how to copy a file after instance launch by auto scaling group

[ghost]

i know its silly to create a another ticket, but seriously i am burning my nights to solve this issue but still did not get any success. for every solution i found on internet it require instance ip to make connection and do some changes.

# Copies the file as the root user using SSH
provisioner "file" {
  source      = "conf/myapp.conf"
  destination = "/etc/myapp.conf"

  connection {
    type     = "ssh"
    user     = "root"
    password = "${var.root_password}"
  }
}