CODEWITHSUNDEEP
terraform
sebastian
sebastian

Reputation: 2358

Terraform conditionals - if variable does not exist

I have the following condition:

resource "aws_elastic_beanstalk_application" "service" {
  appversion_lifecycle {
    service_role          = "service-role"
    delete_source_from_s3 = "${var.env == "production" ?   false : true}"
  }
}

If var.env is set to production, I get the result I want.

However if var.env is not defined, terraform plan will fail because the variable was never defined.
How can I get this to work, without ever having to define that variable?

Upvotes: 66

Views: 195695

Answers (3)

Erik-Jan Riemers
Erik-Jan Riemers

Reputation: 1412

Seems these days you can also use try to check if something is set.

try(var.env, false)

After that your code will work since var.env is now defined with the value false even if var.env was never defined somewhere.

https://www.terraform.io/docs/configuration/functions/try.html

Upvotes: 110

Shiv Rajawat
Shiv Rajawat

Reputation: 998

if you are using Terraform 0.12 or later, you can assign the special value null to an argument to mark it as "unset".

variable "env" {
    type = "string"
    default = null
}

You can't just leave it blank, not with the current versions.

Upvotes: 41

Konstantin Grigorov
Konstantin Grigorov

Reputation: 1642

You can have the default of the variable set to an empty string:

variable "env" {
  description = "Env where the module is deployed."
  type        = string
  default     = ""
}

Once that is done, your check var.env == "production" will produce false and the argument delete_source_from_s3 will be assigned to the value true.

Side note, there is no need for interpolation in the statement,

"${var.env == "production" ? false : true}"

just go with,

delete_source_from_s3 = var.env == "production" ? false : true

https://discuss.hashicorp.com/t/how-do-write-an-if-else-block/2563

Upvotes: 19

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