Explore: Remove datasource testing on selector (#19910)

* Explore: Remove datasource testing on selector

- datasource testing gets in the way of fast query iteration: switching
between datasources can take seconds
- it should not be explore's duty to test datasources in the first place
- removed the concept of datasourceError in Explore, should not be its
concern
- datasource erorrs will express themselves in query errors just fine
- connection errors are still bubbled up
- removed reconnection logic from explore, should not be its concern
- missing labels in loki are still "visible" via an empty label selector
- Loki and Prometheus treated connection errors differently than other
datasources, making sure to pass through the original error message

* Show datasource error in query field for prom/loki/influx

* Removed connection test case, fixed disabled state

packages/grafana-ui/src/types/datasource.ts

@@ -295,7 +295,6 @@ export interface ExploreQueryFieldProps<
   TQuery extends DataQuery = DataQuery,
   TOptions extends DataSourceJsonData = DataSourceJsonData
 > extends QueryEditorProps<DSType, TQuery, TOptions> {
-  datasourceStatus: DataSourceStatus;
   history: any[];
   onHint?: (action: QueryFixAction) => void;
 }

public/app/features/explore/Explore.tsx

@@ -9,7 +9,7 @@ import memoizeOne from 'memoize-one';
 // Services & Utils
 import store from 'app/core/store';
 // Components
-import { Alert, ErrorBoundaryAlert, DataQuery, ExploreStartPageProps, DataSourceApi, PanelData } from '@grafana/ui';
+import { ErrorBoundaryAlert, DataQuery, ExploreStartPageProps, DataSourceApi, PanelData } from '@grafana/ui';
 import LogsContainer from './LogsContainer';
 import QueryRows from './QueryRows';
 import TableContainer from './TableContainer';
@@ -21,7 +21,6 @@ import {
   scanStart,
   setQueries,
   refreshExplore,
-  reconnectDatasource,
   updateTimeRange,
   toggleGraph,
 } from './state/actions';
@@ -46,7 +45,6 @@ import {
 import { Emitter } from 'app/core/utils/emitter';
 import { ExploreToolbar } from './ExploreToolbar';
 import { NoDataSourceCallToAction } from './NoDataSourceCallToAction';
-import { FadeIn } from 'app/core/components/Animations/FadeIn';
 import { getTimeZone } from '../profile/state/selectors';
 import { ErrorContainer } from './ErrorContainer';
 import { scanStopAction } from './state/actionTypes';
@@ -65,7 +63,6 @@ const getStyles = memoizeOne(() => {
 interface ExploreProps {
   StartPage?: ComponentType<ExploreStartPageProps>;
   changeSize: typeof changeSize;
-  datasourceError: string;
   datasourceInstance: DataSourceApi;
   datasourceMissing: boolean;
   exploreId: ExploreId;
@@ -73,7 +70,6 @@ interface ExploreProps {
   initialized: boolean;
   modifyQueries: typeof modifyQueries;
   update: ExploreUpdateState;
-  reconnectDatasource: typeof reconnectDatasource;
   refreshExplore: typeof refreshExplore;
   scanning?: boolean;
   scanRange?: RawTimeRange;
@@ -238,18 +234,10 @@ export class Explore extends React.PureComponent<ExploreProps> {
     );
   };
 
-  onReconnect = (event: React.MouseEvent<HTMLButtonElement>) => {
-    const { exploreId, reconnectDatasource } = this.props;
-
-    event.preventDefault();
-    reconnectDatasource(exploreId);
-  };
-
   render() {
     const {
       StartPage,
       datasourceInstance,
-      datasourceError,
       datasourceMissing,
       exploreId,
       showingStartPage,
@@ -272,17 +260,6 @@ export class Explore extends React.PureComponent<ExploreProps> {
       <div className={exploreClass} ref={this.getRef}>
         <ExploreToolbar exploreId={exploreId} onChangeTime={this.onChangeTime} />
         {datasourceMissing ? this.renderEmptyState() : null}
-
-        <FadeIn duration={datasourceError ? 150 : 5} in={datasourceError ? true : false}>
-          <div className="explore-container">
-            <Alert
-              title={`Error connecting to datasource: ${datasourceError}`}
-              buttonText={'Reconnect'}
-              onButtonClick={this.onReconnect}
-            />
-          </div>
-        </FadeIn>
-
         {datasourceInstance && (
           <div className="explore-container">
             <QueryRows exploreEvents={this.exploreEvents} exploreId={exploreId} queryKeys={queryKeys} />
@@ -357,7 +334,6 @@ function mapStateToProps(state: StoreState, { exploreId }: ExploreProps): Partia
   const timeZone = getTimeZone(state.user);
   const {
     StartPage,
-    datasourceError,
     datasourceInstance,
     datasourceMissing,
     initialized,
@@ -402,7 +378,6 @@ function mapStateToProps(state: StoreState, { exploreId }: ExploreProps): Partia
 
   return {
     StartPage,
-    datasourceError,
     datasourceInstance,
     datasourceMissing,
     initialized,
@@ -431,7 +406,6 @@ const mapDispatchToProps: Partial<ExploreProps> = {
   changeSize,
   initializeExplore,
   modifyQueries,
-  reconnectDatasource,
   refreshExplore,
   scanStart,
   scanStopAction,

