tf-ec2-var-secret.tf

data "aws_secretsmanager_secret" "my_secret" {
  name = "my_secret_name"
}

data "aws_secretsmanager_secret_version" "global_secret_version" {
  secret_id = "${data.aws_secretsmanager_secret.my_secret.id}"
}
variable volume_size {
  default = null
}

resource "aws_instance" "web" {
  ami           = "AL2_x86_64"
  instance_type = "t2.micro"
  root_block_device {
    ### If volume_size variable is set (not null) - take the value from there, else (if null, which is default) - take value from secrets manager data.
     volume_size = ${var.volume_size != null ? var.volume_size : jsonencode(data.aws_secretsmanager_secret_version.global_secret_version.secret_string)["volume_size"]}
  }
}