index_lifecycle.md

Index Lifecycle

This guide covers OpenSearch Ruby Client API actions for Index Lifecycle. You'll learn how to create, read, update, and delete indices in your OpenSearch cluster. We will also leverage index templates to create default settings and mappings for indices of certain patterns.

Setup

In this guide, we will need an OpenSearch cluster with more than one node. Let's use the sample docker-compose.yml to start a cluster with two nodes. The cluster's API will be available at localhost:9200 with basic authentication enabled with default username and password of admin:admin.

To start the cluster, run the following command:

cd /path/to/docker-compose.yml
docker-compose up -d

Let's create a client instance to access this cluster:

require 'opensearch-ruby'

client = OpenSearch::Client.new(
  host: 'https://admin:admin@localhost:9200',
  transport_options: { ssl: { verify: false } })

puts client.info # Check server info and make sure the client is connected

Index API Actions

Create a new index

You can quickly create an index with default settings and mappings by using the indices.create API action. The following example creates an index named paintings with default settings and mappings:

client.indices.create(index: :paintings)

To specify settings and mappings, you can pass them as the body of the request. The following example creates an index named movies with custom settings and mappings:

client.indices.create(
  index: :movies,
  body: {
    settings: {
      index: {
        number_of_shards: 2,
        number_of_replicas: 1
      }
    },
    mappings: {
      properties: {
        title: { type: 'text' },
        year: { type: 'integer' }
      }
    }
  }
)

When you create a new document for an index, OpenSearch will automatically create the index if it doesn't exist:

puts client.indices.exists?(index: :burner) # => false
client.create(index: :burner, body: { lorem: 'ipsum' })
puts client.indices.exists?(index: :burner) # => true

Update an Index

You can update an index's settings and mappings by using the indices.put_settings and indices.put_mapping API actions.

The following example updates the movies index's number of replicas to 0:

client.indices.put_settings(
  index: :movies,
  body: {
    index: {
      number_of_replicas: 0
    }
  }
)

The following example updates the movies index's mappings to add a new field named director:

client.indices.put_mapping(
  index: :movies,
  body: {
    properties: {
      director: { type: 'text' }
    }
  }
)

Get Metadata for an Index

Let's check if the index's settings and mappings have been updated by using the indices.get API action:

puts client.indices.get(index: :movies)

The response body contains the index's settings and mappings:

{ 
  "movies" => { 
    "aliases" => {}, 
    "mappings" => { 
        "properties" => { 
          "title" => { "type" => "text" }, 
          "year" => { "type" => "integer" },
          "director" => { "type" => "text" } 
        } 
    }, 
    "settings" => { 
      "index" => { 
        "creation_date" => "1680297372024", 
        "number_of_shards" => "2", 
        "number_of_replicas" => "0", 
        "uuid" => "FEDWXgmhSLyrCqWa8F_aiA", 
        "version" => { "created" => "136277827" }, 
        "provided_name" => "movies" 
      } 
    }
  } 
}

Delete an Index

Let's delete the movies index by using the indices.delete API action:

client.indices.delete(index: :movies)

We can also delete multiple indices at once:

client.indices.delete(index: [:movies, :paintings, :burner], ignore: 404)

Notice that we are passing ignore: 404 to the request. This tells the client to ignore the 404 error if the index doesn't exist for deletion. Without it, the above delete request will throw an error because the movies index has already been deleted in the previous example.

Cleanup

All resources created in this guide are automatically deleted when the cluster is stopped. You can stop the cluster by running the following command:

docker-compose down