Prometheus: Fix label value suggestion (#21294)

* Prometheus: Fix label value suggestion

- remove quotes from typeahead input to suggest correct label values
- fix acceptance of partial label values

* Disable mid-word suggestions

* Fix test

public/app/plugins/datasource/prometheus/language_provider.test.ts

@@ -301,7 +301,7 @@ describe('Language completion provider', () => {
       instance.lookupsDisabled = false;
       const value = Plain.deserialize('{job!=}');
       const ed = new SlateEditor({ value });
-      const valueWithSelection = ed.moveForward(8).value;
+      const valueWithSelection = ed.moveForward(6).value;
       const result = await instance.provideCompletionItems({
         text: '!=',
         prefix: '',

public/app/plugins/datasource/prometheus/language_provider.ts

@@ -88,7 +88,10 @@ export default class PromQlLanguageProvider extends LanguageProvider {
   cleanText(s: string) {
     const parts = s.split(PREFIX_DELIMITER_REGEX);
     const last = parts.pop();
-    return last.trimLeft().replace(/"$/, '');
+    return last
+      .trimLeft()
+      .replace(/"$/, '')
+      .replace(/^"/, '');
   }
 
   get syntax() {
@@ -297,8 +300,15 @@ export default class PromQlLanguageProvider extends LanguageProvider {
     labelKey,
     value,
   }: TypeaheadInput): Promise<TypeaheadOutput> => {
+    const suggestions: CompletionItemGroup[] = [];
     const line = value.anchorBlock.getText();
     const cursorOffset = value.selection.anchor.offset;
+    const nextChar = line[cursorOffset];
+    const isValueContext = wrapperClasses.includes('attr-value');
+    if (!nextChar.match(/["}]/)) {
+      // Don't suggest anything inside a value
+      return { suggestions };
+    }
 
     // Get normalized selector
     let selector;
@@ -313,7 +323,6 @@ export default class PromQlLanguageProvider extends LanguageProvider {
     const containsMetric = selector.includes('__name__=');
     const existingKeys = parsedSelector ? parsedSelector.labelKeys : [];
 
-    const suggestions: CompletionItemGroup[] = [];
     let labelValues;
     // Query labels for selector
     if (selector) {
@@ -326,7 +335,7 @@ export default class PromQlLanguageProvider extends LanguageProvider {
     }
 
     let context: string;
-    if ((text && text.match(/^!?=~?/)) || wrapperClasses.includes('attr-value')) {
+    if ((text && text.match(/^!?=~?/)) || isValueContext) {
       // Label values
       if (labelKey && labelValues[labelKey]) {
         context = 'context-label-values';

public/app/plugins/datasource/prometheus/language_utils.test.ts

@@ -31,6 +31,13 @@ describe('parseSelector()', () => {
 
     parsed = parseSelector('{foo="bar",baz="}');
     expect(parsed.selector).toBe('{foo="bar"}');
+
+    // Cursor in value area counts as incomplete
+    parsed = parseSelector('{foo="bar",baz=""}', 16);
+    expect(parsed.selector).toBe('{foo="bar"}');
+
+    parsed = parseSelector('{foo="bar",baz="4"}', 17);
+    expect(parsed.selector).toBe('{foo="bar"}');
   });
 
   it('throws if not inside a selector', () => {
@@ -55,7 +62,7 @@ describe('parseSelector()', () => {
     parsed = parseSelector('bar{foo}', 4);
     expect(parsed.selector).toBe('{__name__="bar"}');
 
-    parsed = parseSelector('baz{foo="bar"}', 12);
+    parsed = parseSelector('baz{foo="bar"}', 13);
     expect(parsed.selector).toBe('{__name__="baz",foo="bar"}');
 
     parsed = parseSelector('bar:metric:1m{}', 14);

public/app/plugins/datasource/prometheus/language_utils.ts

@@ -79,8 +79,14 @@ export function parseSelector(query: string, cursorOffset = 1): { labelKeys: any
   // Extract clean labels to form clean selector, incomplete labels are dropped
   const selector = query.slice(prefixOpen, suffixClose);
   const labels: { [key: string]: { value: string; operator: string } } = {};
-  selector.replace(labelRegexp, (_, key, operator, value) => {
-    labels[key] = { value, operator };
+  selector.replace(labelRegexp, (label, key, operator, value) => {
+    const labelOffset = query.indexOf(label);
+    const valueStart = labelOffset + key.length + operator.length + 1;
+    const valueEnd = labelOffset + key.length + operator.length + value.length - 1;
+    // Skip label if cursor is in value
+    if (cursorOffset < valueStart || cursorOffset > valueEnd) {
+      labels[key] = { value, operator };
+    }
     return '';
   });