Refactor setup/finalization (#637)

Refactor setup/configuration/finalization code

  - Use components directly in the loader
  - Use components when finalizing schemas
  - Use components when finalizing relations
  - Use components when finalizing commands
  - Use components when finalizing mappers
  - Remove usage for *_classes methods
  - Components => Components::Registry
  - Introduce Components::Relation
  - Drastically simplify handling of environment and notifications
  - Remove unused environment config from finalize
  - Remove unused repo_adapter
  - Use configuration in Finalize instead of options
  - Remove redundant configuration.finalize
  - Move setting default command registry to relation class method

[changelog]

added: "New component API that replaces internal implementation of the finalization code and makes it possible to extend ROM with arbitrary component types (see #637) (@solnic)"

Author: solnic

lib/rom/command_registry.rb

@@ -100,6 +100,13 @@ def set_mappers(mappers)
       options[:mappers] = @mappers = mappers
     end
 
+    # @api private
+    def add(key, command)
+      raise CommandAlreadyDefinedError, "+#{key}+ is already defined" if key?(key)
+
+      elements[key] = command
+    end
+
     private
 
     # Allow checking if a certain command is available using dot-notation

lib/rom/compat/setup.rb

@@ -21,10 +21,25 @@ class Setup
     # @api public
     def auto_registration(directory, **options)
       auto_registration = AutoRegistration.new(directory, inflector: inflector, **options)
-      auto_registration.relations.map { |r| register_relation(r) }
-      auto_registration.commands.map { |r| register_command(r) }
-      auto_registration.mappers.map { |r| register_mapper(r) }
+      auto_registration.relations.each { |r| register_relation(r) }
+      auto_registration.commands.each { |r| register_command(r) }
+      auto_registration.mappers.each { |r| register_mapper(r) }
       self
     end
+
+    # @api public
+    def relation_classes
+      components.relations.map(&:constant)
+    end
+
+    # @api public
+    def command_classes
+      components.commands.map(&:constant)
+    end
+
+    # @api public
+    def mapper_classes
+      components.mappers.map(&:constant)
+    end
   end
 end

lib/rom/components.rb

@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+require "rom/constants"
+require "rom/components/schema"
+require "rom/components/command"
+require "rom/components/relation"
+require "rom/components/mapper"
+
+module ROM
+  # Setup objects collect component classes during setup/finalization process
+  #
+  # @api public
+  module Components
+    CORE_TYPES = %i[schemas relations commands mappers].freeze
+
+    HANDLERS = {
+      relations: Relation,
+      commands: Command,
+      mappers: Mapper,
+      schemas: Schema
+    }.freeze
+
+    # @api public
+    def components
+      @components ||= Registry.new
+    end
+
+    class Registry
+      # @api private
+      attr_reader :types
+
+      # @api private
+      attr_reader :store
+
+      # @api private
+      attr_reader :handlers
+
+      # @api private
+      def initialize(types: CORE_TYPES.dup, handlers: HANDLERS)
+        @types = types
+        @store = types.map { |type| [type, EMPTY_ARRAY.dup] }.to_h
+        @handlers = handlers
+      end
+
+      # @api private
+      def [](type)
+        store[type]
+      end
+
+      # @api private
+      def update(other)
+        store.each { |type, items| items.concat(other[type]) }
+        self
+      end
+
+      # @api private
+      def add(type, **options)
+        component = handlers.fetch(type).new(**options)
+
+        # TODO: this needs a nicer abstraction
+        # TODO: respond_to? is only needed because auto_register specs use POROs :(
+        update(component.constant.components) if component.constant.respond_to?(:components)
+
+        store[type] << component
+
+        component
+      end
+
+      CORE_TYPES.each do |type|
+        define_method(type) do |**opts|
+          all = self[type]
+          return all if opts.empty?
+          all.select { |el| opts.all? { |key, value| el.public_send(key).eql?(value) } }
+        end
+      end
+    end
+  end
+end

