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Elastic Docs ›Elasticsearch JavaScript Client [8.15]

Client helpers

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Client helpers

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The client comes with an handy collection of helpers to give you a more comfortable experience with some APIs.

The client helpers are experimental, and the API may change in the next minor releases. The helpers will not work in any Node.js version lower than 10.

Bulk helper

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Added in v7.7.0

Running bulk requests can be complex due to the shape of the API, this helper aims to provide a nicer developer experience around the Bulk API.

Usage

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const { createReadStream } = require('fs')
const split = require('split2')
const { Client } = require('@elastic/elasticsearch')

const client = new Client({
  cloud: { id: '<cloud-id>' },
  auth: { apiKey: 'base64EncodedKey' }
})
const result = await client.helpers.bulk({
  datasource: createReadStream('./dataset.ndjson').pipe(split()),
  onDocument (doc) {
    return {
      index: { _index: 'my-index' }
    }
  }
})

console.log(result)
// {
//   total: number,
//   failed: number,
//   retry: number,
//   successful: number,
//   time: number,
//   bytes: number,
//   aborted: boolean
// }

To create a new instance of the Bulk helper, access it as shown in the example above, the configuration options are:

datasource

An array, async generator or a readable stream with the data you need to index/create/update/delete. It can be an array of strings or objects, but also a stream of json strings or JavaScript objects.
If it is a stream, we recommend to use the split2 package, that splits the stream on new lines delimiters.
This parameter is mandatory.

const { createReadStream } = require('fs')
const split = require('split2')
const b = client.helpers.bulk({
  // if you just use split(), the data will be used as array of strings
  datasource: createReadStream('./dataset.ndjson').pipe(split())
  // if you need to manipulate the data, you can pass JSON.parse to split
  datasource: createReadStream('./dataset.ndjson').pipe(split(JSON.parse))
})

onDocument

A function that is called for each document of the datasource. Inside this function you can manipulate the document and you must return the operation you want to execute with the document. Look at the Bulk API documentation to see the supported operations.
This parameter is mandatory.

const b = client.helpers.bulk({
  onDocument (doc) {
    return {
      index: { _index: 'my-index' }
    }
  }
})

onDrop

A function that is called for everytime a document can’t be indexed and it has reached the maximum amount of retries.

const b = client.helpers.bulk({
  onDrop (doc) {
    console.log(doc)
  }
})

onSuccess

A function that is called for each successful operation in the bulk request, which includes the result from Elasticsearch along with the original document that was sent, or null for delete operations.

const b = client.helpers.bulk({
  onSuccess ({ result, document }) {
    console.log(`SUCCESS: Document ${result.index._id} indexed to ${result.index._index}`)
  }
})

flushBytes

The size of the bulk body in bytes to reach before to send it. Default of 5MB.
Default: 5000000

const b = client.helpers.bulk({
  flushBytes: 1000000
})

flushInterval

How much time (in milliseconds) the helper waits before flushing the body from the last document read.
Default: 30000

const b = client.helpers.bulk({
  flushInterval: 30000
})

concurrency

How many request is executed at the same time.
Default: 5

const b = client.helpers.bulk({
  concurrency: 10
})

retries

How many times a document is retried before to call the onDrop callback.
Default: Client max retries.

const b = client.helpers.bulk({
  retries: 3
})

wait

How much time to wait before retries in milliseconds.
Default: 5000.

const b = client.helpers.bulk({
  wait: 3000
})

refreshOnCompletion

If true, at the end of the bulk operation it runs a refresh on all indices or on the specified indices.
Default: false.

const b = client.helpers.bulk({
  refreshOnCompletion: true
  // or
  refreshOnCompletion: 'index-name'
})

Supported operations

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Index
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client.helpers.bulk({
  datasource: myDatasource,
  onDocument (doc) {
    return {
      index: { _index: 'my-index' }
    }
  }
})
Create
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client.helpers.bulk({
  datasource: myDatasource,
  onDocument (doc) {
    return {
      create: { _index: 'my-index', _id: doc.id }
    }
  }
})
Update
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client.helpers.bulk({
  datasource: myDatasource,
  onDocument (doc) {
    // Note that the update operation requires you to return
    // an array, where the first element is the action, while
    // the second are the document option
    return [
      { update: { _index: 'my-index', _id: doc.id } },
      { doc_as_upsert: true }
    ]
  }
})
Delete
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client.helpers.bulk({
  datasource: myDatasource,
  onDocument (doc) {
    return {
      delete: { _index: 'my-index', _id: doc.id }
    }
  }
})

Abort a bulk operation

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If needed, you can abort a bulk operation at any time. The bulk helper returns a thenable, which has an abort method.

