feat(toolkit-lib): diff (#279)

introduces diff support for programmatic toolkit.

- has feature parity with the existing CLI diff
- programmatic toolkit functionality is unit tested.
- AI disclosure: no AI

does most of aws/aws-cdk#33182, but typed
return will come later

---
By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache-2.0 license

---------

Signed-off-by: github-actions <github-actions@github.com>
Co-authored-by: github-actions <github-actions@github.com>

Author: kaizencc

packages/@aws-cdk/tmp-toolkit-helpers/src/api/diff/diff-formatter.ts

@@ -43,7 +43,7 @@ class StringWriteStream extends Writable {
 /**
  * Output of formatSecurityDiff
  */
-export interface FormatSecurityDiffOutput {
+interface FormatSecurityDiffOutput {
   /**
    * Complete formatted security diff, if it is prompt-worthy
    */
@@ -53,7 +53,7 @@ export interface FormatSecurityDiffOutput {
 /**
  * Output of formatStackDiff
  */
-export interface FormatStackDiffOutput {
+interface FormatStackDiffOutput {
   /**
    * Number of stacks with diff changes
    */
@@ -68,7 +68,7 @@ export interface FormatStackDiffOutput {
 /**
  * Props for the Diff Formatter
  */
-export interface DiffFormatterProps {
+interface DiffFormatterProps {
   /**
    * Helper for the IoHost class
    */
@@ -88,7 +88,7 @@ export interface DiffFormatterProps {
 /**
  * Properties specific to formatting the security diff
  */
-export interface FormatSecurityDiffOptions {
+interface FormatSecurityDiffOptions {
   /**
    * The approval level of the security diff
    */
@@ -110,7 +110,7 @@ export interface FormatSecurityDiffOptions {
 /**
  * PRoperties specific to formatting the stack diff
  */
-export interface FormatStackDiffOptions {
+interface FormatStackDiffOptions {
   /**
    * do not filter out AWS::CDK::Metadata or Rules
    *
@@ -326,15 +326,15 @@ function diffRequiresApproval(diff: TemplateDiff, requireApproval: RequireApprov
   }
 }
 
-export function buildLogicalToPathMap(stack: cxapi.CloudFormationStackArtifact) {
+function buildLogicalToPathMap(stack: cxapi.CloudFormationStackArtifact) {
   const map: { [id: string]: string } = {};
   for (const md of stack.findMetadataByType(cxschema.ArtifactMetadataEntryType.LOGICAL_ID)) {
     map[md.data as string] = md.path;
   }
   return map;
 }
 
-export function logicalIdMapFromTemplate(template: any) {
+function logicalIdMapFromTemplate(template: any) {
   const ret: Record<string, string> = {};
 
   for (const [logicalId, resource] of Object.entries(template.Resources ?? {})) {
@@ -352,7 +352,7 @@ export function logicalIdMapFromTemplate(template: any) {
  * - AWS::CDK::Metadata resource
  * - CheckBootstrapVersion Rule
  */
-export function obscureDiff(diff: TemplateDiff) {
+function obscureDiff(diff: TemplateDiff) {
   if (diff.unknown) {
     // see https://github.com/aws/aws-cdk/issues/17942
     diff.unknown = diff.unknown.filter(change => {

packages/@aws-cdk/tmp-toolkit-helpers/src/api/index.ts

@@ -4,3 +4,4 @@ export * from './diff';
 export * from './io';
 export * from './toolkit-error';
 export * from './require-approval';
+export * from './resource-import';

packages/@aws-cdk/tmp-toolkit-helpers/src/api/io/payloads/diff.ts

@@ -1,3 +1,5 @@
+import type { Duration } from './types';
+
 /**
  * Different types of permission related changes in a diff
  */
@@ -17,3 +19,18 @@ export enum PermissionChangeType {
    */
   NON_BROADENING = 'non-broadening',
 }
+
+/**
+ * Output of the diff command
+ */
+export interface DiffResult extends Duration {
+  /**
+   * Stack diff formatted as a string
+   */
+  readonly formattedStackDiff: string;
+
+  /**
+   * Security diff formatted as a string
+   */
+  readonly formattedSecurityDiff: string;
+}

