,
+ physicalName: nestedStackTemplates.deployedStackName,
+ nestedStackTemplates: await loadNestedStacks(
  rootStackArtifact,
  sdk,
  nestedStackTemplates,
  ),
  };
  }
 
- return nestedStackNames;
+ return nestedStacks;
 }
 
 async function getNestedStackTemplates(
@@ -153,16 +124,6 @@ function isCdkManagedNestedStack(stackResource: any): stackResource is NestedSta
  return stackResource.Type === 'AWS::CloudFormation::Stack' && stackResource.Metadata && stackResource.Metadata['aws:asset:path'];
 }
 
-function flattenNestedStacksHelper(nestedStackNames: { [logicalId: string]: NestedStackNames }, nameList: string[]) {
- for (const key of Object.keys(nestedStackNames)) {
- nameList.push(key);
-
- if (Object.keys(nestedStackNames[key].nestedChildStackNames).length !== 0) {
- flattenNestedStacksHelper(nestedStackNames[key].nestedChildStackNames, nameList);
- }
- }
-}
-
 interface StackTemplates {
  readonly generatedTemplate: any;
  readonly deployedTemplate: any;