Loki: Update copy for missing label filter error message (#53449)

* Loki: Update copy for missing label filter

* Update

e2e/various-suite/loki-query-builder.spec.ts

@@ -1,5 +1,6 @@
 import { e2e } from '@grafana/e2e';
 
+const MISSING_LABEL_FILTER_ERROR_MESSAGE = 'Select at least 1 label filter (label and value)';
 const dataSourceName = 'LokiBuilder';
 const addDataSource = () => {
   e2e.flows.addDataSource({
@@ -56,7 +57,7 @@ describe('Loki query builder', () => {
     e2e().contains('rate({} | logfmt | __error__=`` [$__interval]').should('be.visible');
 
     // Check for expected error
-    e2e().contains('You need to specify at least 1 label filter (stream selector)').should('be.visible');
+    e2e().contains(MISSING_LABEL_FILTER_ERROR_MESSAGE).should('be.visible');
 
     // Add labels to remove error
     e2e.components.QueryBuilder.labelSelect().should('be.visible').click().type('instance{enter}');
@@ -66,7 +67,7 @@ describe('Loki query builder', () => {
       .click()
       .type('instance1{enter}')
       .type('instance2{enter}');
-    e2e().contains('You need to specify at least 1 label filter (stream selector)').should('not.exist');
+    e2e().contains(MISSING_LABEL_FILTER_ERROR_MESSAGE).should('not.exist');
     e2e().contains(finalQuery).should('be.visible');
 
     // Switch to code editor and check if query was parsed

public/app/plugins/datasource/loki/querybuilder/components/LokiQueryBuilder.test.tsx

@@ -7,7 +7,7 @@ import { DataSourceInstanceSettings, DataSourcePluginMeta } from '@grafana/data'
 import { LokiDatasource } from '../../datasource';
 import { LokiOperationId, LokiVisualQuery } from '../types';
 
-import { LokiQueryBuilder } from './LokiQueryBuilder';
+import { MISSING_LABEL_FILTER_ERROR_MESSAGE, LokiQueryBuilder } from './LokiQueryBuilder';
 import { EXPLAIN_LABEL_FILTER_CONTENT } from './LokiQueryBuilderExplained';
 
 const defaultQuery: LokiVisualQuery = {
@@ -54,9 +54,7 @@ describe('LokiQueryBuilder', () => {
     const query = { labels: [], operations: [{ id: LokiOperationId.Logfmt, params: [] }] };
     render(<LokiQueryBuilder {...createDefaultProps()} query={query} />);
 
-    expect(
-      await screen.findByText('You need to specify at least 1 label filter (stream selector)')
-    ).toBeInTheDocument();
+    expect(await screen.findByText(MISSING_LABEL_FILTER_ERROR_MESSAGE)).toBeInTheDocument();
   });
 
   it('shows no error for query with empty __line_contains operation and no stream selector', async () => {
@@ -64,9 +62,7 @@ describe('LokiQueryBuilder', () => {
     render(<LokiQueryBuilder {...createDefaultProps()} query={query} />);
 
     await waitFor(() => {
-      expect(
-        screen.queryByText('You need to specify at least 1 label filter (stream selector)')
-      ).not.toBeInTheDocument();
+      expect(screen.queryByText(MISSING_LABEL_FILTER_ERROR_MESSAGE)).not.toBeInTheDocument();
     });
   });
   it('shows explain section when showExplain is true', async () => {

public/app/plugins/datasource/loki/querybuilder/components/LokiQueryBuilder.tsx

@@ -31,6 +31,7 @@ export interface Props {
   onChange: (update: LokiVisualQuery) => void;
   onRunQuery: () => void;
 }
+export const MISSING_LABEL_FILTER_ERROR_MESSAGE = 'Select at least 1 label filter (label and value)';
 
 export const LokiQueryBuilder = React.memo<Props>(({ datasource, query, onChange, onRunQuery, showExplain }) => {
   const [sampleData, setSampleData] = useState<PanelData>();
@@ -83,7 +84,7 @@ export const LokiQueryBuilder = React.memo<Props>(({ datasource, query, onChange
       if (op.length === 1 && op[0].id === LokiOperationId.LineContains && op[0].params[0] === '') {
         return undefined;
       }
-      return 'You need to specify at least 1 label filter (stream selector)';
+      return MISSING_LABEL_FILTER_ERROR_MESSAGE;
     }
     return undefined;
   }, [query]);