A cheatsheet by @ankane|Refreshed about 1 year ago.Refresh|View source on Github

:rocket: Best practices for running Rails in production

This guide covers different concepts you should be familiar with. Recommendations come from personal experience and work at Instacart. A number of open source projects are ones I’ve created. For a comprehensive list of gems, check out Awesome Ruby.

Everyone writing code must be responsible for security. See best practices and how to secure sensitive data.

Use an error reporting service like Rollbar.

Use Safely to rescue and report exceptions in non-critical code.

Use a centralized logging service like LogDNA.

Use Lograge to reduce volume. Configure it to add request_id, user_id, and params.

# config/environments/production.rb
config.lograge.enabled = true
config.lograge.custom_options = lambda do |event|
  options = event.payload.slice(:request_id, :user_id)
  options[:params] = event.payload[:params].except("controller", "action")
  options
end

# app/controllers/application_controller.rb
def append_info_to_payload(payload)
  super
  payload[:request_id] = request.uuid
  payload[:user_id] = current_user.id if current_user
end

Use an auditing library like Audited.

Use Strong Migrations to catch unsafe migrations at dev time.

Use a high performance web server like Puma.

Use Rack::Deflater for compression.

Use a CDN like Amazon CloudFront to serve assets.

Use Slowpoke for request timeouts.

Use a high performance background processing framework like Sidekiq with Active Job.

config.active_job.queue_adapter = :sidekiq
  • quickly disable jobs
  • throttle
  • limit concurrency
BadJob.disable!

For transactional emails, use an email delivery service like SendGrid.

For marketing emails, use a service like MailChimp.

For styling, use a CSS inliner like Roadie.

class ApplicationMailer < ActionMailer::Base
  include Roadie::Rails::Automatic
end

Add UTM parameters to links.

Use Memcached and Dalli for caching.

config.cache_store = :dalli_store

Use a library like Memoist for memoizing.

memoize :time_consuming_method

Add Oj to speed up JSON parsing.

Tracing

Tracing

Use a performance monitoring service with transaction traces like New Relic or AppSignal.

Uptime

Uptime

Use an uptime monitoring service like Pingdom or Uptime Robot.

Database

Database

The database is a common bottleneck for Rails apps and deserves some special monitoring attention. There are some dedicated tools for this:

  • If you use Postgres, PgHero can help identify issues
  • Use Marginalia to track the origin of SQL queries

Notable Events

Notable Events

Use Notable to track notable requests and background jobs.

  • errors
  • slow requests, jobs, and timeouts
  • 404s
  • validation failures
  • CSRF failures
  • unpermitted parameters
  • blocked and throttled requests

One very important place is Active Record. Add to config/database.yml and adjust as needed.

PostgreSQL

production:
  connect_timeout: 2
  checkout_timeout: 5
  variables:
    statement_timeout: 5000 # ms

MySQL and MariaDB

production:
  connect_timeout: 1
  read_timeout: 1
  write_timeout: 1
  checkout_timeout: 5
  variables:
    max_execution_time: 5000 # ms, for MySQL 5.7.8 or higher
    max_statement_time: 5 # sec, for MariaDB 10.1.1 or higher

Use an analytics tool to measure important events. Consider a first-party library like Ahoy, or use a third-party service like Amplitude or Mixpanel.

Use a feature flipper library like Rollout to easily enable and disable new features without pushing code.

To A/B test features, use a library like Field Test.