RDS - Throw error when name or username supplied on DB snapshot restore

[brent-au]

This PR will introduce a behaviour to throw an error when restoring from a MySQL, PostgreSQL or MariaDB RDS snapshot and a name or username attribute is supplied as part of a template.

This is to change the current behaviour where the RDS instance is restored from snapshot, but subsequent applies of the same template cause the RDS to be recreated because the name and/or username attribute has not been honoured during creation.

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Closes #17037

Release note for CHANGELOG:

An error will now be thrown when supplying a name and/or username attribute when restoring a snapshot to a MySQL, PostgreSQL or MariaDB to an RDS instance.

Output from acceptance testing:

I modifed the MySQL snapshot restore with engine version test template here to include a name attribute for the mysql_restore resource, to provoke an error

$ make testacc TESTARGS='-run=TestAccAWSDBInstance_MySQL_SnapshotRestoreWithEngineVersion'
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./aws -v -count 1 -parallel 20 -run=TestAccAWSDBInstance_MySQL_SnapshotRestoreWithEngineVersion -timeout 120m
=== RUN   TestAccAWSDBInstance_MySQL_SnapshotRestoreWithEngineVersion
=== PAUSE TestAccAWSDBInstance_MySQL_SnapshotRestoreWithEngineVersion
=== CONT  TestAccAWSDBInstance_MySQL_SnapshotRestoreWithEngineVersion
    resource_aws_db_instance_test.go:2193: Step 1/1 error: Error running apply: 
        Error: Error restoring database from AWS DB Snapshot: tf-acc-test-4765336381358846440: name attribute is not supported when engine is mysql
        
        

--- FAIL: TestAccAWSDBInstance_MySQL_SnapshotRestoreWithEngineVersion (590.06s)
FAIL
FAIL    github.com/terraform-providers/terraform-provider-aws/aws       590.092s
FAIL
make: *** [GNUmakefile:28: testacc] Error 1
...

[gdavison]

Thanks for the PR, @brent-au! I've moved the validation to plan-time and fixed an acceptance test that now causes an error

[ghost]

This has been released in version 3.29.0 of the Terraform AWS provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template for triage. Thanks!

[konstl000]

It seems, that raising an error is not enough, since the name of the DB instance is present in the state after it is created from the snapshot. It seems that this PR introduces #17712.

[JeremyPDC]

It seems, that raising an error is not enough, since the name of the DB instance is present in the state after it is created from the snapshot. It seems that this PR introduces #17712.

Yeah we are having this problem now.

[aleon1220]

is happenning to me now and i am on terraform cloud. I believe the conflict is in
the duplicate use of the var.snapshot_identifier

Take a look at line 63 and 139

https://github.com/terraform-aws-modules/terraform-aws-rds/blob/master/modules/db_instance/main.tf#L139

[aleon1220]

I think the majority of the community is tracking the issue at #17712

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!