Variable Validation in Terraform

terraform-validation.tf

## Service Plan Variable
variable "service_plan_sku_name" {
  type        = string
  description = "The SKU for the plan. Possible values include EP1, EP2 and EP3."

  validation {
    condition = contains(["EP1", "EP2", "EP3"], var.service_plan_sku_name)
    error_message = "Valid values for the service_plan_sku_name variable are EP1, EP2, EP3"
  }
}