Use variables in Azure DevOps Pipeline templates

Question

We have a collection of Azure DevOps pipeline templates that we re-use across multiple repositories. Therefore we wanted to have a file that contains variables for all of our templates.

The repo structure looks like this

template repo
  ├── template-1.yml
  ├── template-2.yml
  └── variables.yml

project repo
  ├── ...
  └── azure-pipelines.yml

The variables.yml looks like this

...
variables:
  foo: bar

In template-1.yml we are importing the variables.yml as described in here

variables:
- template: variables.yml

In the azure-pipelines.yml we are using the template like this

resources:
  repositories:
    - repository: build-scripts
      type: git
      name: project-name/build-scripts

steps:
  ...
  - template: template-1.yml@build-scripts
    

When we now try to run the pipeline, we get the following error message:

template-1.yml@build-scripts (Line: 10, Col: 1): Unexpected value 'variables'

Answer 1

The issue is because you used variable template at steps scope. And variables simply doesn't exists at that level. This should work for you:

resources:
  repositories:
    - repository: build-scripts
      type: git
      name: project-name/build-scripts

variables:
  - template: template-1.yml@build-scripts

steps:
  ...

this is available to use at any place where variables are possible to use. So for instance you can use this in that way:

jobs:
- job: myJob
  timeoutInMinutes: 10
  variables:
  - template: template-1.yml  # Template reference
  pool:
    vmImage: 'ubuntu-16.04'
  steps:
  - script: echo My favorite vegetable is ${{ variables.favoriteVeggie }}.

Answer 2

If your template file only has variables, you can refer to Krzysztof Madej's answer.

If your template file has both variables and steps as shown below, it can only be used by extends.

# File: template-1.yml
variables: ...

steps: ...

Or you can write them in a stage, as shown below.

# File: template-1.yml
stages:
- stage: {stage}
  variables: ...
  jobs:
  - job: {job}
    steps: ...

Then insert it as a separate stage.

# azure-pipelines.yml
stages:
- stage: ...
- template: template-1.yml