feat(appmesh): add listener TLS certificates for VirtualNodes and Vir…

…tualGateways (#11863)

This change allows customers to include an ACM certificiate or specify a file certificate for their listeners to use to terminate TLS. #10051 

```typescript
const cert = new Certificate(stack, 'cert', {
  domainName: '',
});

new appmesh.VirtualNode(stack, 'test-node', {
  mesh,
  dnsHostName: 'test',
  listeners: [appmesh.VirtualNodeListener.grpc({
    port: 80,
    tlsCertificate: appmesh.TlsCertificate.acm({
      acmCertificate: cert,
      tlsMode: TlsMode.STRICT,
    }),
  },
  )],
});
```
----
*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

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

@@ -241,6 +241,44 @@ The `backends` property can be added with `node.addBackend()`. We define a virtu
 
 The `backendsDefaultClientPolicy` property are added to the node while creating the virtual node. These are virtual node's service backends client policy defaults.
 
+## Adding TLS to a listener
+
+The `tlsCertificate` property can be added to a Virtual Node listener or Virtual Gateway listener to add TLS configuration. 
+A certificate from AWS Certificate Manager can be incorporated or a customer provided certificate can be specified with a `certificateChain` path file and a `privateKey` file path.
+
+```typescript
+import * as certificatemanager from '@aws-cdk/aws-certificatemanager';
+
+// A Virtual Node with listener TLS from an ACM provided certificate
+const cert = new certificatemanager.Certificate(this, 'cert', {...});
+
+const node = new appmesh.VirtualNode(stack, 'node', {
+  mesh,
+  dnsHostName: 'node',
+  listeners: [appmesh.VirtualNodeListener.grpc({
+    port: 80,
+    tlsCertificate: appmesh.TlsCertificate.acm({
+      certificate: cert,
+      tlsMode: TlsMode.STRICT,
+    }),
+  })],
+});
+
+// A Virtual Gateway with listener TLS from a customer provided file certificate
+const gateway = new appmesh.VirtualGateway(this, 'gateway', {
+  mesh: mesh,
+  listeners: [appmesh.VirtualGatewayListener.grpc({
+    port: 8080,
+    tlsCertificate: appmesh.TlsCertificate.file({
+      certificateChain: 'path/to/certChain',
+      privateKey: 'path/to/privateKey',
+      tlsMode: TlsMode.STRICT,
+    }),
+  })],
+  virtualGatewayName: 'gateway',
+});
+```
+
 ## Adding a Route
 
 A `route` is associated with a virtual router, and it's used to match requests for a virtual router and distribute traffic accordingly to its associated virtual nodes.

packages/@aws-cdk/aws-appmesh/lib/index.ts

@@ -5,6 +5,7 @@ export * from './route';
 export * from './service-discovery';
 export * from './route-spec';
 export * from './shared-interfaces';
+export * from './tls-certificate';
 export * from './virtual-node';
 export * from './virtual-router';
 export * from './virtual-router-listener';

packages/@aws-cdk/aws-appmesh/lib/tls-certificate.ts

@@ -0,0 +1,173 @@
+import * as acm from '@aws-cdk/aws-certificatemanager';
+import * as cdk from '@aws-cdk/core';
+import { CfnVirtualNode } from './appmesh.generated';
+
+/**
+ * Enum of supported TLS modes
+ */
+export enum TlsMode {
+  /**
+   * Only accept encrypted traffic
+   */
+  STRICT = 'STRICT',
+
+  /**
+   * Accept encrypted and plaintext traffic.
+   */
+  PERMISSIVE = 'PERMISSIVE',
+
+  /**
+   * TLS is disabled, only accept plaintext traffic.
+   */
+  DISABLED = 'DISABLED',
+}
+
+/**
+ * A wrapper for the tls config returned by {@link TlsCertificate.bind}
+ */
+export interface TlsCertificateConfig {
+  /**
+   * The CFN shape for a listener TLS certificate
+   */
+  readonly tlsCertificate: CfnVirtualNode.ListenerTlsCertificateProperty,
+
+  /**
+   * The TLS mode.
+   */
+  readonly tlsMode: TlsMode;
+}
+
+/**
+ * ACM Certificate Properties
+ */
+export interface AcmCertificateOptions {
+  /**
+   * The TLS mode.
+   */
+  readonly tlsMode: TlsMode;
+
+  /**
+   * The ACM certificate
+   */
+  readonly certificate: acm.ICertificate;
+}
+
+/**
+ * File Certificate Properties
+ */
+export interface FileCertificateOptions {
+  /**
+   * The TLS mode.
+   */
+  readonly tlsMode: TlsMode;
+
+  /**
+   * The file path of the certificate chain file.
+   */
+  readonly certificateChainPath: string;
+
+  /**
+   * The file path of the private key file.
+   */
+  readonly privateKeyPath: string;
+}
+
+/**
+ * Represents a TLS certificate
+ */
+export abstract class TlsCertificate {
+  /**
+   * Returns an File TLS Certificate
+   */
+  public static file(props: FileCertificateOptions): TlsCertificate {
+    return new FileTlsCertificate(props);
+  }
+
+  /**
+   * Returns an ACM TLS Certificate
+   */
+  public static acm(props: AcmCertificateOptions): TlsCertificate {
+    return new AcmTlsCertificate(props);
+  }
+
+  /**
+   * Returns TLS certificate based provider.
+   */
+  public abstract bind(_scope: cdk.Construct): TlsCertificateConfig;
+
+}
+
+/**
+ * Represents a ACM provided TLS certificate
+ */
+class AcmTlsCertificate extends TlsCertificate {
+  /**
+   * The TLS mode.
+   *
+   * @default - TlsMode.DISABLED
+   */
+  readonly tlsMode: TlsMode;
+
+  /**
+   * The ARN of the ACM certificate
+   */
+  readonly acmCertificate: acm.ICertificate;
+
+  constructor(props: AcmCertificateOptions) {
+    super();
+    this.tlsMode = props.tlsMode;
+    this.acmCertificate = props.certificate;
+  }
+
+  bind(_scope: cdk.Construct): TlsCertificateConfig {
+    return {
+      tlsCertificate: {
+        acm: {
+          certificateArn: this.acmCertificate.certificateArn,
+        },
+      },
+      tlsMode: this.tlsMode,
+    };
+  }
+}
+
+/**
+ * Represents a file provided TLS certificate
+ */
+class FileTlsCertificate extends TlsCertificate {
+  /**
+   * The TLS mode.
+   *
+   * @default - TlsMode.DISABLED
+   */
+  readonly tlsMode: TlsMode;
+
+  /**
+   * The file path of the certificate chain file.
+   */
+  readonly certificateChain: string;
+
+  /**
+   * The file path of the private key file.
+   */
+  readonly privateKey: string;
+
+  constructor(props: FileCertificateOptions) {
+    super();
+    this.tlsMode = props.tlsMode;
+    this.certificateChain = props.certificateChainPath;
+    this.privateKey = props.privateKeyPath;
+  }
+
+  bind(_scope: cdk.Construct): TlsCertificateConfig {
+    return {
+      tlsCertificate: {
+        file: {
+          certificateChain: this.certificateChain,
+          privateKey: this.privateKey,
+        },
+      },
+      tlsMode: this.tlsMode,
+    };
+  }
+}