Variable validation blocks in Terraform - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

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

Terraform

variable "region" {
  type = string

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

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Avar.region == ""

Bvar.region != ""

Cvar.region == null

Dvar.region == 0

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of '!=' causes the validation to fail incorrectly.

Checking for null instead of empty string when the variable is a string.

The validation condition must check that the variable is not an empty string to ensure a value is provided.

2fill in blank

medium

Complete the code to validate that the number variable is greater than zero.

Terraform

variable "instance_count" {
  type = number

  validation {
    condition     = [1]
    error_message = "Instance count must be greater than zero."
  }
}

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Avar.instance_count > 0

Bvar.instance_count == 0

Cvar.instance_count <= 0

Dvar.instance_count < 0

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' or '<=' which would allow zero or negative numbers.

Checking for equality to zero instead of greater than zero.

The condition must ensure the number is greater than zero to be valid.

3fill in blank

hard

Fix the error in the validation condition to check if the string variable is one of allowed values.

Terraform

variable "environment" {
  type = string

  validation {
    condition     = contains(["dev", "staging", "prod"], [1])
    error_message = "Environment must be dev, staging, or prod."
  }
}

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Aenvironment_var

Bvar.env

Cvar.environment

Denvironment

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable name without 'var.' prefix causes an error.

Using a wrong variable name that does not exist.

The variable must be referenced with 'var.' prefix to access its value inside the validation block.

4fill in blank

hard

Fill both blanks to validate a list variable has at least two items and all are strings.

Terraform

variable "zones" {
  type = list(string)

  validation {
    condition     = length([1]) >= 2 && alltrue([for z in [2] : length(z) > 0])
    error_message = "Zones list must have at least two valid strings."
  }
}

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Avar.zones

Bzones

Cvar.zone_list

Dzone_list

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable name without 'var.' prefix.

Using different variable names in the two blanks.

Both blanks must reference the variable with 'var.zones' to check its length and iterate over its items.

5fill in blank

hard

Fill all three blanks to validate a map variable keys and values meet conditions.

Terraform

variable "tags" {
  type = map(string)

  validation {
    condition     = alltrue([for k, v in [1] : length(k) > 0 && length(v) [2] 0 && v != [3]])
    error_message = "Tags keys and values must be non-empty strings and values cannot be 'none'."
  }
}

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Avar.tags

B>

C"none"

Dtags

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable name without 'var.' prefix.

Using wrong comparison operators.

Not quoting the string 'none'.

The condition iterates over 'var.tags', checks keys length > 0, values length > 0, and values not equal to 'none'.