From f2814046d1ef68ebb0cc894deb7c37ea9ccb7076 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=A1bor=20Farkas?= <gabor.farkas@gmail.com>
Date: Fri, 22 Apr 2022 08:43:33 +0200
Subject: [PATCH] loki: logrowcontext: explicitly name fields (#48043)

---
 .../app/plugins/datasource/loki/datasource.ts | 49 +++++++++++++++----
 1 file changed, 39 insertions(+), 10 deletions(-)

diff --git a/public/app/plugins/datasource/loki/datasource.ts b/public/app/plugins/datasource/loki/datasource.ts
index 476a1b95a17..96a2357254b 100644
--- a/public/app/plugins/datasource/loki/datasource.ts
+++ b/public/app/plugins/datasource/loki/datasource.ts
@@ -557,17 +557,46 @@ export class LokiDatasource
     const limit = (options && options.limit) || 10;
     const { query, range } = this.prepareLogRowContextQueryTarget(row, limit, direction);
 
-    const sortResults = (result: DataQueryResponse): DataQueryResponse => {
+    const processDataFrame = (frame: DataFrame): DataFrame => {
+      // log-row-context requires specific field-names to work, so we set them here: "ts", "line", "id"
+      const cache = new FieldCache(frame);
+      const timestampField = cache.getFirstFieldOfType(FieldType.time);
+      const lineField = cache.getFirstFieldOfType(FieldType.string);
+      const idField = cache.getFieldByName('id');
+
+      if (timestampField === undefined || lineField === undefined || idField === undefined) {
+        // this should never really happen, but i want to keep typescript happy
+        return { ...frame, fields: [] };
+      }
+
+      return {
+        ...frame,
+        fields: [
+          {
+            ...timestampField,
+            name: 'ts',
+          },
+          {
+            ...lineField,
+            name: 'line',
+          },
+          {
+            ...idField,
+            name: 'id',
+          },
+        ],
+      };
+    };
+
+    const processResults = (result: DataQueryResponse): DataQueryResponse => {
+      const frames: DataFrame[] = result.data;
+      const processedFrames = frames
+        .map((frame) => sortDataFrameByTime(frame, 'DESCENDING'))
+        .map((frame) => processDataFrame(frame)); // rename fields if needed
+
       return {
         ...result,
-        data: result.data.map((frame: DataFrame) => {
-          const timestampFieldIndex = frame.fields.findIndex((field) => field.type === FieldType.time);
-          if (timestampFieldIndex === -1) {
-            return frame;
-          }
-
-          return sortDataFrameByTime(frame, 'DESCENDING');
-        }),
+        data: processedFrames,
       };
     };
 
@@ -584,7 +613,7 @@ export class LokiDatasource
           };
           throw error;
         }),
-        switchMap((res) => of(sortResults(res)))
+        switchMap((res) => of(processResults(res)))
       )
     );
   };