diff --git a/src/core/MIGRATION_EXAMPLES.md b/src/core/MIGRATION_EXAMPLES.md index 6bb5a845ea2ab..d630fec652a37 100644 --- a/src/core/MIGRATION_EXAMPLES.md +++ b/src/core/MIGRATION_EXAMPLES.md @@ -27,6 +27,10 @@ APIs to their New Platform equivalents. - [Changes in structure compared to legacy](#changes-in-structure-compared-to-legacy) - [Remarks](#remarks) - [UiSettings](#uisettings) + - [Elasticsearch client](#elasticsearch-client) + - [Client API Changes](#client-api-changes) + - [Accessing the client from a route handler](#accessing-the-client-from-a-route-handler) + - [Creating a custom client](#creating-a-custom-client) ## Configuration @@ -1003,4 +1007,259 @@ setup(core: CoreSetup){ }, }) } -``` \ No newline at end of file +``` + +## Elasticsearch client + +The new elasticsearch client is a thin wrapper around `@elastic/elasticsearch`'s `Client` class. Even if the API +is quite close to the legacy client Kibana was previously using, there are some subtle changes to take into account +during migration. + +[Official documentation](https://www.elastic.co/guide/en/elasticsearch/client/javascript-api/current/index.html) + +### Client API Changes + +The most significant changes for the consumers are the following: + +- internal / current user client accessors has been renamed and are now properties instead of functions + - `callAsInternalUser('ping')` -> `asInternalUser.ping()` + - `callAsCurrentUser('ping')` -> `asCurrentUser.ping()` + +- the API now reflects the `Client`'s instead of leveraging the string-based endpoint names the `LegacyAPICaller` was using + +before: + +```ts +const body = await client.callAsInternalUser('indices.get', { index: 'id' }); +``` + +after: + +```ts +const { body } = await client.asInternalUser.indices.get({ index: 'id' }); +``` + +- calling any ES endpoint now returns the whole response object instead of only the body payload + +before: + +```ts +const body = await legacyClient.callAsInternalUser('get', { id: 'id' }); +``` + +after: + +```ts +const { body } = await client.asInternalUser.get({ id: 'id' }); +``` + +Note that more information from the ES response is available: + +```ts +const { + body, // response payload + statusCode, // http status code of the response + headers, // response headers + warnings, // warnings returned from ES + meta // meta information about the request, such as request parameters, number of attempts and so on +} = await client.asInternalUser.get({ id: 'id' }); +``` + +- all API methods are now generic to allow specifying the response body type + +before: + +```ts +const body: GetResponse = await legacyClient.callAsInternalUser('get', { id: 'id' }); +``` + +after: + +```ts +// body is of type `GetResponse` +const { body } = await client.asInternalUser.get({ id: 'id' }); +// fallback to `Record` if unspecified +const { body } = await client.asInternalUser.get({ id: 'id' }); +``` + +- the returned error types changed + +There are no longer specific errors for every HTTP status code (such as `BadRequest` or `NotFound`). A generic +`ResponseError` with the specific `statusCode` is thrown instead. + +before: + +```ts +import { errors } from 'elasticsearch'; +try { + await legacyClient.callAsInternalUser('ping'); +} catch(e) { + if(e instanceof errors.NotFound) { + // do something + } +} +``` + +after: + +```ts +import { errors } from '@elastic/elasticsearch'; +try { + await client.asInternalUser.ping(); +} catch(e) { + if(e instanceof errors.ResponseError && e.statusCode === 404) { + // do something + } + // also possible, as all errors got a name property with the name of the class, + // so this slightly better in term of performances + if(e.name === 'ResponseError' && e.statusCode === 404) { + // do something + } +} +``` + +- the parameter property names changed from camelCase to snake_case + +Even if technically, the javascript client accepts both formats, the typescript definitions are only defining the snake_case +properties. + +before: + +```ts +legacyClient.callAsCurrentUser('get', { + id: 'id', + storedFields: ['some', 'fields'], +}) +``` + +after: + +```ts +client.asCurrentUser.get({ + id: 'id', + stored_fields: ['some', 'fields'], +}) +``` + +- the request abortion API changed + +All promises returned from the client API calls now have an `abort` method that can be used to cancel the request. + +before: + +```ts +const controller = new AbortController(); +legacyClient.callAsCurrentUser('ping', {}, { + signal: controller.signal, +}) +// later +controller.abort(); +``` + +after: + +```ts +const request = client.asCurrentUser.ping(); +// later +request.abort(); +``` + +- it is now possible to override headers when performing specific API calls. + +Note that doing so is strongly discouraged due to potential side effects with the ES service internal +behavior when scoping as the internal or as the current user. + +```ts +const request = client.asCurrentUser.ping({}, { + headers: { + authorization: 'foo', + custom: 'bar', + } +}); +``` + +Please refer to the [Breaking changes list](https://www.elastic.co/guide/en/elasticsearch/client/javascript-api/current/breaking-changes.html) +for more information about the changes between the legacy and new client. + +### Accessing the client from a route handler + +Apart from the API format change, accessing the client from within a route handler +did not change. As it was done for the legacy client, a preconfigured scoped client +bound to the request is accessible using `core` context provider: + +before: + +```ts +router.get( + { + path: '/my-route', + }, + async (context, req, res) => { + const { client } = context.core.elasticsearch.legacy; + // call as current user + const res = await client.callAsCurrentUser('ping'); + // call as internal user + const res2 = await client.callAsInternalUser('search', options); + return res.ok({ body: 'ok' }); + } +); +``` + +after: + +```ts +router.get( + { + path: '/my-route', + }, + async (context, req, res) => { + const { client } = context.core.elasticsearch; + // call as current user + const res = await client.asCurrentUser.ping(); + // call as internal user + const res2 = await client.asInternalUser.search(options); + return res.ok({ body: 'ok' }); + } +); +``` + +### Creating a custom client + +Note that the `plugins` option is now longer available on the new client. As the API is now exhaustive, adding custom +endpoints using plugins should no longer be necessary. + +The API to create custom clients did not change much: + +before: + +```ts +const customClient = coreStart.elasticsearch.legacy.createClient('my-custom-client', customConfig); +// do something with the client, such as +await customClient.callAsInternalUser('ping'); +// custom client are closable +customClient.close(); +``` + +after: + +```ts +const customClient = coreStart.elasticsearch.createClient('my-custom-client', customConfig); +// do something with the client, such as +await customClient.asInternalUser.ping(); +// custom client are closable +customClient.close(); +``` + +If, for any reasons, one still needs to reach an endpoint not listed on the client API, using `request.transport` +is still possible: + +```ts +const { body } = await client.asCurrentUser.transport.request({ + method: 'get', + path: '/my-custom-endpoint', + body: { my: 'payload'}, + querystring: { param: 'foo' } +}) +``` + +Remark: the new client creation API is now only available from the `start` contract of the elasticsearch service.