Hashicorp Configuration Language

External

• https://www.terraform.io/docs/configuration/index.html

Internal

• Terraform Concepts

Comments

# This is a comment

Block

Terraform Block

terraform {
  required_version = ">= 0.12"
}

Resource Block

Declares a resource.

Module Block

Declares the intent to use a module.

Input Variable

https://www.terraform.io/docs/configuration/variables.html

variable "region" {
  default = "us-east-1"
}

To use the variable:

region= var.region

This is also an interpolation expression, prefixed with “var.”

Variables can be assigned in multiples way, and this is the descending order of precedence:

• command-line flags (-var = ‘region=something’)
• from a file (.tfvars, -var-file=…) terraform.tfvars or *.auto.tfvars in the current directory are automatically loaded. Multiple -var-file can be used.
• From environment variables: TF_VAR_name. This can only be used for string variables.
• UI Input
• Variable defaults (“default” keyword).

Lists

https://learn.hashicorp.com/terraform/getting-started/variables#lists

Maps

https://learn.hashicorp.com/terraform/getting-started/variables#maps

Output Variable

https://www.terraform.io/docs/configuration/outputs.html

https://learn.hashicorp.com/terraform/getting-started/outputs

Output variables are a way to organize data to be easily queried and shown back to the Terraform user. Terraform usually stores hundred or thousands of attribute values, but only a few of those are important. Output variables can be used as an input to other modules.

Also see:

terraform output