Add a Firestore Document data source

[lgerard-pass]

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Description

Add the ability to read data from Firestore using a data source. Our use case is as follows :

We would love to be able to share data between Terraform root modules so that one root modules can consume the outputs of another. This process is described in the Terraform official documentation by using resource and data source pairs : https://developer.hashicorp.com/terraform/language/state/remote-state-data#alternative-ways-to-share-data-between-configurations

We would like to implement this using firestore, but for now we only have the google_firestore_document resource which is great for writing data into Firestore. But we don't have an easy way to read from Firestore.

New or Affected Resource(s)

• google_firestore_document

Potential Terraform Configuration

data "google_firestore_document" "mydoc" {
  project     = "my_project"
  database    = "my_database"
  collection  = "my_collection"
  document_id = "my-doc-id"
}

I guess it should return the same attributes as the google_firestore_document resource but the fields should be an attribute instead of an argument.

References

https://developer.hashicorp.com/terraform/language/state/remote-state-data#alternative-ways-to-share-data-between-configurations

b/391379797

[Ludovic-Emo-Pyl-Tech]

@lgerard-pass Funny coincidence—we just discussed this exact need with a colleague 15 minutes ago! 😊