Скачать или смотреть How to Reindex in Elasticsearch: Transform Your Logs Effectively

Learn how to efficiently use Elasticsearch to `reindex` your logs by transforming an array into a single document. Simple steps provided for optimal results.
---
This video is based on the question https://stackoverflow.com/q/67700421/ asked by the user 'Farid Niasti' ( https://stackoverflow.com/u/14147152/ ) and on the answer https://stackoverflow.com/a/67700593/ provided by the user 'Val' ( https://stackoverflow.com/u/4604579/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Reindex in Elasticsearch

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Mastering Elasticsearch Reindexing: A Guide to Transforming Your Logs

If you're working with Elasticsearch and need to reorganize your logs according to a specific template, you're not alone. Many users face the challenge of needing to modify or restructure their data for improved searchability and functionality. One common adjustment involves reindexing data, specifically when elements are stored in arrays. In this guide, we'll explore how to use Elasticsearch's reindex API to transform your log data effectively.

The Problem: Array Structures in Logs

As an Elasticsearch user, you might find yourself needing to convert an array field into a document format. For instance, you have logs structured like this:

[[See Video to Reveal this Text or Code Snippet]]

In this log, the events field is an array and contains only one object. You want to reindex this so that events are converted from an array to a single document, allowing for clearer structure and improved access.

The Solution: Writing a Reindex Script

To achieve this transformation, you can utilize the Elasticsearch reindex API along with a simple script. Here’s how you can do it step by step:

Step 1: Define Your Source and Destination Indices

Start by specifying the source index containing your existing log data and the destination index where you want the reformatted logs to reside. In our example, let’s say the source index is testlog-2020.05.03.

Step 2: Write the Reindex Script

Here’s the core of the operation—the script that transforms the events array into a document. This script checks if the events field is not null and then assigns the first element of the array to the events field.

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Execute the Reindex Command

After writing your script in the Elasticsearch Dev Tools, simply execute the command. This will process all documents from your source index, applying the transformation specified in your script.

Final Thoughts

Reindexing in Elasticsearch is a powerful way to restructure your data for better performance and accessibility. By following these outlined steps, you can successfully convert array fields into documents, enhancing your log management strategy.

If you have any further questions or need additional examples on using the Elasticsearch reindex API, don’t hesitate to reach out!