From b13395afbccde52d02ac926919234032237794e1 Mon Sep 17 00:00:00 2001
From: Fabrizio <135109076+fabrizio-grafana@users.noreply.github.com>
Date: Thu, 2 Nov 2023 11:23:18 +0100
Subject: [PATCH] Tempo: Handle empty responses in ServiceGraph (#77539)

---
 .../datasource/tempo/graphTransform.test.ts   | 21 +++++++++++++++++++
 .../datasource/tempo/graphTransform.ts        |  2 +-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/public/app/plugins/datasource/tempo/graphTransform.test.ts b/public/app/plugins/datasource/tempo/graphTransform.test.ts
index e6acd91ddd1..efebee60cd6 100644
--- a/public/app/plugins/datasource/tempo/graphTransform.test.ts
+++ b/public/app/plugins/datasource/tempo/graphTransform.test.ts
@@ -80,6 +80,27 @@ it('assigns correct field type even if values are numbers', async () => {
   ]);
 });
 
+it('do not fail on response with empty list', async () => {
+  const range = {
+    from: dateTime('2000-01-01T00:00:00'),
+    to: dateTime('2000-01-01T00:01:00'),
+  };
+  const { nodes } = mapPromMetricsToServiceMap([], {
+    ...range,
+    raw: range,
+  });
+
+  expect(nodes.fields).toMatchObject([
+    { name: 'id', values: [], type: FieldType.string },
+    { name: 'title', values: [], type: FieldType.string },
+    { name: 'subtitle', type: FieldType.string, values: [] },
+    { name: 'mainstat', values: [], type: FieldType.number },
+    { name: 'secondarystat', values: [], type: FieldType.number },
+    { name: 'arc__success', values: [], type: FieldType.number },
+    { name: 'arc__failed', values: [], type: FieldType.number },
+  ]);
+});
+
 describe('mapPromMetricsToServiceMap', () => {
   it('transforms prom metrics to service graph', async () => {
     const range = {
diff --git a/public/app/plugins/datasource/tempo/graphTransform.ts b/public/app/plugins/datasource/tempo/graphTransform.ts
index 4b7b4b56fed..08cbbf19c6b 100644
--- a/public/app/plugins/datasource/tempo/graphTransform.ts
+++ b/public/app/plugins/datasource/tempo/graphTransform.ts
@@ -249,7 +249,7 @@ function createServiceMapDataFrames() {
  * @param responses
  */
 function getMetricFrames(responses: DataQueryResponse[]): Record<string, DataFrameView> {
-  return responses[0].data.reduce<Record<string, DataFrameView>>((acc, frameDTO) => {
+  return (responses[0]?.data || []).reduce<Record<string, DataFrameView>>((acc, frameDTO) => {
     const frame = toDataFrame(frameDTO);
     acc[frame.refId ?? 'A'] = new DataFrameView(frame);
     return acc;