[index patterns] Add pattern validation method to index patterns fetcher

docs/development/plugins/data/server/kibana-plugin-plugins-data-server.indexpatternsfetcher.md

@@ -22,4 +22,5 @@ export declare class IndexPatternsFetcher
 |  --- | --- | --- |
 |  [getFieldsForTimePattern(options)](./kibana-plugin-plugins-data-server.indexpatternsfetcher.getfieldsfortimepattern.md) |  | Get a list of field objects for a time pattern |
 |  [getFieldsForWildcard(options)](./kibana-plugin-plugins-data-server.indexpatternsfetcher.getfieldsforwildcard.md) |  | Get a list of field objects for an index pattern that may contain wildcards |
+|  [validatePatternListActive(patternList)](./kibana-plugin-plugins-data-server.indexpatternsfetcher.validatepatternlistactive.md) |  | Returns an index pattern list of only those index pattern strings in the given list that return indices |
 

docs/development/plugins/data/server/kibana-plugin-plugins-data-server.indexpatternsfetcher.validatepatternlistactive.md

@@ -0,0 +1,24 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [kibana-plugin-plugins-data-server](./kibana-plugin-plugins-data-server.md) &gt; [IndexPatternsFetcher](./kibana-plugin-plugins-data-server.indexpatternsfetcher.md) &gt; [validatePatternListActive](./kibana-plugin-plugins-data-server.indexpatternsfetcher.validatepatternlistactive.md)
+
+## IndexPatternsFetcher.validatePatternListActive() method
+
+Returns an index pattern list of only those index pattern strings in the given list that return indices
+
+<b>Signature:</b>
+
+```typescript
+validatePatternListActive(patternList: string[]): Promise<string[]>;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  patternList | <code>string[]</code> |  |
+
+<b>Returns:</b>
+
+`Promise<string[]>`
+

src/plugins/data/server/index_patterns/fetcher/index_patterns_fetcher.test.ts

@@ -0,0 +1,50 @@
+/*
+ * 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 { IndexPatternsFetcher } from '.';
+import { ElasticsearchClient } from 'kibana/server';
+
+describe('Index Pattern Fetcher - server', () => {
+  let indexPatterns: IndexPatternsFetcher;
+  let esClient: ElasticsearchClient;
+  const emptyResponse = {
+    body: {
+      indices: [],
+    },
+  };
+  const response = {
+    body: {
+      indices: ['hello', 'world'],
+    },
+  };
+  const patternList = ['a', 'b', 'c'];
+  beforeEach(() => {
+    esClient = ({
+      transport: {
+        request: jest.fn().mockReturnValueOnce(emptyResponse).mockReturnValue(response),
+      },
+    } as unknown) as ElasticsearchClient;
+    indexPatterns = new IndexPatternsFetcher(esClient);
+  });
+
+  it('Removes pattern without matching indices', async () => {
+    const result = await indexPatterns.validatePatternListActive(patternList);
+    expect(result).toEqual(['b', 'c']);
+  });
+
+  it('Returns all patterns when all match indices', async () => {
+    esClient = ({
+      transport: {
+        request: jest.fn().mockReturnValue(response),
+      },
+    } as unknown) as ElasticsearchClient;
+    indexPatterns = new IndexPatternsFetcher(esClient);
+    const result = await indexPatterns.validatePatternListActive(patternList);
+    expect(result).toEqual(patternList);
+  });
+});

src/plugins/data/server/index_patterns/fetcher/index_patterns_fetcher.ts

@@ -58,16 +58,24 @@ export class IndexPatternsFetcher {
     rollupIndex?: string;
   }): Promise<FieldDescriptor[]> {
     const { pattern, metaFields, fieldCapsOptions, type, rollupIndex } = options;
+    const patternList = Array.isArray(pattern) ? pattern : pattern.split(',');
+    let patternListActive: string[] = patternList;
+    // if only one pattern, don't bother with validation. We let getFieldCapabilities fail if the single pattern is bad regardless
+    if (patternList.length > 1) {
+      patternListActive = await this.validatePatternListActive(patternList);
+    }
     const fieldCapsResponse = await getFieldCapabilities(
       this.elasticsearchClient,
-      pattern,
+      // if none of the patterns are active, pass the original list to get an error
+      patternListActive.length > 0 ? patternListActive : patternList,
       metaFields,
       {
         allow_no_indices: fieldCapsOptions
           ? fieldCapsOptions.allow_no_indices
           : this.allowNoIndices,
       }
     );
+
     if (type === 'rollup' && rollupIndex) {
       const rollupFields: FieldDescriptor[] = [];
       const rollupIndexCapabilities = getCapabilitiesForRollupIndices(
@@ -118,4 +126,25 @@ export class IndexPatternsFetcher {
     }
     return await getFieldCapabilities(this.elasticsearchClient, indices, metaFields);
   }
+
+  /**
+   *  Returns an index pattern list of only those index pattern strings in the given list that return indices
+   *
+   *  @param patternList string[]
+   *  @return {Promise<string[]>}
+   */
+  async validatePatternListActive(patternList: string[]) {
+    const result = await Promise.all(
+      patternList.map((pattern) =>
+        this.elasticsearchClient.count({
+          index: pattern,
+        })
+      )
+    );
+    return result.reduce(
+      (acc: string[], { body: { count } }, patternListIndex) =>
+        count > 0 ? [...acc, patternList[patternListIndex]] : acc,
+      []
+    );
+  }
 }

