Adds chaos endpoints to Sidekiq

This allows the chaos endpoints to be invoked in Sidekiq so that this
environment can be tested for resilience.

app/controllers/chaos_controller.rb

 # frozen_string_literal: true
 
 class ChaosController < ActionController::Base
-  before_action :validate_chaos_secret, unless: :development?
-  before_action :request_start_time
+  before_action :validate_chaos_secret, unless: :development_or_test?
 
   def leakmem
-    retainer = []
-    # Add `n` 1mb chunks of memory to the retainer array
-    memory_mb.times { retainer << "x" * 1.megabyte }
-
-    Kernel.sleep(duration_left)
-
-    render plain: "OK"
+    do_chaos :leak_mem, Chaos::LeakMemWorker, memory_mb, duration_s
   end
 
   def cpu_spin
-    rand while Time.now < expected_end_time
-
-    render plain: "OK"
+    do_chaos :cpu_spin, Chaos::CpuSpinWorker, duration_s
   end
 
   def db_spin
-    while Time.now < expected_end_time
-      ActiveRecord::Base.connection.execute("SELECT 1")
-
-      end_interval_time = Time.now + [duration_s, interval_s].min
-      rand while Time.now < end_interval_time
-    end
+    do_chaos :db_spin, Chaos::DbSpinWorker, duration_s, interval_s
   end
 
   def sleep
-    Kernel.sleep(duration_left)
-
-    render plain: "OK"
+    do_chaos :sleep, Chaos::SleepWorker, duration_s
   end
 
   def kill
-    Process.kill("KILL", Process.pid)
+    do_chaos :kill, Chaos::KillWorker
   end
 
   private
 
-  def request_start_time
-    @start_time ||= Time.now
-  end
-
-  def expected_end_time
-    request_start_time + duration_s
-  end
+  def do_chaos(method, worker, *args)
+    if async
+      worker.perform_async(*args)
+    else
+      Gitlab::Chaos.public_send(method, *args) # rubocop: disable GitlabSecurity/PublicSend
+    end
 
-  def duration_left
-    # returns 0 if over time
-    [expected_end_time - Time.now, 0].max
+    render plain: "OK"
   end
 
   def validate_chaos_secret
@@ -91,7 +72,12 @@ class ChaosController < ActionController::Base
     memory_mb.to_i
   end
 
-  def development?
-    Rails.env.development?
+  def async
+    async = params[:async] || false
+    Gitlab::Utils.to_boolean(async)
+  end
+
+  def development_or_test?
+    Rails.env.development? || Rails.env.test?
   end
 end

app/workers/all_queues.yml

@@ -3,6 +3,12 @@
 
 - auto_merge:auto_merge_process
 
+- chaos:chaos_cpu_spin
+- chaos:chaos_db_spin
+- chaos:chaos_kill
+- chaos:chaos_leak_mem
+- chaos:chaos_sleep
+
 - cronjob:admin_email
 - cronjob:expire_build_artifacts
 - cronjob:gitlab_usage_ping

app/workers/chaos/cpu_spin_worker.rb

+# frozen_string_literal: true
+
+module Chaos
+  class CpuSpinWorker
+    include ApplicationWorker
+    include ChaosQueue
+
+    def perform(duration_s)
+      Gitlab::Chaos.cpu_spin(duration_s)
+    end
+  end
+end

app/workers/chaos/db_spin_worker.rb

+# frozen_string_literal: true
+
+module Chaos
+  class DbSpinWorker
+    include ApplicationWorker
+    include ChaosQueue
+
+    def perform(duration_s, interval_s)
+      Gitlab::Chaos.db_spin(duration_s, interval_s)
+    end
+  end
+end

app/workers/chaos/kill_worker.rb

+# frozen_string_literal: true
+
+module Chaos
+  class KillWorker
+    include ApplicationWorker
+    include ChaosQueue
+
+    def perform
+      Gitlab::Chaos.kill
+    end
+  end
+end

app/workers/chaos/leak_mem_worker.rb

+# frozen_string_literal: true
+
+module Chaos
+  class LeakMemWorker
+    include ApplicationWorker
+    include ChaosQueue
+
+    def perform(memory_mb, duration_s)
+      Gitlab::Chaos.leak_mem(memory_mb, duration_s)
+    end
+  end
+end

