Loki: Add label filters after label_format if present (#86124)

* Loki ad-hoc filters: add filters after label_format

* Chore: add comment explaining rationale

* Formatting

* Formatting

public/app/plugins/datasource/loki/datasource.test.ts

@@ -1180,6 +1180,22 @@ describe('LokiDatasource', () => {
             defaultAdHocFilters
           );
         });
+        it('should add the filter after other label filters', () => {
+          assertAdHocFilters(
+            '{bar="baz"} | logfmt | test="value" | line_format "test"',
+            '{bar="baz"} | logfmt | test="value" | job=`grafana` | line_format "test"',
+            ds,
+            defaultAdHocFilters
+          );
+        });
+        it('should add the filter after label_format', () => {
+          assertAdHocFilters(
+            '{bar="baz"} | logfmt | test="value" | label_format process="{{.process}}"',
+            '{bar="baz"} | logfmt | test="value" | label_format process="{{.process}}" | job=`grafana`',
+            ds,
+            defaultAdHocFilters
+          );
+        });
       });
     });
 

public/app/plugins/datasource/loki/modifyQuery.test.ts

@@ -43,6 +43,8 @@ describe('addLabelToQuery()', () => {
     ${'{foo="bar"} | logfmt | x="y"'}                                                                                                 | ${'query with parser and label filter'}                                        | ${'bar'} | ${'='}   | ${'baz'}       | ${'{foo="bar"} | logfmt | x="y" | bar=`baz`'}
     ${'rate({foo="bar"} | logfmt [5m])'}                                                                                              | ${'metric query with parser'}                                                  | ${'bar'} | ${'='}   | ${'baz'}       | ${'rate({foo="bar"} | logfmt | bar=`baz` [5m])'}
     ${'sum by(host) (rate({foo="bar"} | logfmt | x="y" | line_format "{{.status}}" [5m]))'}                                           | ${'metric query with parser'}                                                  | ${'bar'} | ${'='}   | ${'baz'}       | ${'sum by(host) (rate({foo="bar"} | logfmt | x="y" | bar=`baz` | line_format "{{.status}}" [5m]))'}
+    ${'sum by(host) (rate({foo="bar"} | logfmt | x="y" | label_format process="{{.process}}" [5m]))'}                                 | ${'metric query with parser and label format'}                                 | ${'bar'} | ${'='}   | ${'baz'}       | ${'sum by(host) (rate({foo="bar"} | logfmt | x="y" | label_format process="{{.process}}" | bar=`baz` [5m]))'}
+    ${'{foo="bar"} | logfmt | x="y" | label_format process="{{.process}}"'}                                                           | ${'query with parser and label format'}                                        | ${'bar'} | ${'='}   | ${'baz'}       | ${'{foo="bar"} | logfmt | x="y" | label_format process="{{.process}}" | bar=`baz`'}
     ${'{foo="bar"} | logfmt | line_format "{{.status}}"'}                                                                             | ${'do not add filter to line_format expressions in query with parser'}         | ${'bar'} | ${'='}   | ${'baz'}       | ${'{foo="bar"} | logfmt | bar=`baz` | line_format "{{.status}}"'}
     ${'{foo="bar"} | logfmt | line_format "{{status}}"'}                                                                              | ${'do not add filter to line_format expressions in query with parser'}         | ${'bar'} | ${'='}   | ${'baz'}       | ${'{foo="bar"} | logfmt | bar=`baz` | line_format "{{status}}"'}
     ${'{}'}                                                                                                                           | ${'query without stream selector'}                                             | ${'bar'} | ${'='}   | ${'baz'}       | ${'{bar="baz"}'}

public/app/plugins/datasource/loki/modifyQuery.ts

@@ -21,6 +21,7 @@ import {
   JsonExpressionParser,
   LogfmtExpressionParser,
   Expr,
+  LabelFormatExpr,
 } from '@grafana/lezer-logql';
 
 import { unescapeLabelValue } from './languageUtils';
@@ -162,6 +163,8 @@ export function addLabelToQuery(
   const parserPositions = getParserPositions(query);
   const labelFilterPositions = getLabelFilterPositions(query);
   const hasStreamSelectorMatchers = getMatcherInStreamPositions(query);
+  // For non-indexed labels we want to add them after label_format to, for example, allow ad-hoc filters to use formatted labels
+  const labelFormatPositions = getNodePositionsFromQuery(query, [LabelFormatExpr]);
   const everyStreamSelectorHasMatcher = streamSelectorPositions.every((streamSelectorPosition) =>
     hasStreamSelectorMatchers.some(
       (matcherPosition) =>
@@ -175,6 +178,7 @@ export function addLabelToQuery(
       ...streamSelectorPositions,
       ...labelFilterPositions,
       ...parserPositions,
+      ...labelFormatPositions,
     ]);
 
     return addFilterAsLabelFilter(query, lastPositionsPerExpression, filter);
@@ -191,6 +195,7 @@ export function addLabelToQuery(
       const lastPositionsPerExpression = getLastPositionPerExpression(query, [
         ...parserPositions,
         ...labelFilterPositions,
+        ...labelFormatPositions,
       ]);
 
       return addFilterAsLabelFilter(query, lastPositionsPerExpression, filter);