Playground gem for Ruby 3.2+ features initially designed to be used with FaaS (Function as a Service) computing instances. Inspired by aws-sdk v3 gem structure & rails/activesupport.

• Ruby Version Compatibility: Implemented with most of ruby 3.2+ features, BUT supports Ruby versions >= 2.6 through the use of the RubyNext transpiler. (CI'ed)
• Type Safety: Achieves type safety through the use of RBS and Steep. (CI'ed)
  • Note: disabled due to the presence of Ruby::UnsupportedSyntax errors.
• Plugins System: Provides a simple Plugin system (inspired by Polishing Ruby Programming by Jeremy Evans) to load gem plugins as well as self-defined plugins.
• Gem Collection: Provides a collection of gems designed to be used within ActiveFunction or standalone.

• activefunction - Main gem, provides rails/action-controller like API with callbacks, strong parameters and rendering under plugins.
• activefunction-core - Provides RubyNext integration and External Standalone Plugins
• activefunction-orm - WIP (ORM around AWS PartiQL)

Here's a simple example of a function that uses ActiveFunction(w/o plugins):

require "active_function"

class AppFunction < ActiveFunction::Base
  def index
    response_with_error if @request[:data].nil?

    return if performed?

    @response.body = @request[:data]
  end

  private def response_with_error
    @response.status = 400
    @response.commit!
  end
end

The #process method is used to run the function.

AppFunction.process(:index, {data: {id: 1}}) # => { 
#   :statusCode => 200, 
#   :headers => { }, 
#   :body => {id: 1}"
# }

ActiveFunction supports plugins which can be loaded by ActiveFunction.config method. Currently, there are 3 plugins available:

• :callbacks - provides :before_action, :after_action & :set_callback DSL with :if, :unless & :only options.
• :strong_parameters - provides strong parameters support via #params instance method around @request object.
• :rendering - provides rendering support via #render instance method around @response object.

To configure ActiveFunction with plugins, use the ActiveFunction.config method.

# config/initializers/active_function.rb
require "active_function"

ActiveFunction.config do
  plugin :callbacks
  plugin :strong_parameters
  plugin :rendering
end

# app/functions/app_function.rb
class AppFunction < ActiveFunction::Base
  before_action :parse_user_data

  def index
    render json: @user_data
  end

  private def parse_user_data = @user_data = params.require(:data).permit(:id, :name).to_h
end

AppFunction.process(:index, {data: { id: 1, name: 2}}) # => { 
#   :statusCode => 200, 
#   :headers => {"Content-Type"=>"application/json"}, 
#   :body=>"{\"id\":1,\"name\":2}"
# }

See Plugins Docs for more details.

Simple callbacks engined by ActiveFunctionCore::Plugins::Hooks external plugin and provides :before_action and :after_action which runs around provided action in #process.

require "active_function"

ActiveFunction.config do
  plugin :callbacks
end

class AppFunction < ActiveFunction::Base
  before_action :set_user
  after_action :log_response

  def index
    # some actions ...
  end

  private

  def set_user     = @_user ||= User.find(@request[:id])
  def log_response = Logger.info(@response)
end

Supports default ActiveFunctionCore::Plugins::Hooks::Hook::Callback options :if => Symbol & :unless => Symbol options.

Support custom defined in ActiveFunction::Function::Callbacks only: Array[Symbol] option.

class AppFunction < ActiveFunction::Base
  before_action :set_user, only: %i[show update destroy], if: :request_valid?

  # some actions ...

  private def request_valid? = true
end

External Plugin ActiveFunctionCore::Plugins::Hooks provides :define_hooks_for & :set_callback_options DSL to define custom callbacks & options.

class MessagingApp < ActiveFunction::Base
  set_callback_options retries: ->(times, context:) { context.retry if context.retries < times }
  define_hooks_for :retry

  after_action :retry, if: :failed?, only: %i[send_message], retries: 3
  after_retry :increment_retries

  def send_message
    @response.status = 200 if SomeApi.send(@request[:message_content]).success?
  end

  def retry
    @response.committed = false
 
    process
  end

  private def increment_retries = @response.body[:tries] += 1
  private def failed? = @response.status != 200
  private def retries = @response.body[:tries] ||= 0
end

MessagingApp.process(:send_message, { sender_name: "Alice", message_content: "How are you?" })

See Callbacks Doc for more details.

ActiveFunction supports strong parameters which can be accessed by #params instance method.

The #params method represents a Ruby 3.2 Data class that allows the manipulation of request parameters. It supports the following methods:

• []: Access parameters by key.
• permit: Specify the allowed parameters.
• require: Ensure the presence of a specific parameter.
• to_h: Convert the parameters to a hash.

Usage Example:

require "active_function"

ActiveFunction.config do
  plugin :strong_parameters
end

class PostsFunction < ActiveFunction::Base
  def index
    @response.body = permitted_params
  end

  def permitted_params = params
    .require(:data)
    .permit(:id, :name)
    .to_h
end

PostFunction.process(:index, data: {id: 1, name: "Pupa"})

Strong params supports nested attributes

params.permit(:id, :name, :address => [:city, :street])

See StrongParameters Doc for more details.

ActiveFunction supports rendering of JSON. The #render method is used for rendering responses. It accepts the following options:

• head: Set response headers. Defaults to { "Content-Type" => "application/json" }.
• json: Set the response body with a JSON-like object. Defaults to {}.
• status: Set the HTTP status code. Defaults to 200.

Additionally, the method automatically commits the response and JSONifies the body.

Usage Example:

require "active_function"

ActiveFunction.config do
  plugin :rendering
end

class PostsFunction < ActiveFunction::Base
  def index
    render json: {id: 1, name: "Pupa"}, status: 200, head: {"Some-Header" => "Some-Value"}
  end
end

PostFunction.process(:index) # => { :statusCode=>200, :headers=> {"Content-Type"=>"application/json", "Some-Header" => "Some-Value"}, :body=>"{\"id\":1,\"name\":\"Pupa\"}"}

See Rendering Doc for more details.

Add this line to your application's Gemfile:

gem "activefunction"

After checking out the repo, run bin/setup to install dependencies. Then, run bin/rake test:all to run the tests and bin/rake steep to run type checker.

To install this gem onto your local machine, run bundle exec rake install.

Bug reports and pull requests are welcome on GitHub at https://github.com/DanilMaximov/activefunction. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

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

Everyone interacting in the ActiveFunction::Functions project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.