fix(elasticloadbalancingv2): fix to be able to set deregistrationDelay (#3075)

Author: cohalz

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

@@ -205,7 +205,7 @@ export abstract class TargetGroupBase extends cdk.Construct implements ITargetGr
     super(scope, id);
 
     if (baseProps.deregistrationDelay !== undefined) {
-      this.setAttribute('deregistration_delay.timeout_seconds', baseProps.deregistrationDelay.toString());
+      this.setAttribute('deregistration_delay.timeout_seconds', baseProps.deregistrationDelay.toSeconds().toString());
     }
 
     this.healthCheck = baseProps.healthCheck || {};

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

@@ -1,7 +1,7 @@
 import { expect, haveResource, MatchStyle } from '@aws-cdk/assert';
 import ec2 = require('@aws-cdk/aws-ec2');
 import cdk = require('@aws-cdk/core');
-import { ConstructNode } from '@aws-cdk/core';
+import { ConstructNode, Duration } from '@aws-cdk/core';
 import { Test } from 'nodeunit';
 import elbv2 = require('../../lib');
 import { FakeSelfRegisteringTarget } from '../helpers';
@@ -534,6 +534,31 @@ export = {
     test.done();
   },
 
+  'Can configure deregistration_delay for targets'(test: Test) {
+    // GIVEN
+    const stack = new cdk.Stack();
+    const vpc = new ec2.Vpc(stack, 'Stack');
+
+    // WHEN
+    new elbv2.ApplicationTargetGroup(stack, 'TargetGroup', {
+      vpc,
+      port: 80,
+      deregistrationDelay: Duration.seconds(30)
+    });
+
+    // THEN
+    expect(stack).to(haveResource('AWS::ElasticLoadBalancingV2::TargetGroup', {
+      TargetGroupAttributes: [
+        {
+          Key: "deregistration_delay.timeout_seconds",
+          Value: "30"
+        }
+      ]
+    }));
+
+    test.done();
+  },
+
   'Throws with bad fixed responses': {
 
     'status code'(test: Test) {