add terraform

Author: niqdev

.gitignore

@@ -26,3 +26,9 @@ target/
 *.log
 
 site
+
+.terraform/
+*.tfstate
+*.tfplan
+plan.out
+*.tfvars

docs/terraform.md

@@ -0,0 +1,60 @@
+# Terraform
+
+> **Terraform** is an infrastructure as code tool that lets you build, change, and version infrastructure safely and efficiently
+
+Resources
+
+* [Terraform in Action](https://www.manning.com/books/terraform-in-action)
+* [Documentation](https://developer.hashicorp.com/terraform)
+* [Terraform Registry](https://registry.terraform.io)
+
+Setup
+```sh
+brew tap hashicorp/tap
+brew install hashicorp/tap/terraform
+
+terraform version
+```
+
+Terraform's core building blocks:
+
+* `terraform` Terraform's own settings (required version, providers, backend/state config)
+* `provider` tells Terraform which cloud/API to talk to and how to authenticate
+* `resource` something Terraform creates/updates/deletes e.g. VM, subnet, bucket
+* `data` something Terraform reads only (already exists)
+* `variable` input values for your config (like function arguments)
+* `locals` internal named values/calculations to avoid repeating logic
+* `output` values Terraform prints after apply (and exposes to parent modules)
+* `module` reusable Terraform package/folder you call from another config
+
+Examples
+```sh
+# formatting/linting
+terraform fmt -check 
+
+# initializing a configuration directory downloads and installs the providers defined in the configuration
+cd terraform/docker-example
+terraform init
+
+# validatiom
+terraform validate
+# dry run
+terraform plan
+
+# with rancher desktop
+terraform plan -var="docker_host=unix:///${HOME}/.rd/docker.sock"
+# apply with "TF_VAR_<name>" convention
+TF_VAR_docker_host="unix:///${HOME}/.rd/docker.sock" terraform apply -auto-approve
+
+# verify state
+terraform show
+terraform state list
+
+# http://localhost:8080
+terraform output -json
+
+# controlled/appoved deployments (binary format)
+terraform plan -out=plan.out
+terraform show -json plan.out
+terraform apply plan.out
+```

terraform/docker-example/.terraform.lock.hcl

@@ -0,0 +1,6 @@
+locals {
+  image_name     = "nginx:latest"
+  container_name = "my-nginx"
+  container_port = 80
+  host_port      = 8080
+}

terraform/docker-example/locals.tf

@@ -0,0 +1,47 @@
+terraform {
+  required_providers {
+    # https://github.com/kreuzwerker/terraform-provider-docker
+    # https://registry.terraform.io/providers/kreuzwerker/docker/latest/docs
+    docker = {
+      # shorthand for "registry.terraform.io/kreuzwerker/docker"
+      source  = "kreuzwerker/docker"
+      version = "~> 3.0.1"
+    }
+  }
+}
+
+provider "docker" {
+  host = var.docker_host
+}
+
+# resource <type> <name> defines components of the infrastructure
+# the prefix of the type maps to the name of the provider i.e. "docker_"
+# resource <type> and <name> form a unique ID i.e. "docker_image.nginx"
+resource "docker_image" "nginx" {
+  # arguments
+  name         = local.image_name
+  keep_locally = false
+}
+
+resource "docker_container" "my-nginx" {
+  image = docker_image.nginx.image_id
+  name  = local.container_name
+  ports {
+    internal = local.container_port
+    external = local.host_port
+  }
+}
+
+output "port_message" {
+  description = "host/container port mapping"
+  value       = "Exposed port: ${local.host_port} -> ${local.container_port}"
+}
+
+output "container_info" {
+  value = {
+    container_id   = docker_container.my-nginx.id
+    container_name = docker_container.my-nginx.name
+    image_id       = docker_image.nginx.image_id
+    image_name     = docker_image.nginx.image_id
+  }
+}

terraform/docker-example/main.tf

@@ -0,0 +1,5 @@
+variable "docker_host" {
+  description = "Docker daemon socket/endpoint"
+  type        = string
+  default     = "unix:///var/run/docker.sock"
+}