Count

複数リソースを立ち上げる時に効率的に記載する

連番ではなくhash keyを使用して、明示的に名前をつける方が、間違いが少なく良い。

locals.tf

locals {
  env_config = {
    develop = {
      instance_type = "t3.small"
      instances     = ["web", "worker"]          # 2個
    }
    production = {
      instance_type = "t3.large"
      instances     = ["web-a", "web-b", "worker-a", "worker-b"]  # 4個
    }
  }

  config = local.env_config[terraform.workspace]
}

ec2.tf

resource "aws_instance" "app" {
  for_each = toset(local.config.instances)

  instance_type = local.config.instance_type
  ami           = "ami-xxxxxxxxxxxxxxxxx"

  tags = {
    Name = "app-${terraform.workspace}-${each.key}"
  }
}

productionのみにリソースを作成する場合

locals.tf

locals {
  is_production = terraform.workspace == "production"
}

aws_cloudwatch_log_group

  count = local.is_production ? 1 : 0
  name  = "/debug/logs"