Terraform CodePipeline Dynamic Stages and Actions

build_actions.tmpl

${jsonencode([
  {
    "name": "Build",
    "category": "Build",
    "owner": "AWS",
    "provider": "CodeBuild",
    "input_artifacts": ["SourceArtifact"],
    "output_artifacts": ["BuildArtifact"],
    "version": "1",
    "configuration": {
      "keys": ["ProjectName"],
      "values": ["${client}-${stage}-build"]
    }
  }
])}

main.tf

locals {
  build_actions = fileexists("./build_actions.tmpl") ? jsondecode(templatefile("./build_actions.tmpl", { client = var.client, stage = var.stage })) : null
}

resource "aws_codepipeline" "codepipeline" {
  name     = "${var.client}-${var.stage}-codepipeline"
  role_arn = aws_iam_role.codepipeline_role.arn

  dynamic "stage" {
    for_each = fileexists("./build_actions.json") ? [""] : []
    content {
      name = "Build"

      dynamic "action" {
        for_each = local.build_actions
        content {
          name             = action.value.name
          category         = action.value.category
          owner            = action.value.owner
          provider         = action.value.provider
          input_artifacts  = contains(keys(action.value), "input_artifacts") ? action.value.input_artifacts : null
          output_artifacts = contains(keys(action.value), "output_artifacts") ? action.value.output_artifacts : null
          version          = action.value.version
          configuration = zipmap(
            action.value.configuration.keys,
            action.value.configuration.values
          )
        }
      }
    }
  }
}

variables.tf

variable "stage" {
  description = "Environment Stage Name i.e.: ['dev', 'staging', 'prod']"
  type        = string
  default     = "dev"
}

variable "client" {
  description = "Client identifier"
  type        = string
  default     = "xyz"
}