Merge pull request #14147 from grafana/davkal/explore-data-query

Explore: Introduce DataQuery interface for query handling

public/app/core/utils/explore.test.ts

@@ -1,5 +1,13 @@
-import { DEFAULT_RANGE, serializeStateToUrlParam, parseUrlState } from './explore';
+import {
+  DEFAULT_RANGE,
+  serializeStateToUrlParam,
+  parseUrlState,
+  updateHistory,
+  clearHistory,
+  hasNonEmptyQuery,
+} from './explore';
 import { ExploreState } from 'app/types/explore';
+import store from 'app/core/store';
 
 const DEFAULT_EXPLORE_STATE: ExploreState = {
   datasource: null,
@@ -10,7 +18,7 @@ const DEFAULT_EXPLORE_STATE: ExploreState = {
   exploreDatasources: [],
   graphRange: DEFAULT_RANGE,
   history: [],
-  queries: [],
+  initialQueries: [],
   queryTransactions: [],
   range: DEFAULT_RANGE,
   showingGraph: true,
@@ -33,10 +41,10 @@ describe('state functions', () => {
 
     it('returns a valid Explore state from URL parameter', () => {
       const paramValue =
-        '%7B"datasource":"Local","queries":%5B%7B"query":"metric"%7D%5D,"range":%7B"from":"now-1h","to":"now"%7D%7D';
+        '%7B"datasource":"Local","queries":%5B%7B"expr":"metric"%7D%5D,"range":%7B"from":"now-1h","to":"now"%7D%7D';
       expect(parseUrlState(paramValue)).toMatchObject({
         datasource: 'Local',
-        queries: [{ query: 'metric' }],
+        queries: [{ expr: 'metric' }],
         range: {
           from: 'now-1h',
           to: 'now',
@@ -45,10 +53,10 @@ describe('state functions', () => {
     });
 
     it('returns a valid Explore state from a compact URL parameter', () => {
-      const paramValue = '%5B"now-1h","now","Local","metric"%5D';
+      const paramValue = '%5B"now-1h","now","Local",%7B"expr":"metric"%7D%5D';
       expect(parseUrlState(paramValue)).toMatchObject({
         datasource: 'Local',
-        queries: [{ query: 'metric' }],
+        queries: [{ expr: 'metric' }],
         range: {
           from: 'now-1h',
           to: 'now',
@@ -66,18 +74,20 @@ describe('state functions', () => {
           from: 'now-5h',
           to: 'now',
         },
-        queries: [
+        initialQueries: [
           {
-            query: 'metric{test="a/b"}',
+            refId: '1',
+            expr: 'metric{test="a/b"}',
           },
           {
-            query: 'super{foo="x/z"}',
+            refId: '2',
+            expr: 'super{foo="x/z"}',
           },
         ],
       };
       expect(serializeStateToUrlParam(state)).toBe(
-        '{"datasource":"foo","queries":[{"query":"metric{test=\\"a/b\\"}"},' +
+        '{"datasource":"foo","queries":[{"expr":"metric{test=\\"a/b\\"}"},' +
-          '{"query":"super{foo=\\"x/z\\"}"}],"range":{"from":"now-5h","to":"now"}}'
+          '{"expr":"super{foo=\\"x/z\\"}"}],"range":{"from":"now-5h","to":"now"}}'
       );
     });
 
@@ -89,17 +99,19 @@ describe('state functions', () => {
           from: 'now-5h',
           to: 'now',
         },
-        queries: [
+        initialQueries: [
           {
-            query: 'metric{test="a/b"}',
+            refId: '1',
+            expr: 'metric{test="a/b"}',
           },
           {
-            query: 'super{foo="x/z"}',
+            refId: '2',
+            expr: 'super{foo="x/z"}',
           },
         ],
       };
       expect(serializeStateToUrlParam(state, true)).toBe(
-        '["now-5h","now","foo","metric{test=\\"a/b\\"}","super{foo=\\"x/z\\"}"]'
+        '["now-5h","now","foo",{"expr":"metric{test=\\"a/b\\"}"},{"expr":"super{foo=\\"x/z\\"}"}]'
       );
     });
   });
@@ -113,12 +125,14 @@ describe('state functions', () => {
           from: 'now - 5h',
           to: 'now',
         },
-        queries: [
+        initialQueries: [
           {
-            query: 'metric{test="a/b"}',
+            refId: '1',
+            expr: 'metric{test="a/b"}',
           },
           {
-            query: 'super{foo="x/z"}',
+            refId: '2',
+            expr: 'super{foo="x/z"}',
           },
         ],
       };
@@ -126,14 +140,50 @@ describe('state functions', () => {
       const parsed = parseUrlState(serialized);
 
       // Account for datasource vs datasourceName
-      const { datasource, ...rest } = parsed;
+      const { datasource, queries, ...rest } = parsed;
-      const sameState = {
+      const resultState = {
         ...rest,
         datasource: DEFAULT_EXPLORE_STATE.datasource,
         datasourceName: datasource,
+        initialQueries: queries,
       };
 
-      expect(state).toMatchObject(sameState);
+      expect(state).toMatchObject(resultState);
     });
   });
 });
+
+describe('updateHistory()', () => {
+  const datasourceId = 'myDatasource';
+  const key = `grafana.explore.history.${datasourceId}`;
+
+  beforeEach(() => {
+    clearHistory(datasourceId);
+    expect(store.exists(key)).toBeFalsy();
+  });
+
+  test('should save history item to localStorage', () => {
+    const expected = [
+      {
+        query: { refId: '1', expr: 'metric' },
+      },
+    ];
+    expect(updateHistory([], datasourceId, [{ refId: '1', expr: 'metric' }])).toMatchObject(expected);
+    expect(store.exists(key)).toBeTruthy();
+    expect(store.getObject(key)).toMatchObject(expected);
+  });
+});
+
+describe('hasNonEmptyQuery', () => {
+  test('should return true if one query is non-empty', () => {
+    expect(hasNonEmptyQuery([{ refId: '1', key: '2', expr: 'foo' }])).toBeTruthy();
+  });
+
+  test('should return false if query is empty', () => {
+    expect(hasNonEmptyQuery([{ refId: '1', key: '2' }])).toBeFalsy();
+  });
+
+  test('should return false if no queries exist', () => {
+    expect(hasNonEmptyQuery([])).toBeFalsy();
+  });
+});

public/app/core/utils/explore.ts

@@ -1,11 +1,20 @@
 import { renderUrl } from 'app/core/utils/url';
-import { ExploreState, ExploreUrlState } from 'app/types/explore';
+import { ExploreState, ExploreUrlState, HistoryItem } from 'app/types/explore';
+import { DataQuery, RawTimeRange } from 'app/types/series';
+
+import kbn from 'app/core/utils/kbn';
+import colors from 'app/core/utils/colors';
+import TimeSeries from 'app/core/time_series2';
+import { parse as parseDate } from 'app/core/utils/datemath';
+import store from 'app/core/store';
 
 export const DEFAULT_RANGE = {
   from: 'now-6h',
   to: 'now',
 };
 
+const MAX_HISTORY_ITEMS = 100;
+
 /**
  * Returns an Explore-URL that contains a panel's queries and the dashboard time range.
  *
@@ -23,7 +32,7 @@ export async function getExploreUrl(
   timeSrv: any
 ) {
   let exploreDatasource = panelDatasource;
-  let exploreTargets = panelTargets;
+  let exploreTargets: DataQuery[] = panelTargets;
   let url;
 
