Add support for linking existing vercel_shared_environment_variable to a vercel_project

[joaquingatica]

As a follow up request of #152, a way of linking a pre-existing Shared Environment Variable to a project would be great. The following configuration would result in duplicating the value of the vercel_shared_environment_variable in the vercel_project as a new variable, instead of linking the existing shared variable to the project.

data "vercel_shared_environment_variable" "my_shared_var" {
  key    = "MY_SHARED_VAR"
  target = ["production", "preview"]
}

resource "vercel_project" "my_project" {
  name      = "my-project"
  // ...other project props
}

resource "vercel_project_environment_variable" "my_project_my_shared_var" {
  project_id = vercel_project.my_project.id
  key        = data.vercel_shared_environment_variable.my_shared_var.key
  value      = data.vercel_shared_environment_variable.my_shared_var.value
  target     = data.vercel_shared_environment_variable.my_shared_var.target
  sensitive  = data.vercel_shared_environment_variable.my_shared_var.sensitive
}

[dglsparsons]

Hey @joaquingatica, this is a really good idea. I'll look to getting something added 🙏

[dglsparsons]

Hi @joaquingatica, I haven't looked into adding support for this yet, as I haven't figured out how to make an API that works nicely with what already exists.

As a thought, is there any reason that importing the existing shared environment variable wouldn't work?

[joaquingatica]

Hi @dglsparsons! Importing the shared variable would work as an alternative I believe, but I opted to manually link it through the Vercel Dashboard instead, to leverage the native feature intead of working around it.

Also, I'd have to reconfirm, but I seem to recall that if the environment variable was sensitive, importing the existing shared variable didn't work as expected. This isn't confirmed though. Thank you!