Allow projects to use instance level clusters

There are two cluster hierarchies one for the deployment platform and
one for controllers. The main difference is that deployment platforms do
not check user permissions and only return the first match.

4 files changed, 34 insertions, 3 deletions

diff --git a/app/controllers/admin/clusters_controller.rb b/app/controllers/admin/clusters_controller.rb
index 777bdf5c981..f2b54125d48 100644
--- a/app/controllers/admin/clusters_controller.rb
+++ b/app/controllers/admin/clusters_controller.rb
@@ -8,10 +8,18 @@ class Admin::ClustersController < Clusters::ClustersController
   private
 
   def clusterable
-    @clusterable ||= InstanceClusterablePresenter.fabricate(Clusters::Instance.new, current_user: current_user)
+    @clusterable ||= InstanceClusterablePresenter.fabricate(cluster_instance, current_user: current_user)
+  end
+
+  def cluster_instance
+    @cluster_instance ||= Clusters::Instance.new
   end
 
   def check_instance_clusters_feature_flag!
-    render_404 unless Feature.enabled?(:instance_clusters, default_enabled: true)
+    render_404 unless instance_clusters_enabled?
+  end
+
+  def instance_clusters_enabled?
+    cluster_instance.instance_clusters_enabled?
   end
 end
diff --git a/app/models/clusters/cluster.rb b/app/models/clusters/cluster.rb
index 7220159ac95..9299e61dad3 100644
--- a/app/models/clusters/cluster.rb
+++ b/app/models/clusters/cluster.rb
@@ -115,10 +115,12 @@ module Clusters
     }
 
     def self.ancestor_clusters_for_clusterable(clusterable, hierarchy_order: :asc)
+      return [] if clusterable.is_a?(Instance)
+
       hierarchy_groups = clusterable.ancestors_upto(hierarchy_order: hierarchy_order).eager_load(:clusters)
       hierarchy_groups = hierarchy_groups.merge(current_scope) if current_scope
 
-      hierarchy_groups.flat_map(&:clusters)
+      hierarchy_groups.flat_map(&:clusters) + Instance.new.clusters
     end
 
     def status_name
diff --git a/app/models/clusters/instance.rb b/app/models/clusters/instance.rb
index fde83c5a8ad..bbbf6da16fb 100644
--- a/app/models/clusters/instance.rb
+++ b/app/models/clusters/instance.rb
@@ -8,4 +8,8 @@ class Clusters::Instance
   def feature_available?(feature)
     ::Feature.enabled?(feature, default_enabled: true)
   end
+
+  def instance_clusters_enabled?
+    ::Feature.enabled?(:instance_clusters, default_enabled: true)
+  end
 end
diff --git a/app/models/concerns/deployment_platform.rb b/app/models/concerns/deployment_platform.rb
index 0107af5f8ec..c2dafec1a54 100644
--- a/app/models/concerns/deployment_platform.rb
+++ b/app/models/concerns/deployment_platform.rb
@@ -14,6 +14,7 @@ module DeploymentPlatform
   def find_deployment_platform(environment)
     find_cluster_platform_kubernetes(environment: environment) ||
       find_group_cluster_platform_kubernetes_with_feature_guard(environment: environment) ||
+      find_instance_cluster_platform_kubernetes_with_feature_guard(environment: environment) ||
       find_kubernetes_service_integration ||
       build_cluster_and_deployment_platform
   end
@@ -36,6 +37,22 @@ module DeploymentPlatform
       .first&.platform_kubernetes
   end
 
+  def find_instance_cluster_platform_kubernetes_with_feature_guard(environment: nil)
+    return unless instance_clusters_enabled?
+
+    find_instance_cluster_platform_kubernetes(environment: environment)
+  end
+
+  # EE would override this and utilize environment argument
+  def find_instance_cluster_platform_kubernetes(environment: nil)
+    Clusters::Instance.new.clusters.enabled.default_environment
+      .first&.platform_kubernetes
+  end
+
+  def instance_clusters_enabled?
+    Feature.enabled?(:instance_clusters, default_enabled: true)
+  end
+
   def find_kubernetes_service_integration
     services.deployment.reorder(nil).find_by(active: true)
   end