   // Mixed datasources need to choose only one datasource
@@ -57,6 +66,8 @@ export async function getExploreUrl(
   return url;
 }
 
+const clearQueryKeys: ((query: DataQuery) => object) = ({ key, refId, ...rest }) => rest;
+
 export function parseUrlState(initial: string | undefined): ExploreUrlState {
   if (initial) {
     try {
@@ -70,7 +81,7 @@ export function parseUrlState(initial: string | undefined): ExploreUrlState {
           to: parsed[1],
         };
         const datasource = parsed[2];
-        const queries = parsed.slice(3).map(query => ({ query }));
+        const queries = parsed.slice(3);
         return { datasource, queries, range };
       }
       return parsed;
@@ -84,16 +95,97 @@ export function parseUrlState(initial: string | undefined): ExploreUrlState {
 export function serializeStateToUrlParam(state: ExploreState, compact?: boolean): string {
   const urlState: ExploreUrlState = {
     datasource: state.datasourceName,
-    queries: state.queries.map(q => ({ query: q.query })),
+    queries: state.initialQueries.map(clearQueryKeys),
     range: state.range,
   };
   if (compact) {
-    return JSON.stringify([
+    return JSON.stringify([urlState.range.from, urlState.range.to, urlState.datasource, ...urlState.queries]);
-      urlState.range.from,
-      urlState.range.to,
-      urlState.datasource,
-      ...urlState.queries.map(q => q.query),
-    ]);
   }
   return JSON.stringify(urlState);
 }
+
+export function generateKey(index = 0): string {
+  return `Q-${Date.now()}-${Math.random()}-${index}`;
+}
+
+export function generateRefId(index = 0): string {
+  return `${index + 1}`;
+}
+
+export function generateQueryKeys(index = 0): { refId: string; key: string } {
+  return { refId: generateRefId(index), key: generateKey(index) };
+}
+
+/**
+ * Ensure at least one target exists and that targets have the necessary keys
+ */
+export function ensureQueries(queries?: DataQuery[]): DataQuery[] {
+  if (queries && typeof queries === 'object' && queries.length > 0) {
+    return queries.map((query, i) => ({ ...query, ...generateQueryKeys(i) }));
+  }
+  return [{ ...generateQueryKeys() }];
+}
+
+/**
+ * A target is non-empty when it has keys other than refId and key.
+ */
+export function hasNonEmptyQuery(queries: DataQuery[]): boolean {
+  return queries.some(query => Object.keys(query).length > 2);
+}
+
+export function getIntervals(
+  range: RawTimeRange,
+  datasource,
+  resolution: number
+): { interval: string; intervalMs: number } {
+  if (!datasource || !resolution) {
+    return { interval: '1s', intervalMs: 1000 };
+  }
+  const absoluteRange: RawTimeRange = {
+    from: parseDate(range.from, false),
+    to: parseDate(range.to, true),
+  };
+  return kbn.calculateInterval(absoluteRange, resolution, datasource.interval);
+}
+
+export function makeTimeSeriesList(dataList) {
+  return dataList.map((seriesData, index) => {
+    const datapoints = seriesData.datapoints || [];
+    const alias = seriesData.target;
+    const colorIndex = index % colors.length;
+    const color = colors[colorIndex];
+
+    const series = new TimeSeries({
+      datapoints,
+      alias,
+      color,
+      unit: seriesData.unit,
+    });
+
+    return series;
+  });
+}
+
+/**
+ * Update the query history. Side-effect: store history in local storage
+ */
+export function updateHistory(history: HistoryItem[], datasourceId: string, queries: DataQuery[]): HistoryItem[] {
+  const ts = Date.now();
+  queries.forEach(query => {
+    history = [{ query, ts }, ...history];
+  });
+
+  if (history.length > MAX_HISTORY_ITEMS) {
+    history = history.slice(0, MAX_HISTORY_ITEMS);
+  }
+
+  // Combine all queries of a datasource type into one history
+  const historyKey = `grafana.explore.history.${datasourceId}`;
+  store.setObject(historyKey, history);
+  return history;
+}
+
+export function clearHistory(datasourceId: string) {
+  const historyKey = `grafana.explore.history.${datasourceId}`;
+  store.delete(historyKey);
+}

public/app/features/explore/Explore.tsx

@@ -4,14 +4,26 @@ import Select from 'react-select';
 import _ from 'lodash';
 
 import { DataSource } from 'app/types/datasources';
-import { ExploreState, ExploreUrlState, HistoryItem, Query, QueryTransaction, ResultType } from 'app/types/explore';
+import {
+  ExploreState,
+  ExploreUrlState,
+  QueryTransaction,
+  ResultType,
+  QueryHintGetter,
+  QueryHint,
+} from 'app/types/explore';
 import { RawTimeRange, DataQuery } from 'app/types/series';
-import kbn from 'app/core/utils/kbn';
-import colors from 'app/core/utils/colors';
 import store from 'app/core/store';
-import TimeSeries from 'app/core/time_series2';
+import {
-import { parse as parseDate } from 'app/core/utils/datemath';
+  DEFAULT_RANGE,
-import { DEFAULT_RANGE } from 'app/core/utils/explore';
+  ensureQueries,
+  getIntervals,
+  generateKey,
+  generateQueryKeys,
+  hasNonEmptyQuery,
+  makeTimeSeriesList,
+  updateHistory,
+} from 'app/core/utils/explore';
 import ResetStyles from 'app/core/components/Picker/ResetStyles';
 import PickerOption from 'app/core/components/Picker/PickerOption';
 import IndicatorsContainer from 'app/core/components/Picker/IndicatorsContainer';
@@ -26,57 +38,6 @@ import Logs from './Logs';
 import Table from './Table';
 import ErrorBoundary from './ErrorBoundary';
 import TimePicker from './TimePicker';
-import { ensureQueries, generateQueryKey, hasQuery } from './utils/query';
-
-const MAX_HISTORY_ITEMS = 100;
-
-function getIntervals(range: RawTimeRange, datasource, resolution: number): { interval: string; intervalMs: number } {
-  if (!datasource || !resolution) {
-    return { interval: '1s', intervalMs: 1000 };
-  }
-  const absoluteRange: RawTimeRange = {
-    from: parseDate(range.from, false),
-    to: parseDate(range.to, true),
-  };
-  return kbn.calculateInterval(absoluteRange, resolution, datasource.interval);
-}
-
-function makeTimeSeriesList(dataList, options) {
-  return dataList.map((seriesData, index) => {
-    const datapoints = seriesData.datapoints || [];
-    const alias = seriesData.target;
-    const colorIndex = index % colors.length;
-    const color = colors[colorIndex];
-
-    const series = new TimeSeries({
-      datapoints,
-      alias,
-      color,
-      unit: seriesData.unit,
-    });
-
-    return series;
-  });
-}
-
-/**
- * Update the query history. Side-effect: store history in local storage
- */
-function updateHistory(history: HistoryItem[], datasourceId: string, queries: string[]): HistoryItem[] {
-  const ts = Date.now();
-  queries.forEach(query => {
-    history = [{ query, ts }, ...history];
-  });
-
-  if (history.length > MAX_HISTORY_ITEMS) {
-    history = history.slice(0, MAX_HISTORY_ITEMS);
-  }
-
-  // Combine all queries of a datasource type into one history
-  const historyKey = `grafana.explore.history.${datasourceId}`;
-  store.setObject(historyKey, history);
-  return history;
-}
 
 interface ExploreProps {
   datasourceSrv: DatasourceSrv;
@@ -89,14 +50,49 @@ interface ExploreProps {
   urlState: ExploreUrlState;
 }
 
