feat(elasticloadbalancingv2): more health check validations to NLB ta…

…rget group (aws#3703) (aws#10205)


Add the following Health Check validations for Network Target Group:
 - `healthyThresholdCount` and `unhealthyThresholdCount` must the same
 - `healthyThresholdCount` and `unhealthyThresholdCount` must be between 2 and 10

----

*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/lib/nlb/network-target-group.ts

@@ -126,6 +126,28 @@ export class NetworkTargetGroup extends TargetGroupBase implements INetworkTarge
       }
     }
 
+    if (healthCheck.healthyThresholdCount) {
+      const thresholdCount = healthCheck.healthyThresholdCount;
+      if (thresholdCount < 2 || thresholdCount > 10) {
+        ret.push(`Healthy Threshold Count '${thresholdCount}' not supported. Must be a number between 2 and 10.`);
+      }
+    }
+
+    if (healthCheck.unhealthyThresholdCount) {
+      const thresholdCount = healthCheck.unhealthyThresholdCount;
+      if (thresholdCount < 2 || thresholdCount > 10) {
+        ret.push(`Unhealthy Threshold Count '${thresholdCount}' not supported. Must be a number between 2 and 10.`);
+      }
+    }
+
+    if (healthCheck.healthyThresholdCount && healthCheck.unhealthyThresholdCount &&
+        healthCheck.healthyThresholdCount !== healthCheck.unhealthyThresholdCount) {
+      ret.push([
+        `Healthy and Unhealthy Threshold Counts must be the same: ${healthCheck.healthyThresholdCount}`,
+        `is not equal to ${healthCheck.unhealthyThresholdCount}.`,
+      ].join(' '));
+    }
+
     if (!healthCheck.protocol) {
       return ret;
     }

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

@@ -91,4 +91,117 @@ describe('tests', () => {
       });
     }).toThrow();
   });
+
+  test('Throws error for invalid health check interval', () => {
+    const app = new cdk.App();
+    const stack = new cdk.Stack(app, 'Stack');
+    const vpc = new ec2.Vpc(stack, 'Vpc');
+
+    new elbv2.NetworkTargetGroup(stack, 'Group', {
+      vpc,
+      port: 80,
+      healthCheck: {
+        interval: cdk.Duration.seconds(5),
+      },
+    });
+
+    expect(() => {
+      app.synth();
+    }).toThrow(/Health check interval '5' not supported. Must be one of the following values '10,30'./);
+  });
+
+  test('Throws error for invalid health check protocol', () => {
+    const app = new cdk.App();
+    const stack = new cdk.Stack(app, 'Stack');
+    const vpc = new ec2.Vpc(stack, 'Vpc');
+
+    new elbv2.NetworkTargetGroup(stack, 'Group', {
+      vpc,
+      port: 80,
+      healthCheck: {
+        protocol: elbv2.Protocol.UDP,
+      },
+    });
+
+    expect(() => {
+      app.synth();
+    }).toThrow(/Health check protocol 'UDP' is not supported. Must be one of \[HTTP, HTTPS, TCP\]/);
+  });
+
+  test('Throws error for health check path property when protocol does not support it', () => {
+    const app = new cdk.App();
+    const stack = new cdk.Stack(app, 'Stack');
+    const vpc = new ec2.Vpc(stack, 'Vpc');
+
+    new elbv2.NetworkTargetGroup(stack, 'Group', {
+      vpc,
+      port: 80,
+      healthCheck: {
+        path: '/my-path',
+        protocol: elbv2.Protocol.TCP,
+      },
+    });
+
+    expect(() => {
+      app.synth();
+    }).toThrow(/'TCP' health checks do not support the path property. Must be one of \[HTTP, HTTPS\]/);
+  });
+
+  test('Throws error for invalid health check healthy threshold', () => {
+    const app = new cdk.App();
+    const stack = new cdk.Stack(app, 'Stack');
+    const vpc = new ec2.Vpc(stack, 'Vpc');
+
+    new elbv2.NetworkTargetGroup(stack, 'Group', {
+      vpc,
+      port: 80,
+      healthCheck: {
+        protocol: elbv2.Protocol.TCP,
+        healthyThresholdCount: 11,
+      },
+    });
+
+    expect(() => {
+      app.synth();
+    }).toThrow(/Healthy Threshold Count '11' not supported. Must be a number between 2 and 10./);
+  });
+
+  test('Throws error for invalid health check unhealthy threshold', () => {
+    const app = new cdk.App();
+    const stack = new cdk.Stack(app, 'Stack');
+    const vpc = new ec2.Vpc(stack, 'Vpc');
+
+    new elbv2.NetworkTargetGroup(stack, 'Group', {
+      vpc,
+      port: 80,
+      healthCheck: {
+        protocol: elbv2.Protocol.TCP,
+        unhealthyThresholdCount: 1,
+      },
+    });
+
+    expect(() => {
+      app.synth();
+    }).toThrow(/Unhealthy Threshold Count '1' not supported. Must be a number between 2 and 10./);
+  });
+
+  test('Throws error for unequal healthy and unhealthy threshold counts', () => {
+    const app = new cdk.App();
+    const stack = new cdk.Stack(app, 'Stack');
+    const vpc = new ec2.Vpc(stack, 'Vpc');
+
+    new elbv2.NetworkTargetGroup(stack, 'Group', {
+      vpc,
+      port: 80,
+      healthCheck: {
+        protocol: elbv2.Protocol.TCP,
+        healthyThresholdCount: 5,
+        unhealthyThresholdCount: 3,
+      },
+    });
+
+    expect(() => {
+      app.synth();
+    }).toThrow(/Healthy and Unhealthy Threshold Counts must be the same: 5 is not equal to 3./);
+  });
 });