feat(core): new RemovalPolicy.RETAIN_EXCEPT_ON_CREATE to only retain resources that have been successfully created

packages/aws-cdk-lib/core/lib/cfn-resource-policy.ts

@@ -91,6 +91,14 @@ export enum CfnDeletionPolicy {
  */
  RETAIN = 'Retain',
 
+ /**
+ * RetainExceptOnCreate behaves like Retain for stack operations, except for the stack operation that initially created the resource.
+ * If the stack operation that created the resource is rolled back, CloudFormation deletes the resource. For all other stack operations,
+ * such as stack deletion, CloudFormation retains the resource and its contents. The result is that new, empty, and unused resources are deleted,
+ * while in-use resources and their data are retained.
+ */
+ RETAIN_EXCEPT_ON_CREATE = 'RetainExceptOnCreate',
+
  /**
  * For resources that support snapshots (AWS::EC2::Volume, AWS::ElastiCache::CacheCluster, AWS::ElastiCache::ReplicationGroup,
  * AWS::RDS::DBInstance, AWS::RDS::DBCluster, and AWS::Redshift::Cluster), AWS CloudFormation creates a snapshot for the

packages/aws-cdk-lib/core/lib/cfn-resource.ts

@@ -120,14 +120,22 @@ export class CfnResource extends CfnRefElement {
  policy = policy || options.default || RemovalPolicy.RETAIN;
 
  let deletionPolicy;
+ let updateReplacePolicy;
 
  switch (policy) {
  case RemovalPolicy.DESTROY:
  deletionPolicy = CfnDeletionPolicy.DELETE;
+ updateReplacePolicy = CfnDeletionPolicy.DELETE;
  break;
 
  case RemovalPolicy.RETAIN:
  deletionPolicy = CfnDeletionPolicy.RETAIN;
+ updateReplacePolicy = CfnDeletionPolicy.RETAIN;
+ break;
+
+ case RemovalPolicy.RETAIN_ON_UPDATE_OR_DELETE:
+ deletionPolicy = CfnDeletionPolicy.RETAIN_EXCEPT_ON_CREATE;
+ updateReplacePolicy = CfnDeletionPolicy.RETAIN;
  break;
 
  case RemovalPolicy.SNAPSHOT:
@@ -153,6 +161,7 @@ export class CfnResource extends CfnRefElement {
  }
 
  deletionPolicy = CfnDeletionPolicy.SNAPSHOT;
+ updateReplacePolicy = CfnDeletionPolicy.SNAPSHOT;
  break;
 
  default:
@@ -161,7 +170,7 @@ export class CfnResource extends CfnRefElement {
 
  this.cfnOptions.deletionPolicy = deletionPolicy;
  if (options.applyToUpdateReplacePolicy !== false) {
- this.cfnOptions.updateReplacePolicy = deletionPolicy;
+ this.cfnOptions.updateReplacePolicy = updateReplacePolicy;
  }
  }
 

packages/aws-cdk-lib/core/lib/removal-policy.ts

@@ -48,6 +48,21 @@ export enum RemovalPolicy {
  * @see https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-attribute-deletionpolicy.html#aws-attribute-deletionpolicy-options
  */
  SNAPSHOT = 'snapshot',
+
+ /**
+ * Resource will be retained when they are requested to be deleted during a stack delete request
+ * or need to be replaced due to a stack update request.
+ * Resource are not retained, if the creation is rolled back.
+ *
+ * The result is that new, empty, and unused resources are deleted,
+ * while in-use resources and their data are retained.
+ *
+ * This uses the 'RetainExceptOnCreate' DeletionPolicy,
+ * and the 'Retain' UpdateReplacePolicy, when `applyToUpdateReplacePolicy` is set.
+ *
+ * @see https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-attribute-deletionpolicy.html#aws-attribute-deletionpolicy-options
+ */
+ RETAIN_ON_UPDATE_OR_DELETE = 'retain-on-update-or-delete',
 }
 
 export interface RemovalPolicyOptions {

packages/aws-cdk-lib/core/test/removal-policy.test.ts

@@ -0,0 +1,48 @@
+import { toCloudFormation } from './util';
+import { CfnResource, Stack, RemovalPolicy } from '../lib';
+
+describe('removal policy', () => {
+ test.each([
+ [RemovalPolicy.RETAIN, 'Retain'],
+ [RemovalPolicy.DESTROY, 'Delete'],
+ [RemovalPolicy.SNAPSHOT, 'Snapshot'],
+ [RemovalPolicy.RETAIN_ON_UPDATE_OR_DELETE, 'RetainExceptOnCreate'],
+ ])('should set correct DeletionPolicy for RemovalPolicy.%s', (removalPolicy: RemovalPolicy, deletionPolicy: string) => {
+ const stack = new Stack();
+
+ const resource = new CfnResource(stack, 'Resource', { type: 'MOCK' });
+ resource.applyRemovalPolicy(removalPolicy);
+
+ expect(toCloudFormation(stack)).toEqual({
+ Resources: {
+ Resource: expect.objectContaining({
+ Type: 'MOCK',
+ DeletionPolicy: deletionPolicy,
+ }),
+ },
+ });
+ });
+
+ test.each([
+ [RemovalPolicy.RETAIN, 'Retain'],
+ [RemovalPolicy.DESTROY, 'Delete'],
+ [RemovalPolicy.SNAPSHOT, 'Snapshot'],
+ [RemovalPolicy.RETAIN_ON_UPDATE_OR_DELETE, 'Retain'],
+ ])('should set correct UpdateReplacePolicy for RemovalPolicy.%s', (removalPolicy: RemovalPolicy, updateReplacePolicy: string) => {
+ const stack = new Stack();
+
+ const resource = new CfnResource(stack, 'Resource', { type: 'MOCK' });
+ resource.applyRemovalPolicy(removalPolicy, {
+ applyToUpdateReplacePolicy: true,
+ });
+
+ expect(toCloudFormation(stack)).toEqual({
+ Resources: {
+ Resource: expect.objectContaining({
+ Type: 'MOCK',
+ UpdateReplacePolicy: updateReplacePolicy,
+ }),
+ },
+ });
+ });
+});