+/**
+ * Explore provides an area for quick query iteration for a given datasource.
+ * Once a datasource is selected it populates the query section at the top.
+ * When queries are run, their results are being displayed in the main section.
+ * The datasource determines what kind of query editor it brings, and what kind
+ * of results viewers it supports.
+ *
+ * QUERY HANDLING
+ *
+ * TLDR: to not re-render Explore during edits, query editing is not "controlled"
+ * in a React sense: values need to be pushed down via `initialQueries`, while
+ * edits travel up via `this.modifiedQueries`.
+ *
+ * By default the query rows start without prior state: `initialQueries` will
+ * contain one empty DataQuery. While the user modifies the DataQuery, the
+ * modifications are being tracked in `this.modifiedQueries`, which need to be
+ * used whenever a query is sent to the datasource to reflect what the user sees
+ * on the screen. Query rows can be initialized or reset using `initialQueries`,
+ * by giving the respective row a new key. This wipes the old row and its state.
+ * This property is also used to govern how many query rows there are (minimum 1).
+ *
+ * This flow makes sure that a query row can be arbitrarily complex without the
+ * fear of being wiped or re-initialized via props. The query row is free to keep
+ * its own state while the user edits or builds a query. Valid queries can be sent
+ * up to Explore via the `onChangeQuery` prop.
+ *
+ * DATASOURCE REQUESTS
+ *
+ * A click on Run Query creates transactions for all DataQueries for all expanded
+ * result viewers. New runs are discarding previous runs. Upon completion a transaction
+ * saves the result. The result viewers construct their data from the currently existing
+ * transactions.
+ *
+ * The result viewers determine some of the query options sent to the datasource, e.g.,
+ * `format`, to indicate eventual transformations by the datasources' result transformers.
+ */
 export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
   el: any;
   /**
    * Current query expressions of the rows including their modifications, used for running queries.
    * Not kept in component state to prevent edit-render roundtrips.
-   * TODO: make this generic (other datasources might not have string representations of current query state)
    */
-  queryExpressions: string[];
+  modifiedQueries: DataQuery[];
   /**
    * Local ID cache to compare requested vs selected datasource
    */
@@ -105,11 +101,11 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
   constructor(props) {
     super(props);
     const splitState: ExploreState = props.splitState;
-    let initialQueries: Query[];
+    let initialQueries: DataQuery[];
     if (splitState) {
       // Split state overrides everything
       this.state = splitState;
-      initialQueries = splitState.queries;
+      initialQueries = splitState.initialQueries;
     } else {
       const { datasource, queries, range } = props.urlState as ExploreUrlState;
       initialQueries = ensureQueries(queries);
@@ -122,8 +118,8 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
         datasourceName: datasource,
         exploreDatasources: [],
         graphRange: initialRange,
+        initialQueries,
         history: [],
-        queries: initialQueries,
         queryTransactions: [],
         range: initialRange,
         showingGraph: true,
@@ -135,7 +131,7 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
         supportsTable: null,
       };
     }
-    this.queryExpressions = initialQueries.map(q => q.query);
+    this.modifiedQueries = initialQueries.slice();
   }
 
   async componentDidMount() {
@@ -198,32 +194,26 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
     }
 
     // Check if queries can be imported from previously selected datasource
-    let queryExpressions = this.queryExpressions;
+    let modifiedQueries = this.modifiedQueries;
     if (origin) {
       if (origin.meta.id === datasource.meta.id) {
         // Keep same queries if same type of datasource
-        queryExpressions = [...this.queryExpressions];
+        modifiedQueries = [...this.modifiedQueries];
       } else if (datasource.importQueries) {
-        // Datasource-specific importers, wrapping to satisfy interface
+        // Datasource-specific importers
-        const wrappedQueries: DataQuery[] = this.queryExpressions.map((query, index) => ({
+        modifiedQueries = await datasource.importQueries(this.modifiedQueries, origin.meta);
-          refId: String(index),
-          expr: query,
-        }));
-        const modifiedQueries: DataQuery[] = await datasource.importQueries(wrappedQueries, origin.meta);
-        queryExpressions = modifiedQueries.map(({ expr }) => expr);
       } else {
         // Default is blank queries
-        queryExpressions = this.queryExpressions.map(() => '');
+        modifiedQueries = ensureQueries();
       }
     }
 
     // Reset edit state with new queries
-    const nextQueries = this.state.queries.map((q, i) => ({
+    const nextQueries = this.state.initialQueries.map((q, i) => ({
-      ...q,
+      ...modifiedQueries[i],
-      key: generateQueryKey(i),
+      ...generateQueryKeys(i),
-      query: queryExpressions[i],
     }));
-    this.queryExpressions = queryExpressions;
+    this.modifiedQueries = modifiedQueries;
 
     // Custom components
     const StartPage = datasource.pluginExports.ExploreStartPage;
@@ -239,7 +229,7 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
         supportsTable,
         datasourceLoading: false,
         datasourceName: datasource.name,
-        queries: nextQueries,
+        initialQueries: nextQueries,
         showingStartPage: Boolean(StartPage),
       },
       () => {
@@ -256,16 +246,15 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
 
   onAddQueryRow = index => {
     // Local cache
-    this.queryExpressions[index + 1] = '';
+    this.modifiedQueries[index + 1] = { ...generateQueryKeys(index + 1) };
 
     this.setState(state => {
-      const { queries, queryTransactions } = state;
+      const { initialQueries, queryTransactions } = state;
 
-      // Add row by generating new react key
       const nextQueries = [
-        ...queries.slice(0, index + 1),
+        ...initialQueries.slice(0, index + 1),
-        { query: '', key: generateQueryKey() },
+        { ...this.modifiedQueries[index + 1] },
-        ...queries.slice(index + 1),
+        ...initialQueries.slice(index + 1),
       ];
 
       // Ongoing transactions need to update their row indices
@@ -279,7 +268,7 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
         return qt;
       });
 
-      return { queries: nextQueries, queryTransactions: nextQueryTransactions };
+      return { initialQueries: nextQueries, queryTransactions: nextQueryTransactions };
     });
   };
 
@@ -296,26 +285,32 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
     this.setDatasource(datasource as any, origin);
   };
 
-  onChangeQuery = (value: string, index: number, override?: boolean) => {
+  onChangeQuery = (value: DataQuery, index: number, override?: boolean) => {
+    // Null value means reset
+    if (value === null) {
+      value = { ...generateQueryKeys(index) };
+    }
+
     // Keep current value in local cache
-    this.queryExpressions[index] = value;
+    this.modifiedQueries[index] = value;
 
     if (override) {
       this.setState(state => {
-        // Replace query row
+        // Replace query row by injecting new key
-        const { queries, queryTransactions } = state;
+        const { initialQueries, queryTransactions } = state;
-        const nextQuery: Query = {
+        const query: DataQuery = {
-          key: generateQueryKey(index),
+          ...value,
-          query: value,
+          ...generateQueryKeys(index),
         };
-        const nextQueries = [...queries];
+        const nextQueries = [...initialQueries];
-        nextQueries[index] = nextQuery;
+        nextQueries[index] = query;
+        this.modifiedQueries = [...nextQueries];
 
