fix(ecs): stack name can result in noncompliant capacity provider name

packages/aws-cdk-lib/aws-ecs/lib/cluster.ts

@@ -11,7 +11,7 @@ import * as kms from '../../aws-kms';
 import * as logs from '../../aws-logs';
 import * as s3 from '../../aws-s3';
 import * as cloudmap from '../../aws-servicediscovery';
-import { Duration, IResource, Resource, Stack, Aspects, ArnFormat, IAspect, Token } from '../../core';
+import { Duration, IResource, Resource, Stack, Aspects, ArnFormat, IAspect, Token, Names } from '../../core';
 
 const CLUSTER_SYMBOL = Symbol.for('@aws-cdk/aws-ecs/lib/cluster.Cluster');
 
@@ -1168,6 +1168,8 @@ export interface AsgCapacityProviderProps extends AddAutoScalingGroupCapacityOpt
    * The name of the capacity provider. If a name is specified,
    * it cannot start with `aws`, `ecs`, or `fargate`. If no name is specified,
    * a default name in the CFNStackName-CFNResourceName-RandomString format is used.
+   * If the stack name starts with `aws`, `ecs`, or `fargate`, a unique resource name
+   * is generated that starts with `cp-`.
    *
    * @default CloudFormation-generated name
    */
@@ -1288,6 +1290,7 @@ export class AsgCapacityProvider extends Construct {
 
   constructor(scope: Construct, id: string, props: AsgCapacityProviderProps) {
     super(scope, id);
+    let capacityProviderName = props.capacityProviderName;
     this.autoScalingGroup = props.autoScalingGroup as autoscaling.AutoScalingGroup;
     this.machineImageType = props.machineImageType ?? MachineImageType.AMAZON_LINUX_2;
     this.canContainersAccessInstanceRole = props.canContainersAccessInstanceRole;
@@ -1306,9 +1309,17 @@ export class AsgCapacityProvider extends Construct {
       this.autoScalingGroup.protectNewInstancesFromScaleIn();
     }
 
-    if (props.capacityProviderName) {
-      if (!(/^(?!aws|ecs|fargate).+/gm.test(props.capacityProviderName))) {
-        throw new Error(`Invalid Capacity Provider Name: ${props.capacityProviderName}, If a name is specified, it cannot start with aws, ecs, or fargate.`);
+    const capacityProviderNameRegex = /^(?!aws|ecs|fargate).+/gm;
+    if (capacityProviderName) {
+      if (!(capacityProviderNameRegex.test(capacityProviderName))) {
+        throw new Error(`Invalid Capacity Provider Name: ${capacityProviderName}, If a name is specified, it cannot start with aws, ecs, or fargate.`);
+      }
+    } else {
+      if (!(capacityProviderNameRegex.test(Stack.of(this).stackName))) {
+        // name cannot start with 'aws|ecs|fargate', so append 'cp-'
+        // 255 is the max length, subtract 3 because of 'cp-'
+        // if the regex condition isn't met, CFN will name the capacity provider
+        capacityProviderName = 'cp-' + Names.uniqueResourceName(this, { maxLength: 252, allowedSpecialCharacters: '-_' });
       }
     }
 
@@ -1319,7 +1330,7 @@ export class AsgCapacityProvider extends Construct {
     }
 
     const capacityProvider = new CfnCapacityProvider(this, id, {
-      name: props.capacityProviderName,
+      name: capacityProviderName,
       autoScalingGroupProvider: {
         autoScalingGroupArn: this.autoScalingGroup.autoScalingGroupName,
         managedScaling: props.enableManagedScaling === false ? undefined : {

packages/aws-cdk-lib/aws-ecs/test/cluster.test.ts

@@ -2928,7 +2928,7 @@ test('can add ASG capacity via Capacity Provider by not specifying machineImageT
 
 });
 
-test('throws when ASG Capacity Provider with capacityProviderName starting with aws, ecs or faragte', () => {
+test('throws when ASG Capacity Provider with capacityProviderName starting with aws, ecs or fargate', () => {
   // GIVEN
   const app = new cdk.App();
   const stack = new cdk.Stack(app, 'test');
@@ -2965,6 +2965,31 @@ test('throws when ASG Capacity Provider with capacityProviderName starting with
   }).toThrow(/Invalid Capacity Provider Name: ecscp, If a name is specified, it cannot start with aws, ecs, or fargate./);
 });
 
+test('throws when ASG Capacity Provider with no capacityProviderName but stack name starting with aws, ecs or fargate', () => {
+  // GIVEN
+  const app = new cdk.App();
+  const stack = new cdk.Stack(app, 'ecscp');
+  const vpc = new ec2.Vpc(stack, 'Vpc');
+  const cluster = new ecs.Cluster(stack, 'EcsCluster');
+
+  const autoScalingGroupAl2 = new autoscaling.AutoScalingGroup(stack, 'asgal2', {
+    vpc,
+    instanceType: new ec2.InstanceType('bogus'),
+    machineImage: ecs.EcsOptimizedImage.amazonLinux2(),
+  });
+
+  expect(() => {
+    // WHEN Capacity Provider when stack name starts with ecs.
+    const capacityProvider = new ecs.AsgCapacityProvider(stack, 'provideral2-2', {
+      autoScalingGroup: autoScalingGroupAl2,
+      enableManagedTerminationProtection: false,
+    });
+
+    cluster.addAsgCapacityProvider(capacityProvider);
+
+  }).not.toThrow();
+});
+
 test('throws when InstanceWarmupPeriod is less than 0', () => {
   // GIVEN
   const app = new cdk.App();