Referencing count created resources from another module in map array

[jaekunchoi]

Terraform Version

0.12.26

Terraform Configuration Files

Modules in path ./ecs/ecs-service/*.tf

resource "aws_lb_target_group" "app" {
  count = length(var.target_groups)
  name = "test-${var.env}"
  port = var.target_groups[count.index].app_port
  protocol = "HTTP"
  vpc_id = var.vpc_id
  ...
}

output "app_target_group_arns" {
  value = aws_lb_target_group.app.*.arn
}

parent module ./ecs

module "ecs-service" {
  source = "./ecs-service"
  ...
}

module "alb" {
  source = "./ecs/alb"
  rules = [
    {
      priority : 100,
      target_group_arn : element(module.ecs-service.app_target_group_arns, 0),
      condition_field : "host-header",
      condition_values : [element(module.alb.alb_record_fqdn, 0)]
    },
    {
      priority : 101,
      target_group_arn : element(module.ecs-service.app_target_group_arns, 1),
      condition_field : "host-header",
      condition_values : [element(module.alb.alb_record_fqdn, 1)]
    }
  ]
}

Debug Output

Call to function "element" failed: cannot use element function with an empty list

Expected Behavior

module ecs-service targetgroup should wait until alb rules are deleted first so alb module doesn't reference elements that does not exist.

Actual Behavior

errors with Call to function "element" failed: cannot use element function with an empty list

Steps to Reproduce

run terraform destroy with above config

References

#11210

[danieldreier]

@apparentlymart I think that this is basically an instance of #25162 ("non-obvious ordering of functions and resources") - does it look that way to you?

[jbardin]

This looks like the result of the variable values being evaluated during destroy, which should be one of the situations fixed in 0.13.

@hybmg57 There's not enough information here for me to reproduce the issue, but if you have the ability to test with the latest 0.13 beta, we can see if my hunch is correct and this is fixed already.

[mildwonkey]

I am going to close this issue due to inactivity.

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Thanks!

[ghost]

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