[Infra] Change host count KPI query

x-pack/plugins/observability_solution/infra/common/http_api/asset_count_api.ts

@@ -0,0 +1,48 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import { dateRt } from '@kbn/io-ts-utils';
+import * as rt from 'io-ts';
+
+const AssetTypeRT = rt.type({
+  assetType: rt.literal('host'),
+});
+
+export const GetInfraAssetCountRequestBodyPayloadRT = rt.intersection([
+  rt.partial({
+    query: rt.UnknownRecord,
+  }),
+  rt.type({
+    sourceId: rt.string,
+    from: dateRt,
+    to: dateRt,
+  }),
+]);
+
+export const GetInfraAssetCountRequestParamsPayloadRT = AssetTypeRT;
+
+export const GetInfraAssetCountResponsePayloadRT = rt.intersection([
+  AssetTypeRT,
+  rt.type({
+    count: rt.number,
+  }),
+]);
+
+export type GetInfraAssetCountRequestParamsPayload = rt.TypeOf<
+  typeof GetInfraAssetCountRequestParamsPayloadRT
+>;
+export type GetInfraAssetCountRequestBodyPayload = Omit<
+  rt.TypeOf<typeof GetInfraAssetCountRequestBodyPayloadRT>,
+  'from' | 'to'
+> & {
+  from: string;
+  to: string;
+};
+
+export type GetInfraAssetCountResponsePayload = rt.TypeOf<
+  typeof GetInfraAssetCountResponsePayloadRT
+>;

x-pack/plugins/observability_solution/infra/common/http_api/index.ts

@@ -11,6 +11,7 @@ export * from './metrics_api';
 export * from './snapshot_api';
 export * from './host_details';
 export * from './infra';
+export * from './asset_count_api';
 
 /**
  * Exporting versioned APIs types

x-pack/plugins/observability_solution/infra/server/infra_server.ts

@@ -31,7 +31,7 @@ import { initNodeDetailsRoute } from './routes/node_details';
 import { initOverviewRoute } from './routes/overview';
 import { initProcessListRoute } from './routes/process_list';
 import { initSnapshotRoute } from './routes/snapshot';
-import { initInfraMetricsRoute } from './routes/infra';
+import { initInfraAssetRoutes } from './routes/infra';
 import { initMetricsExplorerViewRoutes } from './routes/metrics_explorer_views';
 import { initProfilingRoutes } from './routes/profiling';
 import { initServicesRoute } from './routes/services';
@@ -67,7 +67,7 @@ export const initInfraServer = (
   initGetLogAlertsChartPreviewDataRoute(libs);
   initProcessListRoute(libs);
   initOverviewRoute(libs);
-  initInfraMetricsRoute(libs);
+  initInfraAssetRoutes(libs);
   initProfilingRoutes(libs);
   initServicesRoute(libs);
   initCustomDashboardsRoutes(libs.framework);

x-pack/plugins/observability_solution/infra/server/routes/infra/README.md

@@ -1,9 +1,10 @@
-# Infra Hosts API
+# Infra Assets API
 
-This API returns a list of hosts and their metrics.
+## **POST /api/metrics/infra**
 
-**POST /api/metrics/infra**
-parameters:
+This endpoint returns a list of hosts and their metrics.
+
+### Parameters:
 
 - type: asset type. 'host' is the only one supported now
 - metrics: list of metrics to be calculated and returned for each host
@@ -18,7 +19,7 @@ The response includes:
 - metrics: object containing name of the metric and value
 - metadata: object containing name of the metadata and value
 
-## Examples
+### Examples:
 
