feat!: location inverse control in bucket name prefix (#186)

Co-authored-by: g-awmalik <malik.awais@gmail.com>

README.md

@@ -67,7 +67,7 @@ Functional examples are included in the
 | location | Bucket location. | `string` | `"EU"` | no |
 | logging | Map of lowercase unprefixed name => bucket logging config object. Format is the same as described in provider documentation https://www.terraform.io/docs/providers/google/r/storage_bucket.html#logging | `any` | `{}` | no |
 | names | Bucket name suffixes. | `list(string)` | n/a | yes |
-| prefix | Prefix used to generate the bucket name. | `string` | n/a | yes |
+| prefix | Prefix used to generate the bucket name. | `string` | `""` | no |
 | project\_id | Bucket project id. | `string` | n/a | yes |
 | randomize\_suffix | Adds an identical, but randomized 4-character suffix to all bucket names | `bool` | `false` | no |
 | retention\_policy | Map of retention policy values. Format is the same as described in provider documentation https://www.terraform.io/docs/providers/google/r/storage_bucket#retention_policy | `any` | `{}` | no |

docs/upgrading_to_v4.0.md

@@ -0,0 +1,42 @@
+# Upgrading to v4.0
+
+The v4.0 release of the terraform-google-cloud-storage module is a backwards incompatible release, due to the following breaking changes:
+
+- The bucket doesn't have location as mandatory part of the name prefix.
+
+## Migration Instructions
+
+A migration from 3.x to 4.x as showcased below
+
+```diff
+module "cloud_storage" {
+   source  = "terraform-google-modules/cloud-storage/google"
+-  version = "~> 3.0"
++  version = "~> 4.0"
+```
+will produce the following output during a `terraform plan`:
+
+```bash
+# module.cloud_storage.google_storage_bucket.buckets["one"] must be replaced
+...
+~ name = "multiple-buckets-iost-eu-one" -> "multiple-buckets-iost-one" # forces replacement
+...
+# module.cloud_storage.google_storage_bucket.buckets["two"] must be replaced
+...
+~ name = "multiple-buckets-iost-eu-two" -> "multiple-buckets-iost-two" # forces replacement
+...
+Plan: 2 to add, 0 to change, 2 to destroy.
+```
+
+In the module bucket prefix contained `location` before. To preserve the same bucket name with `location` in prefix you should make some code adjustments:
+
+```diff
+- prefix = "multiple-buckets-${random_string.prefix.result}"
++ prefix = "multiple-buckets-${random_string.prefix.result}-eu"
+```
+
+Re-running the plan should show that the storage bucket resources are no longer showing a diff.
+
+```
+Apply complete! Resources: 0 added, 0 changed, 0 destroyed.
+```

main.tf

@@ -22,8 +22,7 @@ resource "random_id" "bucket_suffix" {
 }
 
 locals {
-  prefix       = var.prefix == "" ? "" : join("-", [var.prefix, lower(var.location), ""])
-  suffix       = var.randomize_suffix ? "-${random_id.bucket_suffix.hex}" : ""
+  suffix       = var.randomize_suffix ? random_id.bucket_suffix.hex : ""
   names_set    = toset(var.names)
   buckets_list = [for name in var.names : google_storage_bucket.buckets[name]]
   first_bucket = local.buckets_list[0]
@@ -40,11 +39,11 @@ locals {
 resource "google_storage_bucket" "buckets" {
   for_each = local.names_set
 
-  name          = "${local.prefix}${lower(each.value)}${local.suffix}"
+  name          = join("-", compact([var.prefix, each.value, local.suffix]))
   project       = var.project_id
   location      = var.location
   storage_class = var.storage_class
-  labels        = merge(var.labels, { name = replace("${local.prefix}${lower(each.value)}", ".", "-") })
+  labels        = merge(var.labels, { name = replace(join("-", compact([var.prefix, each.value])), ".", "-") })
   force_destroy = lookup(
     var.force_destroy,
     lower(each.value),

variables.tf

@@ -22,6 +22,7 @@ variable "project_id" {
 variable "prefix" {
   description = "Prefix used to generate the bucket name."
   type        = string
+  default     = ""
 }
 
 variable "names" {