fix(aws-elasticloadbalancingv2): 'targetType' on groups (#1174)

It's now possible to configure a 'targetType' on empty TargetGroups.

Author: rix0rrr

packages/@aws-cdk/aws-elasticloadbalancingv2/lib/shared/base-target-group.ts

@@ -40,6 +40,17 @@ export interface BaseTargetGroupProps {
    * @default No health check
    */
   healthCheck?: HealthCheck;
+
+  /**
+   * The type of targets registered to this TargetGroup, either IP or Instance.
+   *
+   * All targets registered into the group must be of this type. If you
+   * register targets to the TargetGroup in the CDK app, the TargetType is
+   * determined automatically.
+   *
+   * @default Determined automatically
+   */
+  targetType?: TargetType;
 }
 
 /**
@@ -179,6 +190,7 @@ export abstract class BaseTargetGroup extends cdk.Construct implements ITargetGr
     }
 
     this.healthCheck = baseProps.healthCheck || {};
+    this.targetType = baseProps.targetType;
 
     this.resource = new cloudformation.TargetGroupResource(this, 'Resource', {
       targetGroupName: baseProps.targetGroupName,

packages/@aws-cdk/aws-elasticloadbalancingv2/test/alb/test.listener.ts

@@ -93,6 +93,26 @@ export = {
     test.done();
   },
 
+  'Can configure targetType on TargetGroups'(test: Test) {
+    // GIVEN
+    const stack = new cdk.Stack();
+    const vpc = new ec2.VpcNetwork(stack, 'Stack');
+
+    // WHEN
+    new elbv2.ApplicationTargetGroup(stack, 'TargetGroup', {
+      vpc,
+      port: 80,
+      targetType: elbv2.TargetType.Ip
+    });
+
+    // THEN
+    expect(stack).to(haveResource('AWS::ElasticLoadBalancingV2::TargetGroup', {
+      TargetType: 'ip'
+    }));
+
+    test.done();
+  },
+
   'Can add target groups with and without conditions'(test: Test) {
     // GIVEN
     const stack = new cdk.Stack();