Book Image

Elasticsearch 5.x Cookbook - Third Edition

By : Alberto Paro
Book Image

Elasticsearch 5.x Cookbook - Third Edition

By: Alberto Paro

Overview of this book

Elasticsearch is a Lucene-based distributed search server that allows users to index and search unstructured content with petabytes of data. This book is your one-stop guide to master the complete Elasticsearch ecosystem. We’ll guide you through comprehensive recipes on what’s new in Elasticsearch 5.x, showing you how to create complex queries and analytics, and perform index mapping, aggregation, and scripting. Further on, you will explore the modules of Cluster and Node monitoring and see ways to back up and restore a snapshot of an index. You will understand how to install Kibana to monitor a cluster and also to extend Kibana for plugins. Finally, you will also see how you can integrate your Java, Scala, Python, and Big Data applications such as Apache Spark and Pig with Elasticsearch, and add enhanced functionalities with custom plugins. By the end of this book, you will have an in-depth knowledge of the implementation of the Elasticsearch architecture and will be able to manage data efficiently and effectively with Elasticsearch.
Table of Contents (25 chapters)
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Dedication
Preface

Computing return fields with scripting


Elasticsearch allows us to define complex expressions that can be used to return a new calculated field value.

These special fields are called script_fields, and they can be expressed with a script in every available Elasticsearch scripting language.

Getting ready

You need an up-and-running Elasticsearch installation as we described the Downloading and installing Elasticsearch recipe in Chapter 2, Downloading and Setup.

To execute curl via the command-line you need to install curl for your operating system.

To correctly execute the following commands, you need an index populated with the script chapter_09/populate_for_scripting.sh script available in the online code.

How to do it...

For computing return fields with scripting, we will perform the following steps:

  1. Return the following script fields:

    "my_calc_field": This concatenates the texts of the "name" and "description" fields

    "my_calc_field2": This multiplies the "price" value by the "discount" parameter

  2. From...