public/app/features/explore/QueryRow.tsx

@@ -13,7 +13,7 @@ import { changeQuery, modifyQueries, runQueries, addQueryRow } from './state/act
 // Types
 import { StoreState } from 'app/types';
 import { TimeRange, AbsoluteTimeRange, LoadingState } from '@grafana/data';
-import { DataQuery, DataSourceApi, QueryFixAction, DataSourceStatus, PanelData } from '@grafana/ui';
+import { DataQuery, DataSourceApi, QueryFixAction, PanelData } from '@grafana/ui';
 import { HistoryItem, ExploreItemState, ExploreId, ExploreMode } from 'app/types/explore';
 import { Emitter } from 'app/core/utils/emitter';
 import { highlightLogsExpressionAction, removeQueryRowAction } from './state/actionTypes';
@@ -31,7 +31,6 @@ interface QueryRowProps extends PropsFromParent {
   className?: string;
   exploreId: ExploreId;
   datasourceInstance: DataSourceApi;
-  datasourceStatus: DataSourceStatus;
   highlightLogsExpressionAction: typeof highlightLogsExpressionAction;
   history: HistoryItem[];
   query: DataQuery;
@@ -121,7 +120,6 @@ export class QueryRow extends PureComponent<QueryRowProps, QueryRowState> {
       exploreEvents,
       range,
       absoluteRange,
-      datasourceStatus,
       queryResponse,
       latency,
       mode,
@@ -148,7 +146,6 @@ export class QueryRow extends PureComponent<QueryRowProps, QueryRowState> {
             //@ts-ignore
             <QueryField
               datasource={datasourceInstance}
-              datasourceStatus={datasourceStatus}
               query={query}
               history={history}
               onRunQuery={this.onRunQuery}
@@ -190,19 +187,8 @@ export class QueryRow extends PureComponent<QueryRowProps, QueryRowState> {
 function mapStateToProps(state: StoreState, { exploreId, index }: QueryRowProps) {
   const explore = state.explore;
   const item: ExploreItemState = explore[exploreId];
-  const {
+  const { datasourceInstance, history, queries, range, absoluteRange, latency, mode, queryResponse } = item;
-    datasourceInstance,
-    history,
-    queries,
-    range,
-    absoluteRange,
-    datasourceError,
-    latency,
-    mode,
-    queryResponse,
-  } = item;
   const query = queries[index];
-  const datasourceStatus = datasourceError ? DataSourceStatus.Disconnected : DataSourceStatus.Connected;
 
   return {
     datasourceInstance,
@@ -210,7 +196,6 @@ function mapStateToProps(state: StoreState, { exploreId, index }: QueryRowProps)
     query,
     range,
     absoluteRange,
-    datasourceStatus,
     queryResponse,
     latency,
     mode,

public/app/features/explore/state/actionTypes.ts

@@ -105,19 +105,6 @@ export interface LoadDatasourceReadyPayload {
   history: HistoryItem[];
 }
 
-export interface TestDatasourcePendingPayload {
-  exploreId: ExploreId;
-}
-
-export interface TestDatasourceFailurePayload {
-  exploreId: ExploreId;
-  error: string;
-}
-
-export interface TestDatasourceSuccessPayload {
-  exploreId: ExploreId;
-}
-
 export interface ModifyQueriesPayload {
   exploreId: ExploreId;
   modification: QueryFixAction;
@@ -391,15 +378,6 @@ export const toggleLogLevelAction = actionCreatorFactory<ToggleLogLevelPayload>(
  */
 export const resetExploreAction = actionCreatorFactory<ResetExplorePayload>('explore/RESET_EXPLORE').create();
 export const queriesImportedAction = actionCreatorFactory<QueriesImportedPayload>('explore/QueriesImported').create();
-export const testDataSourcePendingAction = actionCreatorFactory<TestDatasourcePendingPayload>(
-  'explore/TEST_DATASOURCE_PENDING'
-).create();
-export const testDataSourceSuccessAction = actionCreatorFactory<TestDatasourceSuccessPayload>(
-  'explore/TEST_DATASOURCE_SUCCESS'
-).create();
-export const testDataSourceFailureAction = actionCreatorFactory<TestDatasourceFailurePayload>(
-  'explore/TEST_DATASOURCE_FAILURE'
-).create();
 export const loadExploreDatasources = actionCreatorFactory<LoadExploreDataSourcesPayload>(
   'explore/LOAD_EXPLORE_DATASOURCES'
 ).create();

public/app/features/explore/state/actions.test.ts

@@ -1,4 +1,4 @@
-import { refreshExplore, testDatasource, loadDatasource } from './actions';
+import { refreshExplore, loadDatasource } from './actions';
 import { ExploreId, ExploreUrlState, ExploreUpdateState, ExploreMode } from 'app/types';
 import { thunkTester } from 'test/core/thunk/thunkTester';
 import {
@@ -6,9 +6,6 @@ import {
   InitializeExplorePayload,
   updateUIStateAction,
   setQueriesAction,
-  testDataSourcePendingAction,
-  testDataSourceSuccessAction,
-  testDataSourceFailureAction,
   loadDatasourcePendingAction,
   loadDatasourceReadyAction,
 } from './actionTypes';
@@ -164,72 +161,6 @@ describe('refreshExplore', () => {
   });
 });
 
