[MODEL] Added an option to the import method to return an array of error messages

Instead of returning just the number of errors, return all error messages from Elasticsearch,
when using the `return_errors` option.

Closes elastic#107

Author: eturino

elasticsearch-model/lib/elasticsearch/model/importing.rb

@@ -91,11 +91,12 @@ module ClassMethods
         #    Article.import preprocess: enrich
         #
         def import(options={}, &block)
-          errors       = 0
+          errors         = []
           refresh      = options.delete(:refresh)   || false
           target_index = options.delete(:index)     || index_name
           target_type  = options.delete(:type)      || document_type
           transform    = options.delete(:transform) || __transform
+          return_errors  = options.delete(:return_errors) || false
 
           unless transform.respond_to?(:call)
             raise ArgumentError,
@@ -114,12 +115,16 @@ def import(options={}, &block)
 
             yield response if block_given?
 
-            errors += response['items'].map { |k, v| k.values.first['error'] }.compact.length
+            errors += response['items'].select { |i| i['index']['error'] }
           end
 
           self.refresh_index! if refresh
 
-          return errors
+          if return_errors
+            errors
+          else
+            errors.size
+          end
         end
 
         def __batch_to_bulk(batch, transform)

elasticsearch-model/test/unit/importing_test.rb

@@ -66,6 +66,26 @@ def importing_mixin
       assert_equal 1, DummyImportingModel.import
     end
 
+    should "return list of errors if passing option 'return_errors'" do
+      Elasticsearch::Model::Adapter.expects(:from_class)
+                                   .with(DummyImportingModel)
+                                   .returns(DummyImportingAdapter)
+
+      DummyImportingModel.__send__ :include, Elasticsearch::Model::Importing
+
+      client = mock('client')
+      error_text = 'FAILED'
+      client.expects(:bulk).returns({'items' => [ {'index' => {}}, {'index' => {'error' => error_text}} ]})
+
+      DummyImportingModel.stubs(:client).returns(client)
+      DummyImportingModel.stubs(:index_name).returns('foo')
+      DummyImportingModel.stubs(:document_type).returns('foo')
+
+      expected_error_element = {'index' => {'error' => error_text}}
+
+      assert_equal [expected_error_element], DummyImportingModel.import(return_errors: true)
+    end
+
     should "yield the response" do
       Elasticsearch::Model::Adapter.expects(:from_class)
                                    .with(DummyImportingModel)