Organization and Modules

Modules

Modules are containers for multiple resources that are used together.

• Consists of a collection of .tf and/or .tf.json files kept together in a directory.
• The main way to package and reuse resource configurations with Terraform.

Types of Modules Root Module: Default module containing all .tf files in the main working directory. Child Module: A separate external module referred to from a .tf file.

Module Sources:

• Local Path

module "web-app" {
    source = "../web-app"
}

• Terraform registry

module "consul" {
    source  = "hashicorp/consul/aws"
    version = "0.1.0
}

• GitHub, Generic Git

# HTTPS
module "example" {
    source = "github.com/hashicorp/your_repo"
}

# SSH
module "example" {
    source = "git@github.com:hashicorp/your_repo.git"
}

Inputs + Meta-Arguments

• Input variables are passed in via module block.

module "web_app" {
    source = "../web-app-module"

    # Input Variables
    domain  = "justinklein.ca"
    db_name = "mydb"
    db_user = "mysql"
    db_pass = var.db_pass
}

What Makes a Good Module?

• Raises the abstraction level from base resource types.
• Groups resources in a logical fashion.
• Exposes input variables to allow necessary customization + composition.
• Provides useful defaults.
• Returns outputs to make further integrations possible.