-describe('test datasource', () => {
-  describe('when testDatasource thunk is dispatched', () => {
-    describe('and testDatasource call on instance is successful', () => {
-      it('then it should dispatch testDataSourceSuccessAction', async () => {
-        const exploreId = ExploreId.left;
-        const mockDatasourceInstance = {
-          testDatasource: () => {
-            return Promise.resolve({ status: 'success' });
-          },
-        };
-
-        const dispatchedActions = await thunkTester({})
-          .givenThunk(testDatasource)
-          .whenThunkIsDispatched(exploreId, mockDatasourceInstance);
-
-        expect(dispatchedActions).toEqual([
-          testDataSourcePendingAction({ exploreId }),
-          testDataSourceSuccessAction({ exploreId }),
-        ]);
-      });
-    });
-
-    describe('and testDatasource call on instance is not successful', () => {
-      it('then it should dispatch testDataSourceFailureAction', async () => {
-        const exploreId = ExploreId.left;
-        const error = 'something went wrong';
-        const mockDatasourceInstance = {
-          testDatasource: () => {
-            return Promise.resolve({ status: 'fail', message: error });
-          },
-        };
-
-        const dispatchedActions = await thunkTester({})
-          .givenThunk(testDatasource)
-          .whenThunkIsDispatched(exploreId, mockDatasourceInstance);
-
-        expect(dispatchedActions).toEqual([
-          testDataSourcePendingAction({ exploreId }),
-          testDataSourceFailureAction({ exploreId, error }),
-        ]);
-      });
-    });
-
-    describe('and testDatasource call on instance throws', () => {
-      it('then it should dispatch testDataSourceFailureAction', async () => {
-        const exploreId = ExploreId.left;
-        const error = 'something went wrong';
-        const mockDatasourceInstance = {
-          testDatasource: () => {
-            throw { statusText: error };
-          },
-        };
-
-        const dispatchedActions = await thunkTester({})
-          .givenThunk(testDatasource)
-          .whenThunkIsDispatched(exploreId, mockDatasourceInstance);
-
-        expect(dispatchedActions).toEqual([
-          testDataSourcePendingAction({ exploreId }),
-          testDataSourceFailureAction({ exploreId, error }),
-        ]);
-      });
-    });
-  });
-});
-
 describe('loading datasource', () => {
   describe('when loadDatasource thunk is dispatched', () => {
     describe('and all goes fine', () => {
@@ -255,8 +186,6 @@ describe('loading datasource', () => {
             exploreId,
             requestedDatasourceName: mockDatasourceInstance.name,
           }),
-          testDataSourcePendingAction({ exploreId }),
-          testDataSourceSuccessAction({ exploreId }),
           loadDatasourceReadyAction({ exploreId, history: [] }),
         ]);
       });
@@ -285,8 +214,6 @@ describe('loading datasource', () => {
             exploreId,
             requestedDatasourceName: mockDatasourceInstance.name,
           }),
-          testDataSourcePendingAction({ exploreId }),
-          testDataSourceSuccessAction({ exploreId }),
         ]);
       });
     });

public/app/features/explore/state/actions.ts

@@ -59,9 +59,6 @@ import {
   ToggleGraphPayload,
   ToggleTablePayload,
   updateUIStateAction,
-  testDataSourcePendingAction,
-  testDataSourceSuccessAction,
-  testDataSourceFailureAction,
   loadExploreDatasources,
   changeModeAction,
   scanStopAction,
@@ -340,41 +337,6 @@ export function importQueries(
   };
 }
 
-/**
- * Tests datasource.
- */
-export const testDatasource = (exploreId: ExploreId, instance: DataSourceApi): ThunkResult<void> => {
-  return async dispatch => {
-    let datasourceError = null;
-
-    dispatch(testDataSourcePendingAction({ exploreId }));
-
-    try {
-      const testResult = await instance.testDatasource();
-      datasourceError = testResult.status === 'success' ? null : testResult.message;
-    } catch (error) {
-      datasourceError = (error && error.statusText) || 'Network error';
-    }
-
-    if (datasourceError) {
-      dispatch(testDataSourceFailureAction({ exploreId, error: datasourceError }));
-      return;
-    }
-
-    dispatch(testDataSourceSuccessAction({ exploreId }));
-  };
-};
-
-/**
- * Reconnects datasource when there is a connection failure.
- */
-export const reconnectDatasource = (exploreId: ExploreId): ThunkResult<void> => {
-  return async (dispatch, getState) => {
-    const instance = getState().explore[exploreId].datasourceInstance;
-    dispatch(changeDatasource(exploreId, instance.name));
-  };
-};
-
 /**
  * Main action to asynchronously load a datasource. Dispatches lots of smaller actions for feedback.
  */
@@ -385,13 +347,6 @@ export function loadDatasource(exploreId: ExploreId, instance: DataSourceApi, or
     // Keep ID to track selection
     dispatch(loadDatasourcePendingAction({ exploreId, requestedDatasourceName: datasourceName }));
 
-    await dispatch(testDatasource(exploreId, instance));
-
-    if (datasourceName !== getState().explore[exploreId].requestedDatasourceName) {
-      // User already changed datasource again, discard results
-      return;
-    }
-
     if (instance.init) {
       try {
         instance.init();
@@ -401,7 +356,7 @@ export function loadDatasource(exploreId: ExploreId, instance: DataSourceApi, or
     }
 
     if (datasourceName !== getState().explore[exploreId].requestedDatasourceName) {
-      // User already changed datasource again, discard results
+      // User already changed datasource, discard results
       return;
     }
 
@@ -441,7 +396,6 @@ export function runQueries(exploreId: ExploreId): ThunkResult<void> {
     const {
       datasourceInstance,
       queries,
-      datasourceError,
       containerWidth,
       isLive: live,
       range,
@@ -454,11 +408,6 @@ export function runQueries(exploreId: ExploreId): ThunkResult<void> {
       showingTable,
     } = exploreItemState;
 
-    if (datasourceError) {
-      // let's not run any queries if data source is in a faulty state
-      return;
-    }
-
     if (!hasNonEmptyQuery(queries)) {
       dispatch(clearQueriesAction({ exploreId }));
       dispatch(stateSave()); // Remember to save to state and update location

public/app/features/explore/state/reducers.test.ts

@@ -10,9 +10,6 @@ import { ExploreId, ExploreItemState, ExploreUrlState, ExploreState, ExploreMode
 import { reducerTester } from 'test/core/redux/reducerTester';
 import {
   scanStartAction,
-  testDataSourcePendingAction,
-  testDataSourceSuccessAction,
-  testDataSourceFailureAction,
   updateDatasourceInstanceAction,
   splitOpenAction,
   splitCloseAction,
@@ -29,7 +26,7 @@ import { updateLocation } from 'app/core/actions/location';
 import { serializeStateToUrlParam } from 'app/core/utils/explore';
 import TableModel from 'app/core/table_model';
 import { DataSourceApi, DataQuery } from '@grafana/ui';
-import { LogsModel, LogsDedupStrategy, dateTime, LoadingState } from '@grafana/data';
+import { LogsDedupStrategy, dateTime, LoadingState } from '@grafana/data';
 
 describe('Explore item reducer', () => {
   describe('scanning', () => {
@@ -65,56 +62,7 @@ describe('Explore item reducer', () => {
     });
   });
 
