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
- 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
You can install it as a gem:
gem install bullet
or add it into a Gemfile (Bundler):
gem 'bullet', group: 'development'
Note: make sure bullet
gem is added after activerecord (rails) and
mongoid.
Bullet won't do ANYTHING unless you tell it to explicitly. Append to
config/environments/development.rb
initializer with the following code:
config.after_initialize do
Bullet.enable = true
Bullet.sentry = true
Bullet.alert = true
Bullet.bullet_logger = true
Bullet.console = true
Bullet.growl = true
Bullet.xmpp = { :account => 'bullets_account@jabber.org',
:password => 'bullets_password_for_jabber',
:receiver => 'your_account@jabber.org',
:show_online_status => true }
Bullet.rails_logger = true
Bullet.honeybadger = true
Bullet.bugsnag = true
Bullet.airbrake = true
Bullet.rollbar = true
Bullet.add_footer = true
Bullet.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 nothingBullet.alert
: pop up a JavaScript alert in the browserBullet.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 configurationBullet.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 logBullet.honeybadger
: add notifications to HoneybadgerBullet.bugsnag
: add notifications to bugsnagBullet.airbrake
: add notifications to airbrakeBullet.rollbar
: add notifications to rollbarBullet.sentry
: add notifications to sentryBullet.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.stacktrace_includes
: include paths with any of these substrings in the stack trace, even if they are not in your main appBullet.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 slackBullet.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 queries
Bullet.n_plus_one_query_enable = false
# Detect eager-loaded associations which are not used
Bullet.unused_eager_loading_enable = false
# Detect unnecessary COUNT queries which could be avoided
# with a counter_cache
Bullet.counter_cache_enable = false
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 => :comments
Bullet.add_whitelist :type => :unused_eager_loading, :class_name => "Post", :association => :comments
Bullet.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
class ApplicationController < ActionController::Base
around_action :skip_bullet, if: -> { defined?(Bullet) }
def skip_bullet
previous_value = Bullet.enable?
Bullet.enable = false
yield
ensure
Bullet.enable = previous_value
end
end
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]
see https://github.com/flyerhzm/uniform_notifier
If you find Bullet does not work for you, please disable your browser's cache.
Include Bullet::ActiveJob
in your ApplicationJob
.
class ApplicationJob < ActiveJob::Base
include Bullet::ActiveJob if Rails.env.development?
end
Use the Bullet.profile method.
class ApplicationJob < ActiveJob::Base
around_perform do |_job, block|
Bullet.profile do
block.call
end
end
end
Configure and use Bullet::Rack
configure :development do
Bullet.enable = true
Bullet.bullet_logger = true
use Bullet::Rack
end
First you need to enable Bullet in test environment.
# config/environments/test.rb
config.after_initialize do
Bullet.enable = true
Bullet.bullet_logger = true
Bullet.raise = true # raise an error if n+1 query occurs
end
Then wrap each test in Bullet api.
# spec/rails_helper.rb
if Bullet.enable?
config.before(:each) do
Bullet.start_request
end
config.after(:each) do
Bullet.perform_out_of_channel_notifications if Bullet.notification?
Bullet.end_request
end
end
Bullet outputs some details info, to enable debug mode, set
BULLET_DEBUG=true
env.
https://github.com/flyerhzm/bullet/contributors
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
class Post < ActiveRecord::Base
has_many :comments
end
class Comment < ActiveRecord::Base
belongs_to :post
end
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
def index
@posts = Post.includes(:comments)
respond_to do |format|
format.html # index.html.erb
format.xml { render :xml => @posts }
end
end
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
def index
@posts = Post.includes(:comments)
respond_to do |format|
format.html # index.html.erb
format.xml { render :xml => @posts }
end
end
<% @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
def index
@posts = Post.all
respond_to do |format|
format.html # index.html.erb
format.xml { render :xml => @posts }
end
end
<% @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