Bullet

The Bullet gem is designed to help you increase your application's performance by reducing the number of queries it makes. It will watch your queries while you develop your application and notify you when you should add eager loading (N+1 queries), when you're using eager loading that isn't necessary and when you should use counter cache.

Best practice is to use Bullet in development mode or custom mode (staging, profile, etc.). The last thing you want is your clients getting alerts about how lazy you are.

Bullet gem now supports activerecord >= 4.0 and mongoid >= 4.0.

If you use activerecord 2.x, please use bullet <= 4.5.0

If you use activerecord 3.x, please use bullet < 5.5.0

External Introduction

• http://railscasts.com/episodes/372-bullet
• http://ruby5.envylabs.com/episodes/9-episode-8-september-8-2009
• http://railslab.newrelic.com/2009/10/23/episode-19-on-the-edge-part-1
• http://weblog.rubyonrails.org/2009/10/22/community-highlights

Install

You can install it as a gem:

gem install bullet

or add it into a Gemfile (Bundler):

gem'bullet',group: 'development'

enable the Bullet gem with generate command

bundleexecrailsgbullet:install

The generate command will auto generate the default configuration and may ask to include in the test environment as well. See below for custom configuration.

Note: make sure bullet gem is added after activerecord (rails) and mongoid.

Configuration

Bullet won't do ANYTHING unless you tell it to explicitly. Append to config/environments/development.rb initializer with the following code:

config.after_initializedoBullet.enable=trueBullet.sentry=trueBullet.alert=trueBullet.bullet_logger=trueBullet.console=trueBullet.growl=trueBullet.xmpp={:account=>'bullets_account@jabber.org',:password=>'bullets_password_for_jabber',:receiver=>'your_account@jabber.org',:show_online_status=>true}Bullet.rails_logger=trueBullet.honeybadger=trueBullet.bugsnag=trueBullet.appsignal=trueBullet.airbrake=trueBullet.rollbar=trueBullet.add_footer=trueBullet.skip_html_injection=falseBullet.stacktrace_includes=['your_gem','your_middleware']Bullet.stacktrace_excludes=['their_gem','their_middleware',['my_file.rb','my_method'],['my_file.rb',16..20]]Bullet.slack={webhook_url: 'http://some.slack.url',channel: '#default',username: 'notifier'}end

The notifier of Bullet is a wrap of uniform_notifier

The code above will enable all of the Bullet notification systems:

• Bullet.enable: enable Bullet gem, otherwise do nothing
• Bullet.alert: pop up a JavaScript alert in the browser
• Bullet.bullet_logger: log to the Bullet log file (Rails.root/log/bullet.log)
• Bullet.console: log warnings to your browser's console.log (Safari/Webkit browsers or Firefox w/Firebug installed)
• Bullet.growl: pop up Growl warnings if your system has Growl installed. Requires a little bit of configuration
• Bullet.xmpp: send XMPP/Jabber notifications to the receiver indicated. Note that the code will currently not handle the adding of contacts, so you will need to make both accounts indicated know each other manually before you will receive any notifications. If you restart the development server frequently, the 'coming online' sound for the Bullet account may start to annoy - in this case set :show_online_status to false; you will still get notifications, but the Bullet account won't announce it's online status anymore.
• Bullet.rails_logger: add warnings directly to the Rails log
• Bullet.honeybadger: add notifications to Honeybadger
• Bullet.bugsnag: add notifications to bugsnag
• Bullet.airbrake: add notifications to airbrake
• Bullet.appsignal: add notifications to AppSignal
• Bullet.rollbar: add notifications to rollbar
• Bullet.sentry: add notifications to sentry
• Bullet.add_footer: adds the details in the bottom left corner of the page. Double click the footer or use close button to hide footer.
• Bullet.skip_html_injection: prevents Bullet from injecting code into the returned HTML. This must be false for receiving alerts, showing the footer or console logging.
• Bullet.skip_http_headers: don't add headers to API requests, and remove the javascript that relies on them. Note that this prevents bullet from logging warnings to the browser console or updating the footer.
• Bullet.stacktrace_includes: include paths with any of these substrings in the stack trace, even if they are not in your main app
• Bullet.stacktrace_excludes: ignore paths with any of these substrings in the stack trace, even if they are not in your main app. Each item can be a string (match substring), a regex, or an array where the first item is a path to match, and the second item is a line number, a Range of line numbers, or a (bare) method name, to exclude only particular lines in a file.
• Bullet.slack: add notifications to slack
• Bullet.raise: raise errors, useful for making your specs fail unless they have optimized queries

Bullet also allows you to disable any of its detectors.

