RUBY-5530 Add transaction method to Mongoid module (#5517)

Author: comandeo-mongo

lib/mongoid.rb

@@ -42,6 +42,7 @@ module Mongoid
   extend Forwardable
   extend Loggable
   extend self
+  extend Clients::Sessions::ClassMethods
 
   # A string added to the platform details of Ruby driver client handshake documents.
   PLATFORM_DETAILS = "mongoid-#{VERSION}".freeze
@@ -113,6 +114,21 @@ def client(name)
   #   Mongoid.database = Mongo::Connection.new.db("test")
   def_delegators Config, *(Config.public_instance_methods(false) - [ :logger=, :logger ])
 
+  # Define persistence context that is used when a transaction method is called
+  # on Mongoid module.
+  #
+  # @api private
+  def persistence_context
+    PersistenceContext.get(Mongoid) || PersistenceContext.new(Mongoid)
+  end
+
+  # Define client that is used when a transaction method is called
+  # on Mongoid module. This MUST be the default client.
+  #
+  # @api private
+  def storage_options
+    { client: :default }
+  end
 
   # Module used to prepend the discriminator key assignment function to change
   # the value assigned to the discriminator key to a string.

spec/mongoid/clients/transactions_spec.rb

@@ -2,6 +2,16 @@
 
 require "spec_helper"
 
+def capture_exception
+  e = nil
+  begin
+    yield
+  rescue => ex
+    e = ex
+  end
+  e
+end
+
 describe Mongoid::Clients::Sessions do
   before(:all) do
     if Gem::Version.new(Mongo::VERSION) < Gem::Version.new('2.6')
@@ -200,37 +210,29 @@
 
           context 'using #with_session' do
             let!(:error) do
-              e = nil
-              begin
+              capture_exception do
                 Person.with_session do |s|
                   s.start_transaction
                   Person.create!
                   Person.create!
                   Post.create!
                   s.commit_transaction
                 end
-              rescue => ex
-                  e = ex
               end
-              e
             end
 
             include_examples 'it does not abort the transaction'
           end
 
           context 'using #transaction' do
             let!(:error) do
-              e = nil
-              begin
+              capture_exception do
                 Person.transaction do
                   Person.create!
                   Person.create!
                   Post.create!
                 end
-              rescue => ex
-                  e = ex
               end
-              e
             end
 
             include_examples 'it does not abort the transaction'
@@ -252,38 +254,30 @@
 
           context 'using #with_session' do
             let!(:error) do
-              e = nil
-              begin
+              capture_exception do
                 Person.with_session do |s|
                   s.start_transaction
                   s.start_transaction
                   Person.create!
                   Post.create!
                   s.commit_transaction
                 end
-              rescue => ex
-                e = ex
               end
-              e
             end
 
             include_examples 'it aborts the transaction', Mongo::Error::InvalidTransactionOperation
           end
 
           context 'using #transaction' do
             let!(:error) do
-              e = nil
-              begin
+              capture_exception do
                 Person.transaction do
                   Person.transaction do
                     Person.create!
                     Post.create!
                   end
                 end
-              rescue => ex
-                e = ex
               end
-              e
             end
 
             include_examples 'it aborts the transaction', Mongoid::Errors::InvalidTransactionNesting
@@ -331,16 +325,12 @@
 
       context 'when Mongoid::Errors:Rollback raised' do
         let!(:error) do
-          error = nil
-          begin
+          capture_exception do
             Person.transaction do
               Person.create!
               raise Mongoid::Errors::Rollback
             end
-          rescue => e
-            error = e
           end
-          error
         end
 
         it 'does not bass on the exception' do
@@ -368,33 +358,25 @@
 
       context 'using #with_session' do
         let!(:error) do
-          e = nil
-          begin
+          capture_exception do
             Person.with_session do |s|
               s.start_transaction
               Person.create!
               s.commit_transaction
             end
-          rescue => ex
-            e = ex
           end
-          e
         end
 
         include_examples 'it raises a transactions not supported error'
       end
 
       context 'using #transaction' do
         let!(:error) do
-          e = nil
-          begin
+          capture_exception do
             Person.transaction do
               Person.create!
             end
-          rescue => ex
-            e = ex
           end
-          e
         end
 
         include_examples 'it raises a transactions not supported error'
@@ -537,37 +519,30 @@
 
           context 'using #with_session' do
             let!(:error) do
-              e = nil
-              begin
+              capture_exception do
                 person.with_session do |s|
                   s.start_transaction
                   person.username = 'Emily'
                   person.save!
                   person.posts << Post.create!
                   s.commit_transaction
                 end
-              rescue => ex
-                e = ex
               end
-              e
             end
 