src/plugins/data/server/server.api.md

@@ -885,6 +885,7 @@ export class IndexPatternsFetcher {
         type?: string;
         rollupIndex?: string;
     }): Promise<FieldDescriptor[]>;
+    validatePatternListActive(patternList: string[]): Promise<string[]>;
 }
 
 // Warning: (ae-forgotten-export) The symbol "IndexPatternsServiceStart" needs to be exported by the entry point index.d.ts

test/api_integration/apis/index_patterns/fields_for_wildcard_route/response.js

@@ -17,6 +17,55 @@ export default function ({ getService }) {
     expect(resp.body.fields).to.eql(sortBy(resp.body.fields, 'name'));
   };
 
+  const testFields = [
+    {
+      type: 'boolean',
+      esTypes: ['boolean'],
+      searchable: true,
+      aggregatable: true,
+      name: 'bar',
+      readFromDocValues: true,
+    },
+    {
+      type: 'string',
+      esTypes: ['text'],
+      searchable: true,
+      aggregatable: false,
+      name: 'baz',
+      readFromDocValues: false,
+    },
+    {
+      type: 'string',
+      esTypes: ['keyword'],
+      searchable: true,
+      aggregatable: true,
+      name: 'baz.keyword',
+      readFromDocValues: true,
+      subType: { multi: { parent: 'baz' } },
+    },
+    {
+      type: 'number',
+      esTypes: ['long'],
+      searchable: true,
+      aggregatable: true,
+      name: 'foo',
+      readFromDocValues: true,
+    },
+    {
+      aggregatable: true,
+      esTypes: ['keyword'],
+      name: 'nestedField.child',
+      readFromDocValues: true,
+      searchable: true,
+      subType: {
+        nested: {
+          path: 'nestedField',
+        },
+      },
+      type: 'string',
+    },
+  ];
+
   describe('fields_for_wildcard_route response', () => {
     before(() => esArchiver.load('index_patterns/basic_index'));
     after(() => esArchiver.unload('index_patterns/basic_index'));
@@ -26,54 +75,7 @@ export default function ({ getService }) {
         .get('/api/index_patterns/_fields_for_wildcard')
         .query({ pattern: 'basic_index' })
         .expect(200, {
-          fields: [
-            {
-              type: 'boolean',
-              esTypes: ['boolean'],
-              searchable: true,
-              aggregatable: true,
-              name: 'bar',
-              readFromDocValues: true,
-            },
-            {
-              type: 'string',
-              esTypes: ['text'],
-              searchable: true,
-              aggregatable: false,
-              name: 'baz',
-              readFromDocValues: false,
-            },
-            {
-              type: 'string',
-              esTypes: ['keyword'],
-              searchable: true,
-              aggregatable: true,
-              name: 'baz.keyword',
-              readFromDocValues: true,
-              subType: { multi: { parent: 'baz' } },
-            },
-            {
-              type: 'number',
-              esTypes: ['long'],
-              searchable: true,
-              aggregatable: true,
-              name: 'foo',
-              readFromDocValues: true,
-            },
-            {
-              aggregatable: true,
-              esTypes: ['keyword'],
-              name: 'nestedField.child',
-              readFromDocValues: true,
-              searchable: true,
-              subType: {
-                nested: {
-                  path: 'nestedField',
-                },
-              },
-              type: 'string',
-            },
-          ],
+          fields: testFields,
         })
         .then(ensureFieldsAreSorted);
     });
@@ -162,11 +164,19 @@ export default function ({ getService }) {
         .then(ensureFieldsAreSorted);
     });
 
-    it('returns 404 when the pattern does not exist', async () => {
+    it('returns fields when one pattern exists and the other does not', async () => {
+      await supertest
+        .get('/api/index_patterns/_fields_for_wildcard')
+        .query({ pattern: 'bad_index,basic_index' })
+        .expect(200, {
+          fields: testFields,
+        });
+    });
+    it('returns 404 when no patterns exist', async () => {
       await supertest
         .get('/api/index_patterns/_fields_for_wildcard')
         .query({
-          pattern: '[non-existing-pattern]its-invalid-*',
+          pattern: 'bad_index',
         })
         .expect(404);
     });