Adding interval information to Metrics Eexplorer API

x-pack/plugins/infra/common/http_api/metrics_explorer.ts

@@ -90,6 +90,10 @@ export const metricsExplorerSeriesRT = rt.type({
   id: rt.string,
   columns: rt.array(metricsExplorerColumnRT),
   rows: rt.array(metricsExplorerRowRT),
+  intervals: rt.partial({
+    current: rt.number,
+    recommended: rt.number,
+  }),
 });
 
 export const metricsExplorerResponseRT = rt.type({

x-pack/plugins/infra/server/routes/metrics_explorer/lib/caclculate_interval_from_rows.ts

@@ -0,0 +1,11 @@
+/*
+ * 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.
+ */
+
+export const calculateIntervalFromRows = (rows: Array<{ timestamp: number }>) => {
+  if (rows.length > 1) {
+    return (rows[1].timestamp - rows[0].timestamp) / 1000;
+  }
+};

x-pack/plugins/infra/server/routes/metrics_explorer/lib/populate_series_with_tsvb_data.ts

@@ -17,6 +17,7 @@ import { createMetricModel } from './create_metrics_model';
 import { JsonObject } from '../../../../common/typed_json';
 import { calculateMetricInterval } from '../../../utils/calculate_metric_interval';
 import { getDatasetForField } from './get_dataset_for_field';
+import { calculateIntervalFromRows } from './caclculate_interval_from_rows';
 
 export const populateSeriesWithTSVBData = (
   request: KibanaRequest,
@@ -130,9 +131,14 @@ export const populateSeriesWithTSVBData = (
       { timestamp, ...rowAttributes } as MetricsExplorerRow
     );
   });
+
   return {
     ...series,
     rows,
+    intervals: {
+      current: calculateIntervalFromRows(rows),
+      recommended: calculatedInterval,
+    },
     columns: [
       { name: 'timestamp', type: 'date' } as MetricsExplorerColumn,
       ...metricColumns,