terraform iterate to associate aws resources

I try to create nat gateway on terraform, on each public subnets that I created.

I create the public subntes like that:

resource "aws_subnet" "public_subnet" {
  count = length(var.vpc.public_subnets)

  vpc_id            = aws_vpc.vpc.id
  availability_zone = var.vpc.public_subnets[count.index].availability_zone
  cidr_block        = var.vpc.public_subnets[count.index].cidr_block
  tags              = var.vpc.public_subnets[count.index].tags
}

I create all elastic ip like that:

resource "aws_eip" "eip" {
  for_each = { for eip in var.vpc.eip : eip.name => eip }

  vpc  = true
  tags = each.value.tags
}

And finally I have a resource block to create 3 nat gateways. Each nat gateway have to use a subnet and an eip:

resource "aws_nat_gateway" "ngw" {
  count = length(var.vpc.public_subnets)

  allocation_id = element(aws_eip.eip.*.allocation_id, count.index)
  subnet_id     = element(aws_subnet.public_subnet.*.id, count.index)
}

results ==> This object does not have an attribute named "allocation_id"

How should I iterate over 2 resources to create the nat gateay for each pair of subnet/eip ?

thanks.

Since you are using for_each for eip it will be a map, not a list. Thus to access its values you can use values:

allocation_id = element(values(aws_eip.eip)[*].allocation_id, count.index)