# Each of these settings defaults to true# Detect N+1 queriesBullet.n_plus_one_query_enable=false# Detect eager-loaded associations which are not usedBullet.unused_eager_loading_enable=false# Detect unnecessary COUNT queries which could be avoided# with a counter_cacheBullet.counter_cache_enable=false

Whitelist

Sometimes Bullet may notify you of query problems you don't care to fix, or which come from outside your code. You can whitelist these to ignore them:

Bullet.add_whitelist:type=>:n_plus_one_query,:class_name=>"Post",:association=>:commentsBullet.add_whitelist:type=>:unused_eager_loading,:class_name=>"Post",:association=>:commentsBullet.add_whitelist:type=>:counter_cache,:class_name=>"Country",:association=>:cities

If you want to skip bullet in some specific controller actions, you can do like

classApplicationController < ActionController::Basearound_action:skip_bullet,if: ->{defined?(Bullet)}defskip_bulletprevious_value=Bullet.enable?Bullet.enable=falseyieldensureBullet.enable=previous_valueendend

Log

The Bullet log log/bullet.log will look something like this:

• N+1 Query:

2009-08-25 20:40:17[INFO] N+1 Query: PATH_INFO: /posts; model: Post => associations: [comments]·
Add to your finder: :include => [:comments]
2009-08-25 20:40:17[INFO] N+1 Query: method call stack:·
/Users/richard/Downloads/test/app/views/posts/index.html.erb:11:in `_run_erb_app47views47posts47index46html46erb'
/Users/richard/Downloads/test/app/views/posts/index.html.erb:8:in `each'
/Users/richard/Downloads/test/app/views/posts/index.html.erb:8:in `_run_erb_app47views47posts47index46html46erb'
/Users/richard/Downloads/test/app/controllers/posts_controller.rb:7:in `index'

The first two lines are notifications that N+1 queries have been encountered. The remaining lines are stack traces so you can find exactly where the queries were invoked in your code, and fix them.

• Unused eager loading:

2009-08-25 20:53:56[INFO] Unused eager loadings: PATH_INFO: /posts; model: Post => associations: [comments]·
Remove from your finder: :include => [:comments]

These two lines are notifications that unused eager loadings have been encountered.

• Need counter cache:

2009-09-11 09:46:50[INFO] Need Counter Cache
Post => [:comments]

Growl, XMPP/Jabber and Airbrake Support

see https://github.com/flyerhzm/uniform_notifier

Important

If you find Bullet does not work for you, please disable your browser's cache.

Advanced

Work with ActiveJob

Include Bullet::ActiveJob in your ApplicationJob.

classApplicationJob < ActiveJob::BaseincludeBullet::ActiveJobifRails.env.development?end

Work with other background job solution

Use the Bullet.profile method.

classApplicationJob < ActiveJob::Basearound_performdo |_job,block|
Bullet.profiledoblock.callendendend

Work with sinatra

Configure and use Bullet::Rack

configure:developmentdoBullet.enable=trueBullet.bullet_logger=trueuseBullet::Rackend

Run in tests

First you need to enable Bullet in test environment.

# config/environments/test.rbconfig.after_initializedoBullet.enable=trueBullet.bullet_logger=trueBullet.raise=true# raise an error if n+1 query occursend

Then wrap each test in Bullet api.

# spec/rails_helper.rbifBullet.enable?config.before(:each)doBullet.start_requestendconfig.after(:each)doBullet.perform_out_of_channel_notificationsifBullet.notification?Bullet.end_requestendend

Debug Mode

Bullet outputs some details info, to enable debug mode, set BULLET_DEBUG=true env.

Contributors

https://github.com/flyerhzm/bullet/contributors

Demo

Bullet is designed to function as you browse through your application in development. To see it in action, you can visit https://github.com/flyerhzm/bullet_test or follow these steps to create, detect, and fix example query problems.

