Global configuration for :ignore_log_data option

CHANGELOG.md

@@ -2,6 +2,22 @@
 
 ## master
 
+- PR [#111](https://github.com/palkan/logidze/pull/111) Global configuration for `:ignore_log_data` option ([@dmitrytsepelev][])
+
+Now it's possible to avoid loading `log_data` from the DB by default with
+
+```ruby
+Logidze.ignore_log_data_by_default = true
+```
+
+In cases when `ignore_log_data: false` is explicitly passed to the `ignore_log_data` the default setting is being overriden. Also, it's possible to change it inside the block:
+
+```ruby
+Logidze.with_log_data do
+  Post.find(params[:id]).log_data
+end
+```
+
 - PR [#110](https://github.com/palkan/logidze/pull/110) Add `reset_log_data` API to nullify log_data column ([@Arkweid][])
 
 Usage:

README.md

@@ -227,7 +227,21 @@ class User < ActiveRecord::Base
 end
 ```
 
-After that, each time you use `User.all` (or any other relation method) `log_data` won't be loaded from the DB.
+If you want Logidze to always behave this way - you can set up a global configuration option:
+
+```ruby
+Rails.application.config.logidze.ignore_log_data_by_default = true
+```
+
+However, you can override it by explicitly passing `ignore_log_data: false` to the `ignore_log_data`. Also, it's possible to change it temporary inside the block:
+
+```ruby
+Logidze.with_log_data do
+  Post.find(params[:id]).log_data
+end
+```
+
+When `ignore_log_data` is turned on, each time you use `User.all` (or any other relation method) `log_data` won't be loaded from the DB.
 
 The chart below shows the difference in PG query time before and after turning `ignore_log_data` on. (Special thanks to [@aderyabin](https://github.com/aderyabin) for sharing it.)
 

lib/logidze.rb

@@ -18,23 +18,48 @@ module Logidze
   class << self
     # Determines if Logidze should append a version to the log after updating an old version.
     attr_accessor :append_on_undo
+
     attr_writer :associations_versioning
 
     def associations_versioning
       @associations_versioning || false
     end
-  end
 
-  # Temporary disable DB triggers.
-  #
-  # @example
-  #   Logidze.without_logging { Post.update_all(active: true) }
-  def self.without_logging
-    ActiveRecord::Base.transaction do
-      ActiveRecord::Base.connection.execute "SET LOCAL logidze.disabled TO on;"
-      res = yield
-      ActiveRecord::Base.connection.execute "SET LOCAL logidze.disabled TO DEFAULT;"
-      res
+    # Determines if Logidze should exclude log data from SELECT statements
+    attr_writer :ignore_log_data_by_default
+
+    def ignore_log_data_by_default
+      @ignore_log_data_by_default || false
+    end
+
+    attr_writer :force_load_log_data
+
+    def force_load_log_data
+      @force_load_log_data || false
+    end
+
+    # Temporary disable DB triggers.
+    #
+    # @example
+    #   Logidze.without_logging { Post.update_all(active: true) }
+    def without_logging
+      ActiveRecord::Base.transaction do
+        ActiveRecord::Base.connection.execute "SET LOCAL logidze.disabled TO on;"
+        res = yield
+        ActiveRecord::Base.connection.execute "SET LOCAL logidze.disabled TO DEFAULT;"
+        res
+      end
+    end
+
+    # Temporary turn off ignore_log_data_by_default config
+    #
+    # @example
+    #   Logidze.with_log_data { Post.update_all(active: true) }
+    def with_log_data
+      Logidze.force_load_log_data = true
+      yield
+    ensure
+      Logidze.force_load_log_data = false
     end
   end
 end

lib/logidze/has_logidze.rb

@@ -10,9 +10,19 @@ module ClassMethods # :nodoc:
       # Include methods to work with history.
       #
       # rubocop:disable Naming/PredicateName
-      def has_logidze(ignore_log_data: false)
+      def has_logidze(ignore_log_data: nil)
         include Logidze::Model
-        include Logidze::IgnoreLogData if ignore_log_data
+        include Logidze::IgnoreLogData
+
+        @ignore_log_data = ignore_log_data
+      end
+
+      def ignores_log_data?
+        if @ignore_log_data.nil? && Logidze.ignore_log_data_by_default
+          !Logidze.force_load_log_data
+        else
+          @ignore_log_data
+        end
       end
     end
   end

lib/logidze/ignore_log_data.rb

@@ -1,8 +1,7 @@
 # frozen_string_literal: true
 
 module Logidze
-  # Add `has_logidze` method to AR::Base
-  module IgnoreLogData
+  module IgnoreLogData # :nodoc:
     extend ActiveSupport::Concern
 
     included do
@@ -16,14 +15,19 @@ module IgnoreLogData
 
         require "logidze/ignore_log_data/missing_attribute_patch"
         include MissingAttributePatch
+
+        require "logidze/ignore_log_data/default_scope_patch"
+        include DefaultScopePatch
       end
 
       self.ignored_columns += ["log_data"]
+
