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⚡  ElasticsearchBook is crafted by Jozef Sorocin (🟢 Book a consulting hour) and powered by:

• Spatialized.io (Elasticsearch & Google Maps consulting)
• in cooperation with Garages-Near-Me.com (Effortless parking across Germany)

Scripting enables you to evaluate custom expressions.

As explored in 2. Insertion & Ingestion, we can modify fields.

And as mentioned in Points Closest to the Origin, we can dynamically score documents and calculate new values on-the-fly.

Scripts can be used in various contexts but are leveraged most often:

• during updates and reindexing
• in queries and aggregations where there are no alternatives (like here)
• and when sorting.

How to Use Scripts

The default scripting language is Painless. Additional lang plugins enable you to run scripts written in other languages. Everywhere a script can be used, you can include a lang parameter to specify the language of the script.

Supported Languages

• ~~groovy~~ — slow and discontinued
• painless — a sandboxed and secure general-purpose language extending a subset of Java’s syntax; offers optional typing through the def keyword
• expression — Lucene expressions — a sandboxed, javascript-like language used for fast custom ranking and sorting but limited to only numeric, boolean, date, and geo_point fields
• mustache — used in (search) templates. Here's an example.
• and good old java — supporting lower-level script engine modules

Script Syntax