-  describe('testing datasource', () => {
+  describe('changing datasource', () => {
-    describe('when testDataSourcePendingAction is dispatched', () => {
-      it('then it should set datasourceError', () => {
-        reducerTester()
-          .givenReducer(itemReducer, { datasourceError: {} })
-          .whenActionIsDispatched(testDataSourcePendingAction({ exploreId: ExploreId.left }))
-          .thenStateShouldEqual({ datasourceError: null });
-      });
-    });
-
-    describe('when testDataSourceSuccessAction is dispatched', () => {
-      it('then it should set datasourceError', () => {
-        reducerTester()
-          .givenReducer(itemReducer, { datasourceError: {} })
-          .whenActionIsDispatched(testDataSourceSuccessAction({ exploreId: ExploreId.left }))
-          .thenStateShouldEqual({ datasourceError: null });
-      });
-    });
-
-    describe('when testDataSourceFailureAction is dispatched', () => {
-      it('then it should set correct state', () => {
-        const error = 'some error';
-        const initalState: Partial<ExploreItemState> = {
-          datasourceError: null,
-          graphResult: [],
-          tableResult: {} as TableModel,
-          logsResult: {} as LogsModel,
-          update: {
-            datasource: true,
-            queries: true,
-            range: true,
-            mode: true,
-            ui: true,
-          },
-        };
-        const expectedState = {
-          datasourceError: error,
-          graphResult: undefined as any[],
-          tableResult: undefined as TableModel,
-          logsResult: undefined as LogsModel,
-          update: makeInitialUpdateState(),
-        };
-
-        reducerTester()
-          .givenReducer(itemReducer, initalState)
-          .whenActionIsDispatched(testDataSourceFailureAction({ exploreId: ExploreId.left, error }))
-          .thenStateShouldEqual(expectedState);
-      });
-    });
-
     describe('when changeDataType is dispatched', () => {
       it('then it should set correct state', () => {
         reducerTester()
@@ -125,9 +73,7 @@ describe('Explore item reducer', () => {
           });
       });
     });
-  });
 
-  describe('changing datasource', () => {
     describe('when updateDatasourceInstanceAction is dispatched', () => {
       describe('and datasourceInstance supports graph, logs, table and has a startpage', () => {
         it('then it should set correct state', () => {

public/app/features/explore/state/reducers.ts

@@ -15,9 +15,6 @@ import { DataQuery, DataSourceApi, PanelData, DataQueryRequest, RefreshPicker, P
 import {
   HigherOrderAction,
   ActionTypes,
-  testDataSourcePendingAction,
-  testDataSourceSuccessAction,
-  testDataSourceFailureAction,
   splitCloseAction,
   SplitCloseActionPayload,
   loadExploreDatasources,
@@ -82,7 +79,6 @@ export const makeExploreItemState = (): ExploreItemState => ({
   containerWidth: 0,
   datasourceInstance: null,
   requestedDatasourceName: null,
-  datasourceError: null,
   datasourceLoading: null,
   datasourceMissing: false,
   exploreDatasources: [],
@@ -475,37 +471,6 @@ export const itemReducer = reducerFactory<ExploreItemState>({} as ExploreItemSta
       };
     },
   })
-  .addMapper({
-    filter: testDataSourcePendingAction,
-    mapper: (state): ExploreItemState => {
-      return {
-        ...state,
-        datasourceError: null,
-      };
-    },
-  })
-  .addMapper({
-    filter: testDataSourceSuccessAction,
-    mapper: (state): ExploreItemState => {
-      return {
-        ...state,
-        datasourceError: null,
-      };
-    },
-  })
-  .addMapper({
-    filter: testDataSourceFailureAction,
-    mapper: (state, action): ExploreItemState => {
-      return {
-        ...state,
-        datasourceError: action.payload.error,
-        graphResult: undefined,
-        tableResult: undefined,
-        logsResult: undefined,
-        update: makeInitialUpdateState(),
-      };
-    },
-  })
   .addMapper({
     filter: loadExploreDatasources,
     mapper: (state, action): ExploreItemState => {

public/app/plugins/datasource/influxdb/components/InfluxLogsQueryField.tsx

@@ -17,6 +17,13 @@ export interface State {
   measurements: CascaderOption[];
   measurement: string;
   field: string;
+  error: string;
+}
+
+interface ChooserOptions {
+  measurement: string;
+  field: string;
+  error: string;
 }
 
 // Helper function for determining if a collection of pairs are valid
@@ -32,37 +39,54 @@ export function pairsAreValid(pairs: KeyValuePair[]) {
   );
 }
 
+function getChooserText({ measurement, field, error }: ChooserOptions): string {
+  if (error) {
+    return '(No measurement found)';
+  }
+  if (measurement) {
+    return `Measurements (${measurement}/${field})`;
+  }
+  return 'Measurements';
+}
+
 export class InfluxLogsQueryField extends React.PureComponent<Props, State> {
   templateSrv: TemplateSrv = new TemplateSrv();
-  state: State = { measurements: [], measurement: null, field: null };
+  state: State = { measurements: [], measurement: null, field: null, error: null };
 
   async componentDidMount() {
     const { datasource } = this.props;
-    const queryBuilder = new InfluxQueryBuilder({ measurement: '', tags: [] }, datasource.database);
+    try {
-    const measureMentsQuery = queryBuilder.buildExploreQuery('MEASUREMENTS');
+      const queryBuilder = new InfluxQueryBuilder({ measurement: '', tags: [] }, datasource.database);
-    const influxMeasurements = await datasource.metricFindQuery(measureMentsQuery);
+      const measureMentsQuery = queryBuilder.buildExploreQuery('MEASUREMENTS');
+      const influxMeasurements = await datasource.metricFindQuery(measureMentsQuery);
 
