Extensions Since 3.0.0

Extensions allow you to expand base service functionality through the Stroma hook system. Define custom behavior that runs before or after service execution stages.

Create extensions in the app/services/application_service/extensions directory.

Quick start

Generate extension

shell

rails generate servactory:extension StatusActive

This creates app/services/application_service/extensions/status_active/dsl.rb.

Connect extension

app/services/application_service/base.rb

ruby

module ApplicationService
  class Base < Servactory::Base
    extensions do
      before :actions, ApplicationService::Extensions::StatusActive::DSL
    end
  end
end

Use in service

ruby

class Posts::Create < ApplicationService::Base
  input :user, type: User
  input :title, type: String

  status_active! :user

  make :create_post

  private

  def create_post
    # ...
  end
end

Creating extensions

Using generator

shell

rails generate servactory:extension MyExtension

Options:

Option	Default	Description
`--path`	`app/services/application_service/extensions`	Output directory
`--namespace`	`ApplicationService`	Base namespace

Examples:

shell

# Basic
rails generate servactory:extension Auditable

# Nested namespace
rails generate servactory:extension Admin::AuditTrail

# Custom path
rails generate servactory:extension MyExtension --path=lib/extensions

Extension structure

app/services/application_service/extensions/my_extension/dsl.rb

ruby

module ApplicationService
  module Extensions
    module MyExtension
      module DSL
        def self.included(base)
          base.extend(ClassMethods)
          base.include(InstanceMethods)
        end

        module ClassMethods
          private

          def my_extension!(value)
            stroma.settings[:actions][:my_extension][:value] = value
          end
        end

        module InstanceMethods
          private

          def call!(**)
            value = self.class.stroma.settings[:actions][:my_extension][:value]

            if value.present?
              # Before logic
            end

            super

            # After logic
          end
        end
      end
    end
  end
end

Module structure explanation

Module	Purpose
`DSL`	Entry point module, connected via hooks
`ClassMethods`	DSL methods called at class definition time
`InstanceMethods`	Runtime methods called during service execution

base.extend(ClassMethods) — adds class-level configuration methods
base.include(InstanceMethods) — adds instance-level runtime behavior

File organization

For complex extensions, split into separate files:

extensions/my_extension/
├── dsl.rb              # Main DSL module with self.included
├── class_methods.rb    # ClassMethods module
└── instance_methods.rb # InstanceMethods module

Connecting extensions

Hooks: before and after

ruby

class ApplicationService::Base < Servactory::Base
  extensions do
    before :actions, ApplicationService::Extensions::Authorization::DSL
    after :actions, ApplicationService::Extensions::Publishable::DSL
  end
end

Available hook keys

Hooks can be attached to these stages (in execution order):

Key	Description
`:configuration`	Service configuration
`:info`	Service info
`:context`	Context setup
`:inputs`	Input processing
`:internals`	Internal attributes
`:outputs`	Output processing
`:actions`	Action execution

Most extensions use :actions — the main execution point.

Multiple extensions

ruby

class ApplicationService::Base < Servactory::Base
  extensions do
    # Before hooks (execute in order)
    before :actions, ApplicationService::Extensions::Authorization::DSL
    before :actions, ApplicationService::Extensions::StatusActive::DSL

    # After hooks (execute in order)
    after :actions, ApplicationService::Extensions::Publishable::DSL
    after :actions, ApplicationService::Extensions::PostCondition::DSL
  end
end

Execution order

before hooks execute in declaration order
Service actions (make methods)
after hooks execute in declaration order

Understanding `super`

Extensions form a call chain. super passes execution to the next module:

ruby

def call!(**)
  # Before logic (runs first)
  settings = self.class.stroma.settings[:actions][:my_extension]
  fail!(message: "Not configured") if settings[:required] && settings[:value].blank?

  super  # Calls next extension or service actions

  # After logic (runs after service completes)
  Rails.logger.info("Service completed: #{self.class.name}")
end

Pattern	`super` placement	Use case
Before	Logic before `super`	Validation, authorization
After	Logic after `super`	Logging, publishing
Around	Wrap `super`	Transactions, timing
Short-circuit	Skip `super`	Caching, early return

Organizing complex extensions

For extensions with complex logic, isolate it into dedicated Tools classes instead of adding methods to the extension module. This pattern is used internally by Servactory.

