Getting EC2 Windows Password from instances when using Terraform - terraform

Question

I'm struggling to get the password from a couple of new ec2 instances when using terraform. Been reading up through a couple of posts and thought i had it but not getting anywhere.
Here's my config:
resource "aws_instance" "example" {
ami = "ami-06f9d25508c9681c3"
count = "2"
instance_type = "t2.small"
key_name = "mykey"
vpc_security_group_ids =["sg-98d190fc","sg-0399f246d12812edb"]
get_password_data = "true"
}
output "public_ip" {
value = "${aws_instance.example.*.public_ip}"
}
output "public_dns" {
value = "${aws_instance.example.*.public_dns}"
}
output "Administrator_Password" {
value = "${rsadecrypt(aws_instance.example.*.password_data,
file("mykey.pem"))}"
}
Managed to clear up all the syntax errors but now when running get the following error:
PS C:\tf> terraform apply
aws_instance.example[0]: Refreshing state... (ID: i-0e087e3610a8ff56d)
aws_instance.example[1]: Refreshing state... (ID: i-09557bc1e0cb09c67)
Error: Error refreshing state: 1 error(s) occurred:
* output.Administrator_Password: At column 3, line 1: rsadecrypt: argument 1
should be type string, got type list in:
${rsadecrypt(aws_instance.example.*.password_data, file("mykey.pem"))}

Answer 1

This error is returned because aws_instance.example.*.password_data is a list of the password_data results from each of the EC2 instances. Each one must be decrypted separately with rsadecrypt.
To do this in Terraform v0.11 requires using null_resource as a workaround to achieve a "for each" operation:
resource "aws_instance" "example" {
count = 2
ami = "ami-06f9d25508c9681c3"
instance_type = "t2.small"
key_name = "mykey"
vpc_security_group_ids = ["sg-98d190fc","sg-0399f246d12812edb"]
get_password_data = true
}
resource "null_resource" "example" {
count = 2
triggers = {
password = "${rsadecrypt(aws_instance.example.*.password_data[count.index], file("mykey.pem"))}"
}
}
output "Administrator_Password" {
value = "${null_resource.example.*.triggers.password}"
}
From Terraform v0.12.0 onwards, this can be simplified using the new for expression construct:
resource "aws_instance" "example" {
count = 2
ami = "ami-06f9d25508c9681c3"
instance_type = "t2.small"
key_name = "mykey"
vpc_security_group_ids = ["sg-98d190fc","sg-0399f246d12812edb"]
get_password_data = true
}
output "Administrator_Password" {
value = [
for i in aws_instance.example : rsadecrypt(i.password_data, file("mykey.pem"))
]
}