         // Discard ongoing transaction related to row query
         const nextQueryTransactions = queryTransactions.filter(qt => qt.rowIndex !== index);
 
         return {
-          queries: nextQueries,
+          initialQueries: nextQueries,
           queryTransactions: nextQueryTransactions,
         };
       }, this.onSubmit);
@@ -330,10 +325,10 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
   };
 
   onClickClear = () => {
-    this.queryExpressions = [''];
+    this.modifiedQueries = ensureQueries();
     this.setState(
       prevState => ({
-        queries: ensureQueries(),
+        initialQueries: [...this.modifiedQueries],
         queryTransactions: [],
         showingStartPage: Boolean(prevState.StartPage),
       }),
@@ -387,10 +382,10 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
   };
 
   // Use this in help pages to set page to a single query
-  onClickQuery = query => {
+  onClickExample = (query: DataQuery) => {
-    const nextQueries = [{ query, key: generateQueryKey() }];
+    const nextQueries = [{ ...query, ...generateQueryKeys() }];
-    this.queryExpressions = nextQueries.map(q => q.query);
+    this.modifiedQueries = [...nextQueries];
-    this.setState({ queries: nextQueries }, this.onSubmit);
+    this.setState({ initialQueries: nextQueries }, this.onSubmit);
   };
 
   onClickSplit = () => {
@@ -430,28 +425,28 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
       const preventSubmit = action.preventSubmit;
       this.setState(
         state => {
-          const { queries, queryTransactions } = state;
+          const { initialQueries, queryTransactions } = state;
-          let nextQueries;
+          let nextQueries: DataQuery[];
           let nextQueryTransactions;
           if (index === undefined) {
             // Modify all queries
-            nextQueries = queries.map((q, i) => ({
+            nextQueries = initialQueries.map((query, i) => ({
-              key: generateQueryKey(i),
+              ...datasource.modifyQuery(this.modifiedQueries[i], action),
-              query: datasource.modifyQuery(this.queryExpressions[i], action),
+              ...generateQueryKeys(i),
             }));
             // Discard all ongoing transactions
             nextQueryTransactions = [];
           } else {
             // Modify query only at index
-            nextQueries = queries.map((q, i) => {
+            nextQueries = initialQueries.map((query, i) => {
               // Synchronise all queries with local query cache to ensure consistency
-              q.query = this.queryExpressions[i];
+              // TODO still needed?
               return i === index
                 ? {
-                    key: generateQueryKey(index),
+                    ...datasource.modifyQuery(this.modifiedQueries[i], action),
-                    query: datasource.modifyQuery(q.query, action),
+                    ...generateQueryKeys(i),
                   }
-                : q;
+                : query;
             });
             nextQueryTransactions = queryTransactions
               // Consume the hint corresponding to the action
@@ -464,9 +459,9 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
               // Preserve previous row query transaction to keep results visible if next query is incomplete
               .filter(qt => preventSubmit || qt.rowIndex !== index);
           }
-          this.queryExpressions = nextQueries.map(q => q.query);
+          this.modifiedQueries = [...nextQueries];
           return {
-            queries: nextQueries,
+            initialQueries: nextQueries,
             queryTransactions: nextQueryTransactions,
           };
         },
@@ -478,22 +473,22 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
 
   onRemoveQueryRow = index => {
     // Remove from local cache
-    this.queryExpressions = [...this.queryExpressions.slice(0, index), ...this.queryExpressions.slice(index + 1)];
+    this.modifiedQueries = [...this.modifiedQueries.slice(0, index), ...this.modifiedQueries.slice(index + 1)];
 
     this.setState(
       state => {
-        const { queries, queryTransactions } = state;
+        const { initialQueries, queryTransactions } = state;
-        if (queries.length <= 1) {
+        if (initialQueries.length <= 1) {
           return null;
         }
         // Remove row from react state
-        const nextQueries = [...queries.slice(0, index), ...queries.slice(index + 1)];
+        const nextQueries = [...initialQueries.slice(0, index), ...initialQueries.slice(index + 1)];
 
         // Discard transactions related to row query
         const nextQueryTransactions = queryTransactions.filter(qt => qt.rowIndex !== index);
 
         return {
-          queries: nextQueries,
+          initialQueries: nextQueries,
           queryTransactions: nextQueryTransactions,
         };
       },
@@ -503,52 +498,68 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
 
   onSubmit = () => {
     const { showingLogs, showingGraph, showingTable, supportsGraph, supportsLogs, supportsTable } = this.state;
+    // Keep table queries first since they need to return quickly
     if (showingTable && supportsTable) {
-      this.runTableQuery();
+      this.runQueries(
+        'Table',
+        {
+          format: 'table',
+          instant: true,
+          valueWithRefId: true,
+        },
+        data => data[0]
+      );
     }
     if (showingGraph && supportsGraph) {
-      this.runGraphQueries();
+      this.runQueries(
+        'Graph',
+        {
+          format: 'time_series',
+          instant: false,
+        },
+        makeTimeSeriesList
+      );
     }
     if (showingLogs && supportsLogs) {
-      this.runLogsQuery();
+      this.runQueries('Logs', { format: 'logs' });
     }
     this.saveState();
   };
 
-  buildQueryOptions(
+  buildQueryOptions(query: DataQuery, queryOptions: { format: string; hinting?: boolean; instant?: boolean }) {
-    query: string,
-    rowIndex: number,
-    targetOptions: { format: string; hinting?: boolean; instant?: boolean }
-  ) {
     const { datasource, range } = this.state;
     const { interval, intervalMs } = getIntervals(range, datasource, this.el.offsetWidth);
-    const targets = [
+
+    const configuredQueries = [
       {
-        ...targetOptions,
+        ...queryOptions,
-        // Target identifier is needed for table transformations
+        ...query,
-        refId: rowIndex + 1,
-        expr: query,
       },
     ];
 
     // Clone range for query request
     const queryRange: RawTimeRange = { ...range };
 
+    // Datasource is using `panelId + query.refId` for cancellation logic.
+    // Using `format` here because it relates to the view panel that the request is for.
+    const panelId = queryOptions.format;
+
     return {
       interval,
       intervalMs,
-      targets,
+      panelId,
+      targets: configuredQueries, // Datasources rely on DataQueries being passed under the targets key.
       range: queryRange,
     };
   }
 
-  startQueryTransaction(query: string, rowIndex: number, resultType: ResultType, options: any): QueryTransaction {
+  startQueryTransaction(query: DataQuery, rowIndex: number, resultType: ResultType, options: any): QueryTransaction {
-    const queryOptions = this.buildQueryOptions(query, rowIndex, options);
+    const queryOptions = this.buildQueryOptions(query, options);
     const transaction: QueryTransaction = {
       query,
       resultType,
       rowIndex,
-      id: generateQueryKey(),
+      id: generateKey(), // reusing for unique ID
       done: false,
       latency: 0,
       options: queryOptions,
@@ -578,7 +589,7 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
     transactionId: string,
     result: any,
     latency: number,
-    queries: string[],
+    queries: DataQuery[],
     datasourceId: string
   ) {
     const { datasource } = this.state;
@@ -597,8 +608,8 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
       }
 
       // Get query hints
-      let hints;
+      let hints: QueryHint[];
-      if (datasource.getQueryHints) {
+      if (datasource.getQueryHints as QueryHintGetter) {
         hints = datasource.getQueryHints(transaction.query, result);
       }
 
@@ -634,7 +645,7 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
 
   failQueryTransaction(transactionId: string, response: any, datasourceId: string) {
     const { datasource } = this.state;
-    if (datasource.meta.id !== datasourceId) {
+    if (datasource.meta.id !== datasourceId || response.cancelled) {
       // Navigated away, queries did not matter
       return;
     }
@@ -678,88 +689,25 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
     });
   }
 
