terraform-provider-hydra

The Terraform Hydra provider is a plugin for Terraform that allows for declarative management of a Hydra instance. You can find it on the Terraform Registry.

Requirements

To use this provider, you will need the following:

• Terraform 0.13+
• A Hydra instance running commit 5b6b826 or later

NOTE: You can use this provider with commit 6e53767 (at the absolute earliest), but it has a known issue where some internal fields were not nullified, leading to state differences between Hydra and Terraform, and is not recommended.

Getting started

To get started with this provider, you'll need to create a configuration file that will tell Terraform to use this provider. This will look something like the following snippet:

terraform {
  required_providers {
    hydra = {
      version = "~> 0.1"
      source  = "DeterminateSystems/hydra"
    }
  }
}

After that's done, you'll need to specify where your Hydra instance can be reached and provide credentials for this provider to be able to work its magic:

NOTE: Hard-coded credentials are not recommended, so while it is possible to use them (just uncomment the username and password items and fill them in with valid values), you are urged to use the HYDRA_USERNAME and HYDRA_PASSWORD environment variables.

provider "hydra" {
  host = "https://hydra.example.com"
  # username = "alice"
  # password = "foobar"
}

Now that you can connect to Hydra, it's time to create a project with the hydra_project resource:

resource "hydra_project" "nixpkgs" {
  name         = "nixpkgs"
  display_name = "Nixpkgs"
  description  = "Nix Packages collection"
  homepage     = "https://nixos.org/nixpkgs"
  owner        = "alice"
  enabled      = true
  visible      = true
}

You can attach a jobset to this project with the hydra_jobset resource:

NOTE: The check_interval is 0 for this example to prevent Hydra from starting an evaluation on the entirety of Nixpkgs. Change this to a non-zero value if you would like to tell Hydra it can start evaluating this jobset.

resource "hydra_jobset" "trunk-flake" {
  project     = hydra_project.nixpkgs.name
  state       = "enabled"
  visible     = true
  name        = "trunk-flake"
  type        = "flake"
  description = "master branch"

  flake_uri = "github:NixOS/nixpkgs/master"

  check_interval    = 0
  scheduling_shares = 3000
  keep_evaluations  = 3

  email_notifications = true
  email_override      = "[email protected]"
}

That's it for the basic usage of this provider!

You may also want to check out the example configurations inside the examples/ directory.

Importing from an existing Hydra instance

You can migrate from a hand-configured Hydra to Terraform-managed configuration files using our included generator, ./tools/generator.sh.

The generator enumerates the server's projects and jobsets, generating a .tf file for each project. The generator also produces a script of terraform import commands.

The workflow is:

1. Execute generator.sh
2. Commit the generated .tf files to your repository
3. Execute the generated terraform import script
4. Discard the terraform import script, as it should not be necessary anymore

Your Terraform network and state file will now have up-to-date data for all of your existing project and jobset resources, and a terraform plan should report no differences were detected.

$ cd tools
$ nix-shell
# Usage: generator.sh <server-root> <out-dir> <import-file>
#
#     Arguments:
#         <server-root>    The root of the Hydra server to import projects and jobsets from.
#         <out-dir>        The directory to output generated Terraform configuration files to.
#         <import-file>    Where to write the generated list of 'terraform import' statements.
nix-shell$ ./generator.sh hydra.example.com outdir generated-tf-import.sh

Development

In addition to the dependencies for using this provider, hacking on this provider also requires the following:

• Go 1.15+
• oapi-codegen

Running locally

This assumes a running instance of Hydra is available.

$ nix-shell
nix-shell$ make install
nix-shell$ cd examples/default
nix-shell$ terraform init && terraform plan

Regenerating API bindings

This will fetch the latest hydra-api.yaml from Hydra and generate API bindings against that specification.

$ nix-shell
nix-shell$ make api

Running acceptance tests locally

NOTE: You should use a throwaway Hydra instance to prevent anything unexpected happening.

$ nix-shell
nix-shell$ HYDRA_HOST=http://0.0.0.0:63333 HYDRA_USERNAME=alice HYDRA_PASSWORD=foobar make testacc

Contributing

Pull requests are welcome. When submitting one, please follow the checklist in the template to ensure everything works properly.

The typical contribution workflow is as follows:

1. Make your change
2. Format it with make fmt (requires goimports)
3. Verify it builds with make build
4. Install it with make install
5. Spin up a local Hydra server to test with (see the Hydra documentation on Executing Hydra During Development)
6. Extend one of the examples so that it will exercise your change (or write your own example!)
7. Remove the .terraform.lock.hcl file (if it exists) and run terraform init && terraform apply
8. Once everything looks good, write a test for your change
9. Commit and open a pull request (be sure to follow the checklist in the template)

FAQ

Q. Does this provider support Basic Authentication?

A. Yes! Just set the HYDRA_HOST environment variable to e.g. https://user:[email protected]. You can also set the host in your configuration to this, but hard-coded credentials are insecure and not recommended.

License

MPL-2.0