CODEWITHSUNDEEP
terraform
user971741
user971741

Reputation:

Providing variables values to a module while calling it

I have a followed directory structure:

|   main.tf
|   module.tf
|   terraform.tf
|   terraform.tfvars

\---modules
    \---org_bd
        \---resource
                resource.tf
                providers.tf

The module/org_bd/resrouce/provider.tf contains:

provider "boundary" {
  api_key = var.api_key
  app_key = var.app_key
}

And these values are declared and defined inside ./terraform.tf and ./terraform.tfvars: However, while trying to plan or validate it gives following error:

Error: Reference to undeclared input variable

  on modules\org_bd\resrouce\providers.tf line 13, in provider " boundary":
  13:   api_key = var.api_key

An input variable with the name "api_key" has not been declared. This variable
can be declared with a variable "api_key" {} block.

As I understand, this is happening because the variable used inside the module are defined outside of it. But I believe its possible that you can provide values from outside to a module while calling it?

Upvotes: 1

Views: 1664

Answers (1)

Software Engineer
Software Engineer

Reputation: 16100

Passing variables to modules is done at the point of invocation. For example (from a project I currently have open:

module "workers" {
  source              = "./modules/workers"
  depends_on          = [module.vpc.dns_record]
  vpc                 = module.vpc.vpc
  az                  = module.vpc.az
  zone                = module.vpc.zone
  bastion_sg_id       = module.bastion.bastion_sg_id
  control_plane_sg_id = module.control_plane.control_plane_sg_id

  name             = var.name
  owner            = var.owner
  project          = var.project
  env              = var.env
  workspace        = var.workspace
  key_name         = var.key_name
  public_key_path  = var.public_key_path
  private_key_path = var.private_key_path
  instance_type    = var.worker_type
  aws_region       = var.region
}

Apart from source and depends_on, which are built-in properties, on the left of the assignments are the input property names and on the right are the values.

Input variables are declared within the module in a file named something like variables.tf, though, in my modules I call this input.tf because the name is arbitrary and I think that input is more meaningful and matches the common output.tf that declares output properties.

This example also shows how to use the output of modules. These are normally declared in a file named output.tf (or something like that). Also shown is the use of variables at this level, they are declared in my top-level input.tf and I've provided values in variables.auto.tfvars, which is a special filename recognised by terraform that is automatically loaded without having to specify a var-file option on the command-line.

Upvotes: 2

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