feat(rds): parameter group for replica instances (#17822)

Move `parameterGroup` from `DatabaseInstanceSourceProps` to
`DatabaseInstanceNewProps` since the parameter group of a replica
instance can be customized.

Closes #17580


----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: jogold

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

@@ -359,6 +359,13 @@ export interface DatabaseInstanceNewProps {
    */
   readonly port?: number;
 
+  /**
+   * The DB parameter group to associate with the instance.
+   *
+   * @default - no parameter group
+   */
+  readonly parameterGroup?: IParameterGroup;
+
   /**
    * The option group to associate with the instance.
    *
@@ -709,6 +716,7 @@ abstract class DatabaseInstanceNew extends DatabaseInstanceBase implements IData
       ? props.instanceIdentifier?.toLowerCase()
       : props.instanceIdentifier;
 
+    const instanceParameterGroupConfig = props.parameterGroup?.bindToInstance({});
     this.newCfnProps = {
       autoMinorVersionUpgrade: props.autoMinorVersionUpgrade,
       availabilityZone: props.multiAz ? undefined : props.availabilityZone,
@@ -732,6 +740,7 @@ abstract class DatabaseInstanceNew extends DatabaseInstanceBase implements IData
       monitoringInterval: props.monitoringInterval?.toSeconds(),
       monitoringRoleArn: monitoringRole?.roleArn,
       multiAz: props.multiAz,
+      dbParameterGroupName: instanceParameterGroupConfig?.parameterGroupName,
       optionGroupName: props.optionGroup?.optionGroupName,
       performanceInsightsKmsKeyId: props.performanceInsightEncryptionKey?.keyArn,
       performanceInsightsRetentionPeriod: enablePerformanceInsights
@@ -813,13 +822,6 @@ export interface DatabaseInstanceSourceProps extends DatabaseInstanceNewProps {
    * @default - no name
    */
   readonly databaseName?: string;
-
-  /**
-   * The DB parameter group to associate with the instance.
-   *
-   * @default - no parameter group
-   */
-  readonly parameterGroup?: IParameterGroup;
 }
 
 /**
@@ -875,15 +877,13 @@ abstract class DatabaseInstanceSource extends DatabaseInstanceNew implements IDa
 
     this.instanceType = props.instanceType ?? ec2.InstanceType.of(ec2.InstanceClass.M5, ec2.InstanceSize.LARGE);
 
-    const instanceParameterGroupConfig = props.parameterGroup?.bindToInstance({});
     this.sourceCfnProps = {
       ...this.newCfnProps,
       associatedRoles: instanceAssociatedRoles.length > 0 ? instanceAssociatedRoles : undefined,
       optionGroupName: engineConfig.optionGroup?.optionGroupName,
       allocatedStorage: props.allocatedStorage?.toString() ?? '100',
       allowMajorVersionUpgrade: props.allowMajorVersionUpgrade,
       dbName: props.databaseName,
-      dbParameterGroupName: instanceParameterGroupConfig?.parameterGroupName,
       engine: engineType,
       engineVersion: props.engine.engineVersion?.fullVersion,
       licenseModel: props.licenseModel,

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

@@ -1603,6 +1603,33 @@ describe('instance', () => {
       });
     }).toThrow(/Cannot set 'backupRetention', as engine 'postgres-13' does not support automatic backups for read replicas/);
   });
+
+  test('can set parameter group on read replica', () => {
+    // GIVEN
+    const instanceType = ec2.InstanceType.of(ec2.InstanceClass.T3, ec2.InstanceSize.SMALL);
+    const engine = rds.DatabaseInstanceEngine.postgres({ version: rds.PostgresEngineVersion.VER_13 });
+    const parameterGroup = new rds.ParameterGroup(stack, 'ParameterGroup', { engine });
+    const source = new rds.DatabaseInstance(stack, 'Source', {
+      engine,
+      instanceType,
+      vpc,
+    });
+
+    // WHEN
+    new rds.DatabaseInstanceReadReplica(stack, 'Replica', {
+      sourceDatabaseInstance: source,
+      parameterGroup,
+      instanceType,
+      vpc,
+    });
+
+    // THEN
+    expect(stack).toHaveResource('AWS::RDS::DBInstance', {
+      DBParameterGroupName: {
+        Ref: 'ParameterGroup5E32DECB',
+      },
+    });
+  });
 });
 
 test.each([

packages/@aws-cdk/aws-rds/test/integ.read-replica.expected.json

@@ -422,6 +422,16 @@
       "UpdateReplacePolicy": "Snapshot",
       "DeletionPolicy": "Snapshot"
     },
+    "ReplicaParameterGroup4BE5EE70": {
+      "Type": "AWS::RDS::DBParameterGroup",
+      "Properties": {
+        "Description": "Parameter group for mysql8.0",
+        "Family": "mysql8.0",
+        "Parameters": {
+          "wait_timeout": "86400"
+        }
+      }
+    },
     "MysqlReplicaSubnetGroup79E1F72A": {
       "Type": "AWS::RDS::DBSubnetGroup",
       "Properties": {
@@ -458,6 +468,9 @@
         "DBInstanceClass": "db.t3.small",
         "BackupRetentionPeriod": 3,
         "CopyTagsToSnapshot": true,
+        "DBParameterGroupName": {
+          "Ref": "ReplicaParameterGroup4BE5EE70"
+        },
         "DBSubnetGroupName": {
           "Ref": "MysqlReplicaSubnetGroup79E1F72A"
         },

packages/@aws-cdk/aws-rds/test/integ.read-replica.ts

@@ -44,12 +44,20 @@ class TestStack extends Stack {
       vpcSubnets,
     });
 
+    const parameterGroup = new rds.ParameterGroup(this, 'ReplicaParameterGroup', {
+      engine: rds.DatabaseInstanceEngine.mysql({ version: rds.MysqlEngineVersion.VER_8_0 }),
+      parameters: {
+        wait_timeout: '86400',
+      },
+    });
+
     new rds.DatabaseInstanceReadReplica(this, 'MysqlReplica', {
       sourceDatabaseInstance: mysqlSource,
       backupRetention: Duration.days(3),
       instanceType,
       vpc,
       vpcSubnets,
+      parameterGroup,
     });
   }
 }