-    const measurements = [];
+      const measurements = [];
-    for (let index = 0; index < influxMeasurements.length; index++) {
+      for (let index = 0; index < influxMeasurements.length; index++) {
-      const measurementObj = influxMeasurements[index];
+        const measurementObj = influxMeasurements[index];
-      const queryBuilder = new InfluxQueryBuilder({ measurement: measurementObj.text, tags: [] }, datasource.database);
+        const queryBuilder = new InfluxQueryBuilder(
-      const fieldsQuery = queryBuilder.buildExploreQuery('FIELDS');
+          { measurement: measurementObj.text, tags: [] },
-      const influxFields = await datasource.metricFindQuery(fieldsQuery);
+          datasource.database
-      const fields: any[] = influxFields.map(
+        );
-        (field: any): any => ({
+        const fieldsQuery = queryBuilder.buildExploreQuery('FIELDS');
-          label: field.text,
+        const influxFields = await datasource.metricFindQuery(fieldsQuery);
-          value: field.text,
+        const fields: any[] = influxFields.map(
-          children: [],
+          (field: any): any => ({
-        })
+            label: field.text,
-      );
+            value: field.text,
-      measurements.push({
+            children: [],
-        label: measurementObj.text,
+          })
-        value: measurementObj.text,
+        );
-        children: fields,
+        measurements.push({
-      });
+          label: measurementObj.text,
+          value: measurementObj.text,
+          children: fields,
+        });
+      }
+      this.setState({ measurements });
+    } catch (error) {
+      const message = error && error.message ? error.message : error;
+      this.setState({ error: message });
     }
-
-    this.setState({ measurements });
   }
 
   componentDidUpdate(prevProps: Props) {
@@ -107,8 +131,8 @@ export class InfluxLogsQueryField extends React.PureComponent<Props, State> {
 
   render() {
     const { datasource } = this.props;
-    const { measurements, measurement, field } = this.state;
+    const { measurements, measurement, field, error } = this.state;
-    const cascadeText = measurement ? `Measurements (${measurement}/${field})` : 'Measurements';
+    const cascadeText = getChooserText({ measurement, field, error });
 
     return (
       <div className="gf-form-inline gf-form-inline--nowrap">
@@ -119,7 +143,7 @@ export class InfluxLogsQueryField extends React.PureComponent<Props, State> {
             onChange={this.onMeasurementsChange}
             expandIcon={null}
           >
-            <button className="gf-form-label gf-form-label--btn">
+            <button className="gf-form-label gf-form-label--btn" disabled={!measurement}>
               {cascadeText} <i className="fa fa-caret-down" />
             </button>
           </Cascader>
@@ -132,6 +156,9 @@ export class InfluxLogsQueryField extends React.PureComponent<Props, State> {
               extendedOptions={{ measurement }}
             />
           )}
+          {error ? (
+            <span className="gf-form-label gf-form-label--transparent gf-form-label--error m-l-2">{error}</span>
+          ) : null}
         </div>
       </div>
     );

public/app/plugins/datasource/loki/components/AnnotationsQueryEditor.tsx

@@ -2,7 +2,6 @@
 import React, { memo } from 'react';
 
 // Types
-import { DataSourceStatus } from '@grafana/ui';
 import { LokiQuery } from '../types';
 import { useLokiSyntax } from './useLokiSyntax';
 import { LokiQueryFieldForm } from './LokiQueryFieldForm';
@@ -25,7 +24,6 @@ export const LokiAnnotationsQueryEditor = memo(function LokiAnnotationQueryEdito
 
   const { isSyntaxReady, setActiveOption, refreshLabels, ...syntaxProps } = useLokiSyntax(
     datasource.languageProvider,
-    DataSourceStatus.Connected,
     absolute
   );
 
@@ -38,7 +36,6 @@ export const LokiAnnotationsQueryEditor = memo(function LokiAnnotationQueryEdito
     <div className="gf-form-group">
       <LokiQueryFieldForm
         datasource={datasource}
-        datasourceStatus={DataSourceStatus.Connected}
         query={query}
         onChange={(query: LokiQuery) => onChange(query.expr)}
         onRunQuery={() => {}}

public/app/plugins/datasource/loki/components/LokiQueryEditor.tsx

@@ -3,7 +3,7 @@ import React, { memo } from 'react';
 
 // Types
 import { AbsoluteTimeRange } from '@grafana/data';
-import { QueryEditorProps, DataSourceStatus } from '@grafana/ui';
+import { QueryEditorProps } from '@grafana/ui';
 import { LokiDatasource } from '../datasource';
 import { LokiQuery } from '../types';
 import { LokiQueryField } from './LokiQueryField';
@@ -30,8 +30,6 @@ export const LokiQueryEditor = memo(function LokiQueryEditor(props: Props) {
 
   const { isSyntaxReady, setActiveOption, refreshLabels, ...syntaxProps } = useLokiSyntax(
     datasource.languageProvider,
-    // TODO maybe use real status
-    DataSourceStatus.Connected,
     absolute
   );
 
