awscc_rds_db_cluster does not support aurora-postgresql engine due to forced backtrack_window

[common-cranberry]

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Terraform CLI and Terraform AWS Cloud Control Provider Version

Affected Resource(s)

• awscc_rds_db_cluster

Terraform Configuration Files

Please include all Terraform configurations required to reproduce the bug. Bug reports without a functional reproduction may be closed without investigation.

resource "awscc_rds_db_cluster" "main" {
  # ...
  engine           = "aurora-postgresql"
}

resource "awscc_rds_db_cluster" "main" {
  # ...
  backtrack_window = 0
  engine           = "aurora-postgresql"
}

resource "awscc_rds_db_cluster" "main" {
  # ...
  backtrack_window = null
  engine           = "aurora-postgresql"
}

Debug Output

https://gist.github.com/common-cranberry/0e81762edaee4adce0c17c4c36fd54ad

Panic Output

Expected Behavior

The provider should not send any value for BacktrackWindow when engine is not implicitly or explicitly aurora-mysql which is the only engine to support this functionality.

Actual Behavior

The following response is tracked in CloudTrail no matter which of the above values for backtrack_window are provided, it is always set to 0 with this error message.

{
    "eventSource": "rds.amazonaws.com",
    "eventName": "CreateDBCluster",
    "awsRegion": "us-east-1",
    "sourceIPAddress": "cloudformation.amazonaws.com",
    "userAgent": "cloudformation.amazonaws.com",
    "errorCode": "InvalidParameterValueException",
    "errorMessage": "Backtrack is not enabled for the aurora-postgresql engine.",
    "requestParameters": {
      "backtrackWindow": 0,
    }
}

Steps to Reproduce

1. terraform apply

Important Factoids

References

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

[quixoticmonk]

Thank you for opening the issue, @common-cranberry . The reason could be the default value set in the schema used by the provider. I have opened an internal ticket to review the schema and the applicability of the property.

[quixoticmonk]

@common-cranberry The change in the schema is available in the registry and is in 1.5.0. Can you retest ?

[quixoticmonk]

Retested the changes for the resource. Closing the issue as the backtrack_window input is updated in schema not to be set for postgres enginer.