Why Template priority and composition in Elasticsearch? - Purpose & Use Cases

The Big Idea

Discover how layering templates can save you hours of tedious updates and keep your searches sharp!

The Scenario

Imagine you have many search templates for different parts of your website, and you try to manage them all by copying and pasting similar code everywhere.

When you want to change a common part, you have to update every single template manually.

The Problem

This manual method is slow and error-prone because you might forget to update some templates.

It becomes hard to keep track of which template is used where, and your code gets messy and duplicated.

The Solution

Template priority and composition let you organize templates in layers, so common parts are defined once and reused.

You can combine templates by priority, letting Elasticsearch pick the right pieces automatically.

Before vs After

✗ Before

POST /_search/template
{
  "id": "template1",
  "params": {"field": "title"}
}

POST /_search/template
{
  "id": "template2",
  "params": {"field": "description"}
}

✓ After

POST /_search/template
{
  "id": "base_template",
  "params": {}
}

POST /_search/template
{
  "id": "composed_template",
  "priority": 10,
  "composed_of": ["base_template", "extra_template"]
}

What It Enables

This lets you build flexible, maintainable search templates that adapt easily as your site grows.

Real Life Example

For example, an e-commerce site can have a base search template for product filtering, and specialized templates for categories like electronics or clothing that add extra filters.

Key Takeaways

Manual template management causes duplication and errors.

Template priority and composition organize templates in layers.

This makes templates reusable, easier to maintain, and scalable.