[Backport 7.x] Added x-elastic-client-meta header

docs/configuration.asciidoc

@@ -218,10 +218,15 @@ _Default:_ `null`
 _Default:_ `{}`
 
 |`context`
-|`object` - A custom object that you can use for observability in yoru events.
+|`object` - A custom object that you can use for observability in your events.
 It will be merged with the API level context option. +
 _Default:_ `null`
 
+|`enableMetaHeader`
+|`boolean` - If true, adds an header named `'x-elastic-client-meta'`, containing some minimal telemetry data,
+such as the client and platform version. +
+_Default:_ `true`
+
 |`cloud`
 a|`object` - Custom configuration for connecting to 
 https://cloud.elastic.co[Elastic Cloud]. See https://www.elastic.co/guide/en/elasticsearch/client/javascript-api/current/auth-reference.html[Authentication] 

index.d.ts

@@ -108,6 +108,7 @@ interface ClientOptions {
   auth?: BasicAuth | ApiKeyAuth;
   context?: Context;
   proxy?: string | URL;
+  enableMetaHeader?: boolean;
   cloud?: {
     id: string;
     // TODO: remove username and password here in 8

index.js

@@ -33,6 +33,8 @@ const Serializer = require('./lib/Serializer')
 const errors = require('./lib/errors')
 const { ConfigurationError } = errors
 const { prepareHeaders } = Connection.internals
+const clientVersion = require('./package.json').version
+const nodeVersion = process.versions.node
 
 const kInitialOptions = Symbol('elasticsearchjs-initial-options')
 const kChild = Symbol('elasticsearchjs-child')
@@ -125,13 +127,18 @@ class Client extends ESAPI {
         auth: null,
         opaqueIdPrefix: null,
         context: null,
-        proxy: null
+        proxy: null,
+        enableMetaHeader: true
       }, opts)
 
     this[kInitialOptions] = options
     this[kExtensions] = []
     this.name = options.name
 
+    if (options.enableMetaHeader) {
+      options.headers['x-elastic-client-meta'] = `es=${clientVersion},js=${nodeVersion},t=${clientVersion},hc=${nodeVersion}`
+    }
+
     if (opts[kChild] !== undefined) {
       this.serializer = options[kChild].serializer
       this.connectionPool = options[kChild].connectionPool
@@ -179,7 +186,13 @@ class Client extends ESAPI {
 
     /* istanbul ignore else */
     if (Helpers !== null) {
-      this.helpers = new Helpers({ client: this, maxRetries: options.maxRetries })
+      this.helpers = new Helpers({
+        client: this,
+        maxRetries: options.maxRetries,
+        metaHeader: options.enableMetaHeader
+          ? `es=${clientVersion},js=${nodeVersion},t=${clientVersion},hc=${nodeVersion}`
+          : null
+      })
     }
   }
 

lib/Helpers.js

@@ -28,12 +28,14 @@ const { ResponseError, ConfigurationError } = require('./errors')
 const pImmediate = promisify(setImmediate)
 const sleep = promisify(setTimeout)
 const kClient = Symbol('elasticsearch-client')
+const kMetaHeader = Symbol('meta header')
 /* istanbul ignore next */
 const noop = () => {}
 
 class Helpers {
   constructor (opts) {
     this[kClient] = opts.client
+    this[kMetaHeader] = opts.metaHeader
     this.maxRetries = opts.maxRetries
   }
 
@@ -71,6 +73,10 @@ class Helpers {
    * @return {iterator} the async iterator
    */
   async * scrollSearch (params, options = {}) {
+    if (this[kMetaHeader] !== null) {
+      options.headers = options.headers || {}
+      options.headers['x-elastic-client-meta'] = this[kMetaHeader] + ',h=s'
+    }
     // TODO: study scroll search slices
     const wait = options.wait || 5000
     const maxRetries = options.maxRetries || this.maxRetries
@@ -99,7 +105,7 @@ class Helpers {
       stop = true
       await this[kClient].clearScroll(
         { body: { scroll_id } },
-        { ignore: [400] }
+        { ignore: [400], ...options }
       )
     }
 
@@ -414,6 +420,7 @@ class Helpers {
   bulk (options) {
     const client = this[kClient]
     const { serialize, deserialize } = client.serializer
+    const reqOptions = this[kMetaHeader] !== null ? { headers: { 'x-elastic-client-meta': this[kMetaHeader] + ',h=bp' } } : {}
     const {
       datasource,
       onDocument,
@@ -676,7 +683,7 @@ class Helpers {
 
       function tryBulk (bulkBody, callback) {
         if (shouldAbort === true) return callback(null, [])
-        client.bulk(Object.assign({}, bulkOptions, { body: bulkBody }), (err, { body }) => {
+        client.bulk(Object.assign({}, bulkOptions, { body: bulkBody }), reqOptions, (err, { body }) => {
           if (err) return callback(err, null)
           if (body.errors === false) {
             stats.successful += body.items.length

lib/Transport.js

@@ -44,6 +44,7 @@ class Transport {
     if (typeof opts.compression === 'string' && opts.compression !== 'gzip') {
       throw new ConfigurationError(`Invalid compression: '${opts.compression}'`)
     }
+
     this.emit = opts.emit
     this.connectionPool = opts.connectionPool
     this.serializer = opts.serializer

test/unit/client.test.js

@@ -26,6 +26,8 @@ const intoStream = require('into-stream')
 const { Client, ConnectionPool, Transport, Connection, errors } = require('../../index')
 const { CloudConnectionPool } = require('../../lib/pool')
 const { buildServer } = require('../utils')
+const clientVersion = require('../../package.json').version
+const nodeVersion = process.versions.node
 
