config/initializers/sidekiq_scheduled.rb
# frozen_string_literal: true

# Some recurring background jobs can take a lot of resources, and others even
# include pinging other pods, like recurring_pod_check. Having all jobs run at
# 0 UTC causes a high local load, as well as a little bit of DDoSing through
# the network, as pods try to ping each other.
#
# As Sidekiq-Cron does not support random offsets, we have to take care of that
# ourselves, so let's add jobs with random work times.

# rubocop:disable Metrics/MethodLength
def default_job_config
  random_hour = lambda { rand(24) }
  random_minute = lambda { rand(60) }

  {
    check_birthday:          {
      "cron":  "0 0 * * *",
      "class": "Workers::CheckBirthday"
    },

    clean_cached_files:      {
      "cron":  "#{random_minute.call} #{random_hour.call} * * *",
      "class": "Workers::CleanCachedFiles"
    },

    cleanup_old_exports:     {
      "cron":  "#{random_minute.call} #{random_hour.call} * * *",
      "class": "Workers::CleanupOldExports"
    },

    cleanup_pending_photos:  {
      "cron":  "#{random_minute.call} #{random_hour.call} * * *",
      "class": "Workers::CleanupPendingPhotos"
    },

    queue_users_for_removal: {
      "cron":  "#{random_minute.call} #{random_hour.call} * * *",
      "class": "Workers::QueueUsersForRemoval"
    },

    recheck_scheduled_pods:  {
      "cron":  "*/30 * * * *",
      "class": "Workers::RecheckScheduledPods"
    },

    recurring_pod_check:     {
      "cron":  "#{random_minute.call} #{random_hour.call} * * *",
      "class": "Workers::RecurringPodCheck"
    }
  }
end
# rubocop:enable Metrics/MethodLength

def valid_config?(path)
  return false unless File.exist?(path)

  current_config = YAML.load_file(path)

  # If they key don't match the current default config keys, a new job has
  # been added, so we nede to regenerate the config to have the new job
  # running
  return false unless current_config.keys == default_job_config.keys

  # If recurring_pod_check is still running at midnight UTC, the config file
  # is probably from a previous version, and that's bad, so we need to
  # regenerate
  current_config[:recurring_pod_check][:cron] != "0 0 * * *"
end

def regenerate_config(path)
  job_config = default_job_config
  File.open(path, "w") do |schedule_file|
    schedule_file.write(job_config.to_yaml)
  end
end

if Sidekiq.server?
  schedule_file_path = Rails.root.join("config", "schedule.yml")
  regenerate_config(schedule_file_path) unless valid_config?(schedule_file_path)

  Rails.application.reloader.to_prepare do
    Sidekiq::Cron::Job.load_from_hash YAML.load_file(schedule_file_path)
  end
end
