CODEWITHSUNDEEP
terraform
Casper
Casper

Reputation: 1723

How to use condition with lists in Terraform 11

I need to create a condition in terraform 11 where I check if a local list variable exists, if it does then use that list and if not use a different one.

For example, I have:

var.localList = ["apples", "oranges"]

var.remoteList = ["bananas", "carrots"]

Now I want to do something like this (which didn't work):

myVar = ["${length(var.localList) > 0 ? var.localList : var.remoteList}"]

So the idea is that if var.localList is not empty, assign that list to myVar, otherwise use var.remoteList.

Not sure if this is possible in Terraform 11.

EDIT: Forgot to mention that I'm using terraform 11.

Upvotes: 0

Views: 11017

Answers (3)

mjgpy3
mjgpy3

Reputation: 8947

The function coalescelist seems to do exactly what you want.

From the docs

coalescelist takes any number of list arguments and returns the first one that isn't empty.

So you would write something like

myVar = coalescelist(var.localList, var.localList)

Upvotes: 2

Casper
Casper

Reputation: 1723

I found the answer here https://github.com/hashicorp/terraform/issues/18259

Basically it's a work-around at this point

myVar   = "${split(",", length(var.localList) > 0 ? join(",", var.localList) : join(",", var.remoteList))}"

Upvotes: 0

Ben Whaley
Ben Whaley

Reputation: 34416

You could do this with Local Values:

variable "local_list" {
  default = ["foo"]
}

variable "remote_list" {
  default = ["bar"]
}

locals {
  myvar = length(var.local_list) > 0 ? var.local_list : var.remote_list
}

# myvar value is "foo"
output "myvar" {
  value = local.myvar
}

Upvotes: 3

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