 Request
 
@@ -113,3 +114,49 @@ Response
    ]
 }
 ```
+
+## **POST /api/infra/{assetType}/count**
+
+This endpoint returns the count of the hosts monitored with the system integration.
+
+### Parameters:
+
+- type: asset type. 'host' is the only one supported now
+- sourceId: sourceId to retrieve configuration such as index-pattern used to query the results
+- from: Start date
+- to: End date
+- (optional) query: filter
+
+The response includes:
+
+- count: number - the count of the hosts monitored with the system integration 
+- type: string - the type of the asset **(currently only 'host' is supported)**
+
+### Examples:
+
+Request
+
+```bash
+curl --location -u elastic:changeme 'http://0.0.0.0:5601/ftw/api/infra/host/count' \
+--header 'kbn-xsrf: xxxx' \
+--header 'Content-Type: application/json' \
+--data '{
+   "query": {
+      "bool": {
+         "must": [],
+         "filter": [],
+         "should": [],
+         "must_not": []
+      }
+   },
+   "from": "2024-07-23T11:34:11.640Z",
+   "to": "2024-07-23T11:49:11.640Z",
+   "sourceId": "default"
+}'
+```
+
+Response
+
+```json
+{"type":"host","count":22}
+```

x-pack/plugins/observability_solution/infra/server/routes/infra/index.ts

@@ -8,18 +8,27 @@
 import Boom from '@hapi/boom';
 import { createRouteValidationFunction } from '@kbn/io-ts-utils';
 
+import type { BoolQuery } from '@kbn/es-query';
 import {
+  type GetInfraMetricsRequestBodyPayload,
   GetInfraMetricsRequestBodyPayloadRT,
-  GetInfraMetricsRequestBodyPayload,
   GetInfraMetricsResponsePayloadRT,
 } from '../../../common/http_api/infra';
-import { InfraBackendLibs } from '../../lib/infra_types';
+import {
+  type GetInfraAssetCountRequestBodyPayload,
+  type GetInfraAssetCountRequestParamsPayload,
+  GetInfraAssetCountRequestBodyPayloadRT,
+  GetInfraAssetCountResponsePayloadRT,
+  GetInfraAssetCountRequestParamsPayloadRT,
+} from '../../../common/http_api/asset_count_api';
+import type { InfraBackendLibs } from '../../lib/infra_types';
 import { getInfraAlertsClient } from '../../lib/helpers/get_infra_alerts_client';
 import { getHosts } from './lib/host/get_hosts';
+import { getHostsCount } from './lib/host/get_hosts_count';
 import { getInfraMetricsClient } from '../../lib/helpers/get_infra_metrics_client';
 
-export const initInfraMetricsRoute = (libs: InfraBackendLibs) => {
-  const validateBody = createRouteValidationFunction(GetInfraMetricsRequestBodyPayloadRT);
+export const initInfraAssetRoutes = (libs: InfraBackendLibs) => {
+  const validateMetricsBody = createRouteValidationFunction(GetInfraMetricsRequestBodyPayloadRT);
 
   const { framework } = libs;
 
@@ -28,7 +37,7 @@ export const initInfraMetricsRoute = (libs: InfraBackendLibs) => {
       method: 'post',
       path: '/api/metrics/infra',
       validate: {
-        body: validateBody,
+        body: validateMetricsBody,
       },
     },
     async (requestContext, request, response) => {
@@ -74,4 +83,64 @@ export const initInfraMetricsRoute = (libs: InfraBackendLibs) => {
       }
     }
   );
+
+  const validateCountBody = createRouteValidationFunction(GetInfraAssetCountRequestBodyPayloadRT);
+  const validateCountParams = createRouteValidationFunction(
+    GetInfraAssetCountRequestParamsPayloadRT
+  );
+
+  framework.registerRoute(
+    {
+      method: 'post',
+      path: '/api/infra/{assetType}/count',
+      validate: {
+        body: validateCountBody,
+        params: validateCountParams,
+      },
+    },
+    async (requestContext, request, response) => {
+      const body: GetInfraAssetCountRequestBodyPayload = request.body;
+      const params: GetInfraAssetCountRequestParamsPayload = request.params;
+      const { assetType } = params;
+      const { query, from, to, sourceId } = body;
+
+      try {
+        const infraMetricsClient = await getInfraMetricsClient({
+          framework,
+          request,
+          infraSources: libs.sources,
+          requestContext,
+          sourceId,
+        });
+
+        const assetCount = await getHostsCount({
+          infraMetricsClient,
+          query: (query?.bool as BoolQuery) ?? undefined,
+          from,
+          to,
+        });
+
+        return response.ok({
+          body: GetInfraAssetCountResponsePayloadRT.encode({
+            assetType,
+            count: assetCount,
+          }),
+        });
+      } catch (err) {
+        if (Boom.isBoom(err)) {
+          return response.customError({
+            statusCode: err.output.statusCode,
+            body: { message: err.output.payload.message },
+          });
+        }
+
+        return response.customError({
+          statusCode: err.statusCode ?? 500,
+          body: {
+            message: err.message ?? 'An unexpected error occurred',
+          },
+        });
+      }
+    }
+  );
 };

x-pack/plugins/observability_solution/infra/server/routes/infra/lib/host/get_hosts_count.ts

@@ -0,0 +1,81 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import { BoolQuery } from '@kbn/es-query';
+import { InfraMetricsClient } from '../../../../lib/helpers/get_infra_metrics_client';
+import { HOST_NAME_FIELD } from '../../../../../common/constants';
+
+export async function getHostsCount({
+  infraMetricsClient,
+  query,
+  from,
+  to,
+}: {
+  infraMetricsClient: InfraMetricsClient;
+  query?: BoolQuery;
+  from: string;
+  to: string;
+}) {
+  const rangeQuery = [
+    {
+      range: {
+        '@timestamp': {
+          gte: from,
+          lte: to,
+        },
+      },
+    },
+  ];
+  const queryFilter = query?.filter ?? [];
+  const queryBool = query ?? {};
+
+  const params = {
+    allow_no_indices: true,
+    ignore_unavailable: true,
+    body: {
+      size: 0,
+      track_total_hits: false,
+      query: {
+        bool: {
+          ...queryBool,
+          filter: [
+            ...queryFilter,
+            ...rangeQuery,
+            {
+              bool: {
+                should: [
+                  {
+                    term: {
+                      'event.module': 'system',
+                    },
+                  },
+                  {
+                    term: {
+                      'metricset.module': 'system',
+                    },
+                  },
+                ],
+                minimum_should_match: 1,
+              },
+            },
+          ],
+        },
+      },
+      aggs: {
+        count: {
+          cardinality: {
+            field: HOST_NAME_FIELD,
+          },
+        },
+      },
+    },
+  };
+
+  const result = await infraMetricsClient.search(params);
+
+  return result.aggregations?.count.value ?? 0;
+}