rails-infrastructure

name	rails-infrastructure
description	This skill should be used when the user asks about deployment, background jobs, caching, WebSockets, security, performance, or Rails 8 infrastructure components. Trigger phrases include "deployment", "Kamal", "Solid Queue", "Solid Cache", "Solid Cable", "background jobs", "caching", "WebSockets", "Action Cable", "security", "performance", "scaling", "production", "Docker", "credentials".

Rails 8 Infrastructure Expert

Expertise in Solid Queue, Solid Cache, Solid Cable, Kamal deployment, security best practices, and performance optimization for Rails 8 applications.

Core Philosophy: The Integrated Stack

Rails 8 ships with everything you need for production. Solid Queue replaces Sidekiq. Solid Cache replaces Redis for caching. Solid Cable handles WebSockets. Don't reach for external dependencies when Rails has you covered.

The Solid Stack

Solid Queue (Background Jobs)

Database-backed job processing. No Redis required.

bin/rails generate solid_queue:install

# config/application.rb
config.active_job.queue_adapter = :solid_queue

# app/jobs/welcome_email_job.rb
class WelcomeEmailJob < ApplicationJob
  queue_as :default

  def perform(user)
    UserMailer.welcome(user).deliver_now
  end
end

# Enqueue
WelcomeEmailJob.perform_later(user)

Configuration

# config/solid_queue.yml
production:
  dispatchers:
    - polling_interval: 1
      batch_size: 500
  workers:
    - queues: "*"
      threads: 5
      polling_interval: 0.1

Queue Priorities

class ImportantJob < ApplicationJob
  queue_as :critical
end

class BackgroundJob < ApplicationJob
  queue_as :low
end

# config/solid_queue.yml
workers:
  - queues: [critical, default, low]
    threads: 5

Solid Cache

Database-backed caching. Replaces Redis/Memcached.

bin/rails generate solid_cache:install

# config/environments/production.rb
config.cache_store = :solid_cache_store

# Usage - same as always
Rails.cache.fetch("user_#{user.id}_stats", expires_in: 1.hour) do
  user.calculate_stats
end

Fragment Caching

<% cache @article do %>
  <article>
    <h1><%= @article.title %></h1>
    <%= @article.formatted_body %>
  </article>
<% end %>

Russian Doll Caching

<% cache @article do %>
  <article>
    <h1><%= @article.title %></h1>
    <% @article.comments.each do |comment| %>
      <% cache comment do %>
        <%= render comment %>
      <% end %>
    <% end %>
  </article>
<% end %>

Solid Cable (WebSockets)

Database-backed Action Cable adapter.

# config/cable.yml
production:
  adapter: solid_cable
  polling_interval: 0.1.seconds

# app/channels/chat_channel.rb
class ChatChannel < ApplicationCable::Channel
  def subscribed
    stream_from "chat_#{params[:room_id]}"
  end

  def speak(data)
    Message.create!(
      content: data["content"],
      user: current_user,
      room_id: params[:room_id]
    )
  end
end

# Broadcasting from model
class Message < ApplicationRecord
  after_create_commit { broadcast_append_to room }
end

Kamal Deployment

What is Kamal?

Docker-based deployment tool from 37signals. Zero-downtime deploys to any server.

Setup

gem install kamal
kamal init

# config/deploy.yml
service: myapp
image: myuser/myapp

servers:
  web:
    - 192.168.1.1
    - 192.168.1.2
  job:
    hosts:
      - 192.168.1.3
    cmd: bin/jobs

registry:
  username: myuser
  password:
    - KAMAL_REGISTRY_PASSWORD

env:
  secret:
    - RAILS_MASTER_KEY
    - DATABASE_URL

accessories:
  db:
    image: postgres:16
    host: 192.168.1.4
    env:
      secret:
        - POSTGRES_PASSWORD
    directories:
      - data:/var/lib/postgresql/data

Common Commands

kamal setup              # First deploy
kamal deploy             # Update deployment
kamal app logs           # View logs
kamal app exec "bin/rails console"  # Rails console
kamal rollback           # Revert to previous version

