在rails上运行cron作业(部署在多个服务器上)

# Gemfile
gem 'whenever', require: false  # 管理cron语法
gem 'sidekiq-cron'              # 分布式任务调度

# config/sidekiq.yml
:schedule:
  daily_report:
    cron: '0 3 * * *' 
    class: 'DailyReportJob'
    queue: reports

# lib/tasks/daily_task.rake
task :generate_reports => :environment do
  ActiveRecord::Base.transaction do
    lock = DistributedLock.acquire('report-generation')
    if lock
      begin
        # 业务逻辑
        ReportGenerator.call
      ensure
        lock.release
      end
    end
  end
end

# app/models/distributed_lock.rb
class DistributedLock
  def self.acquire(key, timeout = 1.hour)
    # 使用数据库唯一约束实现锁
    LockRecord.create!(key: key, expires_at: Time.current + timeout)
    true
  rescue ActiveRecord::RecordNotUnique
    false
  end
end

task :send_reminders => :environment do
  lockfile = Rails.root.join('tmp', 'reminders.lock')
  
  File.open(lockfile, File::RDWR|File::CREAT, 0644) do |f|
    if f.flock(File::LOCK_EX|File::LOCK_NB)
      begin
        ReminderService.process
      ensure
        f.flock(File::LOCK_UN)
      end
    end
  end
end