app/workers/chaos/sleep_worker.rb

+# frozen_string_literal: true
+
+module Chaos
+  class SleepWorker
+    include ApplicationWorker
+    include ChaosQueue
+
+    def perform(duration_s)
+      Gitlab::Chaos.sleep(duration_s)
+    end
+  end
+end

app/workers/concerns/chaos_queue.rb

+# frozen_string_literal: true
+#
+module ChaosQueue
+  extend ActiveSupport::Concern
+
+  included do
+    queue_namespace :chaos
+  end
+end

changelogs/unreleased/an-sidekiq-chaos.yml

+---
+title: Adds chaos endpoints to Sidekiq
+merge_request: 30814
+author:
+type: other

config/routes.rb

@@ -116,7 +116,7 @@ Rails.application.routes.draw do
       end
     end
 
-    if ENV['GITLAB_CHAOS_SECRET'] || Rails.env.development?
+    if ENV['GITLAB_CHAOS_SECRET'] || Rails.env.development? || Rails.env.test?
       resource :chaos, only: [] do
         get :leakmem
         get :cpu_spin

config/sidekiq_queues.yml

@@ -95,6 +95,7 @@
   - [update_project_statistics, 1]
   - [phabricator_import_import_tasks, 1]
   - [update_namespace_statistics, 1]
+  - [chaos, 2]
 
   # EE-specific queues
   - [ldap_group_sync, 2]

doc/development/chaos_endpoints.md

@@ -36,6 +36,10 @@ Replace `secret` with your own secret token.
 
 Once you have enabled the chaos endpoints and restarted the application, you can start testing using the endpoints.
 
+By default, when invoking a chaos endpoint, the web worker process which receives the request will handle it. This means, for example, that if the Kill
+operation is invoked, the Puma or Unicorn worker process handling the request will be killed. To test these operations in Sidekiq, the `async` parameter on
+each endpoint can be set to `true`. This will run the chaos process in a Sidekiq worker.
+
 ## Memory leaks
 
 To simulate a memory leak in your application, use the `/-/chaos/leakmem` endpoint.
@@ -47,12 +51,14 @@ The memory is not retained after the request finishes. Once the request has comp
 GET /-/chaos/leakmem
 GET /-/chaos/leakmem?memory_mb=1024
 GET /-/chaos/leakmem?memory_mb=1024&duration_s=50
+GET /-/chaos/leakmem?memory_mb=1024&duration_s=50&async=true
 ```
 
-| Attribute    | Type    | Required | Description                                                                        |
-| ------------ | ------- | -------- | ---------------------------------------------------------------------------------- |
-| `memory_mb`  | integer | no       | How much memory, in MB, should be leaked. Defaults to 100MB.                       |
+| Attribute    | Type    | Required | Description                                                                          |
+| ------------ | ------- | -------- | ------------------------------------------------------------------------------------ |
+| `memory_mb`  | integer | no       | How much memory, in MB, should be leaked. Defaults to 100MB.                         |
 | `duration_s` | integer | no       | Minimum duration_s, in seconds, that the memory should be retained. Defaults to 30s. |
+| `async`      | boolean | no       | Set to true to leak memory in a Sidekiq background worker process                    |
 
 ```bash
 curl http://localhost:3000/-/chaos/leakmem?memory_mb=1024&duration_s=10 --header 'X-Chaos-Secret: secret'
@@ -69,11 +75,13 @@ If you're using Unicorn, this is done by killing the worker process.
 ```
 GET /-/chaos/cpu_spin
 GET /-/chaos/cpu_spin?duration_s=50
+GET /-/chaos/cpu_spin?duration_s=50&async=true
 ```
 
