不能在 count 內計算數值
使用情境
count 只能計算已知的數值，對於不存在的數值會有問題，當 apply count 有數值時可以正常運作，而 destroy count 為 0 時就會 fail。
範例
- main.tf
resource "aws_security_group_rule" "ingress_with_source_security_group_id" {
count = "${length(var.web_ingress_source_security_group_id)}"
}
- main.auto.tfvars
web_ingress_source_security_group_id = [
{
rule = "http-80-tcp"
source_security_group_id = "${var.alb_sg_id}"
},
{
rule = "https-443-tcp"
source_security_group_id = "${var.alb_sg_id}"
}
]
問題
aws_security_group_rule.ingress_with_source_security_group_id: value of ‘count’ cannot be computed