Cron job trong Rails — Active Job scheduler vs gem whenever? Cách setup scheduled job?

Rails không có built-in cron scheduler. Có hai hướng phổ biến:

1. Gem whenever — viết cron syntax trong Ruby, generate crontab:

# config/schedule.rb
every 1.day, at: "2:00 am" do
  rake "reports:daily"
end

every :hour do
  runner "CleanupJob.perform_later"
end

Chạy bundle exec whenever --update-crontab để apply. Yêu cầu server có cron daemon.

2. Sidekiq-cron / GoodJob — scheduler chạy bên trong process Sidekiq/GoodJob, không cần crontab:

# config/initializers/sidekiq.rb
Sidekiq::Cron::Job.create(
  name: "Daily report",
  cron: "0 2 * * *",
  class: "DailyReportJob"
)

Hướng 2 tốt hơn cho deploy trên cloud (Heroku/Railway không có cron daemon).

Hướng 1 phù hợp VPS có full control.

Rails has no built-in cron scheduler. Two common approaches:

1. whenever gem — write cron syntax in Ruby, generates a crontab:

# config/schedule.rb
every 1.day, at: "2:00 am" do
  rake "reports:daily"
end

every :hour do
  runner "CleanupJob.perform_later"
end

Run bundle exec whenever --update-crontab to apply. Requires a server with a cron daemon.

2. sidekiq-cron / GoodJob — scheduler runs inside the Sidekiq/GoodJob process, no crontab needed:

# config/initializers/sidekiq.rb
Sidekiq::Cron::Job.create(
  name: "Daily report",
  cron: "0 2 * * *",
  class: "DailyReportJob"
)

Approach 2 is better for cloud deployments (Heroku/Railway have no cron daemon).

Approach 1 suits VPS with full OS control.