Health Checks

# config/deploy.yml
healthcheck:
  path: /up
  port: 3000
  interval: 1s

# config/routes.rb
get "up" => "rails/health#show", as: :rails_health_check

Security

Rails 8 Authentication

bin/rails generate authentication

Generates secure session-based authentication:

• has_secure_password with bcrypt
• Session tokens with rotation
• Password reset flow
• Rate limiting ready

Credentials

bin/rails credentials:edit
bin/rails credentials:edit --environment production

# config/credentials.yml.enc
aws:
  access_key_id: xxx
  secret_access_key: xxx

stripe:
  secret_key: xxx

Rails.application.credentials.aws[:access_key_id]
Rails.application.credentials.stripe[:secret_key]

Security Headers

# config/initializers/content_security_policy.rb
Rails.application.configure do
  config.content_security_policy do |policy|
    policy.default_src :self
    policy.script_src  :self
    policy.style_src   :self, :unsafe_inline
    policy.img_src     :self, :data, "https:"
    policy.connect_src :self
  end
end

Common Vulnerabilities

SQL Injection

# BAD
User.where("name = '#{params[:name]}'")

# GOOD
User.where(name: params[:name])
User.where("name = ?", params[:name])

XSS

<%# BAD - renders raw HTML %>
<%= raw user_input %>
<%= user_input.html_safe %>

<%# GOOD - escaped by default %>
<%= user_input %>

<%# For intentional HTML %>
<%= sanitize user_content, tags: %w[p br strong em] %>

Mass Assignment

# Strong parameters protect against this
def user_params
  params.require(:user).permit(:name, :email)
  # admin: true is NOT permitted
end

Rate Limiting

# config/initializers/rack_attack.rb
class Rack::Attack
  throttle("req/ip", limit: 300, period: 5.minutes) do |req|
    req.ip
  end

  throttle("logins/ip", limit: 5, period: 20.seconds) do |req|
    req.ip if req.path == "/login" && req.post?
  end
end

Performance

Database

# Add indexes for foreign keys and common queries
add_index :articles, :user_id
add_index :articles, [:user_id, :published_at]
add_index :users, :email, unique: true

# Use counter caches
belongs_to :user, counter_cache: true

# Avoid N+1 with includes
Article.includes(:user, :comments).published

Background Jobs for Slow Operations

# DON'T block the request
def create
  @user = User.create!(user_params)
  @user.send_welcome_email  # Slow!
end

# DO use background jobs
def create
  @user = User.create!(user_params)
  WelcomeEmailJob.perform_later(@user)
end

Asset Optimization

# config/environments/production.rb
config.assets.css_compressor = :sass
config.assets.js_compressor = :terser

Query Optimization

# Use select to limit columns
User.select(:id, :name).where(active: true)

# Use pluck for simple arrays
User.where(role: :admin).pluck(:email)

# Use exists? instead of any?
User.exists?(email: params[:email])

# Batch processing
User.find_each(batch_size: 1000) do |user|
  UserSyncJob.perform_later(user)
end

Monitoring

Logging

# config/environments/production.rb
config.log_level = :info
config.log_tags = [:request_id]
config.logger = ActiveSupport::TaggedLogging.new(Logger.new(STDOUT))

Health Endpoint

# Already included in Rails 8
# GET /up returns 200 if app is healthy

Error Tracking

Integrate with your preferred service:

# config/initializers/error_tracking.rb
Rails.error.subscribe(ErrorTracker.new) do |error, handled:, severity:, context:, source:|
  ErrorTracker.report(error, context: context, severity: severity)
end

Scaling Considerations

When to Scale

1. Vertical first: Bigger server is often cheaper than complexity
2. Add workers: More Solid Queue workers for job throughput
3. Read replicas: Database replication for read-heavy apps
4. CDN: Serve assets from edge locations

What You Probably Don't Need

• Microservices (until you have 50+ developers)
• Kubernetes (Kamal handles most cases)
• Redis (Solid Cache/Queue use the database)
• Elasticsearch (PostgreSQL full-text search is great)

Additional Resources

• references/solid-stack.md - Deep dive on Solid components
• references/kamal-guide.md - Complete Kamal deployment
• references/security-checklist.md - Production security
• examples/deploy.yml - Sample Kamal config
• examples/solid-queue.yml - Queue configuration