Variable validation rules in Terraform - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a variable with a description.

Terraform

variable "region" {
  type        = string
  description = [1]
}

Drag options to blanks, or click blank then click option'

Aaws_region

B"AWS region to deploy resources"

Cstring

Ddefault = "us-east-1"

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable name instead of a description string

Omitting quotes around the description

The description field must be a string describing the variable's purpose.

2fill in blank

medium

Complete the code to add a validation rule that ensures the variable is not empty.

Terraform

variable "environment" {
  type = string

  validation {
    condition     = [1]
    error_message = "Environment cannot be empty."
  }
}

Drag options to blanks, or click blank then click option'

Avar.environment == ""

Bvar.environment != null

Clength(var.environment) > 0

Dvar.environment == null

Attempts:

3 left

💡 Hint

Common Mistakes

Checking for equality with empty string instead of length

Using null checks which are not appropriate for strings

The condition checks that the length of the string is greater than zero to ensure it is not empty.

3fill in blank

hard

Fix the error in the validation condition to allow only values 'dev', 'staging', or 'prod'.

Terraform

variable "stage" {
  type = string

  validation {
    condition     = contains([[1]], var.stage)
    error_message = "Stage must be one of: dev, staging, prod."
  }
}

Drag options to blanks, or click blank then click option'

A["dev", "staging", "prod"]

B"dev", "staging", "prod"

Cdev, staging, prod

D"dev staging prod"

Attempts:

3 left

💡 Hint

Common Mistakes

Using a string instead of a list

Omitting square brackets around the list

The contains function requires a list as the first argument, so the values must be inside square brackets.

4fill in blank

hard

Fill both blanks to validate a number variable is between 1 and 10 inclusive.

Terraform

variable "instance_count" {
  type = number

  validation {
    condition     = var.instance_count [1] 1 && var.instance_count [2] 10
    error_message = "Instance count must be between 1 and 10."
  }
}

Drag options to blanks, or click blank then click option'

A>=

B<=

C>

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using strict greater than or less than which excludes boundary values

Swapping the operators

The variable must be greater than or equal to 1 and less than or equal to 10.

5fill in blank

hard

Fill all three blanks to validate a list variable contains only allowed strings.

Terraform

variable "allowed_zones" {
  type = list(string)

  validation {
    condition     = alltrue([for zone in var.allowed_zones : zone [1] [[2]]])
    error_message = "Zones must be one of the allowed values."
  }
}

Drag options to blanks, or click blank then click option'

Ain

B"us-east-1a", "us-east-1b", "us-east-1c"

Ccontains

D"us-west-2a", "us-west-2b", "us-west-2c"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'contains' incorrectly as an operator instead of a function

Not using a for expression to check each item

Providing the wrong list of zones

The code uses a for expression to check each zone is in the allowed list using the 'in' operator, and alltrue to ensure all pass. The list of allowed zones is provided as the second argument to contains.