Create Local map(string) By Looping over Variable of Type map(string)

Terraform
1

Hi All,
I’m trying to figure out how to create dynamic locals by looking up a map value stored in a variable.
More context:

  1. I’ve got a variable called all_github_users that looks like this:
variable "all_github_users" {
  type = map(string)
  description = "List of all Github users with their emails."
  default = {
    "user1@company.com" = "their-github-username",
    "user2@domain.com" = "another-github-user",
    "user3@foo.com" = "yet-another-github-user",
  }
}

This essentially contains all the Github usernames in our org.

  1. My Terraform template users will be asked to supply another variable that will look like this:
variable github_collaborators {
  type = map(string)
  description = "List of Github usernames that should be added to the new Github repository as collaborators."
  default = {
    "user1@company.com" = "admin",
    "user2@domain.com" = "push"
  }
}

The above contains the user emails and their respective Github repo permissions the Terraform user would like to add as repo collaborators.

What I am trying to do then is to create a local variable (local presumably, but it doesn’t matter to me as long as it works) of type map(string) that would contain the following data (based on the example above):

variable github_usernames_to_add {
  type = map(string)
  default = {
    "their-github-username" = "admin",
    "another-github-user" = "push"
  }

(I realise that the above is a variable definition, I simply wanted to make the var. type clear)

In short, I simply want to take the github_collaborators variable and replace emails with Github usernames as mapped in the variable all_github_users.

Is there a way to do that?

Thank you!

2

It looks like I managed to solve this by creating the following local var.:

locals {
  users_to_add_as_collaborators = {
    for email, permission in var.github_collaborators :
      lookup(var.all_github_users, email, "") => permission
  }
}