How to combine aws_subnet.prod_subnet.*.id with aws_subnet.prod2_subnet.*.id into a single list

I am trying to combine all subnets to be able to attach an ACL to them.

I have two subnets that exist which different resource names, so it’s forcing me to have two ACL blocks which I don’t want.

Right now the ACL subnet_id blocks for both ACL blocks read as:

resource "aws_network_acl" "prod_public" {
  vpc_id = aws_vpc.prod.id
  subnet_ids = aws_subnet.prod_public.*.id
}

resource "aws_network_acl" "prod2_public" {
  vpc_id = aws_vpc.prod.id
  subnet_ids = aws_subnet.prod2_public.*.id
}

this works, but I’m want something that will create a list of BOTH set of subnet_ids so I can just have be one block.

I’ve tried something like this, but didn’t work.

resource "aws_network_acl" "prods_public" {
  vpc_id = aws_vpc_prod_id
  subnet_ids = [aws_subnet.prod_public.*.id, aws_subnet.prod2_public.*.id]
}

I also tried using tostring and toset which didn’t work either.

>Solution :

You should use concat:

subnet_ids = concat(aws_subnet.prod_public.*.id, aws_subnet.prod2_public.*.id)