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Terraform Input Variables with Collection Type maps

Step-01: Introduction

  • Implement complex type constructors like maps
  • Learn to use lookup function

Step-02: Implement complex type cosntructors like maps

  • Type Constraints
  • map (or object): a group of values identified by named labels, like {name = "Mabel", age = 52}.
  • Implement Map function for variable public_ip_sku and common_tags 
    # 8. Public IP SKU
variable "public_ip_sku" {
  description = "Azure Public IP Address SKU"
  type = map(string)
  default = {
    "eastus" = "Basic"
    "eastus2" = "Standard" 
  }
}

# 9. Common Tags
variable "common_tags" {
  description = "Common Tags for Azure Resources"
  type = map(string)
  default = {
    "CLITool" = "Terraform"
    "Tag1" = "Azure"
  } 
}

Step-03: Update c4-virtual-network.tf Public IP Resource

# Create Public IP Address
resource "azurerm_public_ip" "mypublicip" {
  name                = "mypublicip-1"
  resource_group_name = azurerm_resource_group.myrg.name
  location            = azurerm_resource_group.myrg.location
  allocation_method   = "Static"
  domain_name_label = "app1-vm-${random_string.myrandom.id}"
  #sku = var.public_ip_sku["eastus"]
  sku = lookup(var.public_ip_sku, var.resoure_group_location)
  tags = var.common_tags
}

Step-04: Add tags maps variable to following resources

  • azurerm_resource_group
  • azurerm_virtual_network
  • azurerm_public_ip
  • azurerm_network_interface 
      tags = var.common_tags

Step-04-02: lookup() function

  • Terraform lookup function 
    # Terraform lookup() Function
lookup({a="ay", b="bee"}, "a", "what?")
lookup({a="ay", b="bee"}, "b", "what?")
lookup({a="ay", b="bee"}, "c", "what?")

# Terraform lookup() Function with our map
lookup({"eastus"="Basic", "eastus2"="Standard"},"eastus", "Basic")
lookup({"eastus"="Basic", "eastus2"="Standard"},"eastus2", "Basic")
lookup({"eastus"="Basic", "eastus2"="Standard"},"", "Basic")

Step-05: Execute Terraform Commands

# Initialize Terraform
terraform init

# Validate Terraform configuration files
terraform validate

# Format Terraform configuration files
terraform fmt

# Review the terraform plan
terraform plan 

# Terraform Apply
terraform apply -auto-approve

# Observation
1. Verify Public IP SKU should be "Standard"
2. Verify Tags for Resource Group, Vnet, Public IP and Network Interface

Step-06: Uncomment Public Resource below line

  • Understand how to reference a specific value from a map 
    ## Uncomment
# Reference Specific value from Maps variable var.public_ip_sku
  sku = var.public_ip_sku["eastus"]

## Comment
  sku = lookup(var.public_ip_sku, var.resoure_group_location)  

# Terraform Plan
terraform plan

# Observation
1. Verify Public IP resource and SKU should be "Basic"

Step-07: Clean-Up

# Destroy Resources
terraform destroy -auto-approve

# Delete files
rm -rf .terraform*
rm -rf terraform.tfstate*

Step-08: Important Notation about maps

  • If the key starts with a number in a map 1-development, you must use the colon syntax : instead of = 
    variable "my_env_names" {
  type = map(string)
  default = {
    "1-development": "dev-apps"
    "2-staging": "staging-apps"
    "3-production": "prod-apps"
  }
}

References

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