variables-more.txt

====== Variables and code in same file
#1 - filename - site.tf

provider "aws" {
	region = "us-east-1"
}

variable "ami" {
	default = "ami-04169656fea786776"
}

variable "instance_type" {
	default = "t2.nano"
}

resource "aws_key_pair" "terraform-demo" {
  key_name   = "terraform-demo"
  public_key = "${file("terraform-demo.pub")}"
}

resource "aws_instance" "my-instance" {
	ami = "${var.ami}"
	instance_type = "${var.instance_type}"
	key_name = "${aws_key_pair.terraform-demo.key_name}"
	user_data = "${file("install_apache.sh")}"
	tags = {
		Name = "Terraform"	
		Batch = "5AM"
	}
}

===== 

==== As project grows, we can put variables and code in separate files

#1 - file for variables - vars.tf

variable "ami" {
	default = "ami-04169656fea786776"
}

variable "instance_type" {
	default = "t2.nano"
}

#2 - file for code - site.tf

provider "aws" {
	region = "us-east-1"
}

resource "aws_key_pair" "terraform-demo" {
  key_name   = "terraform-demo"
  public_key = "${file("terraform-demo.pub")}"
}

resource "aws_instance" "my-instance" {
	ami = "${var.ami}"
	instance_type = "${var.instance_type}"
	key_name = "${aws_key_pair.terraform-demo.key_name}"
	user_data = "${file("install_apache.sh")}"
	tags = {
		Name = "Terraform"	
		Batch = "5AM"
	}
}

#####

#### MAPS - Maps are a way to create variables that are lookup tables.

#1 - file for variables - vars.tf

variable "ami" {
  type    = "map"
  default = {
    "us-east-1" = "ami-04169656fea786776"
    "us-west-1" = "ami-006fce2a9625b177f"
  }
}

variable "instance_type" {
	default = "t2.nano"
}

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

####

#2 - file for code - site.tf

provider "aws" {
	region = "${var.aws_region}"
}

resource "aws_key_pair" "terraform-demo" {
  key_name   = "terraform-demo"
  public_key = "${file("terraform-demo.pub")}"
}

resource "aws_instance" "my-instance" {
	ami = "${lookup(var.ami,var.aws_region)}"
	instance_type = "${var.instance_type}"
	key_name = "${aws_key_pair.terraform-demo.key_name}"
	user_data = "${file("install_apache.sh")}"
	tags = {
		Name = "Terraform"	
		Batch = "5AM"
	}
}


### WE can check the value using "terraform console"
# terraform console
> "${lookup(var.ami,var.aws_region)}"