tflocal - Terraform with LocalStack

This package provides tflocal - a small wrapper script to run Terraform against LocalStack.

Prerequisites

• Python 3.x
• pip
• terraform

How it works

The 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).

Installation

The tflocal command line interface can be installed via pip:

pip install terraform-local

Configurations

The following environment variables can be configured:

• DRY_RUN: Generate the override file without invoking Terraform
• TF_CMD: Terraform command to call (default: terraform)
• AWS_ENDPOINT_URL: hostname and port of the target LocalStack instance
• LOCALSTACK_HOSTNAME: (Deprecated) host name of the target LocalStack instance
• EDGE_PORT: (Deprecated) port number of the target LocalStack instance
• S3_HOSTNAME: special hostname to be used to connect to LocalStack S3 (default: s3.localhost.localstack.cloud)
• 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: the AWS region to use (default: us-east-1, or determined from local credentials if boto3 is installed)
• CUSTOMIZE_ACCESS_KEY: enables to override the static AWS Access Key ID. The following cases are taking precedence over each other from top to bottom:
  • AWS_ACCESS_KEY_ID environment variable is set
  • access_key is set in the Terraform AWS provider
  • AWS_PROFILE environment variable is set and configured
  • AWS_DEFAULT_PROFILE environment variable is set and configured
  • default profile's credentials are configured
  • falls back to the default AWS_ACCESS_KEY_ID mock value
• AWS_ACCESS_KEY_ID: AWS Access Key ID to use for multi account setups (default: test -> account ID: 000000000000)
• SKIP_ALIASES: Allows to skip generating AWS provider overrides for specified aliased providers, e.g. SKIP_ALIASES=aws_secrets,real_aws
• ADDITIONAL_TF_OVERRIDE_LOCATIONS: Comma-separated list of folder paths that will also receive a temporary localstack_providers_override.tf file

Usage

The tflocal command has the same usage as the terraform command. For detailed usage, please refer to the man pages of terraform --help.

Validation errors when using local terraform modules

Note that if your project uses local terraform modules, and those modules reference providers, those folders also need to receive a temporary localstack_providers_override.tf file. Without it, you would get an error that looks like this when starting to process code from inside the module

╷
│ Error: No valid credential sources found
│ 
│   with module.lambda.provider["registry.terraform.io/hashicorp/aws"],
│   on ../../providers.tf line 11, in provider "aws":
│   11: provider "aws" {
│ 
│ Please see https://registry.terraform.io/providers/hashicorp/aws
│ for more information about providing credentials.
│ 
│ Error: failed to refresh cached credentials, no EC2 IMDS role found, operation error ec2imds: GetMetadata, access disabled to EC2 IMDS via client option, or "AWS_EC2_METADATA_DISABLED" environment variable

To address this issue, you may include a comma-separated list of folder paths that will recieve additional override files via an environment variable

ADDITIONAL_TF_OVERRIDE_LOCATIONS=/path/to/module1,path/to/module2 tflocal plan

See this issue for more discussion

Change Log

• v0.24.0: Add support to return terraform-local version when calling tflocal -version and fix AWS provider detection
• v0.23.1: Fix endpoint overrides for Terraform AWS provider >= 6.0.0-beta2
• v0.23.0: Add support for terraform_remote_state with s3 backend to read the state stored in local S3 backend; fix S3 backend config detection with multiple Terraform blocks
• v0.22.0: Fix S3 backend forcing DynamoDB State Lock to be enabled by default
• v0.21.0: Add ability to drop an override file in additional locations
• v0.20.1: Fix list config rendering
• v0.20.0: Fix S3 backend option merging
• v0.19.0: Add SKIP_ALIASES configuration environment variable
• v0.18.2: Fix warning on aliased custom endpoint names
• v0.18.1: Fix issue with not proxied commands
• v0.18.0: Add DRY_RUN and patch S3 backend entrypoints
• v0.17.1: Add packaging module to install requirements
• v0.17.0: Add option to use new endpoints S3 backend options
• v0.16.1: Update Setuptools to exclude tests during packaging
• v0.16.0: Introducing semantic versioning and AWS_ENDPOINT_URL variable
• v0.15: Update endpoint overrides for Terraform AWS provider 5.22.0
• v0.14: Add support to multi-account environments
• v0.13: Fix S3 automatic use_s3_path_style detection when setting S3_HOSTNAME or LOCALSTACK_HOSTNAME
• v0.12: Fix local endpoint overrides for Terraform AWS provider 5.9.0; fix parsing of alias and region defined as value lists
• v0.11: Minor fix to handle boolean values in S3 backend configs
• v0.10: Add support for storing state files in local S3 backends
• v0.9: Fix unsupported provider override for emrserverless
• v0.8: Configure the endpoint for opensearch service
• v0.7: Add initial support for provider aliases
• v0.6: Fix selection of default region
• v0.5: Make AWS region configurable, add region to provider config
• v0.4: Fix using use_s3_path_style for S3_HOSTNAME=localhost; exclude meteringmarketplace service endpoint
• v0.3: Fix support for -chdir=... to create providers file in target directory
• v0.2: Add ability to specify custom endpoints; pass INT signals to subprocess
• v0.1: Initial release

License

This software library is released under the Apache License, Version 2.0 (see LICENSE).