Commit cda01665 authored by Rémy Coutable's avatar Rémy Coutable

Merge branch '23223-group-deletion-race-condition' into 'master'

Remove race condition while deleting groups

## What does this MR do?

The intended flow during a group deletion is:

```
  Soft-delete group (sync) -> Delete group projects (async) -> Hard-delete group (async)
```

The soft-delete was run in a transaction, which was committed only after
the async job (for hard-deletion) was kicked off. There was a race
condition here - the soft-delete transaction could complete _after_ the
hard delete completed, leaving a soft-deleted record in the database.

This MR removes this race condition. There is no need to run the
soft-delete in a transaction. The soft-delete completes before the async
job is kicked off.

This MR also adds a migration to delete all existing (soft-deleted) groups left in an inconsistent state
due to this bug.

- Closes #23223 
- EE merge request: gitlab-org/gitlab-ee!886

See merge request !7528
parents bccdf9f5 6806fdf0
......@@ -6,12 +6,10 @@ class DestroyGroupService
end
def async_execute
group.transaction do
# Soft delete via paranoia gem
group.destroy
job_id = GroupDestroyWorker.perform_async(group.id, current_user.id)
Rails.logger.info("User #{current_user.id} scheduled a deletion of group ID #{group.id} with job ID #{job_id}")
end
# Soft delete via paranoia gem
group.destroy
job_id = GroupDestroyWorker.perform_async(group.id, current_user.id)
Rails.logger.info("User #{current_user.id} scheduled a deletion of group ID #{group.id} with job ID #{job_id}")
end
def execute
......
---
title: Fix race condition during group deletion and remove stale records present due to this bug
merge_request: 7528
author: Timothy Andrew
# See http://doc.gitlab.com/ce/development/migration_style_guide.html
# for more information on how to write migrations for GitLab.
class RemoveUndeletedGroups < ActiveRecord::Migration
DOWNTIME = false
def up
execute "DELETE FROM namespaces WHERE deleted_at IS NOT NULL;"
end
def down
# This is an irreversible migration;
# If someone is trying to rollback for other reasons, we should not throw an Exception.
# raise ActiveRecord::IrreversibleMigration
end
end
......@@ -11,7 +11,7 @@
#
# It's strongly recommended that you check this file into your version control system.
ActiveRecord::Schema.define(version: 20161113184239) do
ActiveRecord::Schema.define(version: 20161117114805) do
# These are extensions that must be enabled in order to support this database
enable_extension "plpgsql"
......
require 'spec_helper'
describe DestroyGroupService, services: true do
include DatabaseConnectionHelpers
let!(:user) { create(:user) }
let!(:group) { create(:group) }
let!(:project) { create(:project, namespace: group) }
......@@ -50,6 +52,44 @@ describe DestroyGroupService, services: true do
describe 'asynchronous delete' do
it_behaves_like 'group destruction', true
context 'potential race conditions' do
context "when the `GroupDestroyWorker` task runs immediately" do
it "deletes the group" do
# Commit the contents of this spec's transaction so far
# so subsequent db connections can see it.
#
# DO NOT REMOVE THIS LINE, even if you see a WARNING with "No
# transaction is currently in progress". Without this, this
# spec will always be green, since the group created in setup
# cannot be seen by any other connections / threads in this spec.
Group.connection.commit_db_transaction
group_record = run_with_new_database_connection do |conn|
conn.execute("SELECT * FROM namespaces WHERE id = #{group.id}").first
end
expect(group_record).not_to be_nil
# Execute the contents of `GroupDestroyWorker` in a separate thread, to
# simulate data manipulation by the Sidekiq worker (different database
# connection / transaction).
expect(GroupDestroyWorker).to receive(:perform_async).and_wrap_original do |m, group_id, user_id|
Thread.new { m[group_id, user_id] }.join(5)
end
# Kick off the initial group destroy in a new thread, so that
# it doesn't share this spec's database transaction.
Thread.new { DestroyGroupService.new(group, user).async_execute }.join(5)
group_record = run_with_new_database_connection do |conn|
conn.execute("SELECT * FROM namespaces WHERE id = #{group.id}").first
end
expect(group_record).to be_nil
end
end
end
end
describe 'synchronous delete' do
......
module DatabaseConnectionHelpers
def run_with_new_database_connection
pool = ActiveRecord::Base.connection_pool
conn = pool.checkout
yield conn
ensure
pool.checkin(conn)
end
end
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