-  async runGraphQueries() {
+  async runQueries(resultType: ResultType, queryOptions: any, resultGetter?: any) {
-    const queries = [...this.queryExpressions];
+    const queries = [...this.modifiedQueries];
-    if (!hasQuery(queries)) {
+    if (!hasNonEmptyQuery(queries)) {
       return;
     }
     const { datasource } = this.state;
     const datasourceId = datasource.meta.id;
     // Run all queries concurrently
     queries.forEach(async (query, rowIndex) => {
-      if (query) {
+      const transaction = this.startQueryTransaction(query, rowIndex, resultType, queryOptions);
-        const transaction = this.startQueryTransaction(query, rowIndex, 'Graph', {
+      try {
-          format: 'time_series',
+        const now = Date.now();
-          instant: false,
+        const res = await datasource.query(transaction.options);
-        });
+        const latency = Date.now() - now;
-        try {
+        const results = resultGetter ? resultGetter(res.data) : res.data;
-          const now = Date.now();
+        this.completeQueryTransaction(transaction.id, results, latency, queries, datasourceId);
-          const res = await datasource.query(transaction.options);
+        this.setState({ graphRange: transaction.options.range });
-          const latency = Date.now() - now;
+      } catch (response) {
-          const results = makeTimeSeriesList(res.data, transaction.options);
+        this.failQueryTransaction(transaction.id, response, datasourceId);
-          this.completeQueryTransaction(transaction.id, results, latency, queries, datasourceId);
-          this.setState({ graphRange: transaction.options.range });
-        } catch (response) {
-          this.failQueryTransaction(transaction.id, response, datasourceId);
-        }
-      } else {
-        this.discardTransactions(rowIndex);
-      }
-    });
-  }
-
-  async runTableQuery() {
-    const queries = [...this.queryExpressions];
-    if (!hasQuery(queries)) {
-      return;
-    }
-    const { datasource } = this.state;
-    const datasourceId = datasource.meta.id;
-    // Run all queries concurrently
-    queries.forEach(async (query, rowIndex) => {
-      if (query) {
-        const transaction = this.startQueryTransaction(query, rowIndex, 'Table', {
-          format: 'table',
-          instant: true,
-          valueWithRefId: true,
-        });
-        try {
-          const now = Date.now();
-          const res = await datasource.query(transaction.options);
-          const latency = Date.now() - now;
-          const results = res.data[0];
-          this.completeQueryTransaction(transaction.id, results, latency, queries, datasourceId);
-        } catch (response) {
-          this.failQueryTransaction(transaction.id, response, datasourceId);
-        }
-      } else {
-        this.discardTransactions(rowIndex);
-      }
-    });
-  }
-
-  async runLogsQuery() {
-    const queries = [...this.queryExpressions];
-    if (!hasQuery(queries)) {
-      return;
-    }
-    const { datasource } = this.state;
-    const datasourceId = datasource.meta.id;
-    // Run all queries concurrently
-    queries.forEach(async (query, rowIndex) => {
-      if (query) {
-        const transaction = this.startQueryTransaction(query, rowIndex, 'Logs', { format: 'logs' });
-        try {
-          const now = Date.now();
-          const res = await datasource.query(transaction.options);
-          const latency = Date.now() - now;
-          const results = res.data;
-          this.completeQueryTransaction(transaction.id, results, latency, queries, datasourceId);
-        } catch (response) {
-          this.failQueryTransaction(transaction.id, response, datasourceId);
-        }
-      } else {
-        this.discardTransactions(rowIndex);
       }
     });
   }
@@ -769,7 +717,7 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
     return {
       ...this.state,
       queryTransactions: [],
-      queries: ensureQueries(this.queryExpressions.map(query => ({ query }))),
+      initialQueries: [...this.modifiedQueries],
     };
   }
 
@@ -789,7 +737,7 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
       exploreDatasources,
       graphRange,
       history,
-      queries,
+      initialQueries,
       queryTransactions,
       range,
       showingGraph,
@@ -903,7 +851,7 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
             <QueryRows
               datasource={datasource}
               history={history}
-              queries={queries}
+              initialQueries={initialQueries}
               onAddQueryRow={this.onAddQueryRow}
               onChangeQuery={this.onChangeQuery}
               onClickHintFix={this.onModifyQueries}
@@ -913,7 +861,7 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
             />
             <main className="m-t-2">
               <ErrorBoundary>
-                {showingStartPage && <StartPage onClickQuery={this.onClickQuery} />}
+                {showingStartPage && <StartPage onClickExample={this.onClickExample} />}
                 {!showingStartPage && (
                   <>
                     {supportsGraph && (

public/app/features/explore/QueryField.tsx

@@ -27,14 +27,14 @@ function hasSuggestions(suggestions: CompletionItemGroup[]): boolean {
   return suggestions && suggestions.length > 0;
 }
 
-interface QueryFieldProps {
+export interface QueryFieldProps {
   additionalPlugins?: any[];
   cleanText?: (text: string) => string;
-  initialValue: string | null;
+  initialQuery: string | null;
   onBlur?: () => void;
   onFocus?: () => void;
   onTypeahead?: (typeahead: TypeaheadInput) => TypeaheadOutput;
-  onValueChanged?: (value: Value) => void;
+  onValueChanged?: (value: string) => void;
   onWillApplySuggestion?: (suggestion: string, state: QueryFieldState) => string;
   placeholder?: string;
   portalOrigin?: string;
@@ -60,16 +60,22 @@ export interface TypeaheadInput {
   wrapperNode: Element;
 }
 
+/**
+ * Renders an editor field.
+ * Pass initial value as initialQuery and listen to changes in props.onValueChanged.
+ * This component can only process strings. Internally it uses Slate Value.
+ * Implement props.onTypeahead to use suggestions, see PromQueryField.tsx as an example.
+ */
 export class QueryField extends React.PureComponent<QueryFieldProps, QueryFieldState> {
   menuEl: HTMLElement | null;
   placeholdersBuffer: PlaceholdersBuffer;
   plugins: any[];
   resetTimer: any;
 
-  constructor(props, context) {
+  constructor(props: QueryFieldProps, context) {
     super(props, context);
 
-    this.placeholdersBuffer = new PlaceholdersBuffer(props.initialValue || '');
+    this.placeholdersBuffer = new PlaceholdersBuffer(props.initialQuery || '');
 
     // Base plugins
     this.plugins = [ClearPlugin(), NewlinePlugin(), ...props.additionalPlugins].filter(p => p);
@@ -92,7 +98,7 @@ export class QueryField extends React.PureComponent<QueryFieldProps, QueryFieldS
     clearTimeout(this.resetTimer);
   }
 
-  componentDidUpdate(prevProps, prevState) {
+  componentDidUpdate(prevProps: QueryFieldProps, prevState: QueryFieldState) {
     // Only update menu location when suggestion existence or text/selection changed
     if (
       this.state.value !== prevState.value ||

public/app/features/explore/QueryRows.tsx

@@ -1,10 +1,10 @@
 import React, { PureComponent } from 'react';
 
