How to Import an Google Cloud Spanner Database into Terraform

Import Google Cloud Spanner Database with Terraback (recommended)

Terraback reverse-engineers your live infrastructure: it reads the Cloud Spanner resource with read-only credentials, generates the HCL, and produces the exact import block. Two commands take you from a live Google Cloud Spanner Database to managed Terraform.

terraback scan all gcp --project my-gcp-project

terraback gcp import --method bulk

The Terraform import block

Terraback emits a Terraform 1.5+ import block like the one below. Because the block lives in your configuration, the import is reviewable in a pull request and repeatable across environments.

import {
  to = google_spanner_database.orders
  id = "projects/my-project/instances/prod-spanner/databases/orders"
}

Example google_spanner_database configuration

Here is a realistic Google Cloud Spanner Database block. Terraback generates a fuller version from your actual resource attributes; this is a minimal, valid starting point.

resource "google_spanner_database" "orders" {
  name                = "orders"
  instance            = "prod-spanner"
  database_dialect    = "GOOGLE_STANDARD_SQL"
  deletion_protection = true
}

Gotchas when importing a Google Cloud Spanner Database

• The import ID includes the parent instance; that google_spanner_instance must already exist in the config.
• deletion_protection defaults to true and must be set false before Terraform can destroy the database.
• ddl statements applied through Terraform are append-only; the provider does not reconcile or remove existing schema on import.
• database_dialect (GOOGLE_STANDARD_SQL vs POSTGRESQL) is fixed at creation and cannot be changed.

Doing it manually with terraform import

The native approach is to write the google_spanner_database block by hand, then run terraform import google_spanner_database.example <import-id> for every resource, one at a time. That works for a handful of resources, but it does not scale: you author all the HCL yourself and repeat the command for each item. Terraback generates the HCL and the import blocks for your whole account in one pass.

Import other Google Cloud resources