@@ -39,7 +37,6 @@ export const LokiQueryEditor = memo(function LokiQueryEditor(props: Props) {
     <div>
       <LokiQueryField
         datasource={datasource}
-        datasourceStatus={DataSourceStatus.Connected}
         query={query}
         onChange={onChange}
         onRunQuery={onRunQuery}

public/app/plugins/datasource/loki/components/LokiQueryField.tsx

@@ -3,21 +3,15 @@ import { LokiQueryFieldForm, LokiQueryFieldFormProps } from './LokiQueryFieldFor
 import { useLokiSyntax } from './useLokiSyntax';
 import LokiLanguageProvider from '../language_provider';
 
-export const LokiQueryField: FunctionComponent<LokiQueryFieldFormProps> = ({
+export const LokiQueryField: FunctionComponent<LokiQueryFieldFormProps> = ({ datasource, ...otherProps }) => {
-  datasource,
-  datasourceStatus,
-  ...otherProps
-}) => {
   const { isSyntaxReady, setActiveOption, refreshLabels, ...syntaxProps } = useLokiSyntax(
     datasource.languageProvider as LokiLanguageProvider,
-    datasourceStatus,
     otherProps.absoluteRange
   );
 
   return (
     <LokiQueryFieldForm
       datasource={datasource}
-      datasourceStatus={datasourceStatus}
       syntaxLoaded={isSyntaxReady}
       /**
        * setActiveOption name is intentional. Because of the way rc-cascader requests additional data

public/app/plugins/datasource/loki/components/LokiQueryFieldForm.tsx

@@ -15,17 +15,14 @@ import { Plugin, Node } from 'slate';
 // Types
 import { LokiQuery } from '../types';
 import { TypeaheadOutput } from 'app/types/explore';
-import { ExploreQueryFieldProps, DataSourceStatus, DOMUtil } from '@grafana/ui';
+import { ExploreQueryFieldProps, DOMUtil } from '@grafana/ui';
 import { AbsoluteTimeRange } from '@grafana/data';
 import { Grammar } from 'prismjs';
 import LokiLanguageProvider, { LokiHistoryItem } from '../language_provider';
 import { SuggestionsState } from 'app/features/explore/slate-plugins/suggestions';
 import LokiDatasource from '../datasource';
 
-function getChooserText(hasSyntax: boolean, hasLogLabels: boolean, datasourceStatus: DataSourceStatus) {
+function getChooserText(hasSyntax: boolean, hasLogLabels: boolean) {
-  if (datasourceStatus === DataSourceStatus.Disconnected) {
-    return '(Disconnected)';
-  }
   if (!hasSyntax) {
     return 'Loading labels...';
   }
@@ -144,21 +141,12 @@ export class LokiQueryFieldForm extends React.PureComponent<LokiQueryFieldFormPr
   };
 
   render() {
-    const {
+    const { data, query, syntaxLoaded, logLabelOptions, onLoadOptions, onLabelsRefresh, datasource } = this.props;
-      data,
-      query,
-      syntaxLoaded,
-      logLabelOptions,
-      onLoadOptions,
-      onLabelsRefresh,
-      datasource,
-      datasourceStatus,
-    } = this.props;
     const lokiLanguageProvider = datasource.languageProvider as LokiLanguageProvider;
     const cleanText = datasource.languageProvider ? lokiLanguageProvider.cleanText : undefined;
     const hasLogLabels = logLabelOptions && logLabelOptions.length > 0;
-    const chooserText = getChooserText(syntaxLoaded, hasLogLabels, datasourceStatus);
+    const chooserText = getChooserText(syntaxLoaded, hasLogLabels);
-    const buttonDisabled = !syntaxLoaded || datasourceStatus === DataSourceStatus.Disconnected;
+    const buttonDisabled = !(syntaxLoaded && hasLogLabels);
     const showError = data && data.error && data.error.refId === query.refId;
 
     return (
@@ -166,7 +154,7 @@ export class LokiQueryFieldForm extends React.PureComponent<LokiQueryFieldFormPr
         <div className="gf-form-inline">
           <div className="gf-form">
             <Cascader
-              options={logLabelOptions}
+              options={logLabelOptions || []}
               onChange={this.onChangeLogLabels}
               loadData={onLoadOptions}
               expandIcon={null}

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

@@ -1,7 +1,6 @@
 import { renderHook, act } from 'react-hooks-testing-library';
 import LanguageProvider from 'app/plugins/datasource/loki/language_provider';
 import { useLokiLabels } from './useLokiLabels';
-import { DataSourceStatus } from '@grafana/ui/src/types/datasource';
 import { AbsoluteTimeRange } from '@grafana/data';
 import { makeMockLokiDatasource } from '../mocks';
 
@@ -20,49 +19,10 @@ describe('useLokiLabels hook', () => {
       return Promise.resolve();
     };
 
-    const { result, waitForNextUpdate } = renderHook(() =>
+    const { result, waitForNextUpdate } = renderHook(() => useLokiLabels(languageProvider, true, [], rangeMock));
-      useLokiLabels(languageProvider, true, [], rangeMock, DataSourceStatus.Connected, DataSourceStatus.Connected)
-    );
     act(() => result.current.refreshLabels());
     expect(result.current.logLabelOptions).toEqual([]);
     await waitForNextUpdate();
     expect(result.current.logLabelOptions).toEqual(logLabelOptionsMock);
   });
-
-  it('should force refresh labels after a disconnect', () => {
-    const datasource = makeMockLokiDatasource({});
-
-    const rangeMock: AbsoluteTimeRange = {
-      from: 1560153109000,
-      to: 1560153109000,
-    };
-
-    const languageProvider = new LanguageProvider(datasource);
-    languageProvider.refreshLogLabels = jest.fn();
-
-    renderHook(() =>
-      useLokiLabels(languageProvider, true, [], rangeMock, DataSourceStatus.Connected, DataSourceStatus.Disconnected)
-    );
-
-    expect(languageProvider.refreshLogLabels).toBeCalledTimes(1);
-    expect(languageProvider.refreshLogLabels).toBeCalledWith(rangeMock, true);
-  });
-
-  it('should not force refresh labels after a connect', () => {
-    const datasource = makeMockLokiDatasource({});
-
-    const rangeMock: AbsoluteTimeRange = {
-      from: 1560153109000,
-      to: 1560153109000,
-    };
-
-    const languageProvider = new LanguageProvider(datasource);
-    languageProvider.refreshLogLabels = jest.fn();
-
-    renderHook(() =>
-      useLokiLabels(languageProvider, true, [], rangeMock, DataSourceStatus.Disconnected, DataSourceStatus.Connected)
-    );
-
-    expect(languageProvider.refreshLogLabels).not.toBeCalled();
-  });
 });

