(rds): Add support for replicationSourceIdentifier prop

[moltar]

Describe the feature

Docs: https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/AuroraPostgreSQL.Migrating.RDSPostgreSQL.Replica.html

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

This prop is available on the CfnDBCluster.

Use Case

Migrating RDS types, need to set this prop.

Proposed Solution

The DatabaseCluster class, should accept replicationInstanceSource prop, which accepts IDatabaseInstance:

replicationInstanceSource: IDatabaseInstance

Other Information

• Cannot set masterUserPassword and masterUsername (CDK sets defaults) internally.
• The value of replicationSourceIdentifier is NOT an identifier, but a full ARN.

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

CDK version used

N/A

Environment details (OS name and version, etc.)

N/A

[khushail]

Thanks @moltar for requesting this feature. Its evident from CDK docs that this prop is supported in Cloudformation -https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_rds.CfnDBCluster.html#replicationsourceidentifier, hence can be supported via CDK too.

Marking it as P2 as the workaround of using L1 Construct already exists. Contributions from the community are also welcome.