04-modules.md

Modules

Modules are first class citizens in terraform. They are easy to write and use and can be referenced from the code but also from git repositories or from https://registry.terraform.io. This part demonstrates how to move from a set of resources into a module:

• create a new stack, here modules/public-network and move all the resources into it.
• remove these same resources from the original terraform directory.
• in the module, for each value that cannot be accessed, directly from it, create a variable, for instance, create a variable for the tenancy and compartment.
• if you want to use other parameter, like naming the module, add additional variables
• if you need the module to provide outputs, like the subnet identifiers, add an output to export them
• in the main project, reference the module with the module directory as as source like below:

module "livecode" {
  tenancy = "${var.tenancy}"
  compartment = "${var.compartment}"
  name = "livecode"
  source = "../modules/public-network"
}

• if you need to access some module output, just reference them by their name like module.livecode.public_subnets in this case.
• to use the module, you should run terraform init again. Once done, you can simply apply or destroy the module.