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...