Expose additional fields in resource_sql_source_representation_instance

[rsinnet]

Expose additional fields from the v1beta4 API:

Add the following members:

• username
• password
• caCertificate
• clientCertificate
• clientKey
• dumpFilePath

See also: https://cloud.google.com/sql/docs/mysql/admin-api/rest/v1beta4/instances#onpremisesconfiguration

[rsinnet]

Judging by the API in google_sql_database_instance, it may not be necessary to use source representations for replication? I suspect it can be done with a single resource. It wasn't apparent from the source code so not really sure but going to experiment. All the necessary fields to populate onPremisesConnection are present, so perhaps this API is not fully documented or more likely I don't know how to read the documentation 😆

https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/sql_database_instance

[rsinnet]

@megan07 I saw your comment about MagicModules here: #3596 (review)

If I were to reimplement this upstream, would this PR be valuable? Unfortunately I did this before looking through the upstream repo, but looks like this just requires updating the appropriate api.yaml with no overrides (maybe validation on the dumpFilePath if there is a similar instance of validation in the codebase), and then add/update integration tests.

Thoughts?

[megan07]

Hi @rsinnet! If it would provide value to you then I would say it's valuable! And yes, that should be all you'd need to do is to update the appropriate api.yaml. As for overrides, I can't speak to that as I'm not super familiar with the resource, but of course if you run into issues while implementing you can add the PR and we can respond to any questions/concerns. We'd also appreciate if you added a test with the added fields as well. Let me know if you have further questions and I can try to help out!

Thanks for contributing!