How to Extend a Base Template With Parameters in Azure Pipelines

The extends keyword makes a pipeline inherit a base template, passing typed parameters the template uses to build out stages and jobs.

Define a template that declares parameters and lays out stages. In the consuming pipeline, use extends.template and pass values under parameters. The base controls the overall shape.

Steps

• Write a template that declares parameters and emits stages.
• In the pipeline, set extends.template to that file.
• Pass values under extends.parameters.

Pipeline

# azure-pipelines.yml
extends:
  template: templates/build.yml
  parameters:
    buildConfiguration: Release
    runTests: true

# templates/build.yml
parameters:
  - name: buildConfiguration
    type: string
  - name: runTests
    type: boolean
stages:
  - stage: build
    jobs:
      - job: compile
        steps:
          - script: dotnet build -c ${{ parameters.buildConfiguration }}
          - ${{ if eq(parameters.runTests, true) }}:
            - script: dotnet test

Gotchas

• A pipeline that uses extends cannot also define top-level stages itself.
• Template parameters are typed and evaluated at compile time, so use ${{ }} to read them.
• Required template extends can be enforced as an environment or repo check for governance.

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