-import { QueryTransaction, HistoryItem, Query, QueryHint } from 'app/types/explore';
+import { QueryTransaction, HistoryItem, QueryHint } from 'app/types/explore';
 
 import DefaultQueryField from './QueryField';
 import QueryTransactionStatus from './QueryTransactionStatus';
-import { DataSource } from 'app/types';
+import { DataSource, DataQuery } from 'app/types';
 
 function getFirstHintFromTransactions(transactions: QueryTransaction[]): QueryHint {
   const transaction = transactions.find(qt => qt.hints && qt.hints.length > 0);
@@ -16,7 +16,7 @@ function getFirstHintFromTransactions(transactions: QueryTransaction[]): QueryHi
 
 interface QueryRowEventHandlers {
   onAddQueryRow: (index: number) => void;
-  onChangeQuery: (value: string, index: number, override?: boolean) => void;
+  onChangeQuery: (value: DataQuery, index: number, override?: boolean) => void;
   onClickHintFix: (action: object, index?: number) => void;
   onExecuteQuery: () => void;
   onRemoveQueryRow: (index: number) => void;
@@ -32,11 +32,11 @@ interface QueryRowCommonProps {
 type QueryRowProps = QueryRowCommonProps &
   QueryRowEventHandlers & {
     index: number;
-    query: string;
+    initialQuery: DataQuery;
   };
 
 class QueryRow extends PureComponent<QueryRowProps> {
-  onChangeQuery = (value, override?: boolean) => {
+  onChangeQuery = (value: DataQuery, override?: boolean) => {
     const { index, onChangeQuery } = this.props;
     if (onChangeQuery) {
       onChangeQuery(value, index, override);
@@ -51,7 +51,7 @@ class QueryRow extends PureComponent<QueryRowProps> {
   };
 
   onClickClearButton = () => {
-    this.onChangeQuery('', true);
+    this.onChangeQuery(null, true);
   };
 
   onClickHintFix = action => {
@@ -76,7 +76,7 @@ class QueryRow extends PureComponent<QueryRowProps> {
   };
 
   render() {
-    const { datasource, history, query, transactions } = this.props;
+    const { datasource, history, initialQuery, transactions } = this.props;
     const transactionWithError = transactions.find(t => t.error !== undefined);
     const hint = getFirstHintFromTransactions(transactions);
     const queryError = transactionWithError ? transactionWithError.error : null;
@@ -91,7 +91,7 @@ class QueryRow extends PureComponent<QueryRowProps> {
             datasource={datasource}
             error={queryError}
             hint={hint}
-            initialQuery={query}
+            initialQuery={initialQuery}
             history={history}
             onClickHintFix={this.onClickHintFix}
             onPressEnter={this.onPressEnter}
@@ -116,19 +116,19 @@ class QueryRow extends PureComponent<QueryRowProps> {
 
 type QueryRowsProps = QueryRowCommonProps &
   QueryRowEventHandlers & {
-    queries: Query[];
+    initialQueries: DataQuery[];
   };
 
 export default class QueryRows extends PureComponent<QueryRowsProps> {
   render() {
-    const { className = '', queries, transactions, ...handlers } = this.props;
+    const { className = '', initialQueries, transactions, ...handlers } = this.props;
     return (
       <div className={className}>
-        {queries.map((q, index) => (
+        {initialQueries.map((query, index) => (
           <QueryRow
-            key={q.key}
+            key={query.key}
             index={index}
-            query={q.query}
+            initialQuery={query}
             transactions={transactions.filter(t => t.rowIndex === index)}
             {...handlers}
           />

public/app/features/explore/QueryTransactionStatus.tsx

@@ -35,7 +35,9 @@ export default class QueryTransactionStatus extends PureComponent<QueryTransacti
     const { transactions } = this.props;
     return (
       <div className="query-transactions">
-        {transactions.map((t, i) => <QueryTransactionStatusItem key={`${t.query}:${t.resultType}`} transaction={t} />)}
+        {transactions.map((t, i) => (
+          <QueryTransactionStatusItem key={`${t.rowIndex}:${t.resultType}`} transaction={t} />
+        ))}
       </div>
     );
   }

public/app/features/explore/utils/query.ts

@@ -1,16 +0,0 @@
-import { Query } from 'app/types/explore';
-
-export function generateQueryKey(index = 0): string {
-  return `Q-${Date.now()}-${Math.random()}-${index}`;
-}
-
-export function ensureQueries(queries?: Query[]): Query[] {
-  if (queries && typeof queries === 'object' && queries.length > 0 && typeof queries[0].query === 'string') {
-    return queries.map(({ query }, i) => ({ key: generateQueryKey(i), query }));
-  }
-  return [{ key: generateQueryKey(), query: '' }];
-}
-
-export function hasQuery(queries: string[]): boolean {
-  return queries.some(q => Boolean(q));
-}

public/app/plugins/datasource/logging/components/LoggingCheatSheet.tsx

@@ -19,7 +19,10 @@ export default (props: any) => (
     {CHEAT_SHEET_ITEMS.map(item => (
       <div className="cheat-sheet-item" key={item.expression}>
         <div className="cheat-sheet-item__title">{item.title}</div>
-        <div className="cheat-sheet-item__expression" onClick={e => props.onClickQuery(item.expression)}>
+        <div
+          className="cheat-sheet-item__expression"
+          onClick={e => props.onClickExample({ refId: '1', expr: item.expression })}
+        >
           <code>{item.expression}</code>
         </div>
         <div className="cheat-sheet-item__label">{item.label}</div>

public/app/plugins/datasource/logging/components/LoggingQueryField.tsx

@@ -10,7 +10,8 @@ import { TypeaheadOutput } from 'app/types/explore';
 import { getNextCharacter, getPreviousCousin } from 'app/features/explore/utils/dom';
 import BracesPlugin from 'app/features/explore/slate-plugins/braces';
 import RunnerPlugin from 'app/features/explore/slate-plugins/runner';
-import TypeaheadField, { TypeaheadInput, QueryFieldState } from 'app/features/explore/QueryField';
+import QueryField, { TypeaheadInput, QueryFieldState } from 'app/features/explore/QueryField';
+import { DataQuery } from 'app/types';
 
 const PRISM_SYNTAX = 'promql';
 
@@ -53,10 +54,10 @@ interface LoggingQueryFieldProps {
   error?: string | JSX.Element;
   hint?: any;
   history?: any[];
-  initialQuery?: string | null;
+  initialQuery?: DataQuery;
   onClickHintFix?: (action: any) => void;
   onPressEnter?: () => void;
-  onQueryChange?: (value: string, override?: boolean) => void;
+  onQueryChange?: (value: DataQuery, override?: boolean) => void;
 }
 
 interface LoggingQueryFieldState {
@@ -134,9 +135,13 @@ class LoggingQueryField extends React.PureComponent<LoggingQueryFieldProps, Logg
 
   onChangeQuery = (value: string, override?: boolean) => {
     // Send text change to parent
-    const { onQueryChange } = this.props;
+    const { initialQuery, onQueryChange } = this.props;
     if (onQueryChange) {
-      onQueryChange(value, override);
+      const query = {
+        ...initialQuery,
+        expr: value,
+      };
+      onQueryChange(query, override);
     }
   };
 
@@ -196,15 +201,15 @@ class LoggingQueryField extends React.PureComponent<LoggingQueryFieldProps, Logg
           </Cascader>
         </div>
         <div className="prom-query-field-wrapper">
-          <TypeaheadField
+          <QueryField
             additionalPlugins={this.plugins}
             cleanText={cleanText}
-            initialValue={initialQuery}
+            initialQuery={initialQuery.expr}
             onTypeahead={this.onTypeahead}
             onWillApplySuggestion={willApplySuggestion}
             onValueChanged={this.onChangeQuery}
-            placeholder="Enter a PromQL query"
+            placeholder="Enter a Logging query"
-            portalOrigin="prometheus"
+            portalOrigin="logging"
             syntaxLoaded={syntaxLoaded}
           />
           {error ? <div className="prom-query-field-info text-error">{error}</div> : null}

public/app/plugins/datasource/logging/components/LoggingStartPage.tsx

@@ -52,7 +52,7 @@ export default class LoggingStartPage extends PureComponent<any, { active: strin
           </div>
         </div>
         <div className="page-container page-body">
-          {active === 'start' && <LoggingCheatSheet onClickQuery={this.props.onClickQuery} />}
+          {active === 'start' && <LoggingCheatSheet onClickExample={this.props.onClickExample} />}
         </div>
       </div>
     );

