[data views] Default field formatters based on field meta values (ela…

…stic#174973)

## Summary

Default field formatters based on field meta units data.

Note: the smallest unit our formatter will show is milliseconds which
means micro and nanoseconds may round down to zero for smaller values.
elastic#176112


Closes: elastic#82318

Mapping and doc setup for testing - 

```
PUT my-index-000001

PUT my-index-000001/_mapping
{
    "properties": {
            "nanos": {
        "type": "long",
        "meta": {
          "unit": "nanos"
        }
      },
            "micros": {
        "type": "long",
        "meta": {
          "unit": "micros"
        }
      },
      "ms": {
        "type": "long",
        "meta": {
          "unit": "ms"
        }
      },
                  "second": {
        "type": "long",
        "meta": {
          "unit": "s"
        }
      },
                  "minute": {
        "type": "long",
        "meta": {
          "unit": "m"
        }
      },
                  "hour": {
        "type": "long",
        "meta": {
          "unit": "h"
        }
      },
                  "day": {
        "type": "long",
        "meta": {
          "unit": "d"
        }
      },
      "percent": {
        "type": "long",
        "meta": {
          "unit": "percent"
        }
      },
            "bytes": {
        "type": "long",
        "meta": {
          "unit": "byte"
        }
      }
    }
}

POST my-index-000001/_doc
{
  "nanos" : 1234.5,
  "micros" : 1234.5,
  "ms" : 1234.5,
  "second" : 1234.5,
  "minute" : 1234.5,
  "hour" : 1234.5,
  "day" : 1234.5,
  "percent" : 1234.5,
  "bytes" : 1234.5
}

```

src/plugins/data_views/common/data_views/abstract_data_views.ts

@@ -24,6 +24,7 @@ import type {
   RuntimeField,
 } from '../types';
 import { removeFieldAttrs } from './utils';
+import { metaUnitsToFormatter } from './meta_units_to_formatter';
 
 import type { DataViewAttributes, FieldAttrs, FieldAttrSet } from '..';
 
@@ -251,6 +252,11 @@ export abstract class AbstractDataView {
       return fieldFormat;
     }
 
+    const fmt = field.defaultFormatter ? metaUnitsToFormatter[field.defaultFormatter] : undefined;
+    if (fmt) {
+      return this.fieldFormats.getInstance(fmt.id, fmt.params);
+    }
+
     return this.fieldFormats.getDefaultInstance(
       field.type as KBN_FIELD_TYPES,
       field.esTypes as ES_FIELD_TYPES[]

src/plugins/data_views/common/data_views/meta_units_to_formatter.ts

@@ -0,0 +1,34 @@
+/*
+ * 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 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import { FieldFormatParams } from '@kbn/field-formats-plugin/common';
+
+const timeUnitToDurationFmt = (inputFormat = 'milliseconds') => {
+  return {
+    id: 'duration',
+    params: {
+      inputFormat,
+      outputFormat: 'humanizePrecise',
+      outputPrecision: 2,
+      includeSpaceWithSuffix: true,
+      useShortSuffix: true,
+    },
+  };
+};
+
+export const metaUnitsToFormatter: Record<string, { id: string; params?: FieldFormatParams }> = {
+  percent: { id: 'percent' },
+  byte: { id: 'bytes' },
+  nanos: timeUnitToDurationFmt('nanoseconds'),
+  micros: timeUnitToDurationFmt('microseconds'),
+  ms: timeUnitToDurationFmt('milliseconds'),
+  s: timeUnitToDurationFmt('seconds'),
+  m: timeUnitToDurationFmt('minutes'),
+  h: timeUnitToDurationFmt('hours'),
+  d: timeUnitToDurationFmt('days'),
+};

src/plugins/data_views/common/fields/data_view_field.ts

@@ -69,6 +69,10 @@ export class DataViewField implements DataViewFieldBase {
     this.spec.count = count;
   }
 
+  public get defaultFormatter() {
+    return this.spec.defaultFormatter;
+  }
+
   /**
    * Returns runtime field definition or undefined if field is not runtime field.
    */
@@ -370,6 +374,7 @@ export class DataViewField implements DataViewFieldBase {
       readFromDocValues: this.readFromDocValues,
       subType: this.subType,
       customLabel: this.customLabel,
+      defaultFormatter: this.defaultFormatter,
     };
   }
 
@@ -403,6 +408,7 @@ export class DataViewField implements DataViewFieldBase {
       timeSeriesMetric: this.spec.timeSeriesMetric,
       timeZone: this.spec.timeZone,
       fixedInterval: this.spec.fixedInterval,
+      defaultFormatter: this.defaultFormatter,
     };
 
