As part of a project I am working on we have a strong usage of Pipelines templates, and the consumption chain is nested across multiple repositories.
In my situation, let’s say we have a Core repository, that contains a set of baseline assets. There will be another repository in a Department Team Project, aggregating multiple assets from Core and offering them as templates for broader consumption. Which will bring you to a Consumer which will use these templates (and potentially do more things).
The first step is very easy: you define your asset.yml pipeline in the Core Team Project, which does a number of things.
That pipeline is then invoked by a template.yml in the Department Team Project:
resources:
repositories:
- repository: Assets
type: git
name: 'Core/Core'
steps:
- template: asset.yml@Assets
parameters:
param: ["a", "b"]
This is pretty straightforward. But what if you want to consume your template.yml elsewhere, as a nested template? You cannot do the same as between Core and Department, because it will complain about the pipeline being invalid with an unexpected resources value.
The answer is in the extends keyword: it allows a template to be used as-is, and extended as needed:
resources:
repositories:
- repository: Templates
type: git
name: 'Department/Department'
extends:
template: template.yml@Templates
With that I am going to be able to consume the templates in the way I expected.