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
+```
+
 ## 0.9.0 (2018-11-28)
 
 - PR [#98](https://github.com/palkan/logidze/pull/98) Add `:ignore_log_data` option to `#has_logidze` ([@dmitrytsepelev][])

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 +1,5 @@
-class NotLoggedPost < Post
+class NotLoggedPost < ActiveRecord::Base
   has_logidze ignore_log_data: true
+
+  self.table_name = "posts"
 end

spec/dummy/db/schema.rb

@@ -6,7 +6,7 @@
 # database schema. If you need to create the application database on another
 # system, you should be using db:schema:load, not running all the migrations
 # from scratch. The latter is a flawed and unsustainable approach (the more migrations
-# you'll amass, the slower it'll run and the greater likelihood for issues).
+# you'll amass, the slower it'll run and the greater likelihood for issues)
 #
 # It's strongly recommended that you check this file into your version control system.
 

spec/integrations/ignore_log_data_spec.rb

@@ -14,69 +14,93 @@
       # Close active connections to handle db variables
       ActiveRecord::Base.connection_pool.disconnect!
     end
-
-    Post.reset_column_information
-    # For Rails 4
-    Post.instance_variable_set(:@attribute_names, nil)
   end
 
   let(:user) { User.create! }
   let!(:source_post) { Post.create!(user: user) }
 
-  shared_context "test #log_data" do
-    context "#log_data" do
-      it "raises error when log_data is called" do
-        expect { post.log_data }.to raise_error(ActiveModel::MissingAttributeError)
-      end
+  describe "#update!" do
+    it "updates log_data" do
+      expect do
+        NotLoggedPost.find(source_post.id).update!(title: "new")
+      end.to change { Post.find(source_post.id).log_data.version }.by(1)
     end
   end
 
-  shared_context "test #reload_log_data" do
-    context "#reload_log_data" do
-      it "loads data from DB" do
-        expect(post.reload_log_data).not_to be_nil
-        expect(post.log_data).not_to be_nil
+  describe "#log_data" do
+    shared_examples "test loads #log_data" do
+      it "loads log_data" do
+        expect(model.log_data).not_to be_nil
+        expect(model.log_data).to be_a(Logidze::History)
       end
+    end
 
-      it "deserializes log_data properly" do
-        expect(post.reload_log_data).to be_a(Logidze::History)
+    shared_examples "test raises error when #log_data is called" do
+      it "raises error when #log_data is called" do
+        expect { model.reload.log_data }.to raise_error(ActiveModel::MissingAttributeError)
       end
     end
-  end
 
-  context "with .all" do
-    subject(:post) { NotLoggedPost.find(source_post.id) }
+    context "when Logidze.ignore_log_data_by_default = true" do
+      before(:all) { Logidze.ignore_log_data_by_default = true }
+      after(:all) { Logidze.ignore_log_data_by_default = false }
 
-    include_context "test #log_data"
-    include_context "test #reload_log_data"
-  end
+      subject(:model) { Post.create! }
 
-  context "with .with_log_data" do
-    subject(:post) { NotLoggedPost.with_log_data.find(source_post.id) }
+      include_examples "test raises error when #log_data is called"
 
-    context "#log_data" do
-      it "loads log_data" do
-        expect(post.log_data).not_to be_nil
+      context "when inside Logidze.with_log_data block" do
+        it "loads log_data" do
+          Logidze.with_log_data do
+            expect(model.reload.log_data).not_to be_nil
+          end
+        end
       end
+    end
 
-      it "deserializes log_data properly" do
-        expect(post.log_data).to be_a(Logidze::History)
+    context "when model is configured with has_logidze(ignore_log_data: false)" do
+      context "when Logidze.ignore_log_data_by_default = true" do
+        before(:all) { Logidze.ignore_log_data_by_default = true }
+        after(:all) { Logidze.ignore_log_data_by_default = false }
+
+        subject(:model) { AlwaysLoggedPost.find(source_post.id) }
+        include_examples "test loads #log_data"
       end
     end
-  end
 
-  context "#update!" do
-    it "updates log_data" do
-      expect do
-        NotLoggedPost.find(source_post.id).update!(title: "new")
-      end.to change { Post.find(source_post.id).log_data.version }.by(1)
-    end
-  end
+    context "when model is configured with has_logidze(ignore_log_data: true)" do
+      shared_context "test #reload_log_data" do
+        context "#reload_log_data" do
+          it "loads data from DB" do
+            expect(model.reload_log_data).not_to be_nil
+            expect(model.log_data).not_to be_nil
+          end
+
+          it "deserializes log_data properly" do
+            expect(model.reload_log_data).to be_a(Logidze::History)
+          end
+        end
+      end
+
+      context "with default scope" do
+        subject(:model) { NotLoggedPost.find(source_post.id) }
 
-  context "with .eager_load" do
-    subject(:post) { User.eager_load(:not_logged_posts).last.not_logged_posts.last }
+        include_examples "test raises error when #log_data is called"
+        include_context "test #reload_log_data"
+      end
+
+      context ".with_log_data" do
+        subject(:model) { NotLoggedPost.with_log_data.find(source_post.id) }
+
+        include_examples "test loads #log_data"
+      end
 
-    include_context "test #log_data"
-    include_context "test #reload_log_data"
+      describe ".eager_load" do
+        subject(:model) { User.eager_load(:not_logged_posts).last.not_logged_posts.last }
+
+        include_examples "test raises error when #log_data is called"
+        include_context "test #reload_log_data"
+      end
+    end
   end
 end