aws_elb - Name Requirements affect variable interpolation names

[packplusplus]

Related to #2580

AWS ELBs have a naming requirement which prevents chars like _'s. That is all well and good, but the terraform syntax parser (0.6.3) applies the same logic to the variable names and the interpolated value. It's my opinion the parser shouldn't care what the variable/interpolated thing is called, only it's value.

Example:

resource "aws_elb" "es_elb" {
  name = "es-elb"
  internal = true
  subnets = ["${aws_subnet.private.*.id}"]

  listener {
    instance_port = 9200
    instance_protocol = "http"
    lb_port = 9200
    lb_protocol = "http"
  }

  health_check {
    healthy_threshold = 2
    unhealthy_threshold = 4
    timeout = 5
    target = "HTTP:9200/"
    interval = 10
  }
}

resource "aws_autoscaling_group" "elasticsearch" {
  availability_zones = ["${aws_subnet.private.*.availability_zone}"]
  vpc_zone_identifier = ["${aws_subnet.private.*.id}"]
  name = "elasticsearch_as-${var.tier}"

  max_size = 10
  min_size = 2
  health_check_grace_period = 300
  health_check_type = "EC2"
  desired_capacity = 5
  force_delete = true
  termination_policies = ["OldestLaunchConfiguration", "OldestInstance"]
  launch_configuration = "${aws_launch_configuration.es_as_conf.name}"
  load_balancers = ["${aws_elb.es_elb.name}"]
#snip

Tosses

Errors:

  * aws_elb.es_elb: only alphanumeric characters and hyphens allowed in "name"

Short term fix is sed 's/es_elb/es-elb/g', just weird because all my other variables have _'s in them.

Terraform does inspect the value in ${aws_elb.es_elb.name}, and throws an error if theres an underscore, so that's good.

[packplusplus]

I was testing this incorrectly, terraform does the right thing.

[ghost]

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