README.mdx

id	slug	title	image	description	date	tags
kibDataPlugin	/kibana-dev-docs/key-concepts/data-plugin	Data services	https://source.unsplash.com/400x175/?Search	The data plugin contains services for searching, querying and filtering.	2020-12-02	kibana dev contributor api docs

data

The data plugin provides common data access services, such as search and query, for solutions and application developers.

Autocomplete

The autocomplete service provides suggestions for field names and values.

It is wired into the TopNavMenu component, but can be used independently.

Fetch Query Suggestions

The getQuerySuggestions function helps to construct a query.

    // `inputValue` is the user input
    const querySuggestions = await autocomplete.getQuerySuggestions({
        language: 'kuery',
        indexPatterns: [indexPattern],
        query: inputValue,
    });

Fetch Value Suggestions

The getValueSuggestions function returns suggestions for field values. This is helpful when you want to provide a user with options, for example when constructing a filter.

    // `inputValue` is the user input
    const valueSuggestions = await autocomplete.getValueSuggestions({
      indexPattern,
      field,
      query: inputValue,
    });

Query

The query service is responsible for managing the configuration of a search query (QueryState): filters, time range, query string, and settings such as the auto refresh behavior and saved queries.

It contains sub-services for each of those configurations:

• data.query.filterManager - Manages the filters component of a QueryState. The global filter state (filters that are persisted between applications) are owned by this service.
• data.query.timefilter - Responsible for the time range filter and the auto refresh behavior settings.
• data.query.queryString - Responsible for the query string and query language settings.
• data.query.savedQueries - Responsible for persisting a QueryState into a SavedObject, so it can be restored and used by other applications.

Any changes to the QueryState are published on the data.query.state$, which is useful when wanting to persist global state or run a search upon data changes.

A simple use case is:

function searchOnChange(indexPattern: IndexPattern, aggConfigs: AggConfigs) {
   data.query.state$.subscribe(() => {

       // Constuct the query portion of the search request
       const query = data.query.getEsQuery(indexPattern);

       // Construct a request
       const request = {
           params: {
               index: indexPattern.title,
               body: {
                   aggs: aggConfigs.toDsl(),
                   query,
               },
           },
       };

       // Search with the `data.query` config
       const search$ = data.search.search(request);

       ...
   });
}

You can also retrieve a snapshot of the whole QueryState by using data.query.getState()

Timefilter

data.query.timefilter is responsible for the time range filter and the auto refresh behavior settings.

Autorefresh

Timefilter provides an API for setting and getting current auto refresh state:

const { pause, value } = data.query.timefilter.timefilter.getRefreshInterval();

data.query.timefilter.timefilter.setRefreshInterval({ pause: false, value: 5000 }); // start auto refresh with 5 seconds interval

Timefilter API also provides an autoRefreshFetch$ observables that apps should use to get notified when it is time to refresh data because of auto refresh. This API expects apps to confirm when they are done with reloading the data. The confirmation mechanism is needed to prevent excessive queue of fetches.

import { refetchData } from '../my-app'

const autoRefreshFetch$ = data.query.timefilter.timefilter.getAutoRefreshFetch$()
autoRefreshFetch$.subscribe((done) => {
  try {
    await refetchData();
  } finally {
    // confirm that data fetching was finished
    done();
  }
})

function unmount() {
  // don't forget to unsubscribe when leaving the app
  autoRefreshFetch$.unsubscribe()
}

Search

Provides access to Elasticsearch using the high-level SearchSource API or low-level Search Strategies.

SearchSource

The SearchSource API is a convenient way to construct and run an Elasticsearch search query.

    const searchSource = await data.search.searchSource.create();
    const searchResponse = await searchSource
      .setParent(undefined)
      .setField('index', indexPattern)
      .setField('filter', filters)
      .fetch();

Low-level search

Default Search Strategy

One benefit of using the low-level search API, is partial response support, allowing for a better and more responsive user experience.

    import { isRunningResponse } from '../plugins/data/public';

    const search$ = data.search.search(request)
        .subscribe({
        next: (response) => {
            if (!isRunningResponse(response)) {
                // Final result
                search$.unsubscribe();
            } else {
                // Partial result - you can update the UI, but data is still loading
            }
        },
        error: (e: Error) => {
            // Show customized toast notifications.
            // You may choose to handle errors differently if you prefer.
            data.search.showError(e);
        },
    });