Configure Terraform

Atmos natively supports opinionated workflows for Terraform and OpenTofu. It's compatible with every version of terraform and designed to work with multiple different versions of Terraform concurrently.

Keep in mind that Atmos does not handle the downloading or installation of Terraform; it assumes that any required commands are already installed on your system. To automate this, consider creating a Custom Command to install Terraform.

Atmos provides many settings that are specific to Terraform and OpenTofu.

CLI Configuration

All of these settings are defined by default in the Atmos CLI Configuration found in atmos.yaml, but can also be overridden at any level of the Stack configuration.

components:
  terraform:
    # The executable to be called by `atmos` when running Terraform commands
    command: "/usr/bin/terraform-1"
    # Can also be set using 'ATMOS_COMPONENTS_TERRAFORM_BASE_PATH' ENV var, or '--terraform-dir' command-line argument
    # Supports both absolute and relative paths
    base_path: "components/terraform"
    # Can also be set using 'ATMOS_COMPONENTS_TERRAFORM_APPLY_AUTO_APPROVE' ENV var
    apply_auto_approve: false
    # Can also be set using 'ATMOS_COMPONENTS_TERRAFORM_DEPLOY_RUN_INIT' ENV var, or '--deploy-run-init' command-line argument
    deploy_run_init: true
    # Can also be set using 'ATMOS_COMPONENTS_TERRAFORM_INIT_RUN_RECONFIGURE' ENV var, or '--init-run-reconfigure' command-line argument
    init_run_reconfigure: true
    # Can also be set using 'ATMOS_COMPONENTS_TERRAFORM_AUTO_GENERATE_BACKEND_FILE' ENV var, or '--auto-generate-backend-file' command-line argument
    auto_generate_backend_file: false
    # Can also be set using 'ATMOS_COMPONENTS_TERRAFORM_APPEND_USER_AGENT' ENV var, or '--append-user-agent' command-line argument
    append_user_agent: "Acme/1.0 (Build 1234; arm64)"
    plan:
      # Can also be set using 'ATMOS_COMPONENTS_TERRAFORM_PLAN_SKIP_PLANFILE' ENV var, or '--skip-planfile' command-line argument
      skip_planfile: false

components.terraform.command

The executable to be called by Atmos when running Terraform commands

components.terraform.base_path

The root directory where the Terraform components and configurations are located. This path serves as the starting point for resolving any relative paths within the Terraform setup.

components.terraform.apply_auto_approve

if set to true, Atmos automatically adds the -auto-approve option to instruct Terraform to apply the plan without asking for confirmation when executing terraform apply command

components.terraform.deploy_run_init

if set to true, Atmos runs terraform init before executing atmos terraform deploy command

components.terraform.init_run_reconfigure

if set to true, Atmos automatically adds the -reconfigure option to update the backend configuration when executing terraform init command

components.terraform.auto_generate_backend_file

if set to true, Atmos automatically generates the Terraform backend file from the component configuration when executing terraform plan and terraform apply commands

components.terraform.plan.skip_planfile

if set to true, Atmos will skip passing the -out=FILENAME flag when executing the terraform plan command. Set it to true when using Terraform Cloud since the -out flag is not supported. Terraform Cloud automatically stores plans in its backend

Configuration

The settings for terraform can be defined in multiple places and support inheritance. This ensures that projects can override the behavior.

The defaults for everything are defined in the atmos.yaml.

components:
  terraform:
    ...

The same settings, can be overridden by Stack configurations at any level:

• terraform
• components.terraform
• components.terraform._component_

For example, we can change the terraform command used by a component (useful for legacy components)

components:
  terraform:
    vpc:
      command: "/usr/local/bin/terraform-0.13"

Terraform Provider

A Terraform provider (cloudposse/terraform-provider-utils) implements a data source that can read the YAML Stack configurations natively from within terraform.

Terraform Module

A Terraform module (cloudposse/terraform-yaml-stack-config) wraps the data source.

Here's an example of accessing the variables for a given component from within a Terraform module.

module "vars" {
  source = "cloudposse/stack-config/yaml//modules/vars"
  # version     = "x.x.x"

  stack_config_local_path = "./stacks"
  stack                   = "my-stack"
  component_type          = "terraform"
  component               = "my-vpc"

  context = module.this.context
}