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Elastic Docs ›Elasticsearch Node.js client [5.x] ›Observability

Correlation id

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Correlation id

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Correlating events can be quite hard, especially if there are many events at the same time. The client offers you an automatic (and configurable) system to help you handle this problem.

const { Client } = require('@elastic/elasticsearch')
const client = new Client({ node: 'http://localhost:9200' })

client.on('request', (err, result) => {
  const { id } = result.meta.request
  if (err) {
    console.log({ error: err, reqId: id })
  }
})

client.on('response', (err, result) => {
  const { id } = result.meta.request
  if (err) {
    console.log({ error: err, reqId: id })
  }
})

client.search({
  index: 'my-index',
  body: { foo: 'bar' }
}, (err, result) => {
  if (err) console.log(err)
})

By default the id is an incremental integer, but you can easily configure that with the generateRequestId option:

const { Client } = require('@elastic/elasticsearch')
const client = new Client({
  node: 'http://localhost:9200',
  // it takes two parameters, the request parameters and options
  generateRequestId: function (params, options) {
    // your id generation logic
    // must be syncronous
    return 'id'
  }
})

You can also specify a custom id per request:

client.search({
  index: 'my-index',
  body: { foo: 'bar' }
}, {
  id: 'custom-id'
}, (err, result) => {
  if (err) console.log(err)
})
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