Production Configuration

Introduction

Production requires specific configuration for security, performance, and reliability. Rails 8 introduces sensible defaults including Solid Cache, Solid Queue, and Solid Cable — eliminating the need for Redis in most applications.

Key Concepts

• Eager Loading: Loading all application code at boot time (config.eager_load = true) to avoid lazy-loading race conditions in multi-threaded servers.
• Reloading Disabled: In production, code is loaded once and never reloaded (config.enable_reloading = false).
• Credentials: Encrypted files that store secrets securely in version control, decrypted at runtime with a master key.

Real World Context

A misconfigured production app can expose stack traces to users, serve unencrypted traffic, or run out of database connections. Getting production configuration right is the foundation of a secure, performant deployment.

Deep Dive

Rails 8 Production Configuration

ruby
# config/environments/production.rb
Rails.application.configure do
  # Code is loaded once, never reloaded
  config.enable_reloading = false
  config.eager_load = true

  # Don't show detailed errors to users
  config.consider_all_requests_local = false

  # Caching with Solid Cache (Rails 8 default — database-backed)
  config.cache_store = :solid_cache_store

  # Force SSL
  config.force_ssl = true

  # Logging
  config.log_level = :info
  config.log_tags = [:request_id]

  # Background jobs with Solid Queue (Rails 8 default)
  config.active_job.queue_adapter = :solid_queue
  config.solid_queue.connects_to = { database: { writing: :queue } }

  # Email
  config.action_mailer.delivery_method = :smtp
  config.action_mailer.smtp_settings = {
    address: ENV['SMTP_HOST'],
    port: ENV['SMTP_PORT'],
    user_name: ENV['SMTP_USER'],
    password: ENV['SMTP_PASSWORD'],
    authentication: :plain,
    enable_starttls_auto: true
  }
end

Credentials Management

bash
RAILS_MASTER_KEY=xxx bin/rails credentials:edit --environment production

Database Configuration

yaml
# config/database.yml
production:
  primary:
    adapter: postgresql
    encoding: unicode
    pool: <%= ENV.fetch('RAILS_MAX_THREADS', 5) %>
    url: <%= ENV['DATABASE_URL'] %>
  queue:
    adapter: postgresql
    url: <%= ENV.fetch('QUEUE_DATABASE_URL') { ENV['DATABASE_URL'] } %>
    migrations_paths: db/queue_migrate
  cache:
    adapter: postgresql
    url: <%= ENV.fetch('CACHE_DATABASE_URL') { ENV['DATABASE_URL'] } %>
    migrations_paths: db/cache_migrate

Required Environment Variables

bash
RAILS_ENV=production
RAILS_MASTER_KEY=your_master_key
DATABASE_URL=postgres://user:pass@host:5432/app
SECRET_KEY_BASE=generated_secret

Common Pitfalls

1. Using config.cache_classes — This setting is deprecated in Rails 8. Use config.enable_reloading = false instead.
2. Forgetting to set RAILS_MASTER_KEY — Without it, credentials can't be decrypted and the app won't boot.

Best Practices

1. Use the Solid Trifecta — Solid Cache, Solid Queue, and Solid Cable eliminate the Redis dependency for most apps, simplifying infrastructure.
2. Set database pool to match threads — pool should equal RAILS_MAX_THREADS to prevent connection timeouts under load.

Summary

• Rails 8 uses config.enable_reloading = false instead of the deprecated cache_classes.
• Solid Cache is the default cache store — database-backed, no Redis needed.
• Solid Queue is the default job backend — database-backed, no Redis needed.
• Store secrets in encrypted credentials, decrypted by RAILS_MASTER_KEY.
• Set database pool size to match your thread count.

# Rails 8 production defaults — no Redis needed!
Rails.application.configure do
  config.enable_reloading = false        # Don't reload code
  config.eager_load = true               # Load everything at boot
  config.force_ssl = true                # HTTPS only
  config.cache_store = :solid_cache_store # Database-backed cache
  config.active_job.queue_adapter = :solid_queue # Database-backed jobs
end