The abort method stops the execution of the bulk operation, but if you are using a concurrency higher than one, the operations that are already running will not be stopped.

const { createReadStream } = require('fs')
const split = require('split2')
const { Client } = require('@elastic/elasticsearch')

const client = new Client({
  cloud: { id: '<cloud-id>' },
  auth: { apiKey: 'base64EncodedKey' }
})
const b = client.helpers.bulk({
  datasource: createReadStream('./dataset.ndjson').pipe(split()),
  onDocument (doc) {
    return {
      index: { _index: 'my-index' }
    }
  },
  onDrop (doc) {
    b.abort()
  }
})

console.log(await b)

Passing custom options to the Bulk API

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You can pass any option supported by the link: Bulk API to the helper, and the helper uses those options in conjunction with the Bulk API call.

const result = await client.helpers.bulk({
  datasource: [...],
  onDocument (doc) {
    return {
      index: { _index: 'my-index' }
    }
  },
  pipeline: 'my-pipeline'
})

Usage with an async generator

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

async function * generator () {
  const dataset = [
    { user: 'jon', age: 23 },
    { user: 'arya', age: 18 },
    { user: 'tyrion', age: 39 }
  ]
  for (const doc of dataset) {
    yield doc
  }
}

const client = new Client({
  cloud: { id: '<cloud-id>' },
  auth: { apiKey: 'base64EncodedKey' }
})
const result = await client.helpers.bulk({
  datasource: generator(),
  onDocument (doc) {
    return {
      index: { _index: 'my-index' }
    }
  }
})

console.log(result)

Modifying a document before operation

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Added in v8.8.2

If you need to modify documents in your datasource before it is sent to Elasticsearch, you can return an array in the onDocument function rather than an operation object. The first item in the array must be the operation object, and the second item must be the document or partial document object as you’d like it to be sent to Elasticsearch.

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

const client = new Client({
  cloud: { id: '<cloud-id>' },
  auth: { apiKey: 'base64EncodedKey' }
})
const result = await client.helpers.bulk({
  datasource: [...],
  onDocument (doc) {
    return [
      { index: { _index: 'my-index' } },
      { ...doc, favorite_color: 'mauve' },
    ]
  }
})

console.log(result)

Multi search helper

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Added in v7.8.0

If you send search request at a high rate, this helper might be useful for you. It uses the multi search API under the hood to batch the requests and improve the overall performances of your application. The result exposes a documents property as well, which allows you to access directly the hits sources.

Usage

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

const client = new Client({
  cloud: { id: '<cloud-id>' },
  auth: { apiKey: 'base64EncodedKey' }
})
const m = client.helpers.msearch()

m.search(
    { index: 'stackoverflow' },
    { query: { match: { title: 'javascript' } } }
  )
  .then(result => console.log(result.body)) // or result.documents
  .catch(err => console.error(err))

To create a new instance of the multi search (msearch) helper, you should access it as shown in the example above, the configuration options are:

operations

How many search operations should be sent in a single msearch request.
Default: 5

const m = client.helpers.msearch({
  operations: 10
})

flushInterval

How much time (in milliseconds) the helper waits before flushing the operations from the last operation read.
Default: 500

const m = client.helpers.msearch({
  flushInterval: 500
})

concurrency

How many request is executed at the same time.
Default: 5

const m = client.helpers.msearch({
  concurrency: 10
})

retries

How many times an operation is retried before to resolve the request. An operation is retried only in case of a 429 error.
Default: Client max retries.

const m = client.helpers.msearch({
  retries: 3
})

wait

How much time to wait before retries in milliseconds.
Default: 5000.

const m = client.helpers.msearch({
  wait: 3000
})

Stopping the msearch helper

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If needed, you can stop an msearch processor at any time. The msearch helper returns a thenable, which has an stop method.

If you are creating multiple msearch helpers instances and using them for a limitied period of time, remember to always use the stop method once you have finished using them, otherwise your application will start leaking memory.

The stop method accepts an optional error, that will be dispatched every subsequent search request.

The stop method stops the execution of the msearch processor, but if you are using a concurrency higher than one, the operations that are already running will not be stopped.