 | Attribute    | Type    | Required | Description                                                           |
 | ------------ | ------- | -------- | --------------------------------------------------------------------- |
 | `duration_s` | integer | no       | Duration, in seconds, that the core will be utilised. Defaults to 30s |
+| `async`      | boolean | no       | Set to true to consume CPU in a Sidekiq background worker process     |
 
 ```bash
 curl http://localhost:3000/-/chaos/cpu_spin?duration_s=60 --header 'X-Chaos-Secret: secret'
@@ -91,12 +99,14 @@ If you're using Unicorn, this is done by killing the worker process.
 ```
 GET /-/chaos/db_spin
 GET /-/chaos/db_spin?duration_s=50
+GET /-/chaos/db_spin?duration_s=50&async=true
 ```
 
-| Attribute    | Type    | Required | Description                                                           |
-| ------------ | ------- | -------- | --------------------------------------------------------------------- |
-| `interval_s` | float   | no       | Interval, in seconds, for every DB request. Defaults to 1s            |
-| `duration_s` | integer | no       | Duration, in seconds, that the core will be utilised. Defaults to 30s |
+| Attribute    | Type    | Required | Description                                                                 |
+| ------------ | ------- | -------- | --------------------------------------------------------------------------- |
+| `interval_s` | float   | no       | Interval, in seconds, for every DB request. Defaults to 1s                  |
+| `duration_s` | integer | no       | Duration, in seconds, that the core will be utilised. Defaults to 30s       |
+| `async`      | boolean | no       | Set to true to perform the operation in a Sidekiq background worker process |
 
 ```bash
 curl http://localhost:3000/-/chaos/db_spin?interval_s=1&duration_s=60 --header 'X-Chaos-Secret: secret'
@@ -112,11 +122,13 @@ As with the CPU Spin endpoint, this may lead to your request timing out if durat
 ```
 GET /-/chaos/sleep
 GET /-/chaos/sleep?duration_s=50
+GET /-/chaos/sleep?duration_s=50&async=true
 ```
 
 | Attribute    | Type    | Required | Description                                                            |
 | ------------ | ------- | -------- | ---------------------------------------------------------------------- |
 | `duration_s` | integer | no       | Duration, in seconds, that the request will sleep for. Defaults to 30s |
+| `async`      | boolean | no       | Set to true to sleep in a Sidekiq background worker process            |
 
 ```bash
 curl http://localhost:3000/-/chaos/sleep?duration_s=60 --header 'X-Chaos-Secret: secret'
@@ -132,8 +144,13 @@ Since this endpoint uses the `KILL` signal, the worker is not given a chance to
 
 ```
 GET /-/chaos/kill
+GET /-/chaos/kill?async=true
 ```
 
+| Attribute    | Type    | Required | Description                                                            |
+| ------------ | ------- | -------- | ---------------------------------------------------------------------- |
+| `async`      | boolean | no       | Set to true to kill a Sidekiq background worker process                |
+
 ```bash
 curl http://localhost:3000/-/chaos/kill --header 'X-Chaos-Secret: secret'
 curl http://localhost:3000/-/chaos/kill?token=secret

lib/gitlab/chaos.rb

+# frozen_string_literal: true
+
+module Gitlab
+  # Chaos methods for GitLab.
+  # See https://docs.gitlab.com/ee/development/chaos_endpoints.html for more details.
+  class Chaos
+    # leak_mem will retain the specified amount of memory and sleep.
+    # On return, the memory will be released.
+    def self.leak_mem(memory_mb, duration_s)
+      start_time = Time.now
+
+      retainer = []
+      # Add `n` 1mb chunks of memory to the retainer array
+      memory_mb.times { retainer << "x" * 1.megabyte }
+
+      duration_left = [start_time + duration_s - Time.now, 0].max
+      Kernel.sleep(duration_left)
+    end
+
+    # cpu_spin will consume all CPU on a single core for the specified duration
+    def self.cpu_spin(duration_s)
+      expected_end_time = Time.now + duration_s
+
+      rand while Time.now < expected_end_time
+    end
+
+    # db_spin will query the database in a tight loop for the specified duration
+    def self.db_spin(duration_s, interval_s)
+      expected_end_time = Time.now + duration_s
+
+      while Time.now < expected_end_time
+        ActiveRecord::Base.connection.execute("SELECT 1")
+
+        end_interval_time = Time.now + [duration_s, interval_s].min
+        rand while Time.now < end_interval_time
+      end
+    end
+
+    # sleep will sleep for the specified duration
+    def self.sleep(duration_s)
+      Kernel.sleep(duration_s)
+    end
+
+    # Kill will send a SIGKILL signal to the current process
+    def self.kill
+      Process.kill("KILL", Process.pid)
+    end
+  end
+end