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

@@ -7,12 +7,37 @@ describe('Language completion provider', () => {
     metadataRequest: () => ({ data: { data: [] } }),
   };
 
-  it('returns default suggestions on emtpty context', () => {
+  describe('empty query suggestions', () => {
-    const instance = new LanguageProvider(datasource);
+    it('returns default suggestions on emtpty context', () => {
-    const result = instance.provideCompletionItems({ text: '', prefix: '', wrapperClasses: [] });
+      const instance = new LanguageProvider(datasource);
-    expect(result.context).toBeUndefined();
+      const result = instance.provideCompletionItems({ text: '', prefix: '', wrapperClasses: [] });
-    expect(result.refresher).toBeUndefined();
+      expect(result.context).toBeUndefined();
-    expect(result.suggestions.length).toEqual(0);
+      expect(result.refresher).toBeUndefined();
+      expect(result.suggestions.length).toEqual(0);
+    });
+
+    it('returns default suggestions with history on emtpty context when history was provided', () => {
+      const instance = new LanguageProvider(datasource);
+      const value = Plain.deserialize('');
+      const history = [
+        {
+          query: { refId: '1', expr: '{app="foo"}' },
+        },
+      ];
+      const result = instance.provideCompletionItems({ text: '', prefix: '', value, wrapperClasses: [] }, { history });
+      expect(result.context).toBeUndefined();
+      expect(result.refresher).toBeUndefined();
+      expect(result.suggestions).toMatchObject([
+        {
+          label: 'History',
+          items: [
+            {
+              label: '{app="foo"}',
+            },
+          ],
+        },
+      ]);
+    });
   });
 
   describe('label suggestions', () => {

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

@@ -7,6 +7,7 @@ import {
   LanguageProvider,
   TypeaheadInput,
   TypeaheadOutput,
+  HistoryItem,
 } from 'app/types/explore';
 import { parseSelector, labelRegexp, selectorRegexp } from 'app/plugins/datasource/prometheus/language_utils';
 import PromqlSyntax from 'app/plugins/datasource/prometheus/promql';
@@ -19,9 +20,9 @@ const HISTORY_COUNT_CUTOFF = 1000 * 60 * 60 * 24; // 24h
 
 const wrapLabel = (label: string) => ({ label });
 
-export function addHistoryMetadata(item: CompletionItem, history: any[]): CompletionItem {
+export function addHistoryMetadata(item: CompletionItem, history: HistoryItem[]): CompletionItem {
   const cutoffTs = Date.now() - HISTORY_COUNT_CUTOFF;
-  const historyForItem = history.filter(h => h.ts > cutoffTs && h.query === item.label);
+  const historyForItem = history.filter(h => h.ts > cutoffTs && (h.query.expr as string) === item.label);
   const count = historyForItem.length;
   const recent = historyForItem[0];
   let hint = `Queried ${count} times in the last 24h.`;
@@ -96,9 +97,9 @@ export default class LoggingLanguageProvider extends LanguageProvider {
 
     if (history && history.length > 0) {
       const historyItems = _.chain(history)
-        .uniqBy('query')
+        .uniqBy('query.expr')
         .take(HISTORY_ITEM_COUNT)
-        .map(h => h.query)
+        .map(h => h.query.expr)
         .map(wrapLabel)
         .map(item => addHistoryMetadata(item, history))
         .value();
@@ -177,6 +178,10 @@ export default class LoggingLanguageProvider extends LanguageProvider {
   }
 
   async importPrometheusQuery(query: string): Promise<string> {
+    if (!query) {
+      return '';
+    }
+
     // Consider only first selector in query
     const selectorMatch = query.match(selectorRegexp);
     if (selectorMatch) {
@@ -192,7 +197,7 @@ export default class LoggingLanguageProvider extends LanguageProvider {
       const commonLabels = {};
       for (const key in labels) {
         const existingKeys = this.labelKeys[EMPTY_SELECTOR];
-        if (existingKeys.indexOf(key) > -1) {
+        if (existingKeys && existingKeys.indexOf(key) > -1) {
           // Should we check for label value equality here?
           commonLabels[key] = labels[key];
         }

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

@@ -25,7 +25,10 @@ export default (props: any) => (
     {CHEAT_SHEET_ITEMS.map(item => (
       <div className="cheat-sheet-item" key={item.expression}>
         <div className="cheat-sheet-item__title">{item.title}</div>
-        <div className="cheat-sheet-item__expression" onClick={e => props.onClickQuery(item.expression)}>
+        <div
+          className="cheat-sheet-item__expression"
+          onClick={e => props.onClickExample({ refId: '1', expr: item.expression })}
+        >
           <code>{item.expression}</code>
         </div>
         <div className="cheat-sheet-item__label">{item.label}</div>

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

@@ -10,7 +10,8 @@ import { TypeaheadOutput } from 'app/types/explore';
 import { getNextCharacter, getPreviousCousin } from 'app/features/explore/utils/dom';
 import BracesPlugin from 'app/features/explore/slate-plugins/braces';
 import RunnerPlugin from 'app/features/explore/slate-plugins/runner';
-import TypeaheadField, { TypeaheadInput, QueryFieldState } from 'app/features/explore/QueryField';
+import QueryField, { TypeaheadInput, QueryFieldState } from 'app/features/explore/QueryField';
+import { DataQuery } from 'app/types';
 
 const HISTOGRAM_GROUP = '__histograms__';
 const METRIC_MARK = 'metric';
@@ -87,13 +88,13 @@ interface CascaderOption {
 interface PromQueryFieldProps {
   datasource: any;
   error?: string | JSX.Element;
+  initialQuery: DataQuery;
   hint?: any;
   history?: any[];
-  initialQuery?: string | null;
   metricsByPrefix?: CascaderOption[];
   onClickHintFix?: (action: any) => void;
   onPressEnter?: () => void;
-  onQueryChange?: (value: string, override?: boolean) => void;
+  onQueryChange?: (value: DataQuery, override?: boolean) => void;
 }
 
 interface PromQueryFieldState {
@@ -163,9 +164,13 @@ class PromQueryField extends React.PureComponent<PromQueryFieldProps, PromQueryF
 
   onChangeQuery = (value: string, override?: boolean) => {
     // Send text change to parent
-    const { onQueryChange } = this.props;
+    const { initialQuery, onQueryChange } = this.props;
     if (onQueryChange) {
-      onQueryChange(value, override);
+      const query: DataQuery = {
+        ...initialQuery,
+        expr: value,
+      };
+      onQueryChange(query, override);
     }
   };
 
