In an attempt to create a route key named $disconnect for an API Gateway, I'm running the snippet below, while var.route_name should receive the string "disconnect":
resource "aws_apigatewayv2_route" "route" {
api_id = var.apigw_api.id
route_key = "$${var.route_name}"
# more stuff...
}
But it's not escaping it correctly. I coulnd't find a proper way to emit a $, followed by var.route_name's content.
How to do that?
In Terraform's template language, the sequence $${ is the escape sequence for literal ${, and so unfortunately in your example Terraform will understand $${var.route_name} as literally ${var.route_name}, and not as a string interpolation at all.
To avoid this, you can use any strategy that causes the initial $ to be separate from the following ${, so that Terraform will understand the first $ as a literal and the remainder as an interpolation sequence.
One way to do that would be to present that initial literal $ via an interpolation sequence itself:
"${"$"}${var.route_name}"
The above uses an interpolation sequence that would typically be redundant -- its value is a literal string itself -- but in this case it's grammatically useful to change Terraform's interpretation of that initial dollar sign.
Some other permutations:
join("", ["$", var.route_name])
format("$%s", var.route_name)
locals {
dollar = "$"
}
resource "aws_apigatewayv2_route" "route" {
route_key = "${local.dollar}${var.route_name}"
# ...
}
Again, all of these are just serving to present the literal $ in various ways that avoid it being followed by either { or ${ and thus avoid Terraform's parser treating it as a template sequence or template escape.