How can I variablize a template and text file in Terraform

I have this template named : email-passwordless.ar.html.ftl

Its content is as follows:

[#setting url_escaping_charset="UTF-8"]
[#assign url = "https://google.com/auth/prod/${code}" /]

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html lang="ar" dir="rtl">
<head>

The resource using this template is :

resource "fusionauth_email" "passwrodless_template" {
  name                  = var.passwordless_email_template_name
  localized_subjects = {
    "ar" = var.email_passwordless_localized_subjects
  }
  localized_html_templates = {
    "ar" = file("${path.module}/email-templates/email-passwordless.ar.html.ftl")
  }
}

The template will be used across different environments and hence its URL will be different for each environment. How can I make the URL in the template as variable and pass its value in resource or something similar to it

Solution

You would use the templatefile function for this use case. You can create the email-passwordless.ar.html.tmpl file in the same path as your current file:

[#setting url_escaping_charset="UTF-8"]
[#assign url = "${url}" /]

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html lang="ar" dir="rtl">
<head>

where we replace your already named string type variable code with url for the entire url. After assigning a value to var.url in your Terraform config, its value can be passed to the template renderer through the templatefile function arguments:

localized_html_templates = {
  "ar" = templatefile("${path.module}/email-templates/email-passwordless.ar.html.tmpl", { url = var.url })
}