= Terraform, variables, interpolation and networking
== variables
  * tipos nativos: strings, maps (key=value), list ([])
    * boolean no es nativo
  * localización:
    * en el cuerpo de script
    * por línea de comando o entono
    * en un fichero adicional de variables
    * más información: [[tech:terraform:variables|]]
  * <code properties>variable "nombre_variable" {
  default = "valor por defecto"
}

variable "localizaciones" {
  type = map
  default = {
    location1 = "xxxx"
    location2 = "yyyy"
  }
}</code>
  * testeando variables y su uso:<code properties>
variable "server_name" {
    default = "web-server"
}

variable "locations" {
    type = "map"
    default = {
        location1 = "xxx"
        location2 = "yyy"
    }
}

variable "subnets" {
    type = "list"
    default = ["10.0.1.10","10.0.1.11"]
}

variable "live" {
  type = "string"
  default = true
}
</code>
    * ''terraform console''
      * var.server_name
      * var.locations["location1"]
      * var.locations.location1
      * var.subnets[0]
      * var.live

== credentials
  * uso variables [de entorno] para almacenar credenciales
  * **TF_VAR_<NOMBRE>** definida como variable de entorno del sistema

== interpolation
  * variables
    * ''var.<nombre>''
  * resources
    * ''<resource>.<nombre>.<atributo>''
  * data: recoger un dato del estado
    * ''data.<resource>.<nombre>.<atributo>''
  * <code properties>variable "subscription_id" {
  
}

#suponiendo que está en el entorno
provider "azurerm" {
    version         = ">=1.27"
    client_id       = "6c609608-a350-476f-85ff-eaff7e82f981"
    client_secret   = "qW0S]tToc]=]ub8HM7yciLSnwOWh1emD"
    tenant_id       = "c8537169-fe81-494a-a2dd-b4ea067073a1"
    subscription_id = var.subscription_id
    features {}
}</code>

== azure locations
  * [[https://azure.microsoft.com/en-us/global-infrastructure/regions/]]
  * [[https://azure.microsoft.com/en-us/global-infrastructure/geographies/]]
  * [[https://azure.microsoft.com/en-us/global-infrastructure/services/]]
  * ''az login --service-principal -u $TF_VAR_client_id -p $TF_VAR_client_secret -t $TF_VAR_tenant_id''
  * ''az account list-locations -o table''
  * ''az login [--username | -u] <username> [--password | -p ] <password>''

== azure resource groups
  * agrupación lógica de recursos bajo tu criterio
  * cada **resource* ha de ir en **resource group**
  * <code properies; terraform.tfvars>
web_server_location = "westus2"
web_server_rg = "web-rg"
</code>
<code properties; main.tf>
variable web_server_location {}
variable web_server_rg {}

resource "azurerm_resource_group" "web_server_rg" {
  name = var.web_server_rg
  location = var.web_server_location
}
</code>

== azure VNET
  * logical isolates network
  * espacio IP
  * creació de subnets
  * conexión con otras VNET, VPN o Endpoints
  * NSG = Network Security Groups (firewall básico)
  * <code properties>
resource_prefix = "web-server"
web_server_address_space = "1.0.0.0/22"
</code>
<code properties>
variable "resource_prefix" {}
variable "web_server_address_space" {}

resource "azurerm_virtual_network" "web_server_vnet" {
  name = "${var.resource_prefix}-vnet"
  location = var.web_server_location
  resource_group_name = azurerm_resource_group.web_server_rg.name
  address_space = [var.web_server_address_space]
}
</code>

== dependencies
  * decirle a Terraform en que orden se deben crear los recursos
  * al crear elementos que dependen (o no) de otros, se pueden dar los siguientes casos:
    * que no haya dependencia
    * dependencia indirecta: Terraform la asume o las dedice de las variables
    * dependencia directa (o explícita): usando la propiedad ''depends_on''





== azure subnet
  * subnetwork en nuestra VNET
  * address space
  * segmentación
  * NSG = Network Security Groups
  * <code properties; terraform.tfvars>
web_server_address_prefix = "1.0.1.0/24
</code>
<code properties; subnet.tf>
variable web_server_address_prefix {}

resource "axzurerm_subnet" "web_server_subnet"{
  name = "${var.resource_prefix}-subnet"
  resource_group_name = azurerm_resource_group.web_server_rg.name
  virtual_network_name = azurerm_virtual_network.web_server_vnet.name
  address_prefix = var.web_server_address_prefix
}</code>





== azure Network Interface
  * equivalencia con el mundo real
  * atachar a Subnets/VNET
  * IP públicas o privadas
  * Estáticas o dinámicas
  * DNS Settings
  * NSG
  * <code properties; terraform.tfvars>web_server_name = "web-01"</code>
<code properties; nic.tf>
  variable web_server_name {}
  resource "azurerm_network_interface" "web_server_nic" {
    name = "${var.web_server_name}-nic"
    location = var.web_server_location
    resource_group_name = azurerm_resource_group.web_server_rg.name
    
    ip_configuration {
      name = "${var.web_server_name}-ip"
      subnet_id = azurerm_subnet.web_server_subnet.id
      private_ip_address_allocation = "dynamic" 
    }
  }  
</code>