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HCL & Core Workflow · Lesson 7 of 30

HCL Syntax

Source: doonops-curriculum/hcl-core--hcl-syntax.md

Doonops lesson

Goal

Read and write basic HCL blocks without fear.

Simple explanation

HCL is not Python. It is a list of labeled boxes: resource "type" "name" { settings inside }.

Technical view

Blocks: resource, data, variable, output, module, provider. Attributes key = value; types string, number, bool, list, map.

Think of it like

Filling a government form: section title (resource), your name (resource name), fields inside { }.

Steps

  1. Read simple section
  2. Read analogy + diagram
  3. Copy project files
  4. Do local lab

Deep explanation

Layman words first, then technical detail — read slowly

One resource — explained like a form

resource "aws_instance" "doonops_app" {
       │              │            │
       │              │            └── your nickname for this server (only in Terraform)
       │              └── AWS product type (EC2 instance)
       └── keyword: we are CREATING something

  ami           = "ami-xxx"      ← which OS image (like Windows vs Linux DVD)
  instance_type = "t3.micro"     ← size (small / medium machine)
  tags = { Name = "doonops-app" } ← labels for humans
}

Data types (simple)

  • String — text in quotes: "ap-south-1"
  • Number — no quotes: 3
  • List — [ ] multiple values: subnets list
  • Map — { } key-value tags

Terraform HCL mein Python jaisa for i in range() loop resource block ke andar usually nahi likhte — uske liye count / for_each use hota hai (next modules).

Example (Doonops)

Modern HCL — names are examples, not from any third-party course

Example HCL
HCL
resource "aws_instance" "doonops_app" {
  ami           = data.aws_ami.amazon_linux.id
  instance_type = "t3.micro"
  tags = { Name = "doonops-app" }
}

Terraform runs on your computer — copy this HCL into a folder, then follow the local lab steps below.

Check

  • What does resource "aws_instance" "app" mean?
  • String vs number example

Project files for this lab

Full implementation folder — copy all files, then run terraform commands

Lab project files (full folder)

Copy every file below into one folder — same as a real repo module. Then run the local lab steps.

Suggested folder: Suggested path: ~/doonops-terraform/04-hcl-ec2/

versions.tfSee file purpose in the code below
terraform {
  required_version = ">= 1.9.0"
}