Terraform

Terraform is an Infrastructure-as-Code (IaC) framework developed by HashiCorp. It enables users to define and provision infrastructure using a high-level configuration language. Terraform uses HashiCorp Configuration Language (HCL) as its configuration syntax. HCL is a domain-specific language designed for writing configurations that define infrastructure elements and their relationships.

LocalStack supports Terraform via the AWS provider through custom service endpoints. You can configure Terraform to use LocalStack in two ways:

• Using the tflocal wrapper script to automatically configure the service endpoints for you.
• Manually configuring the service endpoints in your Terraform configuration with additional maintenance.

In this guide, we will demonstrate how you can create local AWS resources using Terraform and LocalStack, by using the tflocal wrapper script and a manual configuration example.

tflocal wrapper script

tflocal is a small wrapper script to run Terraform against LocalStack. tflocal script uses the Terraform Override mechanism and creates a temporary file localstack_providers_override.tf to configure the endpoints for the AWS provider section. The endpoints for all services are configured to point to the LocalStack API (http://localhost:4566 by default). It allows you to easily deploy your unmodified Terraform scripts against LocalStack.

Create a Terraform configuration

Create a new file named main.tf and add a minimal S3 bucket configuration to it. The following contents should be added in the main.tf file:

resource "aws_s3_bucket" "test-bucket" {
  bucket = "my-bucket"
}

Install the tflocal wrapper script

To install the tflocal command, you can use pip (assuming you have a local Python installation):

$ pip install terraform-local

After installation, you can use the tflocal command, which has the same interface as the terraform command line.

$ tflocal --help
Usage: terraform [global options] <subcommand> [args]
...
```bash

### Deploy the Terraform configuration

Start your LocalStack container using your preferred method. Initialize Terraform using the following command:

```bash
$ tflocal init

You can now provision the S3 bucket specified in the configuration:

$ tflocal apply

Configuration

Environment Variable	Default value	Description
TF_CMD	terraform	Terraform command to call
AWS_ENDPOINT_URL	-	Hostname and port of the target LocalStack instance
LOCALSTACK_HOSTNAME	localhost	(Deprecated) Host name of the target LocalStack instance
EDGE_PORT	4566	(Deprecated) Port number of the target LocalStack instance
S3_HOSTNAME	s3.localhost.localstack.cloud	Special hostname to be used to connect to LocalStack S3
USE_EXEC	-	Whether to use os.exec instead of subprocess.Popen (try using this in case of I/O issues)
<SERVICE>_ENDPOINT	-	Setting a custom service endpoint, e.g., COGNITO_IDP_ENDPOINT=http://example.com
AWS_DEFAULT_REGION	us-east-1	The AWS region to use (determined from local credentials if boto3 is installed)
CUSTOMIZE_ACCESS_KEY	-	Enables you to override the static AWS Access Key ID
AWS_ACCESS_KEY_ID	test (accountId: 000000000000)	AWS Access Key ID to use for multi-account setups

note

While using CUSTOMIZE_ACCESS_KEY, following cases are taking precedence over each other from top to bottom:

1. If the AWS_ACCESS_KEY_ID environment variable is set.
2. If access_key is configured in the Terraform AWS provider.
3. If the AWS_PROFILE environment variable is set and properly configured.
4. If the AWS_DEFAULT_PROFILE environment variable is set and configured.
5. If credentials for the default profile are configured.
6. If none of the above settings are present, it falls back to using the default AWS_ACCESS_KEY_ID mock value.