use savedObjectsClient to get index-patterns

[nreese]

fixes #25389

Index patterns were getting loaded via a canvas web service /api/canvas/es_indices. Under the covers, es_indices was quering directly against the kibana elasticsearch index.

This PR removes the es_indices web service and just uses the savedObjectsClient

[elasticmachine]

Pinging @elastic/kibana-canvas

[elasticmachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request

[cqliu1]

LGTM 👍

We're also using a canvas web service (/api/canvas/es_fields) to retrieve the fields of a given index. Can we use the savedObjectsClient for getting the fields as well?

It's not a blocker for this PR, but we should make the same change for getFields.

[nreese]

We're also using a canvas web service (/api/canvas/es_fields) to retrieve the fields of a given index. Can we use the savedObjectsClient for getting the fields as well?

Not without some extra leg work. Kibana uses the indexPatterns service to get the list of fields for an index-pattern. This service is still coupled with angular.

The GIS application is using this solution to access the index patterns service in react

export let indexPatternService;

uiModules.get('app/gis').run(($injector) => {
  indexPatternService = $injector.get('indexPatterns');
});

Then react code can import the service like this

import { indexPatternService } from '../../../kibana_services';

indexPattern = await indexPatternService.get(indexPatternId);

[elasticmachine]

💔 Build Failed

• continuous-integration/kibana-ci/pull-request

[elasticmachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request