1. Create an example application

$ rails new test_bullet
$ cd test_bullet
$ rails g scaffold post name:string
$ rails g scaffold comment name:string post_id:integer
$ bundle exec rake db:migrate

2. Change app/model/post.rb and app/model/comment.rb

classPost < ActiveRecord::Basehas_many:commentsendclassComment < ActiveRecord::Basebelongs_to:postend

3. Go to rails c and execute

post1=Post.create(:name=>'first')post2=Post.create(:name=>'second')post1.comments.create(:name=>'first')post1.comments.create(:name=>'second')post2.comments.create(:name=>'third')post2.comments.create(:name=>'fourth')

4. Change the app/views/posts/index.html.erb to produce a N+1 query

<% @posts.each do |post| %>
<tr>
<td><%= post.name %></td>
<td><%= post.comments.map(&:name) %></td>
<td><%= link_to 'Show', post %></td>
<td><%= link_to 'Edit', edit_post_path(post) %></td>
<td><%= link_to 'Destroy', post, :confirm => 'Are you sure?', :method => :delete %></td>
</tr>
<% end %>

5. Add the bullet gem to the Gemfile

gem"bullet"

And run

bundle install

6. enable the Bullet gem with generate command

bundle exec rails g bullet:install

7. Start the server

$ rails s

8. Visit http://localhost:3000/posts in browser, and you will see a popup alert box that says

The request has unused preload associations as follows:
None
The request has N+1 queries as follows:
model: Post => associations: [comment]

which means there is a N+1 query from the Post object to its Comment association.

In the meantime, there's a log appended into log/bullet.log file

2010-03-07 14:12:18[INFO] N+1 Query in /posts
Post => [:comments]
Add to your finder: :include => [:comments]
2010-03-07 14:12:18[INFO] N+1 Query method call stack
/home/flyerhzm/Downloads/test_bullet/app/views/posts/index.html.erb:14:in `_render_template__600522146_80203160_0'
/home/flyerhzm/Downloads/test_bullet/app/views/posts/index.html.erb:11:in `each'
/home/flyerhzm/Downloads/test_bullet/app/views/posts/index.html.erb:11:in `_render_template__600522146_80203160_0'
/home/flyerhzm/Downloads/test_bullet/app/controllers/posts_controller.rb:7:in `index'

The generated SQL is:

Post Load (1.0ms) SELECT * FROM "posts"
Comment Load (0.4ms) SELECT * FROM "comments" WHERE ("comments".post_id = 1)
Comment Load (0.3ms) SELECT * FROM "comments" WHERE ("comments".post_id = 2)

9. To fix the N+1 query, change app/controllers/posts_controller.rb file

defindex@posts=Post.includes(:comments)respond_todo |format|
format.html# index.html.erbformat.xml{render:xml=>@posts}endend

10. Refresh http://localhost:3000/posts. Now there's no alert box and nothing new in the log.

The generated SQL is:

Post Load (0.5ms) SELECT * FROM "posts"
Comment Load (0.5ms) SELECT "comments".* FROM "comments" WHERE ("comments".post_id IN (1,2))

N+1 query fixed. Cool!

11. Now simulate unused eager loading. Change app/controllers/posts_controller.rb and app/views/posts/index.html.erb

defindex@posts=Post.includes(:comments)respond_todo |format|
format.html# index.html.erbformat.xml{render:xml=>@posts}endend

<% @posts.each do |post| %>
<tr>
<td><%= post.name %></td>
<td><%= link_to 'Show', post %></td>
<td><%= link_to 'Edit', edit_post_path(post) %></td>
<td><%= link_to 'Destroy', post, :confirm => 'Are you sure?', :method => :delete %></td>
</tr>
<% end %>

12. Refresh http://localhost:3000/posts, and you will see a popup alert box that says

The request has unused preload associations as follows:
model: Post => associations: [comment]
The request has N+1 queries as follows:
None

Meanwhile, there's a line appended to log/bullet.log

2009-08-25 21:13:22[INFO] Unused preload associations: PATH_INFO: /posts; model: Post => associations: [comments]·
Remove from your finder: :include => [:comments]

13. Simulate counter_cache. Change app/controllers/posts_controller.rb and app/views/posts/index.html.erb

defindex@posts=Post.allrespond_todo |format|
format.html# index.html.erbformat.xml{render:xml=>@posts}endend

<% @posts.each do |post| %>
<tr>
<td><%= post.name %></td>
<td><%= post.comments.size %></td>
<td><%= link_to 'Show', post %></td>
<td><%= link_to 'Edit', edit_post_path(post) %></td>
<td><%= link_to 'Destroy', post, :confirm => 'Are you sure?', :method => :delete %></td>
</tr>
<% end %>

14. Refresh http://localhost:3000/posts, then you will see a popup alert box that says

Need counter cache
Post => [:comments]

Meanwhile, there's a line appended to log/bullet.log

2009-09-11 10:07:10[INFO] Need Counter Cache
Post => [:comments]

Copyright (c) 2009 - 2019 Richard Huang (flyerhzm@gmail.com), released under the MIT license