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Health check endpoint for deployment monitoring

Alex Kumar Jan 2026
2 tabs 
class HealthController < ApplicationController
  skip_before_action :verify_authenticity_token

  def liveness
    render json: { status: 'ok' }, status: :ok
  end

  def readiness
    checks = {
      database: check_database,
      redis: check_redis,
      sidekiq: check_sidekiq
    }

    all_healthy = checks.values.all? { |status| status == 'ok' }
    status_code = all_healthy ? :ok : :service_unavailable

    render json: { status: all_healthy ? 'ok' : 'degraded', checks: checks }, status: status_code
  end

  private

  def check_database
    ActiveRecord::Base.connection.execute('SELECT 1')
    'ok'
  rescue StandardError
    'failed'
  end

  def check_redis
    Redis.current.ping == 'PONG' ? 'ok' : 'failed'
  rescue StandardError
    'failed'
  end

  def check_sidekiq
    Sidekiq.redis(&:ping) == 'PONG' ? 'ok' : 'failed'
  rescue StandardError
    'failed'
  end
end
2 files · ruby Explain with highlit

Load balancers and orchestration platforms like Kubernetes rely on health check endpoints to determine if an application instance is ready to serve traffic. A robust health check doesn't just return 200 OK—it verifies critical dependencies like database connectivity, Redis availability, and background job processing. I implement separate /health/liveness and /health/readiness endpoints: liveness checks if the app process is running, while readiness checks if all dependencies are available. This distinction allows orchestrators to restart unhealthy instances while giving newly deployed instances time to warm up before receiving traffic. Health checks should complete quickly (under 100ms) to avoid triggering false positives during traffic spikes.

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