     // Filter undefined values from the spec

src/plugins/data_views/common/types.ts

@@ -462,6 +462,8 @@ export type FieldSpec = DataViewFieldBase & {
    * Name of parent field for composite runtime field subfields.
    */
   parentName?: string;
+
+  defaultFormatter?: string;
 };
 
 export type DataViewFieldMap = Record<string, FieldSpec>;

src/plugins/data_views/server/fetcher/index_patterns_fetcher.ts

@@ -32,6 +32,7 @@ export interface FieldDescriptor {
   timeZone?: string[];
   timeSeriesMetric?: estypes.MappingTimeSeriesMetricType;
   timeSeriesDimension?: boolean;
+  defaultFormatter?: string;
 }
 
 interface FieldSubType {

src/plugins/data_views/server/fetcher/lib/field_capabilities/field_caps_response.test.js

@@ -165,5 +165,22 @@ describe('index_patterns/field_capabilities/field_caps_response', () => {
         expect(child).not.toHaveProperty('subType');
       });
     });
+
+    it('sets default field formatter', () => {
+      const fields = readFieldCapsResponse({
+        fields: {
+          seconds: {
+            long: {
+              searchable: true,
+              aggregatable: true,
+              meta: {
+                unit: ['s'],
+              },
+            },
+          },
+        },
+      });
+      expect(fields[0].defaultFormatter).toEqual('s');
+    });
   });
 });

src/plugins/data_views/server/fetcher/lib/field_capabilities/field_caps_response.ts

@@ -12,6 +12,11 @@ import { castEsToKbnFieldTypeName } from '@kbn/field-types';
 import { shouldReadFieldFromDocValues } from './should_read_field_from_doc_values';
 import { FieldDescriptor } from '../..';
 
+// The array will have different values if values vary across indices
+const unitsArrayToFormatter = (unitArr: string[]) => {
+  return unitArr.find((unit) => unitArr[0] !== unit) ? undefined : unitArr[0];
+};
+
 /**
  *  Read the response from the _field_caps API to determine the type and
  *  "aggregatable"/"searchable" status of each field.
@@ -134,7 +139,11 @@ export function readFieldCapsResponse(
         timeSeriesMetricType = 'position';
       }
       const esType = types[0];
-      const field = {
+
+      const defaultFormatter =
+        capsByType[types[0]].meta?.unit && unitsArrayToFormatter(capsByType[types[0]].meta?.unit);
+
+      const field: FieldDescriptor = {
         name: fieldName,
         type: castEsToKbnFieldTypeName(esType),
         esTypes: types,
@@ -147,6 +156,11 @@ export function readFieldCapsResponse(
         timeSeriesMetric: timeSeriesMetricType,
         timeSeriesDimension: capsByType[types[0]].time_series_dimension,
       };
+
+      if (defaultFormatter) {
+        field.defaultFormatter = defaultFormatter;
+      }
+
       // This is intentionally using a "hash" and a "push" to be highly optimized with very large indexes
       agg.array.push(field);
       agg.hash[fieldName] = field;

src/plugins/data_views/server/rest_api_routes/internal/fields_for.ts

@@ -99,6 +99,7 @@ const FieldDescriptorSchema = schema.object({
   conflictDescriptions: schema.maybe(
     schema.recordOf(schema.string(), schema.arrayOf(schema.string()))
   ),
+  defaultFormatter: schema.maybe(schema.string()),
 });
 
 export const validate: FullValidationConfig<any, any, any> = {

test/functional/apps/management/data_views/_field_formatter.ts

@@ -413,6 +413,51 @@ export default function ({ getService, getPageObjects }: FtrProviderContext) {
         ]);
       });
     });
+
+    describe('default formatter by field meta value', () => {
+      const indexTitle = 'field_formats_management_functional_tests';
+
+      before(async () => {
+        if (await es.indices.exists({ index: indexTitle })) {
+          await es.indices.delete({ index: indexTitle });
+        }
+      });
+
+      it('should apply default formatter by field meta value', async () => {
+        await es.indices.create({
+          index: indexTitle,
+          body: {
+            mappings: {
+              properties: {
+                seconds: { type: 'long', meta: { unit: 's' } },
+              },
+            },
+          },
+        });
+
+        const docResult = await es.index({
+          index: indexTitle,
+          body: { seconds: 1234 },
+          refresh: 'wait_for',
+        });
+
+        const testDocumentId = docResult._id;
+
+        const indexPatternResult = await indexPatterns.create(
+          { title: `${indexTitle}*` }, // sidesteps field caching when index pattern is reused
+          { override: true }
+        );
+
+        await PageObjects.common.navigateToApp('discover', {
+          hash: `/doc/${indexPatternResult.id}/${indexTitle}?id=${testDocumentId}`,
+        });
+        await testSubjects.exists('doc-hit');
+
+        const renderedValue = await testSubjects.find(`tableDocViewRow-seconds-value`);
+        const text = await renderedValue.getVisibleText();
+        expect(text).to.be('20.57 min');
+      });
+    });
   });
 
   /**