CODEWITHSUNDEEP
terraform
lightweight
lightweight

Reputation: 3327

generating a list of strings based off variables

lets say I have some terraform vars: variable "cluster" {} and variable "kfkcount" {}

and lets say cluster=test and kfkcount=3

how can I use terraform to turn that into a list that looks like this?

["test1.c.com", "test2.c.com", "test3.c.com"]

Upvotes: 3

Views: 9395

Answers (3)

Marek Urcikan
Marek Urcikan

Reputation: 21

Quite late to the party but if you end up here like me. This can be solved with the range function.

formatlist("${var.cluster}%s.c.com", range(1, var.kfkcount + 1))

will output:

tolist(["test1.c.com", "test2.c.com", "test3.c.com",])

Upvotes: 2

bodgit
bodgit

Reputation: 293

This should do what you want:

variable "cluster" {}

variable "kfkcount" {}

data "template_file" "test" {
  template = "$${cluster}$${index}.c.com"
  count    = "${var.kfkcount}"

  vars = {
    index   = "${count.index + 1}"
    cluster = "${var.cluster}"
  }
}

output "list" {
  value = "${data.template_file.test.*.rendered}"
}

It's a bit of a hack using the template_file resource, however it will return the list as required:

$ terraform apply
var.cluster
  Enter a value: test

var.kfkcount
  Enter a value: 3

data.template_file.test[0]: Refreshing state...
data.template_file.test[1]: Refreshing state...
data.template_file.test[2]: Refreshing state...

Apply complete! Resources: 0 added, 0 changed, 0 destroyed.

Outputs:

list = [
    test1.c.com,
    test2.c.com,
    test3.c.com
]

Upvotes: 10

aderubaru
aderubaru

Reputation: 419

EDIT

One thing that can help is to use count for looping, and using the count.index as the value for the names. So you could end up with something like this:

resource ".." "..." {
  count = "${var.kfkcount}"

  something = "${var.cluster}${count.index}.c.com"
}

There is even one example that shows a simple usage of count and, also, list expansion with *.

Have you tried using list(items, ...) described in the Interpolation Syntax page?

Something in the like of

"${list("${var.cluster}", "${var.kfkcount}")}"

Upvotes: 1

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