I’m trying to create a module for GCP firestore that creates a single database which can create multiple indexes with multiple fields but am having some trouble.

I’ve tried with for_each but I don’t know how to do it exactly. I need the collection (from the index) name and the fields to be dynamic together.

This is my code so far:

main.tf (module)

resource "google_firestore_database" "database" {
 project                           = var.project_id
 name                              = var.firestore_name
 location_id                       = var.firestore_location_id
 type                              = var.firestore_type
 concurrency_mode                  = var.firestore_concurrency_mode
 app_engine_integration_mode       = var.firestore_app_engine_integration_mode
 point_in_time_recovery_enablement = var.firestore_point_in_time_recovery_enablement
 delete_protection_state           = var.firestore_delete_protection_state
 # deletion_policy                   = var.firestore_deletion_policy
}

resource "google_firestore_index" "my-index" {
 project    = var.project_id
 database   = var.firestore_name
 collection = var.firestore_collection

 fields {
   field_path = var.firestore_field_path
   order      = var.firestore_order
 }
 fields {
   field_path = var.firestore_field_path
   order      = var.firestore_order
 }
}

I have tried this:

resource "google_firestore_index" "catalog-dev" {
 project    = google_firestore_database.database.project
 database   = google_firestore_database.database.name
 collection = var.firestore_collection

 dynamic "fields" {
   for_each = var.indexfieldvars
   content {
     field_path = fields.value.field_path
     order      = fields.value.order
   }
 }
}

But I need the collection to be related to the specific fields.

I’ve read on nested dynamic blocks, but I’m not sure if that works for my case.