Consolidate how we allow user defined namespace

Use model method as single source of truth instead of splitting between
presenter and Kubernetes model

app/models/clusters/cluster.rb

@@ -144,6 +144,10 @@ module Clusters
       )
     end
 
+    def allow_user_defined_namespace?
+      project_type?
+    end
+
     private
 
     def restrict_modification

app/models/clusters/platforms/kubernetes.rb

@@ -38,7 +38,7 @@ module Clusters
 
       validates :namespace, exclusion: { in: RESERVED_NAMESPACES }
 
-      validate :no_namespace, unless: :project_type?
+      validate :no_namespace, unless: :allow_user_defined_namespace?
 
       # We expect to be `active?` only when enabled and cluster is created (the api_url is assigned)
       validates :api_url, url: true, presence: true
@@ -54,7 +54,7 @@ module Clusters
       delegate :project, to: :cluster, allow_nil: true
       delegate :enabled?, to: :cluster, allow_nil: true
       delegate :managed?, to: :cluster, allow_nil: true
-      delegate :project_type?, to: :cluster, allow_nil: true
+      delegate :allow_user_defined_namespace?, to: :cluster, allow_nil: true
       delegate :kubernetes_namespace, to: :cluster
 
       alias_method :active?, :enabled?

app/presenters/clusters/cluster_presenter.rb

@@ -8,10 +8,6 @@ module Clusters
       "https://console.cloud.google.com/kubernetes/clusters/details/#{provider.zone}/#{name}" if gcp?
     end
 
-    def allow_project_namespace?
-      cluster.project_type?
-    end
-
     def can_toggle_cluster?
       can?(current_user, :update_cluster, cluster) && created?
     end

app/views/clusters/clusters/gcp/_show.html.haml

@@ -33,7 +33,7 @@
             = s_('ClusterIntegration|Show')
           = clipboard_button(text: @cluster.platform_kubernetes.token, title: s_('ClusterIntegration|Copy Token'), class: 'btn-default')
 
-    - if @cluster.allow_project_namespace?
+    - if @cluster.allow_user_defined_namespace?
       .form-group
         = platform_kubernetes_field.label :namespace, s_('ClusterIntegration|Project namespace (optional, unique)')
         = platform_kubernetes_field.text_field :namespace, class: 'form-control', placeholder: s_('ClusterIntegration|Project namespace')

app/views/clusters/clusters/user/_form.html.haml

@@ -21,7 +21,7 @@
       = platform_kubernetes_field.label :token, s_('ClusterIntegration|Token'), class: 'label-bold'
       = platform_kubernetes_field.text_field :token, class: 'form-control', placeholder: s_('ClusterIntegration|Service token'), autocomplete: 'off'
 
-    - if @user_cluster.allow_project_namespace?
+    - if @user_cluster.allow_user_defined_namespace?
       .form-group
         = platform_kubernetes_field.label :namespace, s_('ClusterIntegration|Project namespace (optional, unique)'), class: 'label-bold'
         = platform_kubernetes_field.text_field :namespace, class: 'form-control', placeholder: s_('ClusterIntegration|Project namespace')

app/views/clusters/clusters/user/_show.html.haml

@@ -22,7 +22,7 @@
             %button.js-show-cluster-token.btn-blank{ type: 'button' }
               = s_('ClusterIntegration|Show')
 
-    - if @cluster.allow_project_namespace?
+    - if @cluster.allow_user_defined_namespace?
       .form-group
         = platform_kubernetes_field.label :namespace, s_('ClusterIntegration|Project namespace (optional, unique)'), class: 'label-bold'
         = platform_kubernetes_field.text_field :namespace, class: 'form-control', placeholder: s_('ClusterIntegration|Project namespace')

spec/models/clusters/cluster_spec.rb

@@ -343,4 +343,26 @@ describe Clusters::Cluster do
       it { is_expected.to eq(false) }
     end
   end
+
+  describe '#allow_user_defined_namespace?' do
+    let(:cluster) { create(:cluster, :provided_by_gcp) }
+
+    subject { cluster.allow_user_defined_namespace? }
+
+    context 'project type cluster' do
+      it { is_expected.to be_truthy }
+    end
+
+    context 'group type cluster' do
+      let(:cluster) { create(:cluster, :provided_by_gcp, :group) }
+
+      it { is_expected.to be_falsey }
+    end
+
+    context 'instance type cluster' do
+      let(:cluster) { create(:cluster, :provided_by_gcp, :instance) }
+
+      it { is_expected.to be_falsey }
+    end
+  end
 end