Handling Data Sources in Upjet for Crossplane: Managing Dependencies

[smileisak]

What problem are you facing?

I am currently working on integrating the provider-ovh with Upjet for Crossplane and I've encountered a specific challenge related to managing data sources that are different from Terraform resources.

In Terraform, we have a data source ovh_cloud_project_capabilities_containerregistry_filter which is essential for generating the plan_id used in creating resources like ovh_cloud_project_containerregistry.

For instance, in Terraform, we fetch the plan_id like this:

data "ovh_cloud_project_capabilities_containerregistry_filter" "capability" {
  service_name = "XXXXXX"
  region       = "GRA"
  plan_name    = "SMALL"
}

resource "ovh_cloud_project_containerregistry" "my-registry" {
  service_name = data.ovh_cloud_project_capabilities_containerregistry_filter.regcap.service_name
  plan_id      = data.ovh_cloud_project_capabilities_containerregistry_filter.regcap.id
  region       = data.ovh_cloud_project_capabilities_containerregistry_filter.regcap.region
  name         = "mydockerregistry"
}

However, with Upjet, I am not clear on how to handle this scenario since the data source doesn't directly translate into Terraform resources. I am wondering how to manage a data source in Upjet where the resource configuration relies on data that is typically fetched from a Terraform data source.

How could Upjet help solve your problem?

I am looking for guidance or suggestions on how to approach this scenario within Upjet and Crossplane. Specifically, I would like to understand:

How can Upjet handle situations where a Crossplane resource depends on data typically fetched from a Terraform data source?
Are there recommended practices within Upjet for managing these types of dependencies, especially when the data source does not directly translate into a Crossplane resource?
Any insights or examples of handling similar scenarios would be greatly appreciated.

[smileisak]

any news on this ?

[tomasmota]

I'm having the exact same issue, would also appreciate some guidance on what patterns to use in this case. I have been trying to read the data source using a terraform workspace, but reading it from a composition has been challenging. Any suggestions @ulucinar , @jeanduplessis?

[ytsarev]

We have a couple of related examples in provider-terraform that can help to work around this problem. Both of them are operating within the Composition.

• https://github.com/upbound/provider-terraform/tree/main/examples/observe-only-composition
• https://github.com/upbound/provider-terraform/tree/main/examples/importer

[jeanduplessis]

Unfortunately, unless XP introduces a native data source type to the XRM, it's not going to be feasible to solve this with Upjet. Workarounds like using provider-terraform and using composition are the only viable options until then.