fix(aws-rds): ServerlessCluster.clusterArn is not correct when cluste…

…rIdentifier includes upper cases string. (#13710)

Close #12795 

The problem is that, according to the cloudformation specification, even if the clusterIdentifier contains uppercase letters, the actual generated cluster identifier will be set to a lowercase string. But the resource ref remain the original string (that maybe contain uppercase letters).

https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-rds-dbcluster.html#cfn-rds-dbcluster-dbclusteridentifier

----

*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-rds/lib/cluster.ts

@@ -4,7 +4,8 @@ import * as kms from '@aws-cdk/aws-kms';
 import * as logs from '@aws-cdk/aws-logs';
 import * as s3 from '@aws-cdk/aws-s3';
 import * as secretsmanager from '@aws-cdk/aws-secretsmanager';
-import { Annotations, Duration, RemovalPolicy, Resource, Token } from '@aws-cdk/core';
+import { Annotations, Duration, FeatureFlags, RemovalPolicy, Resource, Token } from '@aws-cdk/core';
+import * as cxapi from '@aws-cdk/cx-api';
 import { Construct } from 'constructs';
 import { IClusterEngine } from './cluster-engine';
 import { DatabaseClusterAttributes, IDatabaseCluster } from './cluster-ref';
@@ -340,11 +341,15 @@ abstract class DatabaseClusterNew extends DatabaseClusterBase {
     const clusterParameterGroupConfig = clusterParameterGroup?.bindToCluster({});
     this.engine = props.engine;
 
+    const clusterIdentifier = FeatureFlags.of(this).isEnabled(cxapi.RDS_LOWERCASE_DB_IDENTIFIER)
+      ? props.clusterIdentifier?.toLowerCase()
+      : props.clusterIdentifier;
+
     this.newCfnProps = {
       // Basic
       engine: props.engine.engineType,
       engineVersion: props.engine.engineVersion?.fullVersion,
-      dbClusterIdentifier: props.clusterIdentifier,
+      dbClusterIdentifier: clusterIdentifier,
       dbSubnetGroupName: this.subnetGroup.subnetGroupName,
       vpcSecurityGroupIds: this.securityGroups.map(sg => sg.securityGroupId),
       port: props.port ?? clusterEngineBindConfig.port,

packages/@aws-cdk/aws-rds/lib/instance.ts

@@ -5,7 +5,17 @@ import * as kms from '@aws-cdk/aws-kms';
 import * as logs from '@aws-cdk/aws-logs';
 import * as s3 from '@aws-cdk/aws-s3';
 import * as secretsmanager from '@aws-cdk/aws-secretsmanager';
-import { Duration, IResource, Lazy, RemovalPolicy, Resource, Stack, Token } from '@aws-cdk/core';
+import {
+  Duration,
+  FeatureFlags,
+  IResource,
+  Lazy,
+  RemovalPolicy,
+  Resource,
+  Stack,
+  Token,
+} from '@aws-cdk/core';
+import * as cxapi from '@aws-cdk/cx-api';
 import { Construct } from 'constructs';
 import { DatabaseSecret } from './database-secret';
 import { Endpoint } from './endpoint';
@@ -687,13 +697,17 @@ abstract class DatabaseInstanceNew extends DatabaseInstanceBase implements IData
       });
     }
 
+    const instanceIdentifier = FeatureFlags.of(this).isEnabled(cxapi.RDS_LOWERCASE_DB_IDENTIFIER)
+      ? props.instanceIdentifier?.toLowerCase()
+      : props.instanceIdentifier;
+
     this.newCfnProps = {
       autoMinorVersionUpgrade: props.autoMinorVersionUpgrade,
       availabilityZone: props.multiAz ? undefined : props.availabilityZone,
       backupRetentionPeriod: props.backupRetention?.toDays(),
       copyTagsToSnapshot: props.copyTagsToSnapshot ?? true,
       dbInstanceClass: Lazy.string({ produce: () => `db.${this.instanceType}` }),
-      dbInstanceIdentifier: props.instanceIdentifier,
+      dbInstanceIdentifier: instanceIdentifier,
       dbSubnetGroupName: subnetGroup.subnetGroupName,
       deleteAutomatedBackups: props.deleteAutomatedBackups,
       deletionProtection: defaultDeletionProtection(props.deletionProtection, props.removalPolicy),