packages/@aws-cdk/tmp-toolkit-helpers/src/api/io/payloads/list.ts

@@ -1,5 +1,5 @@
 import type { StackDetails } from './stack-details';
 
 export interface StackDetailsPayload {
-  stacks: StackDetails[];
+  readonly stacks: StackDetails[];
 }

packages/@aws-cdk/tmp-toolkit-helpers/src/api/io/private/messages.ts

@@ -1,6 +1,7 @@
 import type * as cxapi from '@aws-cdk/cx-api';
 import * as make from './message-maker';
 import type { SpanDefinition } from './span';
+import type { DiffResult } from '../payloads';
 import type { BootstrapEnvironmentProgress } from '../payloads/bootstrap-environment-progress';
 import type { MissingContext, UpdatedContext } from '../payloads/context';
 import type { BuildAsset, DeployConfirmationRequest, PublishAsset, StackDeployProgress, SuccessfulDeployStackResult } from '../payloads/deploy';
@@ -81,6 +82,16 @@ export const IO = {
   }),
 
   // 4: Diff (4xxx)
+  CDK_TOOLKIT_I4000: make.trace<StackSelectionDetails>({
+    code: 'CDK_TOOLKIT_I4000',
+    description: 'Diff stacks is starting',
+    interface: 'StackSelectionDetails',
+  }),
+  CDK_TOOLKIT_I4001: make.info<DiffResult>({
+    code: 'CDK_TOOLKIT_I4001',
+    description: 'Output of the diff command',
+    interface: 'DiffResult',
+  }),
 
   // 5: Deploy & Watch (5xxx)
   CDK_TOOLKIT_I5000: make.info<Duration>({
@@ -484,6 +495,9 @@ export const IO = {
 
 //////////////////////////////////////////////////////////////////////////////////////////
 
+/**
+ * Payload type of the end message must extend Duration
+ */
 export const SPAN = {
   SYNTH_ASSEMBLY: {
     name: 'Synthesis',
@@ -500,6 +514,11 @@ export const SPAN = {
     start: IO.CDK_TOOLKIT_I6100,
     end: IO.CDK_TOOLKIT_I6000,
   },
+  DIFF_STACK: {
+    name: 'Diff',
+    start: IO.CDK_TOOLKIT_I4000,
+    end: IO.CDK_TOOLKIT_I4001,
+  },
   DESTROY_STACK: {
     name: 'Destroy',
     start: IO.CDK_TOOLKIT_I7100,

packages/@aws-cdk/tmp-toolkit-helpers/src/api/resource-import/importer.ts

@@ -0,0 +1,12 @@
+import type { CloudFormationStackArtifact } from '@aws-cdk/cx-api';
+
+/**
+ * Removes CDKMetadata and Outputs in the template so that only resources for importing are left.
+ * @returns template with import resources only
+ */
+export function removeNonImportResources(stack: CloudFormationStackArtifact) {
+  const template = stack.template;
+  delete template.Resources.CDKMetadata;
+  delete template.Outputs;
+  return template;
+}

packages/@aws-cdk/tmp-toolkit-helpers/src/api/resource-import/index.ts

@@ -0,0 +1 @@
+export * from './importer';

packages/@aws-cdk/tmp-toolkit-helpers/test/api/diff/diff.test.ts

@@ -236,7 +236,7 @@ describe('formatSecurityDiff', () => {
     });
 
     // THEN
-    expect(result).toEqual({});
+    expect(result.formattedDiff).toBeUndefined();
     expect(mockIoDefaultMessages.warning).not.toHaveBeenCalled();
   });
 
@@ -320,7 +320,7 @@ describe('formatSecurityDiff', () => {
     });
 
