chore(amplify): domain name validation

package.json

@@ -175,5 +175,6 @@
   },
   "dependencies": {
     "string-width": "^4.2.3"
-  }
+  },
+  "packageManager": "[email protected]+sha1.1959a18351b811cdeedbd484a8f86c3cc3bbaf72"
 }

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

@@ -131,6 +131,13 @@ export class Domain extends Resource {
     this.subDomains = props.subDomains || [];
 
     const domainName = props.domainName || id;
+    if (domainName.length > 255) {
+      throw new Error(`Domain name must be 255 characters or less, got: ${domainName.length}`);
+    }
+    if (!/^(((?!-)[A-Za-z0-9-]{0,62}[A-Za-z0-9])\.)+((?!-)[A-Za-z0-9-]{1,62}[A-Za-z0-9])(\.)?$/.test(domainName)) {
+      throw new Error(`Domain name must be a valid hostname, got: ${domainName}`);
+    }
+
     const domain = new CfnDomain(this, 'Resource', {
       appId: props.app.appId,
       domainName,

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

@@ -176,6 +176,55 @@ test('map a branch to the domain root', () => {
   });
 });
 
+test('throw error for invalid domain name length', () => {
+  const stack = new Stack();
+  const app = new amplify.App(stack, 'App', {
+    sourceCodeProvider: new amplify.GitHubSourceCodeProvider({
+      owner: 'aws',
+      repository: 'aws-cdk',
+      oauthToken: SecretValue.unsafePlainText('secret'),
+    }),
+  });
+  const prodBranch = app.addBranch('main');
+
+  expect(() => app.addDomain('Domain', {
+    subDomains: [
+      {
+        branch: prodBranch,
+        prefix: 'prod',
+      },
+    ],
+    domainName: 'a'.repeat(256),
+  })).toThrow('Domain name must be 255 characters or less, got: 256');
+});
+
+test.each([
+  '-example.com',
+  'example..com',
+  'example.com-',
+  '[email protected]',
+])('throw error for invalid domain name', (domainName) => {
+  const stack = new Stack();
+  const app = new amplify.App(stack, 'App', {
+    sourceCodeProvider: new amplify.GitHubSourceCodeProvider({
+      owner: 'aws',
+      repository: 'aws-cdk',
+      oauthToken: SecretValue.unsafePlainText('secret'),
+    }),
+  });
+  const prodBranch = app.addBranch('main');
+
+  expect(() => app.addDomain('Domain', {
+    subDomains: [
+      {
+        branch: prodBranch,
+        prefix: 'prod',
+      },
+    ],
+    domainName,
+  })).toThrow(`Domain name must be a valid hostname, got: ${domainName}`);
+});
+
 test('throws at synthesis without subdomains', () => {
   // GIVEN
   const app = new App();