packages/@aws-cdk/aws-rds/lib/serverless-cluster.ts

@@ -2,7 +2,8 @@ import * as ec2 from '@aws-cdk/aws-ec2';
 import * as iam from '@aws-cdk/aws-iam';
 import * as kms from '@aws-cdk/aws-kms';
 import * as secretsmanager from '@aws-cdk/aws-secretsmanager';
-import { Resource, Duration, Token, Annotations, RemovalPolicy, IResource, Stack, Lazy } from '@aws-cdk/core';
+import { Resource, Duration, Token, Annotations, RemovalPolicy, IResource, Stack, Lazy, FeatureFlags } from '@aws-cdk/core';
+import * as cxapi from '@aws-cdk/cx-api';
 import { Construct } from 'constructs';
 import { IClusterEngine } from './cluster-engine';
 import { Endpoint } from './endpoint';
@@ -438,10 +439,14 @@ export class ServerlessCluster extends ServerlessClusterBase {
       }),
     ];
 
+    const clusterIdentifier = FeatureFlags.of(this).isEnabled(cxapi.RDS_LOWERCASE_DB_IDENTIFIER)
+      ? props.clusterIdentifier?.toLowerCase()
+      : props.clusterIdentifier;
+
     const cluster = new CfnDBCluster(this, 'Resource', {
       backupRetentionPeriod: props.backupRetention?.toDays(),
       databaseName: props.defaultDatabaseName,
-      dbClusterIdentifier: props.clusterIdentifier,
+      dbClusterIdentifier: clusterIdentifier,
       dbClusterParameterGroupName: clusterParameterGroupConfig?.parameterGroupName,
       dbSubnetGroupName: this.subnetGroup.subnetGroupName,
       deletionProtection: defaultDeletionProtection(props.deletionProtection, props.removalPolicy),

packages/@aws-cdk/aws-rds/package.json

@@ -91,6 +91,7 @@
     "@aws-cdk/aws-s3": "0.0.0",
     "@aws-cdk/aws-secretsmanager": "0.0.0",
     "@aws-cdk/core": "0.0.0",
+    "@aws-cdk/cx-api": "0.0.0",
     "constructs": "^3.3.69"
   },
   "homepage": "https://github.com/aws/aws-cdk",
@@ -104,6 +105,7 @@
     "@aws-cdk/aws-secretsmanager": "0.0.0",
     "@aws-cdk/core": "0.0.0",
     "@aws-cdk/aws-s3": "0.0.0",
+    "@aws-cdk/cx-api": "0.0.0",
     "constructs": "^3.3.69"
   },
   "engines": {

packages/@aws-cdk/aws-rds/test/cluster.test.ts

@@ -1860,6 +1860,48 @@ describe('cluster', () => {
 
 
   });
+
+  test('changes the case of the cluster identifier if the lowercaseDbIdentifier feature flag is enabled', () => {
+    // GIVEN
+    const app = new cdk.App({
+      context: { [cxapi.RDS_LOWERCASE_DB_IDENTIFIER]: true },
+    });
+    const stack = testStack(app);
+    const vpc = new ec2.Vpc(stack, 'VPC');
+
+    // WHEN
+    const clusterIdentifier = 'TestClusterIdentifier';
+    new DatabaseCluster(stack, 'Database', {
+      engine: DatabaseClusterEngine.AURORA,
+      instanceProps: { vpc },
+      clusterIdentifier,
+    });
+
+    // THEN
+    expect(stack).toHaveResourceLike('AWS::RDS::DBCluster', {
+      DBClusterIdentifier: clusterIdentifier.toLowerCase(),
+    });
+  });
+
+  test('does not changes the case of the cluster identifier if the lowercaseDbIdentifier feature flag is disabled', () => {
+    // GIVEN
+    const app = new cdk.App();
+    const stack = testStack(app);
+    const vpc = new ec2.Vpc(stack, 'VPC');
+
+    // WHEN
+    const clusterIdentifier = 'TestClusterIdentifier';
+    new DatabaseCluster(stack, 'Database', {
+      engine: DatabaseClusterEngine.AURORA,
+      instanceProps: { vpc },
+      clusterIdentifier,
+    });
+
+    // THEN
+    expect(stack).toHaveResourceLike('AWS::RDS::DBCluster', {
+      DBClusterIdentifier: clusterIdentifier,
+    });
+  });
 });
 
