Basic cron-like system to schedule jobs

1. Add cron-table gem
2. Run rails app:cron_table:install:migrations
3. Run rails db:migrate to apply migrations

1. Add include CronTable::Schedule to the job
2. Define cron schedule using crontable(every: <interval>)
3. Use block if cron requires params, eg crontable(every: 1.day) { perform_later(Time.current) }

Use every to specify when cron should run. Allowed values include:

1. Positive ActiveSupport::Duration like 1.hour, 2.days
2. Predefined intervals

• midnight
• noon
• beginning_of_hour

3. Custom interval registered in CronTable.every, eg

  # config/initializers/cron_table.rb
  CronTable.every[:custom] = ->(context) { rand(1.hour..1.day).from_now }

Cron execution can be instrumented using middleware, eg

module CronTableInstrumentation
  def process(context)
    ElasticAPM.with_transaction(context.cron.key, "cron") { super }
  end
end
CronTable.register(CronTableInstrumentation)

The gem is available as open source under the terms of the MIT License.