GCP IAM Role to Service Binding

I’m somewhat new to GCP but I in the console i can easily create a new service and grant it a pre-existing role.

I’ve been trying to use something like this:

resource "google_service_account" "sa" {
  account_id   = "docker-logger-service"
  display_name = "Service Record Container Logs to Google Cloud"

resource "google_service_account_iam_binding" "admin-account-iam" {
  service_account_id = google_service_account.sa.name
  role               = "roles/logging.admin"

  members = [

The google_service_account_iam_binding confuses me. I’m trying to grant a right to an entity, so it feels like either service_account_id or members isn’t needed but they’re both required.

According to the google docs, the equivalent CLI command is this:

gcloud projects add-iam-policy-binding projectName --member=serviceAccount:myServiceID@appspot.gserviceaccount.com --role=roles/cloudbuild.builds.viewer  

What am I missing?