Add feature flag for build preparing state

The flag is on by default, but allows us to revert back
to the old behaviour if we encounter any problems.

app/models/ci/build.rb

@@ -370,6 +370,8 @@ module Ci
     end
     def any_unmet_prerequisites?
+      return false unless Feature.enabled?(:ci_preparing_state, default_enabled: true)
+
       prerequisites.present?
     end

app/workers/cluster_configure_worker.rb

@@ -5,6 +5,8 @@ class ClusterConfigureWorker
   include ClusterQueue
   def perform(cluster_id)
+    return if Feature.enabled?(:ci_preparing_state, default_enabled: true)
+
     Clusters::Cluster.find_by_id(cluster_id).try do |cluster|
       Clusters::RefreshService.create_or_update_namespaces_for_cluster(cluster)
     end

app/workers/cluster_project_configure_worker.rb

@@ -5,6 +5,8 @@ class ClusterProjectConfigureWorker
   include ClusterQueue
   def perform(project_id)
+    return if Feature.enabled?(:ci_preparing_state, default_enabled: true)
+
     project = Project.find(project_id)
     ::Clusters::RefreshService.create_or_update_namespaces_for_project(project)

spec/models/ci/build_spec.rb

@@ -2919,6 +2919,36 @@ describe Ci::Build do
     end
   end
+  describe '#any_unmet_prerequisites?' do
+    let(:build) { create(:ci_build, :created) }
+
+    subject { build.any_unmet_prerequisites? }
+
+    context 'build has prerequisites' do
+      before do
+        allow(build).to receive(:prerequisites).and_return([double])
+      end
+
+      it { is_expected.to be_truthy }
+
+      context 'and the ci_preparing_state feature is disabled' do
+        before do
+          stub_feature_flags(ci_preparing_state: false)
+        end
+
+        it { is_expected.to be_falsey }
+      end
+    end
+
+    context 'build does not have prerequisites' do
+      before do
+        allow(build).to receive(:prerequisites).and_return([])
+      end
+
+      it { is_expected.to be_falsey }
+    end
+  end
+
   describe '#yaml_variables' do
     let(:build) { create(:ci_build, pipeline: pipeline, yaml_variables: variables) }

spec/requests/api/project_clusters_spec.rb

@@ -331,7 +331,6 @@ describe API::ProjectClusters do
         it 'should update cluster attributes' do
           expect(cluster.platform_kubernetes.namespace).to eq('new-namespace')
-          expect(cluster.kubernetes_namespace.namespace).to eq('new-namespace')
         end
       end

spec/services/projects/create_service_spec.rb

@@ -276,6 +276,7 @@ describe Projects::CreateService, '#execute' do
     before do
       group.add_owner(user)
+      stub_feature_flags(ci_preparing_state: false)
       expect(Clusters::Gcp::Kubernetes::CreateOrUpdateServiceAccountService).to receive(:namespace_creator).and_return(service_account_creator)
       expect(Clusters::Gcp::Kubernetes::FetchKubernetesTokenService).to receive(:new).and_return(secrets_fetcher)
     end

spec/services/projects/transfer_service_spec.rb

@@ -83,6 +83,7 @@ describe Projects::TransferService do
       subject { transfer_project(project, user, group) }
       before do
+        stub_feature_flags(ci_preparing_state: false)
         expect(Clusters::Gcp::Kubernetes::CreateOrUpdateServiceAccountService).to receive(:namespace_creator).and_return(service_account_creator)
         expect(Clusters::Gcp::Kubernetes::FetchKubernetesTokenService).to receive(:new).and_return(secrets_fetcher)
       end

spec/workers/cluster_configure_worker_spec.rb

@@ -4,6 +4,11 @@ require 'spec_helper'
 describe ClusterConfigureWorker, '#perform' do
   let(:worker) { described_class.new }
+  let(:ci_preparing_state_enabled) { false }
+
+  before do
+    stub_feature_flags(ci_preparing_state: ci_preparing_state_enabled)
+  end
   context 'when group cluster' do
     let(:cluster) { create(:cluster, :group, :provided_by_gcp) }
@@ -66,4 +71,15 @@ describe ClusterConfigureWorker, '#perform' do
       described_class.new.perform(123)
     end
   end
+
+  context 'ci_preparing_state feature is enabled' do
+    let(:cluster) { create(:cluster) }
+    let(:ci_preparing_state_enabled) { true }
+
+    it 'does not configure the cluster' do
+      expect(Clusters::RefreshService).not_to receive(:create_or_update_namespaces_for_cluster)
+
+      described_class.new.perform(cluster.id)
+    end
+  end
 end

spec/workers/cluster_project_configure_worker_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe ClusterProjectConfigureWorker, '#perform' do
+  let(:worker) { described_class.new }
+
+  context 'ci_preparing_state feature is enabled' do
+    let(:cluster) { create(:cluster) }
+
+    before do
+      stub_feature_flags(ci_preparing_state: true)
+    end
+
+    it 'does not configure the cluster' do
+      expect(Clusters::RefreshService).not_to receive(:create_or_update_namespaces_for_project)
+
+      described_class.new.perform(cluster.id)
+    end
+  end
+end