Refactor Terraform Resource Names By One Command

This post introduces tfmv, a CLI tool that simplifies refactoring Terraform resource names with just one command.
For instance, to replace hyphens (-) with underscores (_), you can run:

tfmv -r '-/_'

Then resource are renamed:

-resource "github_repository" "example-1" {
+resource "github_repository" "example_1" {
   name = "example-1"
 }

 data "github_branch" "example" {
-  repository = github_repository.example-1.name
+  repository = github_repository.example_1.name
   branch     = "example"
 }

And a moved block is created:

moved {
  from = github_repository.example-1
  to   = github_repository.example_1
}

Features of tfmv

• Rename Terraform Resources, Data Sources, and Modules
• Modify resource references
• Generate moved blocks
• Easy to install
  • tfmv is a single binary written in Go. You only need to put tfmv into $PATH
  • Cross platform: Windows, macOS, and Linux
• Flexible Resource Filtering with Regular Expressions
  • Use --include <regexp> to rename only resources matching a specific pattern
  • Use --exclude <regexp> to skip renaming for resources matching a specific pattern
• Support for Multiple Renaming Methods
  • Fixed String Replacement: Use --replace (-r) to specify straightforward string substitutions
  • Regular Expression: Use --regexp to perform pattern-based renaming
  • Jsonnet: Use --jsonnet (-j) for advanced, programmatically controlled renaming logic

These features make tfmv a powerful and flexible tool for refactoring Terraform configurations.

Quick start

1. Install tfmv according to the guide
2. Create main.tf and make a backup of it as main.tf.bak:

echo 'resource "github_repository" "example-1" {
  name = "example-1"
}

data "github_branch" "example-2" {
  repository = github_repository.example-1.name
  branch     = "example"
}' > main.tf
cp main.tf main.tf.bak

1. Run tfmv to replace - with _:

tfmv -r '-/_'

Then check the result:

diff main.tf main.tf.bak

1c1
< resource "github_repository" "example_1" {
---
> resource "github_repository" "example-1" {
5,6c5,6
< data "github_branch" "example_2" {
<   repository = github_repository.example_1.name
---
> data "github_branch" "example-2" {
>   repository = github_repository.example-1.name

moved.tf:

moved {
  from = github_repository.example-1
  to   = github_repository.example_1
}

Congratulations! 🎉 You’ve successfully refactored Terraform resource names with just one command.

Conclusion

In this post I introduced tfmv, a powerful Terraform refactoring tool.
Using tfmv, you can efficiently rename Terraform resources and generate moved blocks.
For more details, check out the README.md on GitHub.