initial commit

04-variables-and-outputs/examples/README.md

@@ -0,0 +1,71 @@
+# Variables
+
+## Variable block
+
+must define variable block
+
+```
+variable "var_name" {
+  type = string
+}
+```
+
+## Variable types
+- string
+- number
+- bool
+- list(<TYPE>)
+- set(<TYPE>)
+- map(<TYPE>)
+- object({<ATTR NAME> = <TYPE>, ... })
+- tuple([<TYPE>, ...])
+
+## Variable files
+`variables.tfvars` (or `<FILENAME>.auto.tfvars`) automatically applied 
+
+## Apply default
+`terraform apply`
+
+## Apply a different variable file
+`terraform apply -var-file=another-variable-file.tfvars`
+
+## Passing Variable via Prompt
+If value not specified, Terraform will prompt for value. (this is okay for testing... but don't depend on it since you should be automating things!)
+```
+  var.db_pass
+  password for database
+
+  Enter a value:
+```
+
+## Passing Variables via CLI
+`terraform apply -var="db_pass=$DB_PASS_ENV_VAR"`
+
+# Local Variables
+
+Allows you to store the value of expression for reuse but doesn't allow for passing in values 
+```
+locals {
+  extra_tag = "extra-tag"
+}
+```
+
+# Output Variables
+
+Allows you to output some value  (which might not be known ahead of time).
+
+For example it might be useful to know the IP address of a VM that was created:
+
+```
+output "instance_ip_addr" {
+  value = aws_instance.instance.private_ip
+}
+```
+
+Sample output:
+```
+db_instance_addr = "terraform-20210504182745335900000001.cr2ub9wmsmpg.us-east-1.rds.amazonaws.com"
+instance_ip_addr = "172.31.24.95"
+```
+
+Will be output after `terraform apply` or `terraform output`

04-variables-and-outputs/examples/another-variable-file.tfvars

@@ -0,0 +1 @@
+instance_name = "hello-world-2"

04-variables-and-outputs/examples/main.tf

@@ -0,0 +1,47 @@
+terraform {
+  backend "s3" {
+    bucket         = "devops-directive-tf-state"
+    key            = "04-variables-and-outputs/examples/terraform.tfstate"
+    region         = "us-east-1"
+    dynamodb_table = "terraform-state-locking"
+    encrypt        = true
+  }
+
+  required_providers {
+    aws = {
+      source  = "hashicorp/aws"
+      version = "~> 3.0"
+    }
+  }
+}
+
+provider "aws" {
+  region = "us-east-1"
+}
+
+locals {
+  extra_tag = "extra-tag"
+}
+
+resource "aws_instance" "instance" {
+  ami           = var.ami
+  instance_type = var.instance_type
+
+  tags = {
+    Name     = var.instance_name
+    ExtraTag = local.extra_tag
+  }
+}
+
+resource "aws_db_instance" "db_instance" {
+  allocated_storage   = 20
+  storage_type        = "gp2"
+  engine              = "postgres"
+  engine_version      = "12.4"
+  instance_class      = "db.t2.micro"
+  name                = "mydb"
+  username            = var.db_user
+  password            = var.db_pass
+  skip_final_snapshot = true
+}
+

04-variables-and-outputs/examples/outputs.tf

@@ -0,0 +1,7 @@
+output "instance_ip_addr" {
+  value = aws_instance.instance.private_ip
+}
+
+output "db_instance_addr" {
+  value = aws_db_instance.db_instance.address
+}

04-variables-and-outputs/examples/terraform.tfvars

@@ -0,0 +1,3 @@
+instance_name = "hello-world"
+ami = "ami-011899242bb902164" # Ubuntu 20.04 LTS // us-east-1
+instance_type = "t2.micro"

04-variables-and-outputs/examples/variables.tf

@@ -0,0 +1,30 @@
+# should specify optional vs required
+
+variable "instance_name" {
+  description = "Name of ec2 instance"
+  type        = string
+}
+
+variable "ami" {
+  description = "Amazon machine image to use for ec2 instance"
+  type        = string
+  default     = "ami-011899242bb902164" # Ubuntu 20.04 LTS // us-east-1
+}
+
+variable "instance_type" {
+  description = "ec2 instance type"
+  type        = string
+  default     = "t2.micro"
+}
+
+variable "db_user" {
+  description = "username for database"
+  type        = string
+  default     = "foo"
+}
+
+variable "db_pass" {
+  description = "password for database"
+  type        = string
+  sensitive   = true
+}