Indexing Data in Elasticsearch

Now, let’s dive into how to index data in Elasticsearch. First, you’ll need to have Elasticsearch installed and running on your system. Once you have that set up, you can start indexing data using either the RESTful API or one of the Elasticsearch clients available for various programming languages like Python, Java, or JavaScript.

Using the RESTful API

To index a document using the RESTful API, you’ll typically send a PUT or POST request to the Elasticsearch server with the document data in JSON format. Let’s walk through an example using the curl command:

curl -XPOST "localhost:9200/products/_doc/1" -H 'Content-Type: application/json' -d'
{
  "name": "iPhone 13",
  "description": "The latest iPhone model with advanced features",
  "price": 999
}

In this example:

localhost:9200 is the address of your Elasticsearch server.
products is the name of the index where we want to store the document.
_doc is the type of document (note that in recent versions of Elasticsearch, types are deprecated, and _doc is used as a default).
1 is the ID of the document. If you don’t specify an ID, Elasticsearch will generate one for you.

Output:

If the document is successfully indexed, you’ll receive a response from Elasticsearch indicating that. It will include the index name, document type, and ID. For example:

{
  "_index": "products",
  "_type": "_doc",
  "_id": "1",
  "_version": 1,
  "result": "created",
  "_shards": {
    "total": 2,
    "successful": 1,
    "failed": 0
  },
  "_seq_no": 0,
  "_primary_term": 1
}

Using Elasticsearch Clients

While the RESTful API is useful for manual testing and simple tasks, using Elasticsearch clients in your preferred programming language offers more flexibility and convenience, especially for complex indexing tasks. Here’s an example of indexing a document using the Elasticsearch Python client:

from elasticsearch import Elasticsearch

# Connect to Elasticsearch server
es = Elasticsearch(['localhost:9200'])

# Index a document
doc = {
    "name": "Samsung Galaxy S21",
    "description": "Flagship smartphone with stunning display and camera",
    "price": 799
}
res = es.index(index="products", doc_type="_doc", id=2, body=doc)
print(res)

Output:

The output will be similar to the RESTful API response, confirming the successful indexing of the document.