Merge db48312 into 3c86a58

lib/generators/logux/model/USAGE

@@ -0,0 +1,11 @@
+Description:
+  Generates the necessary migration to enable field tracking for logux updates
+
+Examples:
+  rails generate logux:model User
+
+    This will generate the migration to add a column with update time data.
+
+  rails generate logux:model User --nullable
+
+    This will generate the migration to add a column with update time data and add `null: false` constraint. Be careful, adding the constraint to the table with a big number of rows can cause lots of locks.

lib/generators/logux/model/model_generator.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require 'rails/generators'
+require 'rails/generators/active_record/migration/migration_generator'
+
+module Logux
+  module Generators
+    class ModelGenerator < ::ActiveRecord::Generators::Base # :nodoc:
+      source_root File.expand_path('templates', __dir__)
+
+      class_option :nullable,
+                   type: :boolean,
+                   optional: true,
+                   desc: 'Define whether field should have not-null constraint'
+
+      def generate_migration
+        migration_template(
+          'migration.rb.erb',
+          "db/migrate/add_logux_fields_updated_at_to_#{plural_table_name}.rb"
+        )
+      end
+
+      def nullable?
+        options.fetch(:nullable, false)
+      end
+    end
+  end
+end

lib/generators/logux/model/templates/migration.rb.erb

@@ -0,0 +1,14 @@
+class <%= @migration_class_name %> < ActiveRecord::Migration<%= ActiveRecord::VERSION::MAJOR < 5 ? '' : '[5.0]' %>
+  def up
+    <% if nullable? %>
+    add_column :<%= plural_table_name %>, :logux_fields_updated_at, :jsonb, null: false, default: {}
+    <% else %>
+    add_column :<%= plural_table_name %>, :logux_fields_updated_at, :jsonb, null: true
+    change_column_default :<%= plural_table_name %>, :logux_fields_updated_at, {}
+    <% end %>
+  end
+
+  def down
+    remove_column :<%= plural_table_name %>, :logux_fields_updated_at
+  end
+end

lib/logux.rb

@@ -47,6 +47,7 @@ def initialize(msg, meta: nil)
   autoload :Version, 'logux/version'
   autoload :Test, 'logux/test'
   autoload :ErrorRenderer, 'logux/error_renderer'
+  autoload :Model, 'logux/model'
 
   configurable :logux_host, :verify_authorized,
                :password, :logger,

lib/logux/action_caller.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require 'logux/model/insecure_update_subscriber'
+
 module Logux
   class ActionCaller
     attr_reader :action, :meta
@@ -12,8 +14,12 @@ def initialize(action:, meta:)
     end
 
     def call!
-      logger.info("Searching action for Logux action: #{action}, meta: #{meta}")
-      format(action_controller.public_send(action.action_type))
+      detect_insecure_updates do
+        logger.info(
+          "Searching action for Logux action: #{action}, meta: #{meta}"
+        )
+        format(action_controller.public_send(action.action_type))
+      end
     rescue Logux::UnknownActionError, Logux::UnknownChannelError => e
       logger.warn(e)
       format(nil)
@@ -34,5 +40,15 @@ def class_finder
     def action_controller
       class_finder.find_action_class.new(action: action, meta: meta)
     end
+
+    def detect_insecure_updates
+      ActiveSupport::Notifications.subscribe(
+        'logux.insecure_update',
+        Logux::Model::InsecureUpdateSubscriber.new
+      )
+      yield
+    ensure
+      ActiveSupport::Notifications.unsubscribe('logux.insecure_update')
+    end
   end
 end

lib/logux/meta.rb

@@ -21,5 +21,13 @@ def node_id
     def user_id
       id&.split(' ')&.second&.split(':')&.first
     end
+
+    def sequence_id
+      id&.split(' ')&.third
+    end
+
+    def logux_id
+      [time, node_id, sequence_id].join(' ')
+    end
   end
 end

lib/logux/model.rb

@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require_relative 'model/updater'
+require_relative 'model/proxy'
+require_relative 'model/dsl'
+
+module Logux
+  module Model
+    class InsecureUpdateError < StandardError; end
+
+    def self.included(base)
+      base.extend(DSL)
+
+      base.before_save :update_logux_id
+    end
+
+    def logux
+      Proxy.new(self)
+    end
+
+    private
+
+    def update_logux_id
+      return if changes.key?('logux_fields_updated_at')
+
+      attributes = changed.each_with_object({}) do |attr, res|
+        res[attr] = send(attr)
+      end
+
+      updater = Updater.new(model: self, attributes: attributes)
+      self.logux_fields_updated_at = updater.updated_attributes
+
+      trigger_insecure_update_notification
+    end
+
+    def trigger_insecure_update_notification
+      ActiveSupport::Notifications.instrument(
+        'logux.insecure_update',
+        model_class: self.class,
+        attributes: (changed - ['logux_fields_updated_at']).map(&:to_sym)
+      )
+    end
+  end
+end

