Terraform aws cloudfront distribution with multiple origins

Question

So, I am trying to create mutiple origins based on a list to my terraform module

What I am trying to do is the following:

resource "aws_cloudfront_distribution" "photos" {

  origin {
      for_each = { for redirection in var.redirections : redirection.origin_id => redirection }
    domain_name              = each.value.origin 
    origin_access_control_id = each.value.origin_id 
    origin_id                = each.value.origin_id
  }
#... rest of terraform resource code
}

I know that It alows me to add more than one origin like the following:

resource "aws_cloudfront_distribution" "photos" {

  origin {
    domain_name              = "orig1" 
    origin_access_control_id = "origin1.com"
    origin_id                = "origi1"
  }

  origin {
    domain_name              = "orig2" 
    origin_access_control_id = "origin2.com"
    origin_id                = "origi2"
  }

However, with this pattern I can't send this as variables to iterate

is there any way to iterate over an array on a terraform subfield only? I tried to put the for each under aws_cloudfront_distribution resource, but that creates a cloudfront distribution for each element in the array, which isn't what I want.

Answer 1

You can use a dynamic block, documented here.

resource "aws_cloudfront_distribution" "photos" {
  dynamic "origin" {
    for_each = { for redirection in var.redirections : redirection.origin_id => redirection }
    content {
        domain_name              = each.value.origin 
        origin_access_control_id = each.value.origin_id 
        origin_id                = each.value.origin_id
    }
  }
  #... rest of terraform resource code
}

(this can be likely simplified to just for_each = toset(var.redirections), since you don't use a key and cannot refer to these origin blocks from outside, so the actual key value is of no particular interest for you, and order does not matter here anyway)