When destroying & creating a Spanner instance, its database isn't recreated with it

[quentinms]

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Terraform Version

Terraform v0.12.18
+ provider.google v3.48.0

Affected Resource(s)

• google_spanner_instance
• google_spanner_database

Terraform Configuration Files

Before:

resource "google_spanner_instance" "test" {
  project      = var.project
  name         = "test"
  config       = "regional-us-east1"
  display_name = "Test"
  num_nodes    = 1
}

resource "google_spanner_database" "test" {
  project  = var.project
  instance = google_spanner_instance.test.name
  name     = "test"
}

After:

resource "google_spanner_instance" "test" {
  project      = var.project
  name         = "test"
  config       = "nam11"
  display_name = "Test"
  num_nodes    = 1
}

resource "google_spanner_database" "test" {
  project  = var.project
  instance = google_spanner_instance.test.name
  name     = "test"
}

Debug Output

https://gist.github.com/quentinms/52ad7e765738b986888025b953a0f4cf

Panic Output

Expected Behavior

In addition to recreating the google_spanner_instance it should also recreate the google_spanner_database linked to it.

Actual Behavior

It only recreates the google_spanner_instance (making a spanner instance with no database).
By planning again, it will notice the google_spanner_database is missing and will want to create it. It should all happen at the same time.

Steps to Reproduce

1. terraform plan & terraform apply the following:

resource "google_spanner_instance" "test" {
  project      = var.project
  name         = "test"
  config       = "regional-us-east1"
  display_name = "Test"
  num_nodes    = 1
}

resource "google_spanner_database" "test" {
  project  = var.project
  instance = google_spanner_instance.test.name
  name     = "test"
}

2. Change the google_spanner_instance config to force a destroy & create.

resource "google_spanner_instance" "test" {
  project      = var.project
  name         = "test"
  config       = "nam11" // Will force recreation
  display_name = "Test"
  num_nodes    = 1
}

resource "google_spanner_database" "test" {
  project  = var.project
  instance = google_spanner_instance.test.name
  name     = "test"
}

3. terraform plan

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
-/+ destroy and then create replacement

Terraform will perform the following actions:

  # google_spanner_instance.test must be replaced
-/+ resource "google_spanner_instance" "test" {
      ~ config       = "projects/test-project/instanceConfigs/regional-us-east1" -> "nam11" # forces replacement
        display_name = "Test"
      ~ id           = "test-project/test" -> (known after apply)
      - labels       = {} -> null
        name         = "test"
        num_nodes    = 1
        project      = "test-project"
      ~ state        = "READY" -> (known after apply)
    }

Plan: 1 to add, 0 to change, 1 to destroy.

The plan is missing the google_spanner_database database which will also be destroyed (and should be recreated).

Important Factoids

References

• Possibly related: google_spanner_instance's recreation behavior was recently changed to fix Error 400 when updating a google_spanner_instance's config #7732.

[edwardmedia]

Yes, we have to apply twice to restore the database. Not sure if there is a proper way that the Terraform code can be configured to reflect the underlying relationship.

[rileykarson]

This is an occurrence of an upstream issue in Terraform's resource model (hashicorp/terraform-plugin-sdk#122) for which we're not aware of any solution, unfortunately. Since there's nothing we can do here, I'm closing this out.

[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. If you feel I made an error 🤖 🙉 , please reach out to my human friends 👉 [email protected]. Thanks!