elasticsearch-scroll-stream
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    1.3.5 • Public • Published

    Elasticsearch Scroll Stream

    Build Status

    Elasticsearch Scroll query results as a Node.js Readable Stream.

    This module works with the official Elasticsearch nodejs clients:

    API

    ElasticsearchScrollStream is a Readable Stream, so it supports all the methods of a classic Stream#Readable. In addition it exposes a #close() method to force the stream to stop sourcing from Elasticsearch. When the stream begins to be consumed (starting from the first data event), it will contain an attribute _total that is the total number of matched documents.

    Installing

    To install the latest released version:

    npm install elasticsearch-scroll-stream --save
    

    Usage with the official Elasticsearch js API

    Example with a simple query strings query.

    const { Client } = require('@elastic/elasticsearch')
    const ElasticsearchScrollStream = require('elasticsearch-scroll-stream')
    
    const elasticsearch_client = new Client({ node: 'http://localhost:9200' })
    
    // Create index and add documents here...
    
    // You need to pass the client instance and the query object
    // as parameters in the constructor
    const es_stream = new ElasticsearchScrollStream(client, {
      index: 'elasticsearch-test-scroll-stream',
      type: 'test-type',
      scroll: '10s',
      size: '50',
      _source: ['name'],
      q: 'name:*',
    })
    
    // Pipe the results to other writeble streams..
    es_stream.pipe(process.stdout)
    
    es_stream.on('end', function() {
      console.log('End')
    })

    Example with a simple query strings query, and optional_fields specified (in this case we want _id and _score fields into results).

    const { Client } = require('@elastic/elasticsearch')
    const ElasticsearchScrollStream = require('elasticsearch-scroll-stream')
    
    const elasticsearch_client = new Client({ node: 'http://localhost:9200' })
    
    // Create index and add documents here...
    
    // You need to pass the client instance and the query object
    // as parameters in the constructor
    const es_stream = new ElasticsearchScrollStream(client, {
      index: 'elasticsearch-test-scroll-stream',
      type: 'test-type',
      scroll: '10s',
      size: '50',
      _source: ['name'],
      q: 'name:*'
    }, ['_id', '_score']); // optional_fields parameter: allowed values are those supported by elasticsearch
    
    // Pipe the results to other writeble streams..
    es_stream.pipe(process.stdout)
    
    es_stream.on('end', function() {
      console.log("End")
    });

    Example with a full request definition using the Elasticsearch Query DSL.

    const { Client } = require('@elastic/elasticsearch')
    const ElasticsearchScrollStream = require('elasticsearch-scroll-stream')
    
    const elasticsearch_client = new Client({ node: 'http://localhost:9200' })
    
    // Create index and add documents here...
    
    // You need to pass the client instance and the query object
    // as parameters in the constructor
    const es_stream = new ElasticsearchScrollStream(client, {
      index: 'elasticsearch-test-scroll-stream',
      type: 'test-type',
      scroll: '10s',
      size: '50',
      _source: ['name'],
      body: {
        query: {
          bool: {
            must: [
              {
                query_string: {
                  default_field: "_all",
                  query: 'name:*'
                }
              }
            ]
          }
        }
      }
    });
    
    // Pipe the results to other writeble streams..
    es_stream.pipe(process.stdout)
    
    es_stream.on('end', function() {
      console.log("End")
    });

    Example of using the close() method.

    const { Client } = require('@elastic/elasticsearch')
    const ElasticsearchScrollStream = require('elasticsearch-scroll-stream')
    
    
    // Create index and add documents here...
    
    const pageSize = '5'
    let stopCounterIndex = (parseInt(pageSize) + 1)
    let counter = 0
    let current_doc
    const elasticsearch_client = new Client({ node: 'http://localhost:9200' })
    
    const es_stream = new ElasticsearchScrollStream(elasticsearch_client, {
      index: 'elasticsearch-test-scroll-stream',
      type: 'test-type',
      scroll: '10s',
      size: pageSize,
      _source: ["name"],
      body: {
        query: {
          bool: {
            must: [
              {
                query_string: {
                  default_field: "_all",
                  query: 'name:third*'
                }
              }
            ]
          }
        }
      }
    }, ['_id', '_score']);
    
    es_stream.on('data', function(data) {
      current_doc = JSON.parse(data.toString())
      if (counter == stopCounterIndex) {
        es_stream.close()
      }
      counter++
    });
    
    es_stream.on('end', function() {
      console.log(counter)
    });
    
    es_stream.on('error', function(err) {
      console.log(err)
    });

    See test files for more examples.

    Developing

    Fork the git repo, clone it, then install the dev dependencies.

    cd elasticsearch-scroll-stream
    npm install
    

    Make your changes, add tests, then run the tests to make sure nothing broke.

    make
    

    NOTE: Tests require an ElasticSearch server running at http://127.0.0.1:9200/. You can spawn a docker container for the purpose with:

    docker-compose up -d
    

    which maps host port 127.0.0.1:9200 to container port 9200

    LICENSE

    The MIT License (MIT)

    Copyright (c) 2019 Francesco Valente

    Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

    Install

    npm i elasticsearch-scroll-stream

    DownloadsWeekly Downloads

    7,668

    Version

    1.3.5

    License

    MIT

    Unpacked Size

    25.4 kB

    Total Files

    12

    Last publish

    Collaborators

    • francov
    • alcacoop