How to Resolve Cyclic Dependency Between Google Storage Buckets in Terraform?

I'm trying to set up logging for a Google Storage bucket(already existing) using Terraform, but I'm running into a cyclic dependency issue. Here's my current Terraform configuration:

resource "google_storage_bucket" "user_log_bucket" {
  name          = google_storage_bucket.user_topic_bucket.name + "-logs"
  location      = var.location
  force_destroy = true
}

resource "google_storage_bucket" "user_topic_bucket"{
  name = "user-topic-bucket-${var.env}"
  location = var.location
  force_destroy               = true
  uniform_bucket_level_access = true
  versioning {
    enabled = true
  }
  logging {
    log_bucket        = google_storage_bucket.user_log_bucket.name
    log_object_prefix = "log"
  }
}

The user_topic_bucket is supposed to log to user_log_bucket, but user_log_bucket's name depends on user_topic_bucket, creating a cyclic dependency.

I have tried decoupling the bucket creation and the logging configuration, but I can't find a way to do this within Terraform's current resources and configurations.

How can I resolve this cyclic dependency in Terraform when setting up logging between two Google Storage buckets? Is there a recommended way to separate the creation and logging configuration steps, or is there another approach I should consider?

Any help or examples would be greatly appreciated!

I have tried decoupling the bucket creation and the logging configuration, but I can't find a way to do this within Terraform's current resources and configurations.

Solution #1

Put the name of the bucket in locals and use it in both resources in the name argument. Leave reference to another bucket only in the logging block.

locals {
  bucket_name = "user-topic-bucket-${var.env}"
}

resource "google_storage_bucket" "user_log_bucket" {
  name          = local.bucket_name + "-logs"
  location      = var.location
  force_destroy = true
}

resource "google_storage_bucket" "user_topic_bucket"{
  name = local.bucket_name
  location = var.location
  force_destroy               = true
  uniform_bucket_level_access = true
  versioning {
    enabled = true
  }
  logging {
    log_bucket        = google_storage_bucket.user_log_bucket.name
    log_object_prefix = "log"
  }
}

Solution #2

Put the name of the bucket in user_log_bucket and then reference this name in user_topic_bucket and use trimsuffix function to remove -logs suffix.

resource "google_storage_bucket" "user_log_bucket" {
  name          = "user-topic-bucket-${var.env}-logs"
  location      = var.location
  force_destroy = true
}

resource "google_storage_bucket" "user_topic_bucket"{
  name = trimsuffix(google_storage_bucket.user_log_bucket.name, "-logs")
  location = var.location
  force_destroy               = true
  uniform_bucket_level_access = true
  versioning {
    enabled = true
  }
  logging {
    log_bucket        = google_storage_bucket.user_log_bucket.name
    log_object_prefix = "log"
  }
}