lib/rom/components/command.rb

@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require_relative "core"
+
+module ROM
+  module Components
+    # @api public
+    class Command < Core
+      id :command
+
+      # Registry id
+      #
+      # @return [Symbol]
+      #
+      # @api public
+      def id
+        constant.register_as || constant.default_name
+      end
+
+      # @return [Symbol]
+      #
+      # @api public
+      def relation_id
+        constant.relation
+      end
+
+      # @api public
+      def build(relation:)
+        trigger(
+          "commands.class.before_build",
+          command: constant,
+          gateway: gateways[relation.gateway],
+          dataset: relation.dataset,
+          adapter: adapter
+        )
+
+        constant.extend_for_relation(relation) if constant.restrictable
+
+        constant.build(relation)
+      end
+    end
+  end
+end

lib/rom/components/core.rb

@@ -0,0 +1,107 @@
+# frozen_string_literal: true
+
+require "dry/effects"
+require "dry/core/class_attributes"
+require "dry/core/memoizable"
+
+require "rom/constants"
+require "rom/initializer"
+require "rom/types"
+
+module ROM
+  module Components
+    # Abstract component class
+    #
+    # @api public
+    class Core
+      extend Initializer
+      extend Dry::Core::ClassAttributes
+
+      include Dry::Core::Memoizable
+      include Dry::Effects.Reader(:configuration)
+
+      defines :id
+
+      # @!attribute [r] constant
+      #   @return [Class] Component's target class
+      #   @api public
+      option :constant, optional: true, type: Types.Interface(:new)
+      alias_method :relation, :constant
+
+      # This method is meant to return a run-time component instance
+      #
+      # @api public
+      def build(**)
+        raise NotImplementedError
+      end
+
+      # @api public
+      def trigger(event, payload)
+        notifications.trigger("configuration.#{event}", payload)
+      end
+
+      # @api public
+      def relations
+        configuration.relations
+      end
+
+      # @api public
+      def command_compiler
+        configuration.command_compiler
+      end
+
+      # @api public
+      def notifications
+        configuration.notifications
+      end
+
+      # @api public
+      def gateways
+        configuration.gateways
+      end
+
+      # @api public
+      def components
+        configuration.components
+      end
+
+      # @api public
+      def adapter
+        relation.adapter or raise(
+          MissingAdapterIdentifierError, "+#{constant}+ is missing the adapter identifier"
+        )
+      end
+
+      # @api public
+      def apply_plugins
+        plugins.each do |plugin|
+          plugin.apply_to(constant)
+        end
+      end
+
+      # @api public
+      memoize def plugins
+        configuration.plugins.select { |plugin| plugin.type == self.class.id }
+      end
+
+      # @api public
+      memoize def plugin_options
+        plugins.map(&:config).map(&:to_hash).reduce(:merge) || EMPTY_HASH
+      end
+
+      private
+
+      # @api private
+      def gateway
+        gateways.fetch(gateway_name) do
+          raise "+#{gateway_name.inspect}+ gateway not found for #{constant}"
+        end
+      end
+
+      # @api private
+      def gateway_name
+        relation.gateway
+      end
+    end
+  end
+end

lib/rom/components/mapper.rb

@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require_relative "core"
+
+module ROM
+  module Components
+    # @api public
+    class Mapper < Core
+      id :mapper
+
+      # @!attribute [r] id
+      #   @return [Symbol] Registry key
+      #   @api public
+      option :id, type: Types.Instance(Symbol), optional: true, reader: false
+
+      # @!attribute [r] base_relation
+      #   @return [Symbol] The base relation identifier
+      #   @api public
+      option :base_relation, type: Types.Instance(Symbol), optional: true, reader: false
+
+      # @!attribute [r] object
+      #   @return [Class] Pre-initialized object that should be used instead of the constant
+      #   @api public
+      option :object, optional: true
+
+      # Relation registry id
+      #
+      # @return [Symbol]
+      #
+      # @api public
+      def relation_id
+        options[:base_relation] || constant.base_relation
+      end
+
+      # Registry key
+      #
+      # @return [Symbol]
+      #
+      # @api public
+      def id
+        options[:id] || constant.id
+      end
+
+      # Default container key
+      #
+      # @return [String]
+      #
+      # @api public
+      def key
+        "mappers.#{relation_id}.#{id}"
+      end
+
+      # @api public
+      def build
+        object || constant.build
+      end
+    end
+  end
+end