Virtual Geek

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terraform {
  backend "azurerm" {
    resource_group_name  = "vcloud-lab.com"            # Can be passed via `-backend-config=`"resource_group_name=<resource group name>"` in the `init` command.
    storage_account_name = "vcloudlabtfstate"          # Can be passed via `-backend-config=`"storage_account_name=<storage account name>"` in the `init` command.
    container_name       = "tfstate"                   # Can be passed via `-backend-config=`"container_name=<container name>"` in the `init` command.
    key                  = "example.terraform.tfstate" # Can be passed via `-backend-config=`"key=<blob key name>"` in the `init` command.
    use_azuread_auth     = true                        # Can also be set via `ARM_USE_AZUREAD` environment variable.
  }
}

locals {
  # String Functions
  upper_string   = upper("hello")                # "HELLO"
  lower_string   = lower("HELLO")                # "hello"
  replace_string = replace("hello", "e", "a")    # "hallo"
  substr_string  = substr("hello", 1, 3)         # "ell"
  length_string  = length("hello")               # 5
  format_string  = format("Hello, %s!", "World") # "Hello, World!"

  # Collection Functions
  list         = ["one", "two", "three"]
  length_list  = length(local.list)                 # 3
  merge_map    = merge({ a = 1, b = 2 }, { c = 3 }) # {a = 1, b = 2, c = 3}
  concat_list  = concat(["a", "b"], ["c", "d"])     # ["a", "b", "c", "d"]
  flatten_list = flatten([["a", "b"], ["c", "d"]])  # ["a", "b", "c", "d"]
  sort_list    = sort(["b", "a", "c"])              # ["a", "b", "c"]

  # Numeric Functions
  add_numbers      = 1 + 2        # 3
  subtract_numbers = 5 - 3        # 2
  multiply_numbers = 2 * 3        # 6
  divide_numbers   = 10 / 2       # 5
  min_number       = min(1, 2, 3) # 1
  max_number       = max(1, 2, 3) # 3
  abs_number       = abs(-5)      # 5

  # Logical Functions
  bool_and = true && false # false
  bool_or  = true || false # true
  not_bool = !true         # false

  # Date and Time Functions
  timestamp      = timestamp()                           # Current UTC time in RFC 3339 format
  formatted_date = formatdate("YYYY-MM-DD", timestamp()) # e.g., "2023-07-01"

  # IP Address Functions
  cidr    = "192.168.0.0/16"
  subnet1 = cidrsubnet(local.cidr, 8, 1) // "192.168.1.0/24" #cidrsubnet(prefix, newbits, netnum)
  subnet2 = cidrsubnet(local.cidr, 7, 2) // "192.168.1.0/24" #cidrsubnet(prefix, newbits, netnum)
  host    = cidrhost(local.subnet1, 5)   # "192.168.1.5"

  # Type Conversion Functions
  bool_to_string   = tostring(true)  # "true"
  number_to_string = tostring(123)   # "123"
  string_to_number = tonumber("123") # 123

  # Control Structures and Conditional Functions
  conditional_value = true ? "yes" : "no"              # "yes"
  element_value     = element(["a", "b", "c"], 1)      # "b"
  lookup_value      = lookup({ a = 1, b = 2 }, "b", 0) # 2

  # Validation Functions
  contains_example = contains(["a", "b", "c"], "b") # true

  # Additional Examples
  environment        = upper("dev") # "DEV"
  servers            = ["web1", "web2", "web3"]
  server_count       = length(local.servers) # 3
  server_name_prefix = local.server_count > 2 ? "large-cluster" : "small-cluster"
  server_names       = [for server in local.servers : format("%s-%s", local.server_name_prefix, server)]
  deployment_date    = formatdate("YYYY-MM-DD", timestamp()) # e.g., "2023-07-01"
  network_cidr       = "192.168.0.0/16"
  public_subnet      = cidrsubnet(local.network_cidr, 8, 1) # "192.168.1.0/24"
}

output "functions" {
  value = local.subnet2
}

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PS D:\Projects\Terraform\\Azure_Backend> terraform apply --auto-approve
╷
│ Error: Backend initialization required, please run "terraform init"
│ 
│ Reason: Initial configuration of the requested backend "azurerm"
│ 
│ The "backend" is the interface that Terraform uses to store state,
│ perform operations, etc. If this message is showing up, it means that the
│ Terraform configuration you're using is using a custom configuration for
│ the Terraform backend.
│ 
│ Changes to backend configurations require reinitialization. This allows
│ Terraform to set up the new configuration, copy existing state, etc. Please run
│ "terraform init" with either the "-reconfigure" or "-migrate-state" flags to
│ use the current configuration.
│ 
│ If the change reason above is incorrect, please verify your configuration
│ hasn't changed and try again. At this point, no changes to your existing
│ configuration or state have been made.
╵
PS D:\Projects\Terraform\\Azure_Backend> 
PS D:\Projects\Terraform\\Azure_Backend> terraform init
Initializing the backend...
Acquiring state lock. This may take a few moments...
Do you want to copy existing state to the new backend?
  Pre-existing state was found while migrating the previous "local" backend to the
  newly configured "azurerm" backend. No existing state was found in the newly
  configured "azurerm" backend. Do you want to copy this state to the new "azurerm"
  backend? Enter "yes" to copy and "no" to start with an empty state.

  Enter a value: yes

Releasing state lock. This may take a few moments...

Successfully configured the backend "azurerm"! Terraform will automatically
use this backend unless the backend configuration changes.
Initializing provider plugins...

Terraform has been successfully initialized!

You may now begin working with Terraform. Try running "terraform plan" to see
any changes that are required for your infrastructure. All Terraform commands
should now work.

If you ever set or change modules or backend configuration for Terraform,
rerun this command to reinitialize your working directory. If you forget, other
commands will detect it and remind you to do so if necessary.
PS D:\Projects\Terraform\\Azure_Backend> 
PS D:\Projects\Terraform\\Azure_Backend> terraform apply --auto-approve
Acquiring state lock. This may take a few moments...

No changes. Your infrastructure matches the configuration.

Terraform has compared your real infrastructure against your configuration and found no differences, so no changes are needed.
Releasing state lock. This may take a few moments...

Apply complete! Resources: 0 added, 0 changed, 0 destroyed.

Outputs:

functions = "192.168.1.0/24"
PS D:\Projects\Terraform\\Azure_Backend>