Production Rails

: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.

Security

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

Errors

Use an error reporting service like Rollbar.

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

Logging

Use a centralized logging service like Papertrail.

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

Audits

Use an auditing library like Audited.

Migrations

Use Strong Migrations to catch unsafe migrations at dev time.

Web Requests

Use compression. If not using a reverse proxy like nginx, use Rack::Deflater.

Use a CDN like Amazon CloudFront to serve assets.

Use Slowpoke for request timeouts.

Background Jobs

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

config.active_job.queue_adapter = :sidekiq

Use ActiveJob::TrafficControl to:

• quickly disable jobs
• throttle
• limit concurrency

BadJob.disable!

Email

Use an email delivery service. You can use one that supports both transactional and marketing email like Postmark, or separate ones for each type.

Use Ahoy Email for message history.

AhoyEmail.default_options[:message] = true

Use a CSS inliner like Roadie for styling.

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

Caching and Performance

Use Memcached and Dalli for caching.

config.cache_store = :mem_cache_store

Use a library like MemoWise for memoizing.

memo_wise :time_consuming_method

Monitoring

Tracing

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

Uptime

Use an uptime monitoring service like Pingdom or Uptime Robot.

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 Active Record Query Logs to track the origin of SQL queries

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

Timeouts

Add timeouts.

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
    max_statement_time: 5 # sec

Analytics

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.

New Features

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.

Lastly...

Have suggestions? Help make this guide better for everyone.

Also check out Development Rails and Scaling Rails.