Terraform modules
From wikinotes
A terraform module is a collection of *.tf
files within a specific directory.
A root module is defined at the root of your project.
Input Variables
Basics
Input variables expose optional configuration to the commandline interface.
They are defined in the root module, withinvariable
blocks.variable "image_id" { type = string } variable "availability_zone_names" { type = list(string) default = ["us-west-1a"] }Modify variables on CLI
terraform apply -var="image_id=foobar"Validation
You can assign validators to input variables.
variable "image_id" { type = string description = "The id of the machine image (AMI) to use for the server." validation { condition = length(var.image_id) > 4 && substr(var.image_id, 0, 4) == "ami-" error_message = "The image_id value must be a valid AMI id, starting with \"ami-\"." } }