alphagov/terraform-provider-concourse

Feature - Pipeline template `((variables))` interpolation

dbednall opened this issue · 1 comments

dbednall commented

Thank you for developing and publishing this provider.

requested feature context

Pipeline template variable syntax: https://concourse-ci.org/vars.html#var-syntax

Processes of performing interpolation of variables is handled within fly
https://github.com/concourse/concourse/blob/4189a7ed0b920f1de9d7c468caf40047126383b9/fly/commands/set_pipeline.go#L104

and therefore is missing from this provider, meaning to many/most users the provider cannot act as a drop-in replacement for fly in the trivial usecase and is only suitable where either

❯ fly sp -h
Usage:
✂️
[set-pipeline command options]
✂️
      -v, --var=[NAME=STRING]       Specify a string value to set for a variable in the pipeline
      -l, --load-vars-from=         Variable flag that can be used for filling in template values in configuration from a YAML file
✂️

high-level suggested implementation

Resources affected

  • concourse_pipeline - addition of attribute vars to concourse_pipeline resource.
    • could be map(string) using TF config directly (ex 1) or accept YAML/JSON encoded input similar to pipeline_config attr (ex 2)
resource "concourse_pipeline" "my_pipeline" {
  team_name     = "main"
  pipeline_name = "my-pipeline"

  is_exposed = true
  is_paused  = true

  pipeline_config        = file("pipeline-config.yml")
  pipeline_config_format = "yaml"
  vars = { # 👋 
    "what_day_is_it" = "tuesday",
  }
}

or 2.

resource "concourse_pipeline" "my_pipeline" {
  team_name     = "main"
  pipeline_name = "my-pipeline"

  is_exposed = true
  is_paused  = true

  pipeline_config        = file("pipeline-config.yml")
  pipeline_config_format = "yaml"
  vars                   = file("pipeline-vars.yml") # 👋 
}
  • could consider importing templatehelpers mod or related from fly project to get templating logic for free
MartinSchmidt123 commented

Especially, support for instance vars would be great. However, they are only experimental for now.

Currently, I am doing something like

locals {
  docker_images = {
    debian-11 = {
      image = "debian"
      version = "11"
    }
    alpine-3-14 = {
      image = "alpine"
      version = "3.14"
    }
  }
}
resource "concourse_pipeline" "template_docker" {
  for_each = local.docker_images

  team_name     = data.vault_generic_secret.concourse.data["team"]
  pipeline_name = "docker-${each.key}"

  is_exposed = false
  is_paused  = false

  pipeline_config        = templatefile(format("%s/%s",path.module,"docker-build.yml"),{
    image = each.value.image
    version = each.value.version
  })
  pipeline_config_format = "yaml"
}

It works quite well but you have to use

  • ((variable)) for concourse variables, and
  • ${variable} or "${variable}" for terrraform variables
  • 👍1