 test.each([

packages/@aws-cdk/aws-rds/test/instance.test.ts

@@ -9,7 +9,7 @@ import * as logs from '@aws-cdk/aws-logs';
 import * as s3 from '@aws-cdk/aws-s3';
 import * as cdk from '@aws-cdk/core';
 import * as cxapi from '@aws-cdk/cx-api';
-import { testFutureBehavior } from 'cdk-build-tools/lib/feature-flag';
+import { testFutureBehavior, testLegacyBehavior } from 'cdk-build-tools/lib/feature-flag';
 import * as rds from '../lib';
 
 let stack: cdk.Stack;
@@ -1279,6 +1279,52 @@ describe('instance', () => {
       PubliclyAccessible: true,
     });
   });
+
+  testFutureBehavior(
+    'changes the case of the cluster identifier if the lowercaseDbIdentifier feature flag is enabled',
+    { [cxapi.RDS_LOWERCASE_DB_IDENTIFIER]: true }, cdk.App, (app,
+    ) => {
+      // GIVEN
+      stack = new cdk.Stack( app );
+      vpc = new ec2.Vpc( stack, 'VPC' );
+
+      // WHEN
+      const instanceIdentifier = 'TestInstanceIdentifier';
+      new rds.DatabaseInstance( stack, 'DB', {
+        engine: rds.DatabaseInstanceEngine.mysql({
+          version: rds.MysqlEngineVersion.VER_8_0_19,
+        }),
+        vpc,
+        instanceIdentifier,
+      } );
+
+      // THEN
+      expect(stack).toHaveResource('AWS::RDS::DBInstance', {
+        DBInstanceIdentifier: instanceIdentifier.toLowerCase(),
+      });
+    });
+
+  testLegacyBehavior( 'does not changes the case of the cluster identifier if the lowercaseDbIdentifier feature flag is disabled', cdk.App, (app ) => {
+    // GIVEN
+    stack = new cdk.Stack( app );
+    vpc = new ec2.Vpc( stack, 'VPC' );
+
+    // WHEN
+    const instanceIdentifier = 'TestInstanceIdentifier';
+    new rds.DatabaseInstance( stack, 'DB', {
+      engine: rds.DatabaseInstanceEngine.mysql({
+        version: rds.MysqlEngineVersion.VER_8_0_19,
+      }),
+      vpc,
+      instanceIdentifier,
+    } );
+
+    // THEN
+    expect(stack).toHaveResource('AWS::RDS::DBInstance', {
+      DBInstanceIdentifier: instanceIdentifier,
+    });
+  });
+
 });
 
 test.each([

packages/@aws-cdk/aws-rds/test/serverless-cluster.test.ts

@@ -3,6 +3,7 @@ import * as ec2 from '@aws-cdk/aws-ec2';
 import * as iam from '@aws-cdk/aws-iam';
 import * as kms from '@aws-cdk/aws-kms';
 import * as cdk from '@aws-cdk/core';
+import * as cxapi from '@aws-cdk/cx-api';
 import { nodeunitShim, Test } from 'nodeunit-shim';
 import { AuroraPostgresEngineVersion, ServerlessCluster, DatabaseClusterEngine, ParameterGroup, AuroraCapacityUnit, DatabaseSecret } from '../lib';
 
@@ -818,11 +819,56 @@ nodeunitShim({
 
     test.done();
   },
-});
 
