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Intro To Elasticsearch

Published: Jun 8, 2019

Last updated: Jun 8, 2019

    • Open-source
    • Boardly distributable
    • Readily scalable
    • Enterprise-grade
    • Multi-tenancy (can separate user documents)

    ElasticSearch is Java-based and designed to operate in real-time. ElasticSearch has the capability to search and index document files in a variety of formats.

    ElasticSearch achieves incredible performance as it searches for indexes instead of text directly. A comparison of this can be made to searching keywords.

    A typical setup with extend search capabilities through the use of APIs and query DSLs and there are a bunch of ready-to-go clients.

    Pulling ElasticSearch with Docker

    To install version 6.7.1 of ElasticSearch:

    > docker pull docker.elastic.co/elasticsearch/elasticsearch:6.7.1

    To then start the image for development or testing:

    > docker run -p 9200:9200 -p 9300:9300 -e "discovery.type=single-node" docker.elastic.co/elasticsearch/elasticsearch:6.7.1

    If you want to start a cluster with two ElasticSearch nodes, use the docker-compose.yml file given from the main website - also copied below:

    version: "2.2" services: elasticsearch: image: docker.elastic.co/elasticsearch/elasticsearch:6.7.1 container_name: elasticsearch environment: - cluster.name=docker-cluster - bootstrap.memory_lock=true - "ES_JAVA_OPTS=-Xms512m -Xmx512m" ulimits: memlock: soft: -1 hard: -1 volumes: - esdata1:/usr/share/elasticsearch/data ports: - 9200:9200 networks: - esnet elasticsearch2: image: docker.elastic.co/elasticsearch/elasticsearch:6.7.1 container_name: elasticsearch2 environment: - cluster.name=docker-cluster - bootstrap.memory_lock=true - "ES_JAVA_OPTS=-Xms512m -Xmx512m" - "discovery.zen.ping.unicast.hosts=elasticsearch" ulimits: memlock: soft: -1 hard: -1 volumes: - esdata2:/usr/share/elasticsearch/data networks: - esnet volumes: esdata1: driver: local esdata2: driver: local networks: esnet:

    Run docker-compose up to run the cluster and docker-compose down to tear down. Use docker-compose down -v to also destroy the data volumes, otherwise the cluster data volumes persist.

    Testing cluster health

    Simply run curl http://127.0.0.1:9200/_cat/health

    Interacting with the ElasticSearch Cluster

    In this case, we will use the NodeJS client to run a few commands to interact with the local cluster.

    The official repo for this client can be found here.

    Setting up the client

    > mkdir hello-elasticsearch > cd hello-elasticsearch > yarn init -y > yarn add @elastic/elasticsearch@7

    Basic doc creation

    const { Client } = require("@elastic/elasticsearch"); const client = new Client({ node: "http://localhost:9200" }); // promise API const result = await client.create({ index: "my-index", body: { foo: "bar" }, }); // callback API client.create( { index: "my-index", body: { foo: "bar" }, }, (err, result) => { if (err) console.log(err); } );

    const { Client } = require("@elastic/elasticsearch"); const client = new Client({ node: "http://localhost:9200" }); // promise API const result = await client.search({ index: "my-index", body: { foo: "bar" }, }); // callback API client.search( { index: "my-index", body: { foo: "bar" }, }, (err, result) => { if (err) console.log(err); } );

    For more examples using CURL and the options available, TutorialsPoint have a basic intro for more info found here

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    Dennis O'Keeffe

    @dennisokeeffe92
    • Melbourne, Australia

    Hi, I am a professional Software Engineer. Formerly of Culture Amp, UsabilityHub, Present Company and NightGuru.
    I am currently working on Visibuild.

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    Intro To Elasticsearch

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