Allow formatting PromQL expressions in the UI

web/ui/react-app/src/pages/graph/ExpressionInput.tsx

@@ -1,5 +1,5 @@
 import React, { FC, useState, useEffect, useRef } from 'react';
-import { Button, InputGroup, InputGroupAddon, InputGroupText } from 'reactstrap';
+import { Alert, Button, InputGroup, InputGroupAddon, InputGroupText } from 'reactstrap';
 
 import { EditorView, highlightSpecialChars, keymap, ViewUpdate, placeholder } from '@codemirror/view';
 import { EditorState, Prec, Compartment } from '@codemirror/state';
@@ -18,12 +18,13 @@ import {
 import { baseTheme, lightTheme, darkTheme, promqlHighlighter } from './CMTheme';
 
 import { FontAwesomeIcon } from '@fortawesome/react-fontawesome';
-import { faSearch, faSpinner, faGlobeEurope } from '@fortawesome/free-solid-svg-icons';
+import { faSearch, faSpinner, faGlobeEurope, faIndent, faCheck } from '@fortawesome/free-solid-svg-icons';
 import MetricsExplorer from './MetricsExplorer';
 import { usePathPrefix } from '../../contexts/PathPrefixContext';
 import { useTheme } from '../../contexts/ThemeContext';
 import { CompleteStrategy, PromQLExtension } from '@prometheus-io/codemirror-promql';
 import { newCompleteStrategy } from '@prometheus-io/codemirror-promql/dist/esm/complete';
+import { API_PATH } from '../../constants/constants';
 
 const promqlExtension = new PromQLExtension();
 
@@ -98,6 +99,10 @@ const ExpressionInput: FC<CMExpressionInputProps> = ({
   const pathPrefix = usePathPrefix();
   const { theme } = useTheme();
 
+  const [formatError, setFormatError] = useState<string | null>(null);
+  const [isFormatting, setIsFormatting] = useState<boolean>(false);
+  const [exprFormatted, setExprFormatted] = useState<boolean>(false);
+
   // (Re)initialize editor based on settings / setting changes.
   useEffect(() => {
     // Build the dynamic part of the config.
@@ -169,7 +174,10 @@ const ExpressionInput: FC<CMExpressionInputProps> = ({
             ])
           ),
           EditorView.updateListener.of((update: ViewUpdate): void => {
-            onExpressionChange(update.state.doc.toString());
+            if (update.docChanged) {
+              onExpressionChange(update.state.doc.toString());
+              setExprFormatted(false);
+            }
           }),
         ],
       });
@@ -209,6 +217,47 @@ const ExpressionInput: FC<CMExpressionInputProps> = ({
     );
   };
 
+  const formatExpression = () => {
+    setFormatError(null);
+    setIsFormatting(true);
+
+    fetch(
+      `${pathPrefix}/${API_PATH}/format_query?${new URLSearchParams({
+        query: value,
+      })}`,
+      {
+        cache: 'no-store',
+        credentials: 'same-origin',
+      }
+    )
+      .then((resp) => {
+        if (!resp.ok && resp.status !== 400) {
+          throw new Error(`format HTTP request failed: ${resp.statusText}`);
+        }
+
+        return resp.json();
+      })
+      .then((json) => {
+        if (json.status !== 'success') {
+          throw new Error(json.error || 'invalid response JSON');
+        }
+
+        const view = viewRef.current;
+        if (view === null) {
+          return;
+        }
+
+        view.dispatch(view.state.update({ changes: { from: 0, to: view.state.doc.length, insert: json.data } }));
+        setExprFormatted(true);
+      })
+      .catch((err) => {
+        setFormatError(err.message);
+      })
+      .finally(() => {
+        setIsFormatting(false);
+      });
+  };
+
   return (
     <>
       <InputGroup className="expression-input">
@@ -220,7 +269,21 @@ const ExpressionInput: FC<CMExpressionInputProps> = ({
         <div ref={containerRef} className="cm-expression-input" />
         <InputGroupAddon addonType="append">
           <Button
-            className="metrics-explorer-btn"
+            className="expression-input-action-btn"
+            title={isFormatting ? 'Formatting expression' : exprFormatted ? 'Expression formatted' : 'Format expression'}
+            onClick={formatExpression}
+            disabled={isFormatting || exprFormatted}
+          >
+            {isFormatting ? (
+              <FontAwesomeIcon icon={faSpinner} spin />
+            ) : exprFormatted ? (
+              <FontAwesomeIcon icon={faCheck} />
+            ) : (
+              <FontAwesomeIcon icon={faIndent} />
+            )}
+          </Button>
+          <Button
+            className="expression-input-action-btn"
             title="Open metrics explorer"
             onClick={() => setShowMetricsExplorer(true)}
           >
@@ -232,6 +295,8 @@ const ExpressionInput: FC<CMExpressionInputProps> = ({
         </InputGroupAddon>
       </InputGroup>
 
+      {formatError && <Alert color="danger">Error formatting expression: {formatError}</Alert>}
+
       <MetricsExplorer
         show={showMetricsExplorer}
         updateShow={setShowMetricsExplorer}

web/ui/react-app/src/themes/_shared.scss

@@ -7,7 +7,7 @@
       Example:
 
       $foo = '#000';
- 
+
    2. Add a style rule in _shared.scss (this file) that uses new variable.
       Example:
 
@@ -58,7 +58,7 @@
 .metrics-explorer .metric:hover {
   background: $metrics-explorer-bg;
 }
-button.metrics-explorer-btn {
+button.expression-input-action-btn {
   color: $input-group-addon-color;
   background-color: $input-group-addon-bg;
   border: $input-border-width solid $input-group-addon-border-color;