+  'changes the case of the cluster identifier if the lowercaseDbIdentifier feature flag is enabled'(test: Test) {
+    // GIVEN
+    const app = new cdk.App({
+      context: { [cxapi.RDS_LOWERCASE_DB_IDENTIFIER]: true },
+    });
+    const stack = testStack(app);
+    const clusterIdentifier = 'TestClusterIdentifier';
+    const vpc = ec2.Vpc.fromLookup(stack, 'VPC', { isDefault: true });
+
+    // WHEN
+    new ServerlessCluster(stack, 'Database', {
+      engine: DatabaseClusterEngine.AURORA_MYSQL,
+      vpc,
+      clusterIdentifier,
+    });
+
+    // THEN
+    expect(stack).to(haveResourceLike('AWS::RDS::DBCluster', {
+      DBClusterIdentifier: clusterIdentifier.toLowerCase(),
+    }));
+
+    test.done();
+  },
+
+  'does not change the case of the cluster identifier if the lowercaseDbIdentifier feature flag is disabled'(test: Test) {
+    // GIVEN
+    const app = new cdk.App();
+    const stack = testStack(app);
+    const clusterIdentifier = 'TestClusterIdentifier';
+    const vpc = ec2.Vpc.fromLookup(stack, 'VPC', { isDefault: true });
+
+    // WHEN
+    new ServerlessCluster(stack, 'Database', {
+      engine: DatabaseClusterEngine.AURORA_MYSQL,
+      vpc,
+      clusterIdentifier,
+    });
+
+    // THEN
+    expect(stack).to(haveResourceLike('AWS::RDS::DBCluster', {
+      DBClusterIdentifier: clusterIdentifier,
+    }));
+
+    test.done();
+  },
+});
 
-function testStack() {
-  const stack = new cdk.Stack(undefined, undefined, { env: { account: '12345', region: 'us-test-1' } });
+function testStack(app?: cdk.App, id?: string): cdk.Stack {
+  const stack = new cdk.Stack(app, id, { env: { account: '12345', region: 'us-test-1' } });
   stack.node.setContext('availability-zones:12345:us-test-1', ['us-test-1a', 'us-test-1b']);
   return stack;
 }

packages/@aws-cdk/cx-api/lib/features.ts

@@ -104,6 +104,21 @@ export const S3_GRANT_WRITE_WITHOUT_ACL = '@aws-cdk/aws-s3:grantWriteWithoutAcl'
  */
 export const ECS_REMOVE_DEFAULT_DESIRED_COUNT = '@aws-cdk/aws-ecs-patterns:removeDefaultDesiredCount';
 
+/**
+ * ServerlessCluster.clusterIdentifier currently can has uppercase letters,
+ * and ServerlessCluster pass it through to CfnDBCluster.dbClusterIdentifier.
+ * The identifier is saved as lowercase string in AWS and is resolved as original string in CloudFormation.
+ *
+ * If this flag is not set, original value that one set to ServerlessCluster.clusterIdentifier
+ * is passed to CfnDBCluster.dbClusterIdentifier.
+ * If this flag is true, ServerlessCluster.clusterIdentifier is converted into a string containing
+ * only lowercase characters by the `toLowerCase` function and passed to CfnDBCluster.dbClusterIdentifier.
+ *
+ * This feature flag make correct the ServerlessCluster.clusterArn when
+ * clusterIdentifier contains a Upper case letters.
+ */
+export const RDS_LOWERCASE_DB_IDENTIFIER = '@aws-cdk/aws-rds:lowercaseDbIdentifier';
+
 /**
  * This map includes context keys and values for feature flags that enable
  * capabilities "from the future", which we could not introduce as the default
@@ -126,6 +141,7 @@ export const FUTURE_FLAGS: { [key: string]: any } = {
   [KMS_DEFAULT_KEY_POLICIES]: true,
   [S3_GRANT_WRITE_WITHOUT_ACL]: true,
   [ECS_REMOVE_DEFAULT_DESIRED_COUNT]: true,
+  [RDS_LOWERCASE_DB_IDENTIFIER]: true,
 
   // We will advertise this flag when the feature is complete
   // [NEW_STYLE_STACK_SYNTHESIS_CONTEXT]: 'true',
@@ -152,6 +168,7 @@ const FUTURE_FLAGS_DEFAULTS: { [key: string]: boolean } = {
   [KMS_DEFAULT_KEY_POLICIES]: false,
   [S3_GRANT_WRITE_WITHOUT_ACL]: false,
   [ECS_REMOVE_DEFAULT_DESIRED_COUNT]: false,
+  [RDS_LOWERCASE_DB_IDENTIFIER]: false,
 };
 
 export function futureFlagDefault(flag: string): boolean {