[APM]Create API to return data to be used on the Overview page

x-pack/plugins/apm/public/plugin.ts

@@ -38,6 +38,10 @@ import { setHelpExtension } from './setHelpExtension';
 import { toggleAppLinkInNav } from './toggleAppLinkInNav';
 import { setReadonlyBadge } from './updateBadge';
 import { createStaticIndexPattern } from './services/rest/index_pattern';
+import {
+  fetchLandingPageData,
+  hasData,
+} from './services/rest/observability_dashboard';
 
 export type ApmPluginSetup = void;
 export type ApmPluginStart = void;
@@ -73,6 +77,17 @@ export class ApmPlugin implements Plugin<ApmPluginSetup, ApmPluginStart> {
     pluginSetupDeps.home.environment.update({ apmUi: true });
     pluginSetupDeps.home.featureCatalogue.register(featureCatalogueEntry);
 
+    if (plugins.observability) {
+      const isDarkMode = core.uiSettings.get('theme:darkMode');
+      plugins.observability.dashboard.register({
+        appName: 'apm',
+        fetchData: async (params) => {
+          return fetchLandingPageData(params, { isDarkMode });
+        },
+        hasData,
+      });
+    }
+
     core.application.register({
       id: 'apm',
       title: 'APM',

x-pack/plugins/apm/public/services/rest/observability.dashboard.test.ts

@@ -0,0 +1,114 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { fetchLandingPageData, hasData } from './observability_dashboard';
+import * as createCallApmApi from './createCallApmApi';
+
+describe('Observability dashboard data', () => {
+  const callApmApiMock = jest.spyOn(createCallApmApi, 'callApmApi');
+  afterEach(() => {
+    callApmApiMock.mockClear();
+  });
+  describe('hasData', () => {
+    it('returns false when no data is available', async () => {
+      callApmApiMock.mockImplementation(() => Promise.resolve(false));
+      const response = await hasData();
+      expect(response).toBeFalsy();
+    });
+    it('returns true when data is available', async () => {
+      callApmApiMock.mockImplementation(() => Promise.resolve(true));
+      const response = await hasData();
+      expect(response).toBeTruthy();
+    });
+  });
+
+  describe('fetchLandingPageData', () => {
+    it('returns APM data with series and stats', async () => {
+      callApmApiMock.mockImplementation(() =>
+        Promise.resolve({
+          serviceCount: 10,
+          transactionCoordinates: [
+            { x: 1, y: 1 },
+            { x: 2, y: 2 },
+            { x: 3, y: 3 },
+          ],
+        })
+      );
+      const response = await fetchLandingPageData(
+        {
+          startTime: '1',
+          endTime: '2',
+          bucketSize: '3',
+        },
+        { isDarkMode: false }
+      );
+      expect(response).toEqual({
+        title: 'APM',
+        appLink: '/app/apm',
+        stats: {
+          services: {
+            label: 'Services',
+            value: 10,
+          },
+          transactions: {
+            label: 'Transactions',
+            value: 6,
+            color: '#6092c0',
+          },
+        },
+        series: {
+          transactions: {
+            label: 'Transactions',
+            coordinates: [
+              { x: 1, y: 1 },
+              { x: 2, y: 2 },
+              { x: 3, y: 3 },
+            ],
+            color: '#6092c0',
+          },
+        },
+      });
+    });
+    it('returns empty transaction coordinates', async () => {
+      callApmApiMock.mockImplementation(() =>
+        Promise.resolve({
+          serviceCount: 0,
+          transactionCoordinates: [],
+        })
+      );
+      const response = await fetchLandingPageData(
+        {
+          startTime: '1',
+          endTime: '2',
+          bucketSize: '3',
+        },
+        { isDarkMode: false }
+      );
+      expect(response).toEqual({
+        title: 'APM',
+        appLink: '/app/apm',
+        stats: {
+          services: {
+            label: 'Services',
+            value: 0,
+          },
+          transactions: {
+            label: 'Transactions',
+            value: 0,
+            color: '#6092c0',
+          },
+        },
+        series: {
+          transactions: {
+            label: 'Transactions',
+            coordinates: [],
+            color: '#6092c0',
+          },
+        },
+      });
+    });
+  });
+});