spec/controllers/chaos_controller_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe ChaosController do
+  describe '#leakmem' do
+    it 'calls synchronously' do
+      expect(Gitlab::Chaos).to receive(:leak_mem).with(100, 30.seconds)
+
+      get :leakmem
+
+      expect(response).to have_gitlab_http_status(200)
+    end
+
+    it 'call synchronously with params' do
+      expect(Gitlab::Chaos).to receive(:leak_mem).with(1, 2.seconds)
+
+      get :leakmem, params: { memory_mb: 1, duration_s: 2 }
+
+      expect(response).to have_gitlab_http_status(200)
+    end
+
+    it 'calls asynchronously' do
+      expect(Chaos::LeakMemWorker).to receive(:perform_async).with(100, 30.seconds)
+
+      get :leakmem, params: { async: 1 }
+
+      expect(response).to have_gitlab_http_status(200)
+    end
+  end
+
+  describe '#cpu_spin' do
+    it 'calls synchronously' do
+      expect(Gitlab::Chaos).to receive(:cpu_spin).with(30.seconds)
+
+      get :cpu_spin
+
+      expect(response).to have_gitlab_http_status(200)
+    end
+
+    it 'calls synchronously with params' do
+      expect(Gitlab::Chaos).to receive(:cpu_spin).with(3.seconds)
+
+      get :cpu_spin, params: { duration_s: 3 }
+
+      expect(response).to have_gitlab_http_status(200)
+    end
+
+    it 'calls asynchronously' do
+      expect(Chaos::CpuSpinWorker).to receive(:perform_async).with(30.seconds)
+
+      get :cpu_spin, params: { async: 1 }
+
+      expect(response).to have_gitlab_http_status(200)
+    end
+  end
+
+  describe '#db_spin' do
+    it 'calls synchronously' do
+      expect(Gitlab::Chaos).to receive(:db_spin).with(30.seconds, 1.second)
+
+      get :db_spin
+
+      expect(response).to have_gitlab_http_status(200)
+    end
+
+    it 'calls synchronously with params' do
+      expect(Gitlab::Chaos).to receive(:db_spin).with(4.seconds, 5.seconds)
+
+      get :db_spin, params: { duration_s: 4, interval_s: 5 }
+
+      expect(response).to have_gitlab_http_status(200)
+    end
+
+    it 'calls asynchronously' do
+      expect(Chaos::DbSpinWorker).to receive(:perform_async).with(30.seconds, 1.second)
+
+      get :db_spin, params: { async: 1 }
+
+      expect(response).to have_gitlab_http_status(200)
+    end
+  end
+
+  describe '#sleep' do
+    it 'calls synchronously' do
+      expect(Gitlab::Chaos).to receive(:sleep).with(30.seconds)
+
+      get :sleep
+
+      expect(response).to have_gitlab_http_status(200)
+    end
+
+    it 'calls synchronously with params' do
+      expect(Gitlab::Chaos).to receive(:sleep).with(5.seconds)
+
+      get :sleep, params: { duration_s: 5 }
+
+      expect(response).to have_gitlab_http_status(200)
+    end
+
+    it 'calls asynchronously' do
+      expect(Chaos::SleepWorker).to receive(:perform_async).with(30.seconds)
+
+      get :sleep, params: { async: 1 }
+
+      expect(response).to have_gitlab_http_status(200)
+    end
+  end
+
+  describe '#kill' do
+    it 'calls synchronously' do
+      expect(Gitlab::Chaos).to receive(:kill).with(no_args)
+
+      get :kill
+
+      expect(response).to have_gitlab_http_status(200)
+    end
+
+    it 'calls asynchronously' do
+      expect(Chaos::KillWorker).to receive(:perform_async).with(no_args)
+
+      get :kill, params: { async: 1 }
+
+      expect(response).to have_gitlab_http_status(200)
+    end
+  end
+end