Terraform Module Sources

How Terraform Finds Reusable Modules

Terraform lets you break down your infrastructure configuration into smaller, reusable pieces called modules. But where does Terraform find the code for these modules? That's where the source argument comes in.

The source argument tells Terraform where to look for the module's code. There are several options available, depending on where you store your modules:

Local Files: Perfect for keeping modules within the same project. Just use a path starting with ./ or ../ to point Terraform to the module directory.

module "local_database" {
  source = "./modules/database"
}

Terraform Registry: This is a terraform platform for discovering providers, modules and security policies. You can specify the module's name and version to use a specific one.

module "aws_ec2_instance" {
  source  = "hashicorp/aws/ec2"
  version = "~> 4.0"
}

Version Control Systems (VCS): If your modules live in a Git repository (like GitHub or Bitbucket), or a Mercurial repository, you can provide the URL to the repository.

module "private_module" {
  source = "git@github.com:your-org/your-private-module.git"
}

Http/s URLs: Modules can also be downloaded from web servers using HTTP or HTTPS URLs. Terraform can even follow redirects to other source locations.

module "http_module" {
  source = "https://your-company-registry.com/modules/my-module"
}

Cloud Storage: Modules stored in Amazon S3 buckets can be accessed by prefixing the URL with s3::

module "s3_module" {
  source = "s3::s3.amazonaws.com/your-bucket/my-module.zip"
}