+      scope :with_log_data, -> { select(column_names + ["log_data"]) }
     end
 
-    module ClassMethods # :nodoc:
-      def with_log_data
-        select(column_names + ["log_data"])
+    class_methods do
+      def self.default_scope
+        ignores_log_data? ? super : super.with_log_data
       end
     end
   end

lib/logidze/ignore_log_data/default_scope_patch.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module Logidze
+  module IgnoreLogData
+    # Since Rails caches ignored_columns, we have to patch .column_names and
+    # .unscoped methods to make conditional log_data loading possible
+    module DefaultScopePatch
+      extend ActiveSupport::Concern
+
+      class_methods do
+        def column_names
+          ignores_log_data? ? super : super + ["log_data"]
+        end
+
+        def unscoped
+          if ignores_log_data?
+            super
+          else
+            block_given? ? with_log_data.scoping { yield } : with_log_data
+          end
+        end
+      end
+    end
+  end
+end

lib/logidze/ignore_log_data/ignored_columns.rb

@@ -16,7 +16,7 @@ module Relation # :nodoc:
         private
 
         def build_select(arel)
-          if select_values.blank? && klass.ignored_columns.any?
+          if select_values.blank? && klass.ignored_columns.any? && ignores_log_data?
             arel.project(*arel_columns(klass.column_names - klass.ignored_columns))
           else
             super

lib/logidze/ignore_log_data/missing_attribute_patch.rb

@@ -7,7 +7,9 @@ module IgnoreLogData
     # from Rails 4 - raise ActiveModel::MissingAttributeError
     module MissingAttributePatch
       def log_data
-        raise ActiveModel::MissingAttributeError if attributes["log_data"].nil?
+        if self.class.ignores_log_data? && attributes["log_data"].nil?
+          raise ActiveModel::MissingAttributeError
+        end
 
         super
       end

spec/dummy/app/models/always_logged_post.rb

@@ -0,0 +1,5 @@
+class AlwaysLoggedPost < ActiveRecord::Base
+  has_logidze ignore_log_data: false
+
+  self.table_name = "posts"
+end

spec/dummy/app/models/comment.rb

@@ -1,4 +1,4 @@
 class Comment < ActiveRecord::Base
-  has_logidze
+  has_logidze ignore_log_data: false
   belongs_to :article
 end

spec/dummy/app/models/not_logged_post.rb

@@ -1,3 +1,7 @@
-class NotLoggedPost < Post
+class NotLoggedPost < ActiveRecord::Base
   has_logidze ignore_log_data: true
+
+  self.table_name = "posts"
+
+  belongs_to :user
 end

spec/dummy/db/schema.rb

@@ -1,3 +1,4 @@
+# encoding: UTF-8
 # This file is auto-generated from the current state of the database. Instead
 # of editing this file, please use the migrations feature of Active Record to
 # incrementally modify your database, and then regenerate this schema definition.
@@ -10,49 +11,46 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2017_02_20_153105) do
+ActiveRecord::Schema.define(version: 20170220153105) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
-  create_table "articles", id: :serial, force: :cascade do |t|
-    t.string "title"
-    t.integer "rating"
-    t.boolean "active"
-    t.integer "user_id"
-    t.jsonb "log_data"
+  create_table "articles", force: :cascade do |t|
+    t.string   "title"
+    t.integer  "rating"
+    t.boolean  "active"
+    t.integer  "user_id"
+    t.jsonb    "log_data"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.index ["user_id"], name: "index_articles_on_user_id"
   end
 
-  create_table "comments", id: :serial, force: :cascade do |t|
-    t.text "content"
-    t.jsonb "log_data"
-    t.integer "article_id"
+  create_table "comments", force: :cascade do |t|
+    t.text     "content"
+    t.jsonb    "log_data"
+    t.integer  "article_id"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.index ["article_id"], name: "index_comments_on_article_id"
   end
 
-  create_table "posts", id: :serial, force: :cascade do |t|
-    t.string "title"
-    t.integer "rating"
-    t.boolean "active"
-    t.jsonb "meta"
-    t.integer "user_id"
+  create_table "posts", force: :cascade do |t|
+    t.string   "title"
+    t.integer  "rating"
+    t.boolean  "active"
+    t.jsonb    "meta"
+    t.integer  "user_id"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.index ["user_id"], name: "index_posts_on_user_id"
   end
 
-  create_table "users", id: :serial, force: :cascade do |t|
-    t.string "name"
-    t.integer "age"
-    t.boolean "active"
-    t.jsonb "extra"
-    t.string "settings", array: true
-    t.jsonb "log_data"
+  create_table "users", force: :cascade do |t|
+    t.string   "name"
+    t.integer  "age"
+    t.boolean  "active"
+    t.jsonb    "extra"
+    t.string   "settings", array: true
+    t.jsonb    "log_data"
     t.datetime "time"
   end