Common API Conventions in Elasticsearch

1. RESTful Interface

Elasticsearch exposes its APIs over HTTP, the principles of Representational State Transfer (REST). This means that Elasticsearch API endpoints can be accessed using standard HTTP methods (GET, POST, PUT, DELETE) and follow RESTful URL patterns. For example:

• GET /index/_search: Retrieves documents from the specified index.
• POST /index/_doc: Adds a new document to the index.
• PUT /index/_settings: Updates index settings.

2. Index Naming Convention

• When working with indices in Elasticsearch, it’s common practice to use lowercase alphanumeric characters and hyphens for index names.
• Avoid using uppercase characters or special symbols in index names to ensure compatibility and consistency.
• For example:

PUT /my-index

3. Document Structure

• Elasticsearch stores data in the form of JSON documents, where each document represents a single data entity.
• It’s essential to follow a consistent document structure across documents within the same index to facilitate efficient querying and indexing.
• For example:

{
  "title": "Elasticsearch Conventions",
  "content": "Exploring the best practices for API conventions in Elasticsearch.",
  "tags": ["elasticsearch", "APIs", "conventions"]
}

4. Query DSL

• Elasticsearch provides a powerful Query Domain Specific Language (DSL) for performing searches and aggregations on indexed data.
• The query DSL consists of JSON-based query objects that can be nested and combined to construct complex search queries.
• For example:

{
  "query": {
    "match": {
      "title": "Elasticsearch"
    }
  }
}

5. Bulk Operations

• To improve indexing performance, Elasticsearch supports bulk indexing operations, allowing multiple documents to be indexed in a single API call.
• This reduces network overhead and improves throughput when indexing large datasets.
• For example:

POST /_bulk
{"index":{"_index":"my-index","_id":"1"}}
{"title":"Document 1","content":"Lorem ipsum dolor sit amet."}
{"index":{"_index":"my-index","_id":"2"}}
{"title":"Document 2","content":"Consectetur adipiscing elit."}

6. Error Handling

• Elasticsearch APIs follow a consistent error response format, providing detailed error messages and status codes to help developers diagnose and troubleshoot issues.
• It’s essential to handle errors gracefully in client applications and respond appropriately to different error scenarios.
• For example:

{
  "error": {
    "root_cause": [
      {
        "type": "index_not_found_exception",
        "reason": "no such index [non-existent-index]",
        "resource.type": "index_or_alias",
        "resource.id": "non-existent-index",
        "index_uuid": "_na_",
        "index": "non-existent-index"
      }
    ],
    "type": "index_not_found_exception",
    "reason": "no such index [non-existent-index]",
    "resource.type": "index_or_alias",
    "resource.id": "non-existent-index",
    "index_uuid": "_na_",
    "index": "non-existent-index"
  },
  "status": 404
}

An API or Application Programming Interface serves as a bridge between different software applications and enables them to communicate effectively. Elasticsearch is a powerful search and analytics engine that provides a robust API that allows users to interact with the Elasticsearch server over HTTP.

This RESTful API follows to the principles of Representational State Transfer (REST) and offers a standardized way to perform various operations such as indexing, searching, updating, and deleting documents. In this article, We will learn about the API Conventions in Elasticsearch by understanding the RESTful APIs, What are API Conventions with their types, and also Common API Conventions in Elasticsearch in detail.