From 8a8ddec661eb7a4bca740285622bb3f8419732fd Mon Sep 17 00:00:00 2001
From: Tiger <twatson@gitlab.com>
Date: Thu, 6 Jun 2019 16:45:00 +1000
Subject: [PATCH] Migrate project level clusters with no Kubernetes namespace
 to unmanaged

These clusters were created before we introduced the
option to manage your own cluster, and not having a
Kubernetes namespace present means that we have tried
and failed to create one - and therefore we cannot manage
your cluster for you.

The 5 minute window should prevent a race condition
where a cluster has only just been created and we
haven't had a chance to create any resources for it
yet.
---
 ...-migrate-managed-clusters-to-unmanaged.yml |  6 ++
 ...te_legacy_managed_clusters_to_unmanaged.rb | 48 ++++++++++++++++
 ...gacy_managed_clusters_to_unmanaged_spec.rb | 55 +++++++++++++++++++
 3 files changed, 109 insertions(+)
 create mode 100644 changelogs/unreleased/62772-migrate-managed-clusters-to-unmanaged.yml
 create mode 100644 db/post_migrate/20190606163724_migrate_legacy_managed_clusters_to_unmanaged.rb
 create mode 100644 spec/migrations/migrate_legacy_managed_clusters_to_unmanaged_spec.rb

diff --git a/changelogs/unreleased/62772-migrate-managed-clusters-to-unmanaged.yml b/changelogs/unreleased/62772-migrate-managed-clusters-to-unmanaged.yml
new file mode 100644
index 00000000000..62a67c7b78d
--- /dev/null
+++ b/changelogs/unreleased/62772-migrate-managed-clusters-to-unmanaged.yml
@@ -0,0 +1,6 @@
+---
+title: Migrate GitLab managed project-level clusters to unmanaged if a Kubernetes
+  namespace was unable to be created
+merge_request: 29251
+author:
+type: other
diff --git a/db/post_migrate/20190606163724_migrate_legacy_managed_clusters_to_unmanaged.rb b/db/post_migrate/20190606163724_migrate_legacy_managed_clusters_to_unmanaged.rb
new file mode 100644
index 00000000000..759ab939f7d
--- /dev/null
+++ b/db/post_migrate/20190606163724_migrate_legacy_managed_clusters_to_unmanaged.rb
@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class MigrateLegacyManagedClustersToUnmanaged < ActiveRecord::Migration[5.1]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  class Cluster < ActiveRecord::Base
+    include EachBatch
+
+    self.table_name = 'clusters'
+
+    has_many :kubernetes_namespaces, class_name: 'MigrateLegacyManagedClustersToUnmanaged::KubernetesNamespace'
+
+    scope :managed, -> { where(managed: true) }
+
+    enum cluster_type: {
+      instance_type: 1,
+      group_type: 2,
+      project_type: 3
+    }
+  end
+
+  class KubernetesNamespace < ActiveRecord::Base
+    self.table_name = 'clusters_kubernetes_namespaces'
+
+    belongs_to :cluster, class_name: 'MigrateLegacyManagedClustersToUnmanaged::Cluster'
+  end
+
+  def up
+    Cluster.managed
+      .project_type
+      .left_joins(:kubernetes_namespaces)
+      .where(clusters_kubernetes_namespaces: { cluster_id: nil })
+      .where('clusters.created_at < ?', 5.minutes.ago)
+      .each_batch do |batch|
+        batch.update_all(managed: false)
+      end
+  end
+
+  def down
+  end
+end
diff --git a/spec/migrations/migrate_legacy_managed_clusters_to_unmanaged_spec.rb b/spec/migrations/migrate_legacy_managed_clusters_to_unmanaged_spec.rb
new file mode 100644
index 00000000000..93426f1f273
--- /dev/null
+++ b/spec/migrations/migrate_legacy_managed_clusters_to_unmanaged_spec.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require Rails.root.join('db', 'post_migrate', '20190606163724_migrate_legacy_managed_clusters_to_unmanaged.rb')
+
+describe MigrateLegacyManagedClustersToUnmanaged, :migration do
+  let(:cluster_type) { 'project_type' }
+  let(:created_at) { 1.hour.ago }
+
+  let!(:cluster) do
+    table(:clusters).create!(
+      name: 'cluster',
+      cluster_type: described_class::Cluster.cluster_types[cluster_type],
+      managed: true,
+      created_at: created_at
+    )
+  end
+
+  it 'marks the cluster as unmanaged' do
+    migrate!
+    expect(cluster.reload).not_to be_managed
+  end
+
+  context 'cluster is not project type' do
+    let(:cluster_type) { 'group_type' }
+
+    it 'does not update the cluster' do
+      migrate!
+      expect(cluster.reload).to be_managed
+    end
+  end
+
+  context 'cluster has a kubernetes namespace associated' do
+    before do
+      table(:clusters_kubernetes_namespaces).create!(
+        cluster_id: cluster.id,
+        namespace: 'namespace'
+      )
+    end
+
+    it 'does not update the cluster' do
+      migrate!
+      expect(cluster.reload).to be_managed
+    end
+  end
+
+  context 'cluster was recently created' do
+    let(:created_at) { 2.minutes.ago }
+
+    it 'does not update the cluster' do
+      migrate!
+      expect(cluster.reload).to be_managed
+    end
+  end
+end