File structure:

extensions/authorization/
├── dsl.rb
└── tools/
    └── permission_checker.rb

dsl.rbtools/permission_checker.rb

ruby

module ApplicationService
  module Extensions
    module Authorization
      module DSL
        def self.included(base)
          base.extend(ClassMethods)
          base.include(InstanceMethods)
        end

        module ClassMethods
          private

          def authorize_with(method_name)
            stroma.settings[:actions][:authorization][:method_name] = method_name
          end
        end

        module InstanceMethods
          private

          def call!(incoming_arguments: {}, **)
            method_name = self.class.stroma.settings[:actions][:authorization][:method_name]

            if method_name.present?
              # PORO class for extension logic, not a Servactory service
              Tools::PermissionChecker.check!(self, incoming_arguments, method_name)
            end

            super
          end
        end
      end
    end
  end
end

ruby

module ApplicationService
  module Extensions
    module Authorization
      module Tools
        class PermissionChecker
          def self.check!(...)
            new(...).check!
          end

          def initialize(context, arguments, method_name)
            @context = context
            @arguments = arguments
            @method_name = method_name
          end

          def check!
            authorized = @context.send(@method_name, @arguments)

            return if authorized

            @context.fail!(
              :unauthorized,
              message: "Not authorized to perform this action"
            )
          end
        end
      end
    end
  end
end

Benefits:

Logic is isolated in dedicated classes
No method pollution in extension modules
Easy to test each Tool in isolation
Scales well for complex extensions

Stroma settings

Extensions store configuration in Stroma settings.

Key structure

stroma.settings[:registry_key][:extension_name][:setting_key]

Level	Description	Example
`registry_key`	Hook target	`:actions`
`extension_name`	Extension identifier	`:authorization`
`setting_key`	Specific setting	`:method_name`

Writing settings

In ClassMethods:

ruby

def authorize_with(method_name)
  stroma.settings[:actions][:authorization][:method_name] = method_name
end

Reading settings

In InstanceMethods:

ruby

def call!(**)
  method_name = self.class.stroma.settings[:actions][:authorization][:method_name]
  # ...
  super
end

Auto-vivification

Nested objects are created automatically on first access:

ruby

# This works without explicit initialization
stroma.settings[:actions][:my_extension][:enabled] = true
stroma.settings[:actions][:my_extension][:options] = { timeout: 30 }

Extension patterns

Before pattern

Validate or check conditions before service execution.

extensions/authorization/dsl.rbUsage

ruby

module ApplicationService
  module Extensions
    module Authorization
      module DSL
        def self.included(base)
          base.extend(ClassMethods)
          base.include(InstanceMethods)
        end

        module ClassMethods
          private

          def authorize_with(method_name)
            stroma.settings[:actions][:authorization][:method_name] = method_name
          end
        end

        module InstanceMethods
          private

          def call!(incoming_arguments: {}, **)
            method_name = self.class.stroma.settings[:actions][:authorization][:method_name]

            if method_name.present?
              authorized = send(method_name, incoming_arguments)

              unless authorized
                fail!(
                  :unauthorized,
                  message: "Not authorized to perform this action"
                )
              end
            end

            super
          end
        end
      end
    end
  end
end

ruby

class Posts::Delete < ApplicationService::Base
  input :post, type: Post
  input :user, type: User

  authorize_with :user_can_delete?

  make :delete_post

  private

  def user_can_delete?(args)
    args[:user].admin? || args[:post].author_id == args[:user].id
  end

  def delete_post
    inputs.post.destroy!
  end
end

Around pattern

Wrap service execution in a context.

extensions/transactional/dsl.rbUsage

ruby

module ApplicationService
  module Extensions
    module Transactional
      module DSL
        def self.included(base)
          base.extend(ClassMethods)
          base.include(InstanceMethods)
        end

        module ClassMethods
          private

          def transactional!(transaction_class: nil)
            stroma.settings[:actions][:transactional][:enabled] = true
            stroma.settings[:actions][:transactional][:class] = transaction_class
          end
        end

        module InstanceMethods
          private

          def call!(**)
            settings = self.class.stroma.settings[:actions][:transactional]
            enabled = settings[:enabled]

            unless enabled
              super
              return
            end

            transaction_class = settings[:class]

            fail!(message: "Transaction class not configured") if transaction_class.nil?

            transaction_class.transaction { super }
          end
        end
      end
    end
  end
end

ruby

class Orders::Create < ApplicationService::Base
  transactional! transaction_class: ActiveRecord::Base

  input :user, type: User
  input :items, type: Array

  output :order, type: Order

  make :create_order
  make :create_line_items
  make :charge_payment

  private

  def create_order
    outputs.order = Order.create!(user: inputs.user)
  end

  def create_line_items
    inputs.items.each do |item|
      outputs.order.line_items.create!(item)
    end
  end

  def charge_payment
    Payments::Charge.call!(amount: outputs.order.total_amount)
  end
end

After pattern

Process results after service execution.

extensions/publishable/dsl.rbUsage

ruby

module ApplicationService
  module Extensions
    module Publishable
      module DSL
        def self.included(base)
          base.extend(ClassMethods)
          base.include(InstanceMethods)
        end

        module ClassMethods
          private

          def publishes(event_name, with: nil, event_bus: nil)
            stroma.settings[:actions][:publishable][:configurations] ||= []
            stroma.settings[:actions][:publishable][:configurations] << {
              event_name:,
              payload_method: with,
              event_bus:
            }
          end
        end

        module InstanceMethods
          private

          def call!(**)
            super

            configurations = self.class.stroma.settings[:actions][:publishable][:configurations] || []

            configurations.each do |config|
              event_name = config[:event_name]
              payload_method = config[:payload_method]
              event_bus = config[:event_bus]

              payload = payload_method.present? ? send(payload_method) : {}
              event_bus.publish(event_name, payload)
            end
          end
        end
      end
    end
  end
end

ruby

class Users::Create < ApplicationService::Base
  publishes :user_created, with: :user_payload, event_bus: EventPublisher

  input :email, type: String
  input :name, type: String

  output :user, type: User

  make :create_user

  private

  def create_user
    outputs.user = User.create!(email: inputs.email, name: inputs.name)
  end

  def user_payload
    { user_id: outputs.user.id, email: outputs.user.email }
  end
end

