Client configurationedit

The client is designed to be easily configured as you see fit for your needs, following you can see all the possible basic options that you can use to configure it.

const { Client } = require('@elastic/elasticsearch')

const client = new Client({
  node: 'http://localhost:9200',
  maxRetries: 5,
  requestTimeout: 60000,
  sniffOnStart: true
})

Basic optionsedit

node or nodes

The Elasticsearch endpoint to use. It can be a single string or an array of strings:

node: 'http://localhost:9200'

Or it can be an object (or an array of objects) that represents the node

node: {
  url: new URL('http://localhost:9200'),
  ssl: 'ssl options',
  agent: 'http agent options',
  id: 'custom node id',
  headers: { 'custom': 'headers' }
  roles: {
    master: true,
    data: true,
    ingest: true,
    ml: false
  }
}

auth

Your authentication data. You can use both Basic authentication and ApiKey. See Authentication for more details. Default: null

Basic authentication:

auth: {
  username: 'elastic',
  password: 'changeme'
}

ApiKey authentication:

auth: {
  apiKey: 'base64EncodedKey'
}

maxRetries

number - Max number of retries for each request. Default: 3

requestTimeout

number - Max request timeout for each request. Default: 30000

pingTimeout

number - Max ping request timeout for each request. Default: 3000

sniffInterval

number, boolean - Perform a sniff operation every n milliseconds. Default: false

sniffOnStart

boolean - Perform a sniff once the client is started. Default: false

sniffEndpoint

string - Endpoint to ping during a sniff. Default: '_nodes/_all/http'

sniffOnConnectionFault

boolean - Perform a sniff on connection fault. Default: false

resurrectStrategy

string - Configure the node resurrection strategy. Options: 'ping', 'optimistic', 'none' Default: 'ping'

suggestCompression

boolean - Adds accept-encoding header to every request. Default: false

compression

string, boolean - Enables gzip request body compression. Options: 'gzip', false Default: false

ssl

http.SecureContextOptions - ssl configuraton. Default: null

agent

http.AgentOptions, function - http agent options, or a function that returns an actual http agent instance. Default: null

const client = new Client({
  node: 'http://localhost:9200',
  agent: { agent: 'options' }
})

const client = new Client({
  node: 'http://localhost:9200',
  agent: () => new CustomAgent()
})

nodeFilter

function - Filters which node not to use for a request. Default:

function defaultNodeFilter (node) {
  // avoid master only nodes
  if (node.roles.master === true &&
      node.roles.data === false &&
      node.roles.ingest === false) {
    return false
  }
  return true
}

nodeSelector

function - custom selection strategy. Options: 'round-robin', 'random', custom function Default: 'round-robin' Custom function example:

function nodeSelector (connections) {
  const index = calculateIndex()
  return connections[index]
}

generateRequestId

function - function to generate the request id for every request, it takes two parameters, the request parameters and options. By default it generates an incremental integer for every request. Custom function example:

function generateRequestId (params, options) {
  // your id generation logic
  // must be syncronous
  return 'id'
}

name

string - The name to identify the client instance in the events. Default: elasticsearch-js

headers

object - A set of custom headers to send in every request. Default: {}

cloud

object - Custom configuration for connecting to Elastic Cloud. See Authentication for more details. Default: null Cloud configuration example:

const client = new Client({
  cloud: {
    id: 'name:bG9jYWxob3N0JGFiY2QkZWZnaA=='
  },
  auth: {
    username: 'elastic',
    password: 'changeme'
  }
})

Advanced configurationedit

If you need to customize the client behavior heavily, you are in the right place! The client allows you to customize the following internals:

  • Transport class
  • ConnectionPool class
  • Connection class
  • Serializer class

Transportedit

This class is responsible to perform the request to Elasticsearch and handling errors, it also handle the sniffing.

const { Client, Transport } = require('@elastic/elasticsearch')

class MyTransport extends Transport {
  request (params, options, callback) {
    // your code
  }
}

const client = new Client({
    Transport: MyTransport
})

Sometimes you just need to inject a little snippet of your code and then continue to use the usual client code, in such case, you should call super.method.

class MyTransport extends Transport {
  request (params, options, callback) {
    // your code
    super.request(params, options, callback)
  }
}

ConnectionPooledit

This class is responsible for keeping in memory all the Elasticsearch Connection that we are using, there is a single Connection for every node. Moreover, the connection pool will handle the resurrection strategies and the updates of the pool.

const { Client, ConnectionPool } = require('@elastic/elasticsearch')

class MyConnectionPool extends ConnectionPool {
  markAlive (connection) {
    // your code
    super.markAlive(connection)
  }
}

const client = new Client({
    ConnectionPool: MyConnectionPool
})

Connectionedit

This class represents a single Node, it holds every information we have on the node, such as roles, id, URL, custom headers and so on. The actual HTTP request is performed here, this means that if you want to swap the default HTTP client (Node.js core), you should override this class request method.

const { Client, Connection } = require('@elastic/elasticsearch')

class MyConnection extends Connection {
  request (params, callback) {
    // your code
  }
}

const client = new Client({
  Connection: MyConnection
})

Serializeredit

This class is responsible of the serialization of every request, it offers the following methods:

  • serialize(object: any): string;, serializes request objects
  • deserialize(json: string): any;, deserializes response strings
  • ndserialize(array: any[]): string;, serializes bulk request objects
  • qserialize(object: any): string;, serializes request query parameters
const { Client, Serializer } = require('@elastic/elasticsearch')

class MySerializer extends Serializer {
  serialize (object) {
    // your code
  }
}

const client = new Client({
  Serializer: MySerializer
})