Terraform attaching existing managed policy to a new role

terraform_attach_manged_role.tf

### New role creation
### Here assume_role_policy MUST be defined for the trust relationship

resource "aws_iam_role" "codedeploy_service_role" {
  name = "CodeDeployServiceRole"
  assume_role_policy = <<EOF
{
 "Version": "2012-10-17",
 "Statement": [
   {
     "Action": "sts:AssumeRole",
     "Principal": {
       "Service": "ec2.amazonaws.com"
     },
     "Effect": "Allow",
     "Sid": ""
   }
 ]
}
EOF
}

### AWS policy ARN for existing service role

data "aws_iam_policy" "codedeploy_service_policy" {
  arn = "arn:aws:iam::aws:policy/service-role/AWSCodeDeployRole"
}


### Policy attachment

resource "aws_iam_role_policy_attachment" "codedeploy_service_role_policy_attach" {
   role       = "${aws_iam_role.codedeploy_service_role.name}"
   policy_arn = "${data.aws_iam_policy.codedeploy_service_policy.arn}"
}