public/app/plugins/datasource/loki/components/useLokiLabels.ts

@@ -1,5 +1,4 @@
 import { useState, useEffect } from 'react';
-import { DataSourceStatus } from '@grafana/ui/src/types/datasource';
 import { AbsoluteTimeRange } from '@grafana/data';
 
 import LokiLanguageProvider from 'app/plugins/datasource/loki/language_provider';
@@ -18,18 +17,13 @@ export const useLokiLabels = (
   languageProvider: LokiLanguageProvider,
   languageProviderInitialised: boolean,
   activeOption: CascaderOption[],
-  absoluteRange: AbsoluteTimeRange,
+  absoluteRange: AbsoluteTimeRange
-  datasourceStatus: DataSourceStatus,
-  initialDatasourceStatus?: DataSourceStatus // used for test purposes
 ) => {
   const mounted = useRefMounted();
 
   // State
   const [logLabelOptions, setLogLabelOptions] = useState([]);
   const [shouldTryRefreshLabels, setRefreshLabels] = useState(false);
-  const [prevDatasourceStatus, setPrevDatasourceStatus] = useState(
-    initialDatasourceStatus || DataSourceStatus.Connected
-  );
   const [shouldForceRefreshLabels, setForceRefreshLabels] = useState(false);
 
   // Async
@@ -83,15 +77,6 @@ export const useLokiLabels = (
     }
   }, [shouldTryRefreshLabels, shouldForceRefreshLabels]);
 
-  // This effect is performed on datasourceStatus state change only.
-  // We want to make sure to only force refresh AFTER a disconnected state thats why we store the previous datasourceStatus in state
-  useEffect(() => {
-    if (datasourceStatus === DataSourceStatus.Connected && prevDatasourceStatus === DataSourceStatus.Disconnected) {
-      setForceRefreshLabels(true);
-    }
-    setPrevDatasourceStatus(datasourceStatus);
-  }, [datasourceStatus]);
-
   return {
     logLabelOptions,
     setLogLabelOptions,

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

@@ -1,5 +1,4 @@
 import { renderHook, act } from 'react-hooks-testing-library';
-import { DataSourceStatus } from '@grafana/ui/src/types/datasource';
 import { AbsoluteTimeRange } from '@grafana/data';
 
 import LanguageProvider from 'app/plugins/datasource/loki/language_provider';
@@ -36,9 +35,7 @@ describe('useLokiSyntax hook', () => {
   };
 
   it('should provide Loki syntax when used', async () => {
-    const { result, waitForNextUpdate } = renderHook(() =>
+    const { result, waitForNextUpdate } = renderHook(() => useLokiSyntax(languageProvider, rangeMock));
-      useLokiSyntax(languageProvider, DataSourceStatus.Connected, rangeMock)
-    );
     expect(result.current.syntax).toEqual(null);
 
     await waitForNextUpdate();
@@ -47,9 +44,7 @@ describe('useLokiSyntax hook', () => {
   });
 
   it('should fetch labels on first call', async () => {
-    const { result, waitForNextUpdate } = renderHook(() =>
+    const { result, waitForNextUpdate } = renderHook(() => useLokiSyntax(languageProvider, rangeMock));
-      useLokiSyntax(languageProvider, DataSourceStatus.Connected, rangeMock)
-    );
     expect(result.current.isSyntaxReady).toBeFalsy();
     expect(result.current.logLabelOptions).toEqual([]);
 
@@ -60,9 +55,7 @@ describe('useLokiSyntax hook', () => {
   });
 
   it('should try to fetch missing options when active option changes', async () => {
-    const { result, waitForNextUpdate } = renderHook(() =>
+    const { result, waitForNextUpdate } = renderHook(() => useLokiSyntax(languageProvider, rangeMock));
-      useLokiSyntax(languageProvider, DataSourceStatus.Connected, rangeMock)
-    );
     await waitForNextUpdate();
     expect(result.current.logLabelOptions).toEqual(logLabelOptionsMock2);
 

public/app/plugins/datasource/loki/components/useLokiSyntax.ts

@@ -1,6 +1,5 @@
 import { useState, useEffect } from 'react';
 import Prism from 'prismjs';
-import { DataSourceStatus } from '@grafana/ui/src/types/datasource';
 import { AbsoluteTimeRange } from '@grafana/data';
 import LokiLanguageProvider from 'app/plugins/datasource/loki/language_provider';
 import { useLokiLabels } from 'app/plugins/datasource/loki/components/useLokiLabels';
@@ -14,11 +13,7 @@ const PRISM_SYNTAX = 'promql';
  * @param languageProvider
  * @description Initializes given language provider, exposes Loki syntax and enables loading label option values
  */
-export const useLokiSyntax = (
+export const useLokiSyntax = (languageProvider: LokiLanguageProvider, absoluteRange: AbsoluteTimeRange) => {
-  languageProvider: LokiLanguageProvider,
-  datasourceStatus: DataSourceStatus,
-  absoluteRange: AbsoluteTimeRange
-) => {
   const mounted = useRefMounted();
   // State
   const [languageProviderInitialized, setLanguageProviderInitilized] = useState(false);
@@ -35,8 +30,7 @@ export const useLokiSyntax = (
     languageProvider,
     languageProviderInitialized,
     activeOption,
-    absoluteRange,
+    absoluteRange
-    datasourceStatus
   );
 
