Add logging to error handling in ElasticIndexerWorker

ee/app/workers/elastic_indexer_worker.rb

@@ -32,13 +32,16 @@ class ElasticIndexerWorker
         client.delete index: klass.index_name, type: klass.document_type, id: es_id
       end
     end
-  rescue Elasticsearch::Transport::Transport::Errors::NotFound, ActiveRecord::RecordNotFound
+  rescue Elasticsearch::Transport::Transport::Errors::NotFound, ActiveRecord::RecordNotFound => e
     # These errors can happen in several cases, including:
     # - A record is updated, then removed before the update is handled
     # - Indexing is enabled, but not every item has been indexed yet - updating
     #   and deleting the un-indexed records will raise exception
     #
     # We can ignore these.
+
+    logger.error(message: 'elastic_indexer_worker_caught_exception', error_class: e.class.name, error_message: e.message)
+
     true
   end
 
@@ -65,4 +68,8 @@ class ElasticIndexerWorker
       }
     })
   end
+
+  def logger
+    @logger ||= ::Gitlab::Elasticsearch::Logger.build
+  end
 end

ee/spec/workers/elastic_indexer_worker_spec.rb

@@ -103,4 +103,18 @@ describe ElasticIndexerWorker, :elastic do
       subject.perform("index", 'Project', object.id, object.es_id)
     end.to raise_error
   end
+
+  it 'ignores Elasticsearch::Transport::Transport::Errors::NotFound error' do
+    object = create(:project)
+
+    expect_next_instance_of(Elastic::IndexRecordService) do |service|
+      allow(service).to receive(:execute).and_raise(Elasticsearch::Transport::Transport::Errors::NotFound)
+    end
+
+    expect(subject.perform("index", 'Project', object.id, object.es_id)).to eq(true)
+  end
+
+  it 'ignores missing records' do
+    expect(subject.perform("index", 'Project', -1, 'project_-1')).to eq(true)
+  end
 end