feat: suppress default tags from module (#651)

* remove suppressed tags

* format code

* fix tag list

tags.tf

@@ -1,5 +1,5 @@
 locals {
-  tags = merge(
+  tags_merged = merge(
     {
       "Name" = format("%s", var.environment)
     },
@@ -9,7 +9,9 @@ locals {
     var.tags,
   )
 
-  agent_tags = merge(
+  tags = { for k, v in local.tags_merged : k => v if !contains(var.suppressed_tags, k) }
+
+  agent_tags_merged = merge(
     {
       "Name" = format("%s", local.name_runner_agent_instance)
     },
@@ -20,15 +22,17 @@ locals {
     var.agent_tags
   )
 
+  agent_tags = { for k, v in local.agent_tags_merged : k => v if !contains(var.suppressed_tags, k) }
+
   runner_tags_merged = merge(
     local.tags,
     var.runner_tags,
     # overwrites the `Name` key from `local.tags`
     var.overrides["name_docker_machine_runners"] == "" ? { Name = substr(format("%s", var.environment), 0, 16) } : { Name = var.overrides["name_docker_machine_runners"] },
   )
 
-  # remove the `Name` tag if docker+machine adds one to avoid a failure due to a duplicate `Name` tag
-  runner_tags = local.docker_machine_adds_name_tag ? { for k, v in local.runner_tags_merged : k => v if k != "Name" } : local.runner_tags_merged
+  # remove the `Name` tag in addition if docker+machine adds one to avoid a failure due to a duplicate `Name` tag
+  runner_tags = local.docker_machine_adds_name_tag ? { for k, v in local.runner_tags_merged : k => v if !contains(concat(var.suppressed_tags, ["Name"]), k) } : local.runner_tags_merged
 
   tags_string = join(",", flatten([
     for key in keys(local.tags) : [key, lookup(local.tags, key)]

variables.tf

@@ -502,6 +502,12 @@ variable "runner_tags" {
   default     = {}
 }
 
+variable "suppressed_tags" {
+  description = "List of tag keys which are removed from tags, agent_tags and runner_tags and never added as default tag by the module."
+  type        = list(string)
+  default     = []
+}
+
 variable "role_tags" {
   description = "Map of tags that will be added to the role created. Useful for tag based authorization."
   type        = map(string)