x-pack/plugins/apm/public/services/rest/observability_dashboard.ts

@@ -0,0 +1,72 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { i18n } from '@kbn/i18n';
+import { sum } from 'lodash';
+import lightTheme from '@elastic/eui/dist/eui_theme_light.json';
+import darkTheme from '@elastic/eui/dist/eui_theme_dark.json';
+// eslint-disable-next-line @kbn/eslint/no-restricted-paths
+import { FetchDataParams } from '../../../../observability/public/data_handler';
+import { ApmFetchDataResponse } from '../../../../observability/public/typings/fetch_data_response';
+import { callApmApi } from './createCallApmApi';
+
+interface Options {
+  isDarkMode: boolean;
+}
+
+export const fetchLandingPageData = async (
+  { startTime, endTime, bucketSize }: FetchDataParams,
+  { isDarkMode }: Options
+): Promise<ApmFetchDataResponse> => {
+  const theme = isDarkMode ? darkTheme : lightTheme;
+
+  const data = await callApmApi({
+    pathname: '/api/apm/observability_dashboard',
+    params: { query: { start: startTime, end: endTime, bucketSize } },
+  });
+
+  const { serviceCount, transactionCoordinates } = data;
+
+  return {
+    title: i18n.translate('xpack.apm.observabilityDashboard.title', {
+      defaultMessage: 'APM',
+    }),
+    appLink: '/app/apm',
+    stats: {
+      services: {
+        label: i18n.translate(
+          'xpack.apm.observabilityDashboard.stats.services',
+          { defaultMessage: 'Services' }
+        ),
+        value: serviceCount,
+      },
+      transactions: {
+        label: i18n.translate(
+          'xpack.apm.observabilityDashboard.stats.transactions',
+          { defaultMessage: 'Transactions' }
+        ),
+        value: sum(transactionCoordinates.map((coordinates) => coordinates.y)),
+        color: theme.euiColorVis1,
+      },
+    },
+    series: {
+      transactions: {
+        label: i18n.translate(
+          'xpack.apm.observabilityDashboard.chart.transactions',
+          { defaultMessage: 'Transactions' }
+        ),
+        color: theme.euiColorVis1,
+        coordinates: transactionCoordinates,
+      },
+    },
+  };
+};
+
+export async function hasData() {
+  return await callApmApi({
+    pathname: '/api/apm/observability_dashboard/has_data',
+  });
+}

x-pack/plugins/apm/server/lib/observability_dashboard/get_service_count.ts

@@ -0,0 +1,33 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { rangeFilter } from '../../../common/utils/range_filter';
+import { SERVICE_NAME } from '../../../common/elasticsearch_fieldnames';
+import { Setup, SetupTimeRange } from '../helpers/setup_request';
+
+export async function getServiceCount({
+  setup,
+}: {
+  setup: Setup & SetupTimeRange;
+}) {
+  const { client, indices, start, end } = setup;
+
+  const params = {
+    index: [
+      indices['apm_oss.transactionIndices'],
+      indices['apm_oss.errorIndices'],
+      indices['apm_oss.metricsIndices'],
+    ],
+    body: {
+      size: 0,
+      query: { bool: { filter: [{ range: rangeFilter(start, end) }] } },
+      aggs: { serviceCount: { cardinality: { field: SERVICE_NAME } } },
+    },
+  };
+
+  const { aggregations } = await client.search(params);
+  return aggregations?.serviceCount.value || 0;
+}

x-pack/plugins/apm/server/lib/observability_dashboard/get_transaction_coordinates.ts

@@ -0,0 +1,57 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+import { rangeFilter } from '../../../common/utils/range_filter';
+import { Coordinates } from '../../../../observability/public/typings/fetch_data_response';
+import { PROCESSOR_EVENT } from '../../../common/elasticsearch_fieldnames';
+import { Setup, SetupTimeRange } from '../helpers/setup_request';
+import { ProcessorEvent } from '../../../common/processor_event';
+
+export async function getTransactionCoordinates({
+  setup,
+  bucketSize,
+}: {
+  setup: Setup & SetupTimeRange;
+  bucketSize: string;
+}): Promise<Coordinates[]> {
+  const { client, indices, start, end } = setup;
+
+  const { aggregations } = await client.search({
+    index: indices['apm_oss.transactionIndices'],
+    body: {
+      size: 0,
+      query: {
+        bool: {
+          filter: [
+            { term: { [PROCESSOR_EVENT]: ProcessorEvent.transaction } },
+            { range: rangeFilter(start, end) },
+          ],
+        },
+      },
+      aggs: {
+        distribution: {
+          date_histogram: {
+            field: '@timestamp',
+            fixed_interval: bucketSize,
+            min_doc_count: 0,
+            extended_bounds: { min: start, max: end },
+          },
+        },
+      },
+    },
+  });
+
+  return (
+    aggregations?.distribution.buckets.map((bucket) => ({
+      x: bucket.key,
+      y: bucket.doc_count,
+    })) || []
+  );
+}

x-pack/plugins/apm/server/lib/observability_dashboard/has_data.ts

@@ -0,0 +1,26 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+import { Setup } from '../helpers/setup_request';
+
+export async function hasData({ setup }: { setup: Setup }) {
+  const { client, indices } = setup;
+  try {
+    const params = {
+      index: [
+        indices['apm_oss.transactionIndices'],
+        indices['apm_oss.errorIndices'],
+        indices['apm_oss.metricsIndices'],
+      ],
+      terminateAfter: 1,
+      size: 0,
+    };
+
+    const response = await client.search(params);
+    return response.hits.total.value > 0;
+  } catch (e) {
+    return false;
+  }
+}

x-pack/plugins/apm/server/routes/create_apm_api.ts

@@ -76,6 +76,10 @@ import {
   rumPageViewsTrendRoute,
   rumPageLoadDistributionRoute,
 } from './rum_client';
+import {
+  observabilityDashboardHasDataRoute,
+  observabilityDashboardDataRoute,
+} from './observability_dashboard';
 
 const createApmApi = () => {
   const api = createApi()
@@ -160,7 +164,11 @@ const createApmApi = () => {
     .add(rumOverviewLocalFiltersRoute)
     .add(rumPageViewsTrendRoute)
     .add(rumPageLoadDistributionRoute)
-    .add(rumClientMetricsRoute);
+    .add(rumClientMetricsRoute)
+
+    // Observability dashboard
+    .add(observabilityDashboardHasDataRoute)
+    .add(observabilityDashboardDataRoute);
 
   return api;
 };