try

expected time	requirements
30 minutes	A computer with Terraform installed, terraform knowledge.

Goal: Write modules that have optional parameters.

Explanation

Sometimes you want to use a module that has many parameters, some are optional. For example;

repositories = {
  my_repo_5 = {
    description = "My wonderful fifth repository."
  },
  my_repo_6 = {
    description  = "My wonderful sixth repository."
    homepage_url = "https://robertdebock.nl/"
    has_issues   = false
    has_projects = false
    has_wiki     = false
  }
}

The example above shows a map of two entries; my_repo_5 and my_repo_6. The my_repo_6 has more options than my_repo_5. This means the module should try to see if a variable is set, otherwise return null.

null means the whole parameter is removed, as if it was not described.

Demo

See here.

Howto

Here is how to try parameters:

module "github" {
  source   = "../../"
  for_each = var.repositories

  repository_name         = each.key
  repository_description  = each.value.description
  repository_homepage_url = try(each.value.homepage_url, null)
  repository_has_issues   = try(each.value.has_issues, null)
  repository_has_projects = try(each.value.has_projects, null)
  repository_has_wiki     = try(each.value.has_wiki, null)
}

Solution

See this repository. Or more complex.

Sources

• try