             include_examples 'does not abort the transaction'
           end
 
           context 'using #transaction' do
             let!(:error) do
-              e = nil
-              begin
+              capture_exception do
                 person.transaction do
                   person.username = 'Emily'
                   person.save!
                   person.posts << Post.create!
                 end
               rescue => ex
-                e = ex
               end
-              e
             end
 
             include_examples 'does not abort the transaction'
@@ -577,8 +552,7 @@
         context 'when transactions are nested' do
           context 'use #with_session' do
             let!(:error) do
-              e = nil
-              begin
+              capture_exception do
                 person.with_session do |s|
                   s.start_transaction
                   s.start_transaction
@@ -587,10 +561,7 @@
                   person.posts << Post.create!
                   s.commit_transaction
                 end
-              rescue => ex
-                e = ex
               end
-              e
             end
 
             it 'raises an error' do
@@ -606,19 +577,15 @@
 
           context 'use #transaction' do
             let!(:error) do
-              e = nil
-              begin
+              capture_exception do
                 person.transaction do
                   person.transaction do
                     person.username = 'Emily'
                     person.save!
                     person.posts << Post.create!
                   end
                 end
-              rescue => ex
-                e = ex
               end
-              e
             end
 
             it 'raises an error' do
@@ -637,17 +604,13 @@
 
       context 'when Mongoid::Errors:Rollback raised' do
         let!(:error) do
-          error = nil
-          begin
+          capture_exception do
             person.transaction do
               person.username = 'John'
               person.save!
               raise Mongoid::Errors::Rollback
             end
-          rescue => e
-            error = e
           end
-          error
         end
 
         it 'does not bass on the exception' do
@@ -682,18 +645,14 @@
 
       context 'using #with_session' do
         let!(:error) do
-          e = nil
-          begin
+          capture_exception do
             person.with_session do |s|
               s.start_transaction
               person.username = 'Emily'
               person.save!
               s.commit_transaction
             end
-          rescue => ex
-            e = ex
           end
-          e
         end
 
         it 'raises a transactions not supported error' do
@@ -704,16 +663,12 @@
 
       context 'using #transaction' do
         let!(:error) do
-          e = nil
-          begin
+          capture_exception do
             person.transaction do
               person.username = 'Emily'
               person.save!
             end
-          rescue => ex
-            e = ex
           end
-          e
         end
 
         it 'raises a transactions not supported error' do
@@ -735,4 +690,70 @@
       end
     end
   end
+
+  context 'when a transaction is used on Mongoid module' do
+    let(:subscriber) do
+      Mongoid::Clients.with_name(:default).send(:monitoring).subscribers['Command'].find do |s|
+        s.is_a?(EventSubscriber)
+      end
+    end
+
+    before do
+      Mongoid::Clients.with_name(:default).database.collections.each(&:drop)
+      Person.collection.create
+      Account.collection.create
+      Mongoid::Clients.with_name(:default).subscribe(Mongo::Monitoring::COMMAND, EventSubscriber.new)
+      subscriber.clear_events!
+    end
+
+    after do
+      Mongoid::Clients.with_name(:default).database.collections.each(&:drop)
+    end
+
+    context 'when transactions are supported' do
+      require_transaction_support
+
+      context 'when no error raised' do
+        before do
+          Mongoid.transaction do
+            Person.create!
+          end
+        end
+
+        it 'commits the transacrion' do
+          expect(other_events.count { |e| e.command_name == 'abortTransaction'}).to be(0)
+          expect(other_events.count { |e| e.command_name == 'commitTransaction'}).to be(1)
+        end
+
+        it 'executes the commands inside the transaction' do
+          expect(Person.count).to be(1)
+        end
+      end
+
+      context 'When an error raised' do
+        let!(:error) do
+          capture_exception do
+            Mongoid.transaction do
+              Person.create!
+              Account.create!
+            end
+          end
+        end
+
+        it 'aborts the transaction' do
+          expect(other_events.count { |e| e.command_name == 'abortTransaction'}).to be(1)
+          expect(other_events.count { |e| e.command_name == 'commitTransaction'}).to be(0)
+        end
+
+        it 'passes on the error' do
+          expect(error).to be_a(Mongoid::Errors::Validations)
+        end
+
+        it 'reverts changes' do
+          expect(Account.count).to be(0)
+          expect(Person.count).to be(0)
+        end
+      end
+    end
+  end
 end