How to join terraform subnet variable-CodePudding

variable.tf

variable  "private_subnets" {
    type    = list
    default = ["subnet-abc1,subnet-abc2"]
}

main.tf

resource "aws_db_subnet_group" "rds_subnet_group" {
    name       = var.cluster_name
    subnet_ids = "${var.private_subnets}"

    tags = {
        Name        = var.cluster_name,
        environment = var.environment
    }
}

This the present code i want use varable.tf for subnet this is way i want achive like this subnet-abc1,subnet-abc2

CodePudding user response：

Considering that your variable has a wrongly defined default value, the first thing to fix is that:

variable  "private_subnets" {
    type    = list(string)
    default = ["subnet-abc1", "subnet-abc2"]
}

The way you are currently defining the default value, i.e, ["subnet-abc1,subnet-abc2"], is a list, however, it is a list with one element. Each element in a list of strings needs to start and end with double quotes, i.e. "some value". You can read more about lists in [1].

Then, you would just need to fix the code in the main.tf to look like this:

resource "aws_db_subnet_group" "rds_subnet_group" {
    name       = var.cluster_name
    subnet_ids = var.private_subnets

    tags = {
        Name        = var.cluster_name,
        environment = var.environment
    }
}

The syntax for subnets in the main.tf file is the old terraform syntax, so this will work without double quotes and ${}.

[1] https://developer.hashicorp.com/terraform/language/expressions/types#list

CodePudding user response：

i have sort issue with split this is the answer

variable.tf

variable  "private_subnets" {
    default = "subnet-abc1,subnet-abc2"
}
main.tf
resource "aws_db_subnet_group" "rds_subnet_group" {
    name       = var.cluster_name
    subnet_ids = "${split(",", var.private_subnets)}"

    tags = {
        Name        = var.cluster_name,
        environment = var.environment
    }