How to fix Error: No source for module in Terraform

Open your Terraform configuration file and check that your module block includes the source argument. The source argument is mandatory for all modules.

module "example" {
  source = "./modules/example"  # Local path
  # or
  source = "hashicorp/consul/aws"  # Registry module
}

If the source argument is missing, add it with the correct module path or registry reference.

If using a local module source, ensure the path exists and is spelled correctly:

# Check if local module directory exists
ls -la ./modules/example

Relative paths like ./modules/example are relative to the directory containing your Terraform configuration file, not your current working directory. Use terraform init from the correct directory.

After verifying the source path, initialize Terraform to download the module:

terraform init

This command downloads modules from the specified sources into the .terraform/modules directory. If the module source changed, you may need to use the -upgrade flag:

terraform init -upgrade

If using a module from the Terraform Registry, ensure the source format is correct. Registry modules require three or four slash-separated components:

module "vpc" {
  source = "hashicorp/vpc/aws"  # namespace/name/provider
  version = "~> 3.0"
}

Common mistakes include:
- Using single slashes instead of proper module syntax
- Misspelling the namespace, module name, or provider
- Using submodules without the // syntax (e.g., terraform-google-modules/vm/google//modules/mig)

If the error persists after verifying the source path, clear Terraform caches and reinitialize:

rm -rf .terraform .terraform.lock.hcl
terraform init

This removes cached module data and forces Terraform to re-download modules fresh. The .terraform.lock.hcl file contains version constraints; removing it causes Terraform to re-resolve module versions.

If using modules from private repositories (GitHub, GitLab, private registries), ensure proper authentication:

For GitHub SSH modules:

module "private" {
  source = "[email protected]:myorg/mymodule.git"
}

For Terraform Cloud private registry:

module "private" {
  source = "app.terraform.io/myorg/mymodule/aws"
}

Ensure SSH keys are configured or API tokens are available in your environment for authentication.