feat(aws-elasticloadbalancingv2): add protocol version for ALB Target…

…Groups (#13570)

Fixes #12869


----

*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-elasticloadbalancingv2/README.md

@@ -273,6 +273,20 @@ const tg2 = new elbv2.ApplicationTargetGroup(stack, 'TG2', {
 
 For more information see: https://docs.aws.amazon.com/elasticloadbalancing/latest/application/sticky-sessions.html#application-based-stickiness
 
+### Setting the target group protocol version
+
+By default, Application Load Balancers send requests to targets using HTTP/1.1. You can use the [protocol version](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-target-groups.html#target-group-protocol-version) to send requests to targets using HTTP/2 or gRPC.
+
+```ts
+const tg = new elbv2.ApplicationTargetGroup(stack, 'TG', {
+  targetType: elbv2.TargetType.IP,
+  port: 50051,
+  protocol: elbv2.ApplicationProtocol.HTTP,
+  protocolVersion: elbv2.ApplicationProtocolVersion.GRPC,
+  vpc,
+});
+```
+
 ## Using Lambda Targets
 
 To use a Lambda Function as a target, use the integration class in the

packages/@aws-cdk/aws-elasticloadbalancingv2/lib/alb/application-target-group.ts

@@ -7,7 +7,7 @@ import {
   BaseTargetGroupProps, ITargetGroup, loadBalancerNameFromListenerArn, LoadBalancerTargetProps,
   TargetGroupAttributes, TargetGroupBase, TargetGroupImportProps,
 } from '../shared/base-target-group';
-import { ApplicationProtocol, Protocol, TargetType } from '../shared/enums';
+import { ApplicationProtocol, ApplicationProtocolVersion, Protocol, TargetType } from '../shared/enums';
 import { ImportedTargetGroupBase } from '../shared/imported';
 import { determineProtocolAndPort } from '../shared/util';
 import { IApplicationListener } from './application-listener';
@@ -28,6 +28,13 @@ export interface ApplicationTargetGroupProps extends BaseTargetGroupProps {
    */
   readonly protocol?: ApplicationProtocol;
 
+  /**
+   * The protocol version to use
+   *
+   * @default ApplicationProtocolVersion.HTTP1
+   */
+  readonly protocolVersion?: ApplicationProtocolVersion;
+
   /**
    * The port on which the listener listens for requests.
    *
@@ -110,8 +117,10 @@ export class ApplicationTargetGroup extends TargetGroupBase implements IApplicat
 
   constructor(scope: Construct, id: string, props: ApplicationTargetGroupProps = {}) {
     const [protocol, port] = determineProtocolAndPort(props.protocol, props.port);
+    const { protocolVersion } = props;
     super(scope, id, { ...props }, {
       protocol,
+      protocolVersion,
       port,
     });
 

packages/@aws-cdk/aws-elasticloadbalancingv2/lib/shared/enums.ts

@@ -63,6 +63,26 @@ export enum ApplicationProtocol {
   HTTPS = 'HTTPS'
 }
 
+/**
+ * Load balancing protocol version for application load balancers
+ */
+export enum ApplicationProtocolVersion {
+  /**
+   * GRPC
+   */
+  GRPC = 'GRPC',
+
+  /**
+   * HTTP1
+   */
+  HTTP1 = 'HTTP1',
+
+  /**
+   * HTTP2
+   */
+  HTTP2 = 'HTTP2',
+}
+
 /**
  * Elastic Load Balancing provides the following security policies for Application Load Balancers
  *

packages/@aws-cdk/aws-elasticloadbalancingv2/test/alb/target-group.test.ts

@@ -156,6 +156,24 @@ describe('tests', () => {
     });
   });
 
+  test('Can set a protocol version', () => {
+    // GIVEN
+    const app = new cdk.App();
+    const stack = new cdk.Stack(app, 'Stack');
+    const vpc = new ec2.Vpc(stack, 'VPC', {});
+
+    // WHEN
+    new elbv2.ApplicationTargetGroup(stack, 'TargetGroup', {
+      vpc,
+      protocolVersion: elbv2.ApplicationProtocolVersion.GRPC,
+    });
+
+    // THEN
+    expect(stack).toHaveResource('AWS::ElasticLoadBalancingV2::TargetGroup', {
+      ProtocolVersion: 'GRPC',
+    });
+  });
+
   test('Bad stickiness cookie names', () => {
     // GIVEN
     const app = new cdk.App();