Connecting

This page contains the information you need to connect and use the Client with Elasticsearch.

On this page

This document contains code snippets to show you how to connect to various Elasticsearch providers.

If you are using Elastic Cloud, the client offers an easy way to connect to it. You need the Cloud ID that you can find in the cloud console, then your username and password.

Once you have collected the Cloud ID you can use the client to connect to your Elastic Cloud instance, as follows:

require 'elasticsearch'

client = Elasticsearch::Client.new(
  cloud_id: '<CloudID>'
  user: '<Username>',
  password: '<Password>',
)

You can also connect to the Cloud by using API Key authentication. You can generate an API key in the Management page under the section Security.

When you click on Create API key you can choose a name and set the other options (eg. restrict privileges, expire after time, etc).

After this step you will get the API key in the API keys page.

IMPORTANT: you need to copy and store the API key in a secure place, since you will not be able to view it again in Elastic Cloud.

Once you have collected the Cloud ID and the API key you can use the client to connect to your Elastic Cloud instance, as follows:

client = Elasticsearch::Client.new(
  cloud_id: '<CloudID>',
  api_key: '<ApiKey>'
)

If you create the API Key through the dev console or the REST API, you may get instead a pair of id and APIKey values. The client also accepts a Hash for the api_key parameter, so you can pass in these values and it will encode the API Key internally:

client = Elasticsearch::Client.new(
  cloud_id: '<CloudID>',
  api_key: {id: '<Id>', api_key: '<APIKey>'}
)

Elasticsearch 8.0 offers security by default, that means authentication and TLS are enabled.

To connect to the Elasticsearch cluster you’ll need to configure the Ruby Elasticsearch client to use HTTPS with the generated CA certificate in order to make requests successfully.

If you’re just getting started with Elasticsearch we recommend reading the documentation on configuring and starting Elasticsearch to ensure your cluster is running as expected.

When you start Elasticsearch for the first time you’ll see a distinct block like the one below in the output from Elasticsearch (you may have to scroll up if it’s been a while):

----------------------------------------------------------------
-> Elasticsearch security features have been automatically configured!
-> Authentication is enabled and cluster connections are encrypted.

->  Password for the elastic user (reset with `bin/elasticsearch-reset-password -u elastic`):
  lhQpLELkjkrawaBoaz0Q

->  HTTP CA certificate SHA-256 fingerprint:
  a52dd93511e8c6045e21f16654b77c9ee0f34aea26d9f40320b531c474676228
...
----------------------------------------------------------------

Note down the elastic user password and HTTP CA fingerprint for the next sections. In the examples below they will be stored in the variables ELASTIC_PASSWORD and CERT_FINGERPRINT respectively.

Depending on the circumstances there are two options for verifying the HTTPS connection, either verifying with the CA certificate itself or via the HTTP CA certificate fingerprint.

The generated root CA certificate can be found in the certs directory in your Elasticsearch config location ($ES_CONF_PATH/certs/http_ca.crt). If you’re running Elasticsearch in Docker there is additional documentation for retrieving the CA certificate.

Once you have the http_ca.crt file somewhere accessible pass the path to the client via ca_certs:

client = Elasticsearch::Client.new(
  host: "https://elastic:#{ELASTIC_PASSWORD}@localhost:9200",
  transport_options: { ssl: { ca_path: CERT_DIR } }
)

This method of verifying the HTTPS connection takes advantage of the certificate fingerprint value noted down earlier. Take this SHA256 fingerprint value and pass it to the Ruby Elasticsearch client via ca_fingerprint:

# Colons and uppercase/lowercase don't matter when using
# the 'ca_fingerprint' parameter
CERT_FINGERPRINT = '64F2593F...'

# Password for the 'elastic' user generated by Elasticsearch
ELASTIC_PASSWORD = "<password>"

client = Elasticsearch::Client.new(
  host: "https://elastic:#{ELASTIC_PASSWORD}@localhost:9200",
  transport_options: { ssl: { verify: false } },
  ca_fingerprint: CERT_FINGERPRINT
)

The verification will be run once per connection.

