Wherever scripting is supported in the Elasticsearch APIs, the syntax follows the same pattern; you specify the language of your script, provide the script logic (or source), and add parameters that are passed into the script:

"script": {  "lang":   "...",  "source" | "id": "...",  "params": { ... }}

lang

Specifies the language the script is written in. Defaults topainless.

source,id

The script itself, which you specify assource for an inline script orid for a stored script. Use thestored script APIs to create and manage stored scripts.

params

Specifies any named parameters that are passed into the script as variables.Use parameters instead of hard-coded values to decrease compile time.

Get started with Painless scripting:

• Write your first script
• Use parameters in your script
• Shorten your script
• Store and retrieve scripts
• Update documents using scripts