Simplify YAML Files with Anchors and Aliases
YAML files often contain repeated configurations, making them hard to manage. Anchors (&) and aliases (*) are here to help. To create an anchor, place an ampersand (&) followed by a label. This sets a reference point for a reusable configuration block. For example, default: &default creates an anchor for the subsequent settings.
To reuse these settings elsewhere, use an alias. Insert an asterisk (*) followed by the anchor label. The line <<: *default imports the settings anchored at &default. This technique helps you maintain cleaner, DRY ("Don't Repeat Yourself") YAML files, consolidating shared configurations for efficiency.
For deeper insights, check the official YAML documentation.
config.yml
default: &default
image: node:20
working_directory: ~/project
jobs:
build:
<<: *default
steps:
- checkout
- run: npm install
test:
<<: *default
steps:
- checkout
- run: npm test