feat(amplify-domain): Added config for auto subdomain creation

packages/@aws-cdk/aws-amplify/README.md

@@ -122,7 +122,10 @@ mySinglePageApp.addCustomRule(amplify.CustomRule.SINGLE_PAGE_APPLICATION_REDIREC
 Add a domain and map sub domains to branches:
 
 ```ts
-const domain = amplifyApp.addDomain('example.com');
+const domain = amplifyApp.addDomain('example.com', {
+  enableAutoSubdomain: true, // in case subdomains should be auto registered for branches
+  autoSubdomainCreationPatterns: ['*', 'pr*'], // regex for branches that should auto register subdomains
+});
 domain.mapRoot(master); // map master branch to domain root
 domain.mapSubDomain(master, 'www');
 domain.mapSubDomain(dev); // sub domain prefix defaults to branch name

packages/@aws-cdk/aws-amplify/lib/app.ts

@@ -289,6 +289,7 @@ export class App extends Resource implements IApp, iam.IGrantable {
     return new Domain(this, id, {
       ...options,
       app: this,
+      autoSubDomainIamRole: this.grantPrincipal as iam.IRole,
     });
   }
 }

packages/@aws-cdk/aws-amplify/lib/domain.ts

@@ -1,3 +1,4 @@
+import * as iam from '@aws-cdk/aws-iam';
 import { Lazy, Resource, IResolvable } from '@aws-cdk/core';
 import { Construct } from 'constructs';
 import { CfnDomain } from './amplify.generated';
@@ -21,6 +22,20 @@ export interface DomainOptions {
    * @default - use `addSubDomain()` to add subdomains
    */
   readonly subDomains?: SubDomain[];
+
+  /**
+   * Automatically create subdomains for connected branches
+   *
+   * @default false
+   */
+  readonly enableAutoSubdomain?: boolean;
+
+  /**
+   * Branches which should automatically create subdomains
+   *
+   * @default - all repository branches ['*', 'pr*']
+   */
+  readonly autoSubdomainCreationPatterns?: string[];
 }
 
 /**
@@ -31,6 +46,12 @@ export interface DomainProps extends DomainOptions {
    * The application to which the domain must be connected
    */
   readonly app: IApp;
+
+  /**
+   * The IAM role with access to Route53 when using enableAutoSubdomain
+   * @default the IAM role from App.grantPrincipal
+   */
+  readonly autoSubDomainIamRole?: iam.IRole;
 }
 
 /**
@@ -106,6 +127,9 @@ export class Domain extends Resource {
       appId: props.app.appId,
       domainName,
       subDomainSettings: Lazy.any({ produce: () => this.renderSubDomainSettings() }, { omitEmptyArray: true }),
+      enableAutoSubDomain: !!props.enableAutoSubdomain,
+      autoSubDomainCreationPatterns: props.autoSubdomainCreationPatterns || ['*', 'pr*'],
+      autoSubDomainIamRole: props.autoSubDomainIamRole?.roleArn,
     });
 
     this.arn = domain.attrArn;

packages/@aws-cdk/aws-amplify/test/domain.test.ts

@@ -1,3 +1,4 @@
+import * as iam from '@aws-cdk/aws-iam';
 import '@aws-cdk/assert/jest';
 import { App, SecretValue, Stack } from '@aws-cdk/core';
 import * as amplify from '../lib';
@@ -120,3 +121,113 @@ test('throws at synthesis without subdomains', () => {
   // THEN
   expect(() => app.synth()).toThrow(/The domain doesn't contain any subdomains/);
 });
+
+test('auto subdomain all branches', () => {
+  // GIVEN
+  const stack = new Stack();
+  const app = new amplify.App(stack, 'App', {
+    sourceCodeProvider: new amplify.GitHubSourceCodeProvider({
+      owner: 'aws',
+      repository: 'aws-cdk',
+      oauthToken: SecretValue.plainText('secret'),
+    }),
+  });
+  const prodBranch = app.addBranch('master');
+
+  // WHEN
+  const domain = app.addDomain('amazon.com', {
+    enableAutoSubdomain: true,
+  });
+  domain.mapRoot(prodBranch);
+
+  // THEN
+  expect(stack).toHaveResource('AWS::Amplify::Domain', {
+    EnableAutoSubDomain: true,
+    AutoSubDomainCreationPatterns: [
+      '*',
+      'pr*',
+    ],
+    AutoSubDomainIAMRole: {
+      'Fn::GetAtt': [
+        'AppRole1AF9B530',
+        'Arn',
+      ],
+    },
+  });
+});
+
+test('auto subdomain some branches', () => {
+  // GIVEN
+  const stack = new Stack();
+  const app = new amplify.App(stack, 'App', {
+    sourceCodeProvider: new amplify.GitHubSourceCodeProvider({
+      owner: 'aws',
+      repository: 'aws-cdk',
+      oauthToken: SecretValue.plainText('secret'),
+    }),
+  });
+  const prodBranch = app.addBranch('master');
+
+  // WHEN
+  const domain = app.addDomain('amazon.com', {
+    enableAutoSubdomain: true,
+    autoSubdomainCreationPatterns: ['features/**'],
+  });
+  domain.mapRoot(prodBranch);
+
+  // THEN
+  expect(stack).toHaveResource('AWS::Amplify::Domain', {
+    EnableAutoSubDomain: true,
+    AutoSubDomainCreationPatterns: ['features/**'],
+    AutoSubDomainIAMRole: {
+      'Fn::GetAtt': [
+        'AppRole1AF9B530',
+        'Arn',
+      ],
+    },
+  });
+});
+
+test('auto subdomain with IAM role', () => {
+  // GIVEN
+  const stack = new Stack();
+  const app = new amplify.App(stack, 'App', {
+    sourceCodeProvider: new amplify.GitHubSourceCodeProvider({
+      owner: 'aws',
+      repository: 'aws-cdk',
+      oauthToken: SecretValue.plainText('secret'),
+    }),
+    role: iam.Role.fromRoleArn(
+      stack,
+      'AmplifyRole',
+      `arn:aws:iam::${Stack.of(stack).account}:role/AmplifyRole`,
+      { mutable: false },
+    ),
+  });
+  const prodBranch = app.addBranch('master');
+
+  // WHEN
+  const domain = app.addDomain('amazon.com', {
+    enableAutoSubdomain: true,
+    autoSubdomainCreationPatterns: ['features/**'],
+  });
+  domain.mapRoot(prodBranch);
+
+  // THEN
+  expect(stack).toHaveResource('AWS::Amplify::Domain', {
+    EnableAutoSubDomain: true,
+    AutoSubDomainCreationPatterns: ['features/**'],
+    AutoSubDomainIAMRole: {
+      'Fn::Join': [
+        '',
+        [
+          'arn:aws:iam::',
+          {
+            Ref: 'AWS::AccountId',
+          },
+          ':role/AmplifyRole',
+        ],
+      ],
+    },
+  });
+});