Fix ES aggregation errors when index is empty (#535)

Author: pavolloffay

plugin/storage/es/spanstore/reader.go

@@ -325,7 +325,9 @@ func (s *SpanReader) findTraceIDs(traceQuery *spanstore.TraceQueryParameters) ([
 	if err != nil {
 		return nil, errors.Wrap(err, "Search service failed")
 	}
-
+	if searchResult.Aggregations == nil {
+		return []string{}, nil
+	}
 	bucket, found := searchResult.Aggregations.Terms(traceIDAggregation)
 	if !found {
 		return nil, ErrUnableToFindTraceIDAggregation

plugin/storage/es/spanstore/reader_test.go

@@ -843,3 +843,28 @@ func TestSpanReader_buildTagQuery(t *testing.T) {
 		assert.EqualValues(t, expected, actual)
 	})
 }
+
+func TestSpanReader_GetEmptyIndex(t *testing.T) {
+	withSpanReader(func(r *spanReaderTest) {
+		mockSearchService(r).
+			Return(&elastic.SearchResult{}, nil)
+		mockMultiSearchService(r).
+			Return(&elastic.MultiSearchResult{
+				Responses: []*elastic.SearchResult{},
+			}, nil)
+
+		traceQuery := &spanstore.TraceQueryParameters{
+			ServiceName: serviceName,
+			Tags: map[string]string{
+				"hello": "world",
+			},
+			StartTimeMin: time.Now().Add(-1 * time.Hour),
+			StartTimeMax: time.Now(),
+			NumTraces:    2,
+		}
+
+		services, err := r.reader.FindTraces(traceQuery)
+		require.NoError(t, err)
+		assert.Empty(t, services)
+	})
+}

plugin/storage/es/spanstore/service_operation.go

@@ -102,7 +102,9 @@ func (s *ServiceOperationStorage) getServices(indices []string) ([]string, error
 	if err != nil {
 		return nil, errors.Wrap(err, "Search service failed")
 	}
-
+	if searchResult.Aggregations == nil {
+		return []string{}, nil
+	}
 	bucket, found := searchResult.Aggregations.Terms(servicesAggregation)
 	if !found {
 		return nil, errors.New("Could not find aggregation of " + servicesAggregation)
@@ -132,6 +134,9 @@ func (s *ServiceOperationStorage) getOperations(indices []string, service string
 	if err != nil {
 		return nil, errors.Wrap(err, "Search service failed")
 	}
+	if searchResult.Aggregations == nil {
+		return []string{}, nil
+	}
 	bucket, found := searchResult.Aggregations.Terms(operationsAggregation)
 	if !found {
 		return nil, errors.New("Could not find aggregation of " + operationsAggregation)

plugin/storage/es/spanstore/service_operation_test.go

@@ -110,3 +110,31 @@ func TestSpanReader_GetServices(t *testing.T) {
 func TestSpanReader_GetOperations(t *testing.T) {
 	testGet(operationsAggregation, t)
 }
+
+func TestSpanReader_GetServicesEmptyIndex(t *testing.T) {
+	withSpanReader(func(r *spanReaderTest) {
+		mockSearchService(r).
+			Return(&elastic.SearchResult{}, nil)
+		mockMultiSearchService(r).
+			Return(&elastic.MultiSearchResult{
+				Responses: []*elastic.SearchResult{},
+			}, nil)
+		services, err := r.reader.GetServices()
+		require.NoError(t, err)
+		assert.Empty(t, services)
+	})
+}
+
+func TestSpanReader_GetOperationsEmptyIndex(t *testing.T) {
+	withSpanReader(func(r *spanReaderTest) {
+		mockSearchService(r).
+			Return(&elastic.SearchResult{}, nil)
+		mockMultiSearchService(r).
+			Return(&elastic.MultiSearchResult{
+				Responses: []*elastic.SearchResult{},
+			}, nil)
+		services, err := r.reader.GetOperations("foo")
+		require.NoError(t, err)
+		assert.Empty(t, services)
+	})
+}