Introduction

ElasticSearch has a powerful way of extending its capabilities with custom scripts, which can be written in several programming languages. The most common ones are Groovy, MVEL, JavaScript, and Python.

We already had a taste of ElasticSearch's scripting capabilities in the previous chapter, where we used scripting for aggregations. In this chapter, we will see how it's possible to create custom scoring algorithms, special processed return fields, custom sorting, and complex update operations on records.

The scripting concept of ElasticSearch can be seen as an advanced stored procedures system in the NoSQL world; so, for an advanced usage of ElasticSearch, it is very important to master it.