feat(elasticloadbalancingv2): add Instance target (#4187)

Author: hoegertn

packages/@aws-cdk/aws-elasticloadbalancingv2-targets/lib/instance-target.ts

@@ -1,3 +1,4 @@
+import ec2 = require('@aws-cdk/aws-ec2');
 import elbv2 = require('@aws-cdk/aws-elasticloadbalancingv2');
 
 /**
@@ -43,3 +44,15 @@ export class InstanceIdTarget implements elbv2.IApplicationLoadBalancerTarget, e
     };
   }
 }
+
+export class InstanceTarget extends InstanceIdTarget {
+  /**
+   * Create a new Instance target
+   *
+   * @param instance Instance to register to
+   * @param port Override the default port for the target group
+   */
+  constructor(instance: ec2.Instance, port?: number) {
+    super(instance.instanceId, port);
+  }
+}

packages/@aws-cdk/aws-elasticloadbalancingv2-targets/test/instance-target.test.ts

@@ -4,7 +4,7 @@ import elbv2 = require('@aws-cdk/aws-elasticloadbalancingv2');
 import { Stack } from '@aws-cdk/core';
 import targets = require('../lib');
 
-test('Can create target groups with lambda targets', () => {
+test('Can create target groups with instance id target', () => {
   // GIVEN
   const stack = new Stack();
   const vpc = new ec2.Vpc(stack, 'Stack');
@@ -26,4 +26,34 @@ test('Can create target groups with lambda targets', () => {
     ],
     TargetType: "instance",
   }));
+});
+
+test('Can create target groups with instance target', () => {
+  // GIVEN
+  const stack = new Stack();
+  const vpc = new ec2.Vpc(stack, 'Stack');
+  const lb = new elbv2.ApplicationLoadBalancer(stack, 'LB', { vpc });
+  const listener = lb.addListener('Listener', { port: 80 });
+
+  const instance = new ec2.Instance(stack, 'Instance', {
+    vpc,
+    machineImage: new ec2.AmazonLinuxImage(),
+    instanceType: ec2.InstanceType.of(ec2.InstanceClass.T3, ec2.InstanceSize.LARGE),
+  });
+
+  // WHEN
+  listener.addTargets('Targets', {
+    targets: [new targets.InstanceTarget(instance)],
+    port: 80,
+  });
+
+  // THEN
+  expect(stack).to(haveResource('AWS::ElasticLoadBalancingV2::TargetGroup', {
+    Port: 80,
+    Protocol: "HTTP",
+    Targets: [
+      { Id: {Ref: 'InstanceC1063A87'} }
+    ],
+    TargetType: "instance",
+  }));
 });