   // Async

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

@@ -121,7 +121,7 @@ export class LokiDatasource extends DataSourceApi<LokiQuery, LokiOptions> {
 
   processError = (err: any, target: any): DataQueryError => {
     const error: DataQueryError = {
-      message: 'Unknown error during query transaction. Please check JS console logs.',
+      message: (err && err.statusText) || 'Unknown error during query transaction. Please check JS console logs.',
       refId: target.refId,
     };
 

public/app/plugins/datasource/prometheus/components/PromQueryEditor.tsx

@@ -2,7 +2,7 @@ import _ from 'lodash';
 import React, { PureComponent } from 'react';
 
 // Types
-import { FormLabel, Select, Switch, QueryEditorProps, DataSourceStatus } from '@grafana/ui';
+import { FormLabel, Select, Switch, QueryEditorProps } from '@grafana/ui';
 import { SelectableValue } from '@grafana/data';
 
 import { PrometheusDatasource } from '../datasource';
@@ -104,7 +104,6 @@ export class PromQueryEditor extends PureComponent<Props, State> {
           onChange={this.onFieldChange}
           history={[]}
           data={data}
-          datasourceStatus={DataSourceStatus.Connected} // TODO: replace with real DataSourceStatus
         />
 
         <div className="gf-form-inline">

public/app/plugins/datasource/prometheus/components/PromQueryField.tsx

@@ -13,7 +13,7 @@ import BracesPlugin from 'app/features/explore/slate-plugins/braces';
 import QueryField, { TypeaheadInput } from 'app/features/explore/QueryField';
 import { PromQuery, PromContext, PromOptions } from '../types';
 import { CancelablePromise, makePromiseCancelable } from 'app/core/utils/CancelablePromise';
-import { ExploreQueryFieldProps, DataSourceStatus, QueryHint, DOMUtil } from '@grafana/ui';
+import { ExploreQueryFieldProps, QueryHint, DOMUtil } from '@grafana/ui';
 import { isDataFrame, toLegacyResponseData } from '@grafana/data';
 import { PrometheusDatasource } from '../datasource';
 import PromQlLanguageProvider from '../language_provider';
@@ -24,13 +24,13 @@ const METRIC_MARK = 'metric';
 const PRISM_SYNTAX = 'promql';
 export const RECORDING_RULES_GROUP = '__recording_rules__';
 
-function getChooserText(hasSyntax: boolean, datasourceStatus: DataSourceStatus) {
+function getChooserText(hasSyntax: boolean, metrics: string[]) {
-  if (datasourceStatus === DataSourceStatus.Disconnected) {
-    return '(Disconnected)';
-  }
   if (!hasSyntax) {
     return 'Loading metrics...';
   }
+  if (metrics && metrics.length === 0) {
+    return '(No metrics found)';
+  }
   return 'Metrics';
 }
 
@@ -159,21 +159,6 @@ class PromQueryField extends React.PureComponent<PromQueryFieldProps, PromQueryF
     if (data && prevProps.data && prevProps.data.series !== data.series) {
       this.refreshHint();
     }
-
-    const reconnected =
-      prevProps.datasourceStatus === DataSourceStatus.Disconnected &&
-      this.props.datasourceStatus === DataSourceStatus.Connected;
-    if (!reconnected) {
-      return;
-    }
-
-    if (this.languageProviderInitializationPromise) {
-      this.languageProviderInitializationPromise.cancel();
-    }
-
-    if (this.languageProvider) {
-      this.refreshMetrics(makePromiseCancelable(this.languageProvider.fetchMetrics()));
-    }
   }
 
   refreshHint = () => {
@@ -291,11 +276,11 @@ class PromQueryField extends React.PureComponent<PromQueryFieldProps, PromQueryF
   };
 
   render() {
-    const { data, query, datasourceStatus } = this.props;
+    const { data, query } = this.props;
     const { metricsOptions, syntaxLoaded, hint } = this.state;
     const cleanText = this.languageProvider ? this.languageProvider.cleanText : undefined;
-    const chooserText = getChooserText(syntaxLoaded, datasourceStatus);
+    const chooserText = getChooserText(syntaxLoaded, metricsOptions);
-    const buttonDisabled = !syntaxLoaded || datasourceStatus === DataSourceStatus.Disconnected;
+    const buttonDisabled = !(syntaxLoaded && metricsOptions && metricsOptions.length > 0);
     const showError = data && data.error && data.error.refId === query.refId;
 
     return (

public/app/plugins/datasource/prometheus/components/__snapshots__/PromQueryEditor.test.tsx.snap

@@ -9,7 +9,6 @@ exports[`Render PromQueryEditor with basic options should render 1`] = `
         "getPrometheusTime": [MockFunction],
       }
     }
-    datasourceStatus={0}
     history={Array []}
     onChange={[Function]}
     onRunQuery={[Function]}

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

@@ -447,7 +447,7 @@ export class PrometheusDatasource extends DataSourceApi<PromQuery, PromOptions>
 
   handleErrors = (err: any, target: PromQuery) => {
     const error: DataQueryError = {
-      message: 'Unknown error during query transaction. Please check JS console logs.',
+      message: (err && err.statusText) || 'Unknown error during query transaction. Please check JS console logs.',
       refId: target.refId,
     };
 

public/app/types/explore.ts

@@ -161,10 +161,6 @@ export interface ExploreItemState {
    * Current data source name or null if default
    */
   requestedDatasourceName: string | null;
-  /**
-   * Error to be shown when datasource loading or testing failed.
-   */
-  datasourceError: string;
   /**
    * True if the datasource is loading. `null` if the loading has not started yet.
    */