Terraform Operators and Conditional Expressions

 

Numeric Operators

% terraform console
> 1+2
3
> 2-1
1
> 2*3
6
> 8/2
4

Equality & Comparison Operators

> 1 == 1

true

> 1 < 2

true

> 2 < 1

false

> 2 >= 1

true

> 1 == "1"

false

> 1 != "1"

true

>  

Logical Operators

AND, OR, NOT

> 1 < 2 && false

false

> 1 < 2 && true

true

> 1 < 2 || false

true

> 1 < 2 || true

true

> !(1 < 2) || false

false

> !(1 < 2)

false

main.tf:

variable flag {

type = bool

default = false

}

variable num_a {

type = number

default = 11

}

variable num_b {

        type = number

        default = 22

}

> var.flag

false

> !var.flag

true

> var.num_a

11

> var.num_b

22

> var.num_b < var.num_a

false

Conditional Expressions

value = condition ? value_if_condition_is_true : value_if_condition_is_false

Example: We want to provision a password generator that creates a random password of the length specified by the user. If length is less than 8 characters then generator will use the default length value of 8.

main.tf:

resource "random_password" "pwd-generator" {

length = var.length < 8 ? 8 : var.length

}

output password {

value = random_password.pwd-generator.result

    sensitive = true

}

variable length {

type = number

}

In terminal:

$ terraform apply -var=length=6 -auto-approve

$ terraform output password

"DIo${L-*"

$ terraform apply -var=length=10 -auto-approve

$ terraform output password

"0Y3}Fh2Na2"