Heroku Auto-Terraform Buildpack

Provides support for running Terraform from your application, including as part of the release process.

Basic Installation

heroku buildpacks:add --index 1 (this URL)

Once installed, this buildpack will check that the root of your project includes at least one Terraform manifest. Your build will fail if no manifests are present in the root of your application.

Automatic Deployment

Automatic deployment is a high-risk configuration. This will automatically apply your Terraform manifests to the environment without prompting. It is strongly recommended that you use this feature in tandem with Heroku Pipelines, or that you manually review and apply plans if you are not comfortable with the possibility of automation-induced downtime. You have been warned.

If you're aware of the risks and still think this is a good idea, click here.

Have you considered what to do if automation destroys your data?

Okay, but I warned you.

Add the following to your `Procfile`:

release: auto-terraform

If you have an existing release script, call auto-terraform from that script.

Configuration

The following config vars can be set with heroku config:set to affect the build-time behaviour of this buildpack:

• TERRAFORM_VERSION: Specify the version of Terraform to install. By default, this will install version 0.11.0.

The following config vars can be set to control the runtime behaviour of this buildpack:

• TERRAFORM_WORKSPACE: Specify the workspace to switch to when automatically running Terraform. This requires that the workspace already exist, which generally requires that your manifests specify an external state store, such as S3.

• TERRAFORM_EXPORT: If set to yes, any top-level outputs in your Terraform manifest will be exported as environment variables in your dynos. This requires a remote state store, and is not enabled by default.

  The terraform-export command generates the necessary shell script to export outputs. Running eval "$(terraform-export)" will simulate TERRAFORM_EXPORT's effects, using the current workspace.

Providing Variables

It's generally a bad idea to commit .tfvars files to source control if you can avoid it. If your manifest requires variables, consider writing a script that generates a .tfvars file from environment variables, or using TF_VAR_* environment variables directly.