I am trying to add custom validation for variables in my terraform script using map but i am facing error - variables

Question

I am trying to add custom validation for the variables in my terraform script for S3 bucket. But i am facing an error that is mentioned as below:
Reference to undeclared input variable
on main.tf line 2, in resource "aws_s3_bucket" "gouth_bucket_1_apr_2021":
2: bucket = var.bucket #"terraform-s3-bucket"
An input variable with the name "bucket" has not been declared. This variable
can be declared with a variable "bucket" {} block."
Can anyone help me on the same.please let me know which file needs the necessary changes and how.
Thanks in Advance
Below is my code :
main.tf :
resource "aws_s3_bucket" "gouth_bucket_1_apr_2021" {
bucket = var.bucket
acl = "private"
tags= var.tags
}
s3.tfvars :
bucket = "first-bucket-gouth"
#Variables of Tags
tags= {
name = "s3bucket",
account_id = "1234567",
owner = "abc#def.com",
os= "windows",
backup = "N",
application = "abc",
description = "s3 bucket",
env = "dev",
ticketid = "101",
marketami = "NA",
patching = "NA",
dc = "bangalore"
}
validation.tf :
variable "tags" {
type = map(string)
validation {
condition = length(var.tags["env"]) > 0
error_message = "Environment tag is required !!"
}
validation {
condition = length(var.tags["owner"]) > 0
error_message = "Owner tag is required !!"
}
validation {
condition = length(var.tags["dc"]) > 0
error_message = "DC tag is required !!"
}
validation {
condition = can(var.tags["account_id"])
error_message = "Acoount ID tag is required!!"
}
}

Answer 1

I can see two potential issues.
You are referencing var.bucket in your resource, but you are not defining a variable for it anywhere in your definition. This could simply look like:
variable "bucket" {}
You may not be picking up your tfvars file, if you are running Terraform with the tfvars file as an option like so terraform plan -var-file=s3.tfvars then thats ok, or you can rename your tfvars file to something.auto.tfvars or terraform.tfvars to get automatically used. (See > https://www.terraform.io/docs/language/values/variables.html#variable-definitions-tfvars-files)
I hope this answers your question.