YAML

  
Last updated January 10, 2018
Site BuildingThemingModule Development

YAML, which stands for YAML Ain't Markup Language, is a human-readable data serialization format that's been widely adopted in a variety of use cases in Drupal 8. Anyone wanting to write modules or themes for Drupal 8 will need to understand YAML syntax. Even site-builders are likely to encounter YAML, at least in passing, as YAML is the data serialization format of choice for Drupal 8's configuration management system as well.

You can spot YAML files in your Drupal codebase by looking for the .yml extension.

Example tasks

  • Review updated/exported configuration prior to deploying it to the live site
  • Use YAML files in a theme to provide metadata about the theme, asset libraries, and more
  • Work with YAML files in a module to define routes, menu items, and basic module information

Confidence

YAML syntax is not likely to change, nor is Drupal's use of it. If anything, the specific key/value pairs that Drupal uses will evolve over time.

Drupalize.Me resources

VideoHDCC

An Introduction to YAML

Free
12m35s  //  Site Building, Theming, Module Development, Drupal 9, Drupal 8
Tutorial

Describe Your Theme with an Info File

Theming, Drupal 8, Drupal 9
More information

Info files, aka THEMENAME.info.yml files, provide Drupal with metadata about your theme, the features it supports, and the regions that it defines. All themes are required to have a THEMENAME.info.yml file, and creating one is generally the first step you'll take when creating a new theme.

In this tutorial we'll:

Tutorial

Create an Info File for a Module

Free
Module Development, Drupal 9, Drupal 8
More information

In this tutorial we're going to look at one the first files you will need in order to create a Drupal module: the info file. Each module is required to have a MODULE.info.yml file to help Drupal identify that a bundle of code is a unique module. This specially-formatted YAML file not only tells Drupal about the module, but also allows us to provide other useful metadata. In this tutorial, we'll walk through all of the metadata possibilities that can be included in an info file.

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External resources

  • yaml.org
    • Canonical source for information about the YAML language.
  • YAML Syntax Validator (codebeautify.org)
    • YAML syntax validation tool, useful for locating errors in a YAML file.