The certificate fingerprint can be calculated using openssl x509 with the certificate file:

openssl x509 -fingerprint -sha256 -noout -in /path/to/http_ca.crt

If you don’t have access to the generated CA file from Elasticsearch you can use the following script to output the root CA fingerprint of the Elasticsearch instance with openssl s_client:

# Replace the values of 'localhost' and '9200' to the
# corresponding host and port values for the cluster.
openssl s_client -connect localhost:9200 -servername localhost -showcerts </dev/null 2>/dev/null \
  | openssl x509 -fingerprint -sha256 -noout -in /dev/stdin

The output of openssl x509 will look something like this:

SHA256 Fingerprint=A5:2D:D9:35:11:E8:C6:04:5E:21:F1:66:54:B7:7C:9E:E0:F3:4A:EA:26:D9:F4:03:20:B5:31:C4:74:67:62:28

You can also use ApiKey authentication.

Elasticsearch::Client.new(
  host: host,
  transport_options: transport_options,
  api_key: credentials
)

Where credentials is either the base64 encoding of id and api_key joined by a colon or a hash with the id and api_key:

Elasticsearch::Client.new(
  host: host,
  transport_options: transport_options,
  api_key: {id: 'my_id', api_key: 'my_api_key'}
)

You can pass the authentication credentials, scheme and port in the host configuration hash:

client = Elasticsearch::Client.new(
  hosts:
	  [
  	   {
    	   host: 'my-protected-host',
    	   port: '443',
    	   user: 'USERNAME',
    	   password: 'PASSWORD',
    	   scheme: 'https'
  	   }
	  ]
)

Or use the common URL format:

client = Elasticsearch::Client.new(url: 'https://username:password@localhost:9200')

To pass a custom certificate for SSL peer verification to Faraday-based clients, use the transport_options option:

Elasticsearch::Client.new(
  url: 'https://username:password@localhost:9200',
  transport_options: {
	ssl: { ca_file: '/path/to/http_ca.crt' }
  }
)

The following snippet shows an example of using the Ruby client:

require 'elasticsearch'

client = Elasticsearch::Client.new log: true

client.cluster.health

client.index(index: 'my-index', id: 1, body: { title: 'Test' })

client.indices.refresh(index: 'my-index')

client.search(index: 'my-index', body: { query: { match: { title: 'test' } } })

This section illustrates the best practices for leveraging the Elasticsearch client in a Function-as-a-Service (FaaS) environment. The most influential optimization is to initialize the client outside of the function, the global scope. This practice does not only improve performance but also enables background functionality as – for example – sniffing. The following examples provide a skeleton for the best practices.

require 'functions_framework'
require 'elasticsearch'

client = Elasticsearch::Client.new(
  cloud_id: "elasic-cloud-id",
  user: "elastic",
  password: "password",
  log: true
)

FunctionsFramework.http "hello_world" do |request|
  client.search(
    index: 'stack-overflow',
    body: {
      query: {
        match: {
          title: {
            query: 'phone application'
          }
        }
      }
    }
  )
end

require 'elasticsearch'

def client
  @client ||= Elasticsearch::Client.new(
    cloud_id: "elastic-cloud-id",
    user: "elastic",
    password: "password",
    log: true
  )
end

def lambda_handler(event:, context:)
  client.search(
    index: 'stack-overflow',
    body: {
      query: {
        match: {
          title: {
            query: 'phone application'
          }
        }
      }
    }
  )
end

Resources used to assess these recommendations:

The Elasticsearch server version 8.0 is introducing a new compatibility mode that allows you a smoother upgrade experience from 7 to 8. In a nutshell, you can use the latest 7.x Elasticsearch client with an 8.x Elasticsearch server, giving more room to coordinate the upgrade of your codebase to the next major version.

If you want to leverage this functionality, please make sure that you are using the latest 7.x client and set the environment variable ELASTIC_CLIENT_APIVERSIONING to true. The client is handling the rest internally. For every 8.0 and beyond client, you’re all set! The compatibility mode is enabled by default.