Rails Uptime Monitoring

Set up health check endpoints and uptime monitoring for your Ruby on Rails application. Simple patterns for production-ready monitoring.

Why Monitor Your Rails App?

Rails applications rely on a complex stack of services in production -- ActiveRecord databases, Redis for caching and Sidekiq, Action Cable for WebSockets, and Active Storage for file uploads. A failure in any of these can leave your app partially broken while Puma happily keeps accepting connections.

• Puma worker crashes -- A segfault in a native gem or OOM kill silently removes a worker, reducing capacity without any visible error
• Database connection pool exhaustion -- ActiveRecord's connection pool can be drained under high concurrency, causing requests to queue and timeout
• Sidekiq worker failures -- Background job processors can crash or disconnect from Redis without affecting web requests
• Migration drift -- A failed or skipped migration leaves your schema out of sync with the running code

Simple Health Route

# config/routes.rb
Rails.application.routes.draw do
  get '/health', to: 'health#show'
  get '/ready', to: 'health#ready'
end

# app/controllers/health_controller.rb
class HealthController < ApplicationController
  skip_before_action :authenticate_user!, raise: false

  def show
    render json: { status: 'healthy', timestamp: Time.current.iso8601 }
  end

  def ready
    checks = {}
    healthy = true

    # Check database
    begin
      start = Time.current
      ActiveRecord::Base.connection.execute('SELECT 1')
      checks[:database] = {
        status: 'ok',
        response_time_ms: ((Time.current - start) * 1000).round(2)
      }
    rescue => e
      healthy = false
      checks[:database] = { status: 'error', message: e.message }
    end

    status_code = healthy ? :ok : :service_unavailable
    render json: {
      status: healthy ? 'healthy' : 'unhealthy',
      timestamp: Time.current.iso8601,
      checks: checks
    }, status: status_code
  end
end

Using Rails 7.1+ Built-in Health Check

# Rails 7.1+ has a built-in health check endpoint
# config/routes.rb
Rails.application.routes.draw do
  get "up" => "rails/health#show", as: :rails_health_check
end

# This returns 200 OK if the app is running
# Default path: /up

Comprehensive Health Check

# app/controllers/health_controller.rb
class HealthController < ApplicationController
  skip_before_action :authenticate_user!, raise: false
  skip_before_action :verify_authenticity_token

  def ready
    checks = {}
    healthy = true

    # Database check
    checks[:database] = check_database
    healthy = false unless checks[:database][:status] == 'ok'

    # Redis check
    checks[:redis] = check_redis
    healthy = false unless checks[:redis][:status] == 'ok'

    # Sidekiq check
    checks[:sidekiq] = check_sidekiq

    render json: {
      status: healthy ? 'healthy' : 'unhealthy',
      timestamp: Time.current.iso8601,
      checks: checks,
      version: ENV.fetch('APP_VERSION', 'unknown'),
      ruby_version: RUBY_VERSION,
      rails_version: Rails::VERSION::STRING
    }, status: healthy ? :ok : :service_unavailable
  end

  private

  def check_database
    start = Time.current
    ActiveRecord::Base.connection.execute('SELECT 1')
    {
      status: 'ok',
      response_time_ms: ((Time.current - start) * 1000).round(2)
    }
  rescue => e
    { status: 'error', message: e.message }
  end

  def check_redis
    start = Time.current
    Redis.current.ping
    {
      status: 'ok',
      response_time_ms: ((Time.current - start) * 1000).round(2)
    }
  rescue => e
    { status: 'error', message: e.message }
  end

  def check_sidekiq
    stats = Sidekiq::Stats.new
    {
      status: 'ok',
      enqueued: stats.enqueued,
      processed: stats.processed,
      failed: stats.failed
    }
  rescue => e
    { status: 'error', message: e.message }
  end
end

Using okcomputer Gem

# Gemfile
gem 'okcomputer'

# config/initializers/okcomputer.rb
OkComputer::Registry.register "database", OkComputer::ActiveRecordCheck.new
OkComputer::Registry.register "redis", OkComputer::RedisCheck.new(Redis.current)
OkComputer::Registry.register "sidekiq", OkComputer::SidekiqLatencyCheck.new('default', 100)

# Routes are automatically mounted at /okcomputer
# GET /okcomputer - all checks
# GET /okcomputer/database - specific check

Skip Authentication

# For Devise
class HealthController < ApplicationController
  skip_before_action :authenticate_user!
end

# For basic auth in production
# config/routes.rb
constraints(->(req) { req.path == '/health' }) do
  get '/health', to: 'health#show'
end

Best Practices

• Skip authentication — Health checks need to work without auth
• Check Sidekiq — Background jobs are critical for most Rails apps
• Monitor migrations — Ensure database schema is current
• Add timeouts — Use Timeout.timeout() for dependency checks