 test('Configure host', t => {
   t.test('Single string', t => {
@@ -1300,3 +1302,62 @@ test('Content length too big (string)', t => {
     t.strictEqual(result.meta.attempts, 0)
   })
 })
+
+test('Meta header enabled', t => {
+  t.plan(2)
+
+  class MockConnection extends Connection {
+    request (params, callback) {
+      t.match(params.headers, { 'x-elastic-client-meta': `es=${clientVersion},js=${nodeVersion},t=${clientVersion},hc=${nodeVersion}` })
+      const stream = intoStream(JSON.stringify({ hello: 'world' }))
+      stream.statusCode = 200
+      stream.headers = {
+        'content-type': 'application/json;utf=8',
+        'content-length': '17',
+        connection: 'keep-alive',
+        date: new Date().toISOString()
+      }
+      process.nextTick(callback, null, stream)
+      return { abort () {} }
+    }
+  }
+
+  const client = new Client({
+    node: 'http://localhost:9200',
+    Connection: MockConnection
+  })
+
+  client.info((err, result) => {
+    t.error(err)
+  })
+})
+
+test('Meta header disabled', t => {
+  t.plan(2)
+
+  class MockConnection extends Connection {
+    request (params, callback) {
+      t.notMatch(params.headers, { 'x-elastic-client-meta': `es=${clientVersion},js=${nodeVersion},t=${clientVersion},hc=${nodeVersion}` })
+      const stream = intoStream(JSON.stringify({ hello: 'world' }))
+      stream.statusCode = 200
+      stream.headers = {
+        'content-type': 'application/json;utf=8',
+        'content-length': '17',
+        connection: 'keep-alive',
+        date: new Date().toISOString()
+      }
+      process.nextTick(callback, null, stream)
+      return { abort () {} }
+    }
+  }
+
+  const client = new Client({
+    node: 'http://localhost:9200',
+    Connection: MockConnection,
+    enableMetaHeader: false
+  })
+
+  client.info((err, result) => {
+    t.error(err)
+  })
+})

test/unit/helpers/bulk.test.js

@@ -27,6 +27,8 @@ const semver = require('semver')
 const { test } = require('tap')
 const { Client, errors } = require('../../../')
 const { buildServer, connection } = require('../../utils')
+const clientVersion = require('../../../package.json').version
+const nodeVersion = process.versions.node
 
 const dataset = [
   { user: 'jon', age: 23 },
@@ -41,7 +43,10 @@ test('bulk index', t => {
       const MockConnection = connection.buildMockConnection({
         onRequest (params) {
           t.strictEqual(params.path, '/_bulk')
-          t.match(params.headers, { 'content-type': 'application/x-ndjson' })
+          t.match(params.headers, {
+            'content-type': 'application/x-ndjson',
+            'x-elastic-client-meta': `es=${clientVersion},js=${nodeVersion},t=${clientVersion},hc=${nodeVersion},h=bp`
+          })
           const [action, payload] = params.body.split('\n')
           t.deepEqual(JSON.parse(action), { index: { _index: 'test' } })
           t.deepEqual(JSON.parse(payload), dataset[count++])
@@ -84,6 +89,9 @@ test('bulk index', t => {
         onRequest (params) {
           t.strictEqual(params.path, '/_bulk')
           t.match(params.headers, { 'content-type': 'application/x-ndjson' })
+          t.notMatch(params.headers, {
+            'x-elastic-client-meta': `es=${clientVersion},js=${nodeVersion},t=${clientVersion},hc=${nodeVersion},h=bp`
+          })
           const [action, payload] = params.body.split('\n')
           t.deepEqual(JSON.parse(action), { index: { _index: 'test' } })
           t.deepEqual(JSON.parse(payload), dataset[count++])
@@ -93,7 +101,8 @@ test('bulk index', t => {
 
       const client = new Client({
         node: 'http://localhost:9200',
-        Connection: MockConnection
+        Connection: MockConnection,
+        enableMetaHeader: false
       })
       const result = await client.helpers.bulk({
         datasource: dataset.slice(),

test/unit/helpers/scroll.test.js

@@ -22,11 +22,17 @@
 const { test } = require('tap')
 const { Client, errors } = require('../../../')
 const { connection } = require('../../utils')
+const clientVersion = require('../../../package.json').version
+const nodeVersion = process.versions.node
 
 test('Scroll search', async t => {
   var count = 0
   const MockConnection = connection.buildMockConnection({
     onRequest (params) {
+      t.match(params.headers, {
+        'x-elastic-client-meta': `es=${clientVersion},js=${nodeVersion},t=${clientVersion},hc=${nodeVersion},h=s`
+      })
+
       count += 1
       if (params.method === 'POST') {
         t.strictEqual(params.querystring, 'scroll=1m')
@@ -73,6 +79,9 @@ test('Clear a scroll search', async t => {
   var count = 0
   const MockConnection = connection.buildMockConnection({
     onRequest (params) {
+      t.notMatch(params.headers, {
+        'x-elastic-client-meta': `es=${clientVersion},js=${nodeVersion},t=${clientVersion},hc=${nodeVersion},h=s`
+      })
       if (params.method === 'DELETE') {
         const body = JSON.parse(params.body)
         t.strictEqual(body.scroll_id, 'id')
@@ -95,7 +104,8 @@ test('Clear a scroll search', async t => {
 
   const client = new Client({
     node: 'http://localhost:9200',
-    Connection: MockConnection
+    Connection: MockConnection,
+    enableMetaHeader: false
   })
 
   const scrollSearch = client.helpers.scrollSearch({