terragrunt

Terragrunt Module for Dagger

A powerful Dagger module for managing Terragrunt, Terraform, and OpenTofu operations in a containerized environment.

Features 🎨

Terragrunt Batteries Included 🔋

Configuration 🛠️

Base Container Options

• ctr: Specify a custom base container.
• imageURL: Specify a custom base image URL.
• tgVersion: Set the version of Terragrunt (default: 0.68.1).
• tfVersion: Set the version of Terraform (default: 1.9.5).
• openTofuVersion: Set the version of OpenTofu (default: 1.8.2).
• enableAWSCLI: Enable or disable the installation of the AWS CLI (default: false).
• awscliVersion: Set the version of the AWS CLI to install (default: 2.15.1).
• extraPackages: A list of extra packages to install with APKO, from the Alpine packages repository (default: []).

IaC Tool Versions

• Terragrunt, Terraform, and OpenTofu versions can be specified or will use defaults.

Permissions and Caching

• Configure directory permissions and set up caching for Terragrunt and Terraform.

Environment and Secrets

• Set environment variables and manage secrets securely.

Usage Examples 🚀

Basic Terragrunt Execution

	testEnvVars := []string{
		"AWS_ACCESS_KEY_ID=test",
		"AWS_SECRET_ACCESS_KEY=test",
		"AWS_SESSION_TOKEN=test",
	}

	// Initialize the Terragrunt module
	tgModule := dag.
		Terragrunt(dagger.TerragruntOpts{
			EnvVarsFromHost: testEnvVars,
		}).
		WithTerragruntPermissionsOnDirsDefault().
		WithTerragruntLogOptions(
			dagger.TerragruntWithTerragruntLogOptionsOpts{
				TgLogLevel:        "debug",
				TgForwardTfStdout: true,
			},
		)

	// Execute the init command, but don't run it in a container
	tgCtrConfigured := tgModule.
		Exec("init", dagger.TerragruntExecOpts{
			Source: m.getTestDir("").
				Directory("terragrunt"),
		})

	// Evaluate the terragrunt init command.
	tgInitCmdOut, tgInitCmdErr := tgCtrConfigured.
		Stdout(ctx)

Running Terragrunt with Custom Options

	tgModule := dag.
		Terragrunt(dagger.TerragruntOpts{
			EnvVarsFromHost: testEnvVars,
			TfVersion:       "1.7.0",
		}).
		WithTerragruntPermissionsOnDirsDefault().
		WithTerragruntLogOptions(dagger.TerragruntWithTerragruntLogOptionsOpts{
			TgLogDisableFormatting: true,
			TgLogShowAbsPaths:      true,
			TgLogLevel:             "debug",
		}).
		WithTerraformLogOptions(dagger.TerragruntWithTerraformLogOptionsOpts{
			TfLog:     "debug",
			TfLogPath: "/mnt/tflogs", // it's a directory that the terragrunt user owns.
		}).
		// Extra options added for more realism.
		WithTerragruntOptions(dagger.TerragruntWithTerragruntOptionsOpts{
			IgnoreDependencyErrors:     true,
			IgnoreExternalDependencies: true,
			DisableBucketUpdate:        true,
		})

	// Execute the plan command and get the container back.
	tgCtr := tgModule.Exec("plan", dagger.TerragruntExecOpts{
		Source: m.
			getTestDir("").
			Directory("terragrunt"),
		Secrets: []*dagger.Secret{
			dbPasswordSecret,
			apiKeySecret,
			sshKeySecret,
		},
		// Args to output the plan to a file.
		Args: []string{
			"-out=plan.tfplan",
			"-refresh=true",
		},
	})

Testing 🧪

The module includes comprehensive tests covering various aspects of functionality. You can run these tests using:

just test terragrunt

Developer Experience 🛠️

To contribute or modify the module:

1. Use Just for task automation.
2. Utilize Nix for managing the development environment.

Common commands:

just run-hooks           # Initialize pre-commit hooks
just lintall terragrunt  # Run linter
just test terragrunt    # Run tests
just ci terragrunt # Run entire CI tasks locally

APKO Base Image

This module uses APKO to build its base image, ensuring:

• Enhanced security through minimal attack surface
• Optimized container size and performance
• Reproducible and declarative image builds

For more information on APKO, refer to the Chainguard APKO documentation.

For detailed API documentation and more examples, please refer to the source code and test files in the tests/ directory.