lib/logux/model/dsl.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module Logux
+  module Model
+    module DSL
+      def logux_crdt_map_attributes(*attributes)
+        @logux_crdt_mapped_attributes = attributes
+      end
+
+      def logux_crdt_mapped_attributes
+        @logux_crdt_mapped_attributes ||= []
+      end
+    end
+  end
+end

lib/logux/model/insecure_update_subscriber.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module Logux
+  module Model
+    class InsecureUpdateSubscriber
+      # rubocop:disable Naming/UncommunicativeMethodParamName
+      def call(_, _, _, _, args)
+        model_class = args[:model_class]
+        attributes = args[:attributes]
+
+        logux_attributes =
+          attributes & model_class.logux_crdt_mapped_attributes
+        return if logux_attributes.empty?
+
+        pluralized_attributes = 'attribute'.pluralize(logux_attributes.count)
+
+        raise InsecureUpdateError, <<~TEXT
+          Logux tracked #{pluralized_attributes} (#{logux_attributes.join(', ')}) should be updated using model.logux.update(...)
+        TEXT
+      end
+      # rubocop:enable Naming/UncommunicativeMethodParamName
+    end
+  end
+end

lib/logux/model/proxy.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module Logux
+  module Model
+    class Proxy
+      def initialize(model)
+        @model = model
+      end
+
+      def update(meta, attributes)
+        updater = Updater.new(
+          model: @model,
+          logux_id: meta.logux_id,
+          attributes: attributes
+        )
+        @model.update_attributes(updater.updated_attributes)
+      end
+
+      def updated_at(field)
+        @model.logux_fields_updated_at[field.to_s]
+      end
+    end
+  end
+end

lib/logux/model/updater.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+module Logux
+  module Model
+    class Updater
+      def initialize(model:, attributes:, logux_id: Logux.generate_action_id)
+        @model = model
+        @logux_id = logux_id
+        @attributes = attributes
+      end
+
+      def updated_attributes
+        newer_updates.merge(logux_fields_updated_at: fields_updated_at)
+      end
+
+      private
+
+      def fields_updated_at
+        @fields_updated_at ||=
+          newer_updates.slice(*tracked_fields)
+                       .keys
+                       .reduce(@model.logux_fields_updated_at) do |acc, attr|
+                         acc.merge(attr => @logux_id)
+                       end
+      end
+
+      def newer_updates
+        @newer_updates ||= @attributes.reject do |attr, _|
+          field_updated_at = @model.logux.updated_at(attr)
+          field_updated_at && field_updated_at > @logux_id
+        end
+      end
+
+      def tracked_fields
+        @model.class.logux_crdt_mapped_attributes
+      end
+    end
+  end
+end

spec/dummy/app/models/post.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class Post < ActiveRecord::Base
+  include Logux::Model
+
+  logux_crdt_map_attributes :title, :content
+end

spec/dummy/db/migrate/20181101131807_create_posts.rb

@@ -0,0 +1,10 @@
+class CreatePosts < ActiveRecord::Migration[5.2]
+  def change
+    create_table :posts do |t|
+      t.string :title
+      t.text :content
+
+      t.timestamps
+    end
+  end
+end

spec/dummy/db/migrate/20181101194822_add_logux_fields_updated_at_to_posts.rb

@@ -0,0 +1,10 @@
+class AddLoguxFieldsUpdatedAtToPosts < ActiveRecord::Migration[5.2]
+  def up
+    add_column :posts, :logux_fields_updated_at, :jsonb, null: true
+    change_column_default :posts, :logux_fields_updated_at, {}
+  end
+
+  def down
+    remove_column :posts, :logux_fields_updated_at
+  end
+end

spec/factories/logux_actions_factory.rb

@@ -39,5 +39,14 @@
         )
       end
     end
+
+    factory :logux_actions_post_rename do
+      skip_create
+      initialize_with do
+        new(
+          { type: 'post/rename', key: 'name', value: 'test' }.merge(attributes)
+        )
+      end
+    end
   end
 end

spec/factories/post_factory.rb

@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :post, class: Post do
+    title { 'initial' }
+    content { 'initial' }
+  end
+end

spec/logux/action_caller_spec.rb

@@ -31,5 +31,33 @@ def add
         expect(result.status).to eq(:ok)
       end
     end
+
+    describe 'when insecure update happens' do
+      let(:action) { create(:logux_actions_post_rename) }
+
+      before do
+        module Actions
+          class Post < Logux::ActionController
+            def rename
+              post = FactoryBot.create(:post)
+              post.update_attributes(title: 'new title')
+              respond :processed
+            end
+          end
+        end
+      end
+
+      after do
+        Actions::Post.send :undef_method, :rename
+        Actions.send :remove_const, :Post
+        Actions.send :const_set, :Post, Class.new
+      end
+
+      it 'raises exception when #update_attributes is called inside action' do
+        expect do
+          action_caller.call!
+        end.to raise_exception(Logux::Model::InsecureUpdateError)
+      end
+    end
   end
 end