Rescue pattern

Handle errors and perform cleanup.

extensions/rollbackable/dsl.rbUsage

ruby

module ApplicationService
  module Extensions
    module Rollbackable
      module DSL
        def self.included(base)
          base.extend(ClassMethods)
          base.include(InstanceMethods)
        end

        module ClassMethods
          private

          def on_rollback(method_name)
            stroma.settings[:actions][:rollbackable][:method_name] = method_name
          end
        end

        module InstanceMethods
          private

          def call!(**)
            super
          rescue StandardError => e
            raise e if e.is_a?(Servactory::Exceptions::Success)

            method_name = self.class.stroma.settings[:actions][:rollbackable][:method_name]

            send(method_name) if method_name.present?

            raise
          end
        end
      end
    end
  end
end

ruby

class Payments::Process < ApplicationService::Base
  on_rollback :cleanup_resources

  input :order, type: Order
  input :payment_method, type: PaymentMethod

  output :payment, type: Payment

  make :reserve_inventory
  make :charge_payment
  make :confirm_order

  private

  def reserve_inventory
    Inventory::Reserve.call!(items: inputs.order.items)
  end

  def charge_payment
    result = Payments::Charge.call!(
      payment_method: inputs.payment_method,
      amount: inputs.order.total_amount
    )
    outputs.payment = result.payment
  end

  def confirm_order
    inputs.order.confirm!
  end

  def cleanup_resources
    Inventory::Release.call!(items: inputs.order.items)
    Payments::Refund.call!(payment: outputs.payment) if outputs.payment.present?
  end
end

Migration from 2.x

WARNING

Servactory::DSL.with_extensions(...) is deprecated and will be removed in future releases. Please migrate to the new extensions do block syntax.

Syntax changes

3.x (Current)2.x (Legacy)

ruby

module ApplicationService
  class Base < Servactory::Base
    extensions do
      before :actions, ApplicationService::Extensions::StatusActive::DSL
    end
  end
end

ruby

module ApplicationService
  class Base
    include Servactory::DSL.with_extensions(
      ApplicationService::Extensions::StatusActive::DSL
    )
  end
end

Settings storage changes

Aspect	3.x	2.x
Storage	`stroma.settings[:key][:ext][:setting]`	`attr_accessor` (class instance variable)
Access	`self.class.stroma.settings[:key][:ext][:setting]`	`self.class.send(:var)`
Inheritance	Automatic deep copy	Manual handling

Extension code changes

3.x (Current)2.x (Legacy)

ruby

module ClassMethods
  private

  def status_active!(model_name)
    stroma.settings[:actions][:status_active][:model_name] = model_name
  end
end

module InstanceMethods
  private

  def call!(**)
    model_name = self.class.stroma.settings[:actions][:status_active][:model_name]
    # ...
    super
  end
end

ruby

module ClassMethods
  private

  attr_accessor :status_active_model_name

  def status_active!(model_name)
    self.status_active_model_name = model_name
  end
end

module InstanceMethods
  private

  def call!(**)
    super

    model_name = self.class.send(:status_active_model_name)
    # ...
  end
end

Extensions Since 3.0.0 ​

Quick start ​

Generate extension ​

Connect extension ​

Use in service ​

Creating extensions ​

Using generator ​

Extension structure ​

Module structure explanation ​

File organization ​

Connecting extensions ​

Hooks: before and after ​

Available hook keys ​

Multiple extensions ​

Execution order ​

Understanding super ​

Organizing complex extensions ​

Stroma settings ​

Key structure ​

Writing settings ​

Reading settings ​

Auto-vivification ​

Extension patterns ​

Before pattern ​

Around pattern ​

After pattern ​

Rescue pattern ​

Migration from 2.x ​

Syntax changes ​

Settings storage changes ​

Extension code changes ​

Extensions Since 3.0.0

Quick start

Generate extension

Connect extension

Use in service

Creating extensions

Using generator

Extension structure

Module structure explanation

File organization

Connecting extensions

Hooks: before and after

Available hook keys

Multiple extensions

Execution order

Understanding `super`

Organizing complex extensions

Stroma settings

Key structure

Writing settings

Reading settings

Auto-vivification

Extension patterns

Before pattern

Around pattern

After pattern

Rescue pattern

Migration from 2.x

Syntax changes

Settings storage changes

Extension code changes