     // THEN
-    expect(result).toEqual({});
+    expect(result.formattedDiff).toBeUndefined();
     expect(mockIoDefaultMessages.warning).not.toHaveBeenCalled();
   });
 });

packages/@aws-cdk/toolkit-lib/docs/message-registry.md

@@ -17,6 +17,8 @@ group: Documents
 | `CDK_TOOLKIT_I1902` | Successfully deployed stacks | `result` | {@link AssemblyData} |
 | `CDK_TOOLKIT_I2901` | Provides details on the selected stacks and their dependencies | `result` | {@link StackDetailsPayload} |
 | `CDK_TOOLKIT_E3900` | Resource import failed | `error` | {@link ErrorPayload} |
+| `CDK_TOOLKIT_I4000` | Diff stacks is starting | `trace` | {@link StackSelectionDetails} |
+| `CDK_TOOLKIT_I4001` | Output of the diff command | `info` | {@link DiffResult} |
 | `CDK_TOOLKIT_I5000` | Provides deployment times | `info` | {@link Duration} |
 | `CDK_TOOLKIT_I5001` | Provides total time in deploy action, including synth and rollback | `info` | {@link Duration} |
 | `CDK_TOOLKIT_I5002` | Provides time for resource migration | `info` | {@link Duration} |

packages/@aws-cdk/toolkit-lib/lib/actions/diff/index.ts

@@ -11,14 +11,15 @@ export interface CloudFormationDiffOptions {
 }
 
 export interface ChangeSetDiffOptions extends CloudFormationDiffOptions {
-  /**
-   * Enable falling back to template-based diff in case creating the changeset is not possible or results in an error.
-   *
-   * Should be used for stacks containing nested stacks or when change set permissions aren't available.
-   *
-   * @default true
-   */
-  readonly fallbackToTemplate?: boolean;
+  // @TODO: add this as a feature
+  // /**
+  //  * Enable falling back to template-based diff in case creating the changeset is not possible or results in an error.
+  //  *
+  //  * Should be used for stacks containing nested stacks or when change set permissions aren't available.
+  //  *
+  //  * @default true
+  //  */
+  // readonly fallbackToTemplate?: boolean;
 
   /**
    * Additional parameters for CloudFormation when creating a diff change set
@@ -28,6 +29,13 @@ export interface ChangeSetDiffOptions extends CloudFormationDiffOptions {
   readonly parameters?: { [name: string]: string | undefined };
 }
 
+export interface LocalFileDiffOptions {
+  /**
+   * Path to the local file.
+   */
+  readonly path: string;
+}
+
 export class DiffMethod {
   /**
    * Use a changeset to compute the diff.
@@ -54,10 +62,13 @@ export class DiffMethod {
     }(options);
   }
 
+  /**
+   * Use a local template file to compute the diff.
+   */
   public static LocalFile(path: string): DiffMethod {
     return new class extends DiffMethod {
       public override readonly options: { path: string };
-      public constructor(opts: { path: string }) {
+      public constructor(opts: LocalFileDiffOptions) {
         super('local-file', opts);
         this.options = opts;
       }
@@ -66,32 +77,35 @@ export class DiffMethod {
 
   private constructor(
     public readonly method: 'change-set' | 'template-only' | 'local-file',
-    public readonly options: ChangeSetDiffOptions | CloudFormationDiffOptions | { path: string },
+    public readonly options: ChangeSetDiffOptions | CloudFormationDiffOptions | LocalFileDiffOptions,
   ) {
   }
 }
 
+/**
+ * Optins for the diff method
+ */
 export interface DiffOptions {
   /**
    * Select the stacks
    */
   readonly stacks: StackSelector;
 
   /**
-   * The mode to create a stack diff.
+   * The method to create a stack diff.
    *
    * Use changeset diff for the highest fidelity, including analyze resource replacements.
-   * In this mode, diff will use the deploy role instead of the lookup role.
+   * In this method, diff will use the deploy role instead of the lookup role.
    *
    * Use template-only diff for a faster, less accurate diff that doesn't require
    * permissions to create a change-set.
    *
    * Use local-template diff for a fast, local-only diff that doesn't require
    * any permissions or internet access.
    *
-   * @default DiffMode.ChangeSet
+   * @default DiffMethod.ChangeSet
    */
-  readonly method: DiffMethod;
+  readonly method?: DiffMethod;
 
   /**
    * Strict diff mode
@@ -112,6 +126,8 @@ export interface DiffOptions {
    * Only include broadened security changes in the diff
    *
    * @default false
+   *
+   * @deprecated implement in IoHost
    */
   readonly securityOnly?: boolean;
 }