@@ -230,7 +235,7 @@ class PromQueryField extends React.PureComponent<PromQueryFieldProps, PromQueryF
     const { error, hint, initialQuery } = this.props;
     const { metricsOptions, syntaxLoaded } = this.state;
     const cleanText = this.languageProvider ? this.languageProvider.cleanText : undefined;
-    const chooserText = syntaxLoaded ? 'Metrics' : 'Loading matrics...';
+    const chooserText = syntaxLoaded ? 'Metrics' : 'Loading metrics...';
 
     return (
       <div className="prom-query-field">
@@ -242,10 +247,10 @@ class PromQueryField extends React.PureComponent<PromQueryFieldProps, PromQueryF
           </Cascader>
         </div>
         <div className="prom-query-field-wrapper">
-          <TypeaheadField
+          <QueryField
             additionalPlugins={this.plugins}
             cleanText={cleanText}
-            initialValue={initialQuery}
+            initialQuery={initialQuery.expr}
             onTypeahead={this.onTypeahead}
             onWillApplySuggestion={willApplySuggestion}
             onValueChanged={this.onChangeQuery}

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

@@ -52,7 +52,7 @@ export default class PromStart extends PureComponent<any, { active: string }> {
           </div>
         </div>
         <div className="page-container page-body">
-          {active === 'start' && <PromCheatSheet onClickQuery={this.props.onClickQuery} />}
+          {active === 'start' && <PromCheatSheet onClickExample={this.props.onClickExample} />}
         </div>
       </div>
     );

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

@@ -11,6 +11,8 @@ import { BackendSrv } from 'app/core/services/backend_srv';
 import addLabelToQuery from './add_label_to_query';
 import { getQueryHints } from './query_hints';
 import { expandRecordingRules } from './language_utils';
+import { DataQuery } from 'app/types';
+import { ExploreUrlState } from 'app/types/explore';
 
 export function alignRange(start, end, step) {
   const alignedEnd = Math.ceil(end / step) * step;
@@ -419,24 +421,23 @@ export class PrometheusDatasource {
     });
   }
 
-  getExploreState(targets: any[]) {
+  getExploreState(queries: DataQuery[]): Partial<ExploreUrlState> {
-    let state = {};
+    let state: Partial<ExploreUrlState> = { datasource: this.name };
-    if (targets && targets.length > 0) {
+    if (queries && queries.length > 0) {
-      const queries = targets.map(t => ({
+      const expandedQueries = queries.map(query => ({
-        query: this.templateSrv.replace(t.expr, {}, this.interpolateQueryExpr),
+        ...query,
-        format: t.format,
+        expr: this.templateSrv.replace(query.expr, {}, this.interpolateQueryExpr),
       }));
       state = {
         ...state,
-        queries,
+        queries: expandedQueries,
-        datasource: this.name,
       };
     }
     return state;
   }
 
-  getQueryHints(query: string, result: any[]) {
+  getQueryHints(query: DataQuery, result: any[]) {
-    return getQueryHints(query, result, this);
+    return getQueryHints(query.expr, result, this);
   }
 
   loadRules() {
@@ -454,28 +455,35 @@ export class PrometheusDatasource {
       });
   }
 
-  modifyQuery(query: string, action: any): string {
+  modifyQuery(query: DataQuery, action: any): DataQuery {
+    let expression = query.expr || '';
     switch (action.type) {
       case 'ADD_FILTER': {
-        return addLabelToQuery(query, action.key, action.value);
+        expression = addLabelToQuery(expression, action.key, action.value);
+        break;
       }
       case 'ADD_HISTOGRAM_QUANTILE': {
-        return `histogram_quantile(0.95, sum(rate(${query}[5m])) by (le))`;
+        expression = `histogram_quantile(0.95, sum(rate(${expression}[5m])) by (le))`;
+        break;
       }
       case 'ADD_RATE': {
-        return `rate(${query}[5m])`;
+        expression = `rate(${expression}[5m])`;
+        break;
       }
       case 'ADD_SUM': {
-        return `sum(${query.trim()}) by ($1)`;
+        expression = `sum(${expression.trim()}) by ($1)`;
+        break;
       }
       case 'EXPAND_RULES': {
         if (action.mapping) {
-          return expandRecordingRules(query, action.mapping);
+          expression = expandRecordingRules(expression, action.mapping);
         }
+        break;
       }
       default:
-        return query;
+        break;
     }
+    return { ...query, expr: expression };
   }
 
   getPrometheusTime(date, roundUp) {

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

@@ -125,9 +125,9 @@ export default class PromQlLanguageProvider extends LanguageProvider {
 
     if (history && history.length > 0) {
       const historyItems = _.chain(history)
-        .uniqBy('query')
+        .uniqBy('query.expr')
         .take(HISTORY_ITEM_COUNT)
-        .map(h => h.query)
+        .map(h => h.query.expr)
         .map(wrapLabel)
         .map(item => addHistoryMetadata(item, history))
         .value();

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

@@ -36,6 +36,32 @@ describe('Language completion provider', () => {
         },
       ]);
     });
+
+    it('returns default suggestions with history on emtpty context when history was provided', () => {
+      const instance = new LanguageProvider(datasource);
+      const value = Plain.deserialize('');
+      const history = [
+        {
+          query: { refId: '1', expr: 'metric' },
+        },
+      ];
+      const result = instance.provideCompletionItems({ text: '', prefix: '', value, wrapperClasses: [] }, { history });
+      expect(result.context).toBeUndefined();
+      expect(result.refresher).toBeUndefined();
+      expect(result.suggestions).toMatchObject([
+        {
+          label: 'History',
+          items: [
+            {
+              label: 'metric',
+            },
+          ],
+        },
+        {
+          label: 'Functions',
+        },
+      ]);
+    });
   });
 
   describe('range suggestions', () => {

public/app/types/explore.ts

@@ -1,6 +1,6 @@
 import { Value } from 'slate';
 
-import { RawTimeRange } from './series';
+import { DataQuery, RawTimeRange } from './series';
 
 export interface CompletionItem {
   /**
@@ -79,7 +79,7 @@ interface ExploreDatasource {
 
 export interface HistoryItem {
   ts: number;
-  query: string;
+  query: DataQuery;
 }
 
 export abstract class LanguageProvider {
@@ -107,11 +107,6 @@ export interface TypeaheadOutput {
   suggestions: CompletionItemGroup[];
 }
 
-export interface Query {
-  query: string;
-  key?: string;
-}
-
 export interface QueryFix {
   type: string;
   label: string;
@@ -130,6 +125,10 @@ export interface QueryHint {
   fix?: QueryFix;
 }
 
+export interface QueryHintGetter {
+  (query: DataQuery, results: any[], ...rest: any): QueryHint[];
+}
+
 export interface QueryTransaction {
   id: string;
   done: boolean;
@@ -137,7 +136,7 @@ export interface QueryTransaction {
   hints?: QueryHint[];
   latency: number;
   options: any;
-  query: string;
+  query: DataQuery;
   result?: any; // Table model / Timeseries[] / Logs
   resultType: ResultType;
   rowIndex: number;
@@ -160,15 +159,7 @@ export interface ExploreState {
   exploreDatasources: ExploreDatasource[];
   graphRange: RawTimeRange;
   history: HistoryItem[];
-  /**
+  initialQueries: DataQuery[];
-   * Initial rows of queries to push down the tree.
-   * Modifications do not end up here, but in `this.queryExpressions`.
-   * The only way to reset a query is to change its `key`.
-   */
-  queries: Query[];
-  /**
-   * Hints gathered for the query row.
-   */
   queryTransactions: QueryTransaction[];
   range: RawTimeRange;
   showingGraph: boolean;
@@ -182,7 +173,7 @@ export interface ExploreState {
 
 export interface ExploreUrlState {
   datasource: string;
-  queries: Query[];
+  queries: any[]; // Should be a DataQuery, but we're going to strip refIds, so typing makes less sense
   range: RawTimeRange;
 }