terraform-provider-enos

terraform-provider-enos

A terraform provider that provides resouces for powering Software Quality as Code by writing Terraform-based quality requirement scenarios using a composable, modular, and declarative language.

It is intended to be use in conjunction with the Enos CLI and provide the resources necessary to use Terraform as Enos's execution engine.

• Installing the provider
  • Requirements
  • From the Terraform registry
• Developing the provider
  • Build from source
    • Flight control
      • Commands
        • Download
        • Unzip
    • Remote flight
  • Creating new sources
  • Releasing a new version

Installing the provider

Requirements

• Terraform >= 1.2.0

From the Terraform registry

Install the released version of the provider from the Terraform registry by following the instructions in the Terraform Registry

terraform {
  required_providers {
    enos = {
      source = "hashicorp-forge/enos"
    }
  }
}

provider "enos" {
  # ...
}

Developing the provider

Requirements

• Terraform >= 1.2.0
• Go >= 1.22

Build from source

For local development, first you will need to build flight-control.

• If you're not on macOS, make sure upx installed with your package manager. We use macOS to pack some embedded flight-control binaries. We don't need this on macOS because upx has been removed from Homebrew while they sort out macOS code signing shenanigans.

• Run make flight-control install in the root of this repository. This will build and pack the enos-flight-control binaries, build a new terraform-provider-enos binary and install it into your local Terraform provider cache.

Flight control

Enos resources that take require a transport attribute to be configured work by executing remote commands on a target resources. Often it's resonably safe to assume that the remote target will provide some common POSIX commands for common tasks, however, there are some targets or operations where there is no common POSIX utility we can rely on, such as making remote HTTP requests, unziping archives, or executing against a minimal container. While utilities that can provide those functions might be accessible via a package manager of some sort, installing global utlities and dealing with platform specific package managers can become a serious burden.

Rather than cargo cult brittle and complex script to manage various package managers, our solution to this problem is to bundle common operations into a binary called enos-flight-control. As part of our build pipeline we build this utility for every platform and architecture that we support and embed it into the Terraform plugin. During runtime the provider resources can install it on the remote targets and then call into it when we need advanced operations.

Commands

Download

The download command downloads a file from a given URL and verify the content SHA and send HTTP requests. It's sort of a Kirkland Signature version of curl or wget.

enos-flight-control download --url https://some/remote/file.txt --destination /local/path/file.txt --mode 0755 --timeout 5m --sha256 02b3...

Flags

• auth-user The username to use for basic auth|
• auth-password The password to use for basic auth|
• destination The destination location where the file will be written|
• exit-with-status-code On failure, exit with the HTTP status code returned. Note that status codes over 256 are not supported|
• mode The desired file permissions of the downloaded file|
• replace Replace the destination file if it exists|
• sha256 The expected SHA256 sum of the file to be downloaded. When provided we'll assert that the resulting file matches the SHA or will raise an error|
• stdout Write the output to stdout|
• timeout The maximum allowable time for the download operation|
• url The URL of the remote resource to download|

NOTE one of --destination or --stdout is required.

Unzip

The unzip command unzips a zip archive.

enos-flight-control unzip --source /some/file.zip --destination /some/directory --create true

Flags

• source The path to the source Zip archive|
• destination The destination directory where the expanded files will be written|
• mode The desired file permissions of the expanded archive files|
• create-destination Whether or not create the destination directory if does not exist|
• destination-mode The file mode for the destination directory if it is to be created|
• replace Replace any existing destination file if they already exist|

Remote flight

The remoteflight package is a library where many common operations that need to be performed over a transport are located. The include installing enos-flight-control on a target machines.

Releasing a new version

Triggering a new release requires executing the release workflow and providing the Git SHA you wish to release. It will automatically use the version present on that SHA as the release tag. The version at that SHA must not already exist as a tag.