Introduce new ProjectCiCdSetting10244-add-project-ci-cd-settings

This model and the corresponding table will be used for storing settings
specific to CI/CD, starting with the "group_runners_enabled" boolean.

The model is called ProjectCiCdSetting and not ProjectCiCdSettings. The
project exporter doesn't like plural model names as it uses "classify"
which turns those into singular (so "ProjectCiCdSettings" becomes
"ProjectCiCdSetting", producing an error if said class is undefined).

The initial work in this commit was done by Dylan Griffith, with most of
the migration work being done by Yorick Peterse.

3 files changed, 111 insertions, 1 deletions

diff --git a/db/migrate/20180403035759_create_project_ci_cd_settings.rb b/db/migrate/20180403035759_create_project_ci_cd_settings.rb
new file mode 100644
index 00000000000..06856af6204
--- /dev/null
+++ b/db/migrate/20180403035759_create_project_ci_cd_settings.rb
@@ -0,0 +1,68 @@
+class CreateProjectCiCdSettings < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    unless table_exists?(:project_ci_cd_settings)
+      create_table(:project_ci_cd_settings) do |t|
+        t.integer(:project_id, null: false)
+        t.boolean(:group_runners_enabled, default: true, null: false)
+      end
+    end
+
+    disable_statement_timeout
+
+    # This particular INSERT will take between 10 and 20 seconds.
+    execute 'INSERT INTO project_ci_cd_settings (project_id) SELECT id FROM projects'
+
+    # We add the index and foreign key separately so the above INSERT statement
+    # takes as little time as possible.
+    add_concurrent_index(:project_ci_cd_settings, :project_id, unique: true)
+
+    add_foreign_key_with_retry
+  end
+
+  def down
+    drop_table :project_ci_cd_settings
+  end
+
+  def add_foreign_key_with_retry
+    if Gitlab::Database.mysql?
+      # When using MySQL we don't support online upgrades, thus projects can't
+      # be deleted while we are running this migration.
+      return add_project_id_foreign_key
+    end
+
+    # Between the initial INSERT and the addition of the foreign key some
+    # projects may have been removed, leaving orphaned rows in our new settings
+    # table.
+    loop do
+      remove_orphaned_settings
+
+      begin
+        add_project_id_foreign_key
+        break
+      rescue ActiveRecord::InvalidForeignKey
+        say 'project_ci_cd_settings contains some orphaned rows, retrying...'
+      end
+    end
+  end
+
+  def add_project_id_foreign_key
+    add_concurrent_foreign_key(:project_ci_cd_settings, :projects, column: :project_id)
+  end
+
+  def remove_orphaned_settings
+    execute <<~SQL
+      DELETE FROM project_ci_cd_settings
+      WHERE NOT EXISTS (
+        SELECT 1
+        FROM projects
+        WHERE projects.id = project_ci_cd_settings.project_id
+      )
+    SQL
+  end
+end
diff --git a/db/post_migrate/20180409170809_populate_missing_project_ci_cd_settings.rb b/db/post_migrate/20180409170809_populate_missing_project_ci_cd_settings.rb
new file mode 100644
index 00000000000..3b0fdb3aeea
--- /dev/null
+++ b/db/post_migrate/20180409170809_populate_missing_project_ci_cd_settings.rb
@@ -0,0 +1,34 @@
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class PopulateMissingProjectCiCdSettings < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    # MySQL does not support online upgrades, thus there can't be any missing
+    # rows.
+    return if Gitlab::Database.mysql?
+
+    # Projects created after the initial migration but before the code started
+    # using ProjectCiCdSetting won't have a corresponding row in
+    # project_ci_cd_settings, so let's fix that.
+    execute <<~SQL
+      INSERT INTO project_ci_cd_settings (project_id)
+      SELECT id
+      FROM projects
+      WHERE NOT EXISTS (
+        SELECT 1
+        FROM project_ci_cd_settings
+        WHERE project_ci_cd_settings.project_id = projects.id
+      )
+    SQL
+  end
+
+  def down
+    # There's nothing to revert for this migration.
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index fd75b176318..d741f0113d8 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20180405142733) do
+ActiveRecord::Schema.define(version: 20180409170809) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -1432,6 +1432,13 @@ ActiveRecord::Schema.define(version: 20180405142733) do
 
   add_index "project_auto_devops", ["project_id"], name: "index_project_auto_devops_on_project_id", unique: true, using: :btree
 
+  create_table "project_ci_cd_settings", force: :cascade do |t|
+    t.integer "project_id", null: false
+    t.boolean "group_runners_enabled", default: true, null: false
+  end
+
+  add_index "project_ci_cd_settings", ["project_id"], name: "index_project_ci_cd_settings_on_project_id", unique: true, using: :btree
+
   create_table "project_custom_attributes", force: :cascade do |t|
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
@@ -2157,6 +2164,7 @@ ActiveRecord::Schema.define(version: 20180405142733) do
   add_foreign_key "project_authorizations", "projects", on_delete: :cascade
   add_foreign_key "project_authorizations", "users", on_delete: :cascade
   add_foreign_key "project_auto_devops", "projects", on_delete: :cascade
+  add_foreign_key "project_ci_cd_settings", "projects", name: "fk_24c15d2f2e", on_delete: :cascade
   add_foreign_key "project_custom_attributes", "projects", on_delete: :cascade
   add_foreign_key "project_deploy_tokens", "deploy_tokens", on_delete: :cascade
   add_foreign_key "project_deploy_tokens", "projects", on_delete: :cascade