Active Job基础知识

$ bin/rails generate job guests_cleanup
invoke  test_unit
create    test/jobs/guests_cleanup_job_test.rb
create  app/jobs/guests_cleanup_job.rb

$ bin/rails generate job guests_cleanup --queue urgent

class GuestsCleanupJob < ApplicationJob
  queue_as :default

  def perform(*guests)
    # Do something later
  end
end

$ bin/rails generate job process_payment --parent=payment_job

class ProcessPaymentJob < PaymentJob
  queue_as :default

  def perform(*args)
    # Do something later
  end
end

# 将作业排队，以便在排队系统空闲时立即执行。
GuestsCleanupJob.perform_later guest

# 将作业排队，以便在明天中午执行。
GuestsCleanupJob.set(wait_until: Date.tomorrow.noon).perform_later(guest)

# 将作业排队，以便在一周后执行。
GuestsCleanupJob.set(wait: 1.week).perform_later(guest)

# `perform_now`和`perform_later`将在底层调用`perform`，因此您可以传递与后者中定义的参数一样多的参数。
GuestsCleanupJob.perform_later(guest1, guest2, filter: 'some_filter')

# config/application.rb
module YourApp
  class Application < Rails::Application
    # 确保在Gemfile中有适配器的gem，并遵循适配器的特定安装和部署说明。
    config.active_job.queue_adapter = :sidekiq
  end
end

class GuestsCleanupJob < ApplicationJob
  self.queue_adapter = :resque
  # ...
end

# 现在，您的作业将使用`resque`作为其后端队列适配器，覆盖了在`config.active_job.queue_adapter`中配置的设置。

class GuestsCleanupJob < ApplicationJob
  queue_as :low_priority
  # ...
end

# config/application.rb
module YourApp
  class Application < Rails::Application
    config.active_job.queue_name_prefix = Rails.env
  end
end

# app/jobs/guests_cleanup_job.rb
class GuestsCleanupJob < ApplicationJob
  queue_as :low_priority
  # ...
end

# 现在您的作业将在生产环境的production_low_priority队列上运行，
# 在演示环境的staging_low_priority队列上运行

class GuestsCleanupJob < ApplicationJob
  queue_as :low_priority
  self.queue_name_prefix = nil
  # ...
end

# 现在您的作业的队列名称将不带前缀，覆盖了在`config.active_job.queue_name_prefix`中配置的内容。

# config/application.rb
module YourApp
  class Application < Rails::Application
    config.active_job.queue_name_prefix = Rails.env
    config.active_job.queue_name_delimiter = '.'
  end
end

# app/jobs/guests_cleanup_job.rb
class GuestsCleanupJob < ApplicationJob
  queue_as :low_priority
  # ...
end

# 现在您的作业将在生产环境的production.low_priority队列上运行，
# 在演示环境的staging.low_priority队列上运行

MyJob.set(queue: :another_queue).perform_later(record)

class ProcessVideoJob < ApplicationJob
  queue_as do
    video = self.arguments.first
    if video.owner.premium?
      :premium_videojobs
    else
      :videojobs
    end
  end

  def perform(video)
    # 处理视频
  end
end

ProcessVideoJob.perform_later(Video.last)

class GuestsCleanupJob < ApplicationJob
  queue_as :default

  around_perform :around_cleanup

  def perform
    # 后续操作
  end

  private
    def around_cleanup
      # 在执行之前进行某些操作
      yield
      # 在执行之后进行某些操作
    end
end

class ApplicationJob < ActiveJob::Base
  before_enqueue { |job| $statsd.increment "#{job.class.name.underscore}.enqueue" }
end

# 如果要立即发送电子邮件，请使用#deliver_now
UserMailer.welcome(@user).deliver_now

# 如果要通过Active Job发送电子邮件，请使用#deliver_later
UserMailer.welcome(@user).deliver_later

I18n.locale = :eo

UserMailer.welcome(@user).deliver_later # 电子邮件将被本地化为世界语。

class TrashableCleanupJob < ApplicationJob
  def perform(trashable_class, trashable_id, depth)
    trashable = trashable_class.constantize.find(trashable_id)
    trashable.cleanup(depth)
  end
end

class TrashableCleanupJob < ApplicationJob
  def perform(trashable, depth)
    trashable.cleanup(depth)
  end
end

# app/serializers/money_serializer.rb
class MoneySerializer < ActiveJob::Serializers::ObjectSerializer
  # 检查参数是否应由此序列化器进行序列化。
  def serialize?(argument)
    argument.is_a? Money
  end

  # 使用支持的对象类型将对象转换为更简单的表示形式。
  # 推荐的表示形式是具有特定键的哈希。键只能是基本类型。
  # 您应该调用 `super` 将自定义序列化器类型添加到哈希中。
  def serialize(money)
    super(
      "amount" => money.amount,
      "currency" => money.currency
    )
  end

  # 将序列化的值转换为正确的对象。
  def deserialize(hash)
    Money.new(hash["amount"], hash["currency"])
  end
end

# config/initializers/custom_serializers.rb
Rails.application.config.active_job.custom_serializers << MoneySerializer

# config/application.rb
module YourApp
  class Application < Rails::Application
    config.autoload_once_paths << Rails.root.join('app', 'serializers')
  end
end

class GuestsCleanupJob < ApplicationJob
  queue_as :default

  rescue_from(ActiveRecord::RecordNotFound) do |exception|
    # 处理异常
  end

  def perform
    # 执行操作
  end
end

class RemoteServiceJob < ApplicationJob
  retry_on CustomAppException # 默认等待 3 秒，尝试 5 次

  discard_on ActiveJob::DeserializationError

  def perform(*args)
    # 可能会引发 CustomAppException 或 ActiveJob::DeserializationError
  end
end