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

const client = new Client({
  cloud: { id: '<cloud-id>' },
  auth: { apiKey: 'base64EncodedKey' }
})
const m = client.helpers.msearch()

m.search(
    { index: 'stackoverflow' },
    { query: { match: { title: 'javascript' } } }
  )
  .then(result => console.log(result.body))
  .catch(err => console.error(err))

m.search(
    { index: 'stackoverflow' },
    { query: { match: { title: 'ruby' } } }
  )
  .then(result => console.log(result.body))
  .catch(err => console.error(err))

setImmediate(() => m.stop())

Search helper

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Added in v7.7.0

A simple wrapper around the search API. Instead of returning the entire result object it returns only the search documents source. For improving the performances, this helper automatically adds filter_path=hits.hits._source to the query string.

const documents = await client.helpers.search({
  index: 'stackoverflow',
  query: {
    match: {
      title: 'javascript'
    }
  }
})

for (const doc of documents) {
  console.log(doc)
}

Scroll search helper

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Added in v7.7.0

This helpers offers a simple and intuitive way to use the scroll search API. Once called, it returns an async iterator which can be used in conjuction with a for-await…​of. It handles automatically the 429 error and uses the maxRetries option of the client.

const scrollSearch = client.helpers.scrollSearch({
  index: 'stackoverflow',
  query: {
    match: {
      title: 'javascript'
    }
  }
})

for await (const result of scrollSearch) {
  console.log(result)
}

Clear a scroll search

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If needed, you can clear a scroll search by calling result.clear():

for await (const result of scrollSearch) {
  if (condition) {
    await result.clear()
  }
}

Quickly getting the documents

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If you only need the documents from the result of a scroll search, you can access them via result.documents:

for await (const result of scrollSearch) {
  console.log(result.documents)
}

Scroll documents helper

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Added in v7.7.0

It works in the same way as the scroll search helper, but it returns only the documents instead. Note, every loop cycle returns a single document, and you can’t use the clear method. For improving the performances, this helper automatically adds filter_path=hits.hits._source to the query string.

const scrollSearch = client.helpers.scrollDocuments({
  index: 'stackoverflow',
  query: {
    match: {
      title: 'javascript'
    }
  }
})

for await (const doc of scrollSearch) {
  console.log(doc)
}

ES|QL helper

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ES|QL queries can return their results in several formats. The default JSON format returned by ES|QL queries contains arrays of values for each row, with column names and types returned separately:

Usage

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toRecords
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Added in v8.14.0

The default JSON format returned by ES|QL queries contains arrays of values for each row, with column names and types returned separately:

{
  "columns": [
    { "name": "@timestamp", "type": "date" },
    { "name": "client_ip", "type": "ip" },
    { "name": "event_duration", "type": "long" },
    { "name": "message", "type": "keyword" }
  ],
  "values": [
    [
      "2023-10-23T12:15:03.360Z",
      "172.21.2.162",
      3450233,
      "Connected to 10.1.0.3"
    ],
    [
      "2023-10-23T12:27:28.948Z",
      "172.21.2.113",
      2764889,
      "Connected to 10.1.0.2"
    ]
  ]
}

In many cases, it’s preferable to operate on an array of objects, one object per row, rather than an array of arrays. The ES|QL toRecords helper converts row data into objects.

await client.helpers
  .esql({ query: 'FROM sample_data | LIMIT 2' })
  .toRecords()
// =>
// {
//   "columns": [
//     { "name": "@timestamp", "type": "date" },
//     { "name": "client_ip", "type": "ip" },
//     { "name": "event_duration", "type": "long" },
//     { "name": "message", "type": "keyword" }
//   ],
//   "records": [
//     {
//       "@timestamp": "2023-10-23T12:15:03.360Z",
//       "client_ip": "172.21.2.162",
//       "event_duration": 3450233,
//       "message": "Connected to 10.1.0.3"
//     },
//     {
//       "@timestamp": "2023-10-23T12:27:28.948Z",
//       "client_ip": "172.21.2.113",
//       "event_duration": 2764889,
//       "message": "Connected to 10.1.0.2"
//     },
//   ]
// }

In TypeScript, you can declare the type that toRecords returns:

type EventLog = {
  '@timestamp': string,
  client_ip: string,
  event_duration: number,
  message: string,
}

const result = await client.helpers
  .esql({ query: 'FROM sample_data | LIMIT 2' })
  .toRecords<EventLog>()
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