Use GitHub Actions to validate Bicep files

In this post, I’ll show you how to validate Bicep files using GitHub Actions.

What is GitHub Actions?

GitHub Actions is a continuous integration and continuous delivery (CI/CD) platform built into GitHub. It allows for the automation of build, test, and deployment pipelines.

It can also be used for running workflows based on other repository events, like automatically responding to created issues.

The structure of a GitHub Actions workflow

GitHub Actions workflows are made up of three things.

An event trigger

A GitHub Actions workflow can be configured to trigger based on an event occuring in a GitHub repository, such as a pull request being opened, or a branch being deleted.

A job

A GitHub Actions workflow can contain one or more jobs. These can be run sequentially, or in parallel.

Each job will run inside its own virtual machine runner, or inside a container.

Steps within a job

Each job has one or more steps. A step might be a script that you define, or an action; a reusable extension.

Steps are executed in order, and on the same runner, meaning that you can share data from one step to another.

A GitHub Actions workflow for validating Bicep files

This example GitHub Actions workflow assumes that you want to validate Bicep files when a pull request is raised against your repository. It also assumes that the Bicep files that you wish to validate are contained within the .azure/bicep/ directory.

You should create a .github directory in the root of your repository. In this directory, you should create another directory, this time named workflows. Within here, create a new file named bicep.yml.

First, we have to define a name for the GitHub Actions workflow.

name: Validate Bicep files

Next, we have to define the repository event that will trigger the GitHub Actions workflow.

on: pull_request

Finally, we have to define the job itself, and the steps that make up the job.

jobs:
  validate:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - run: az bicep build --file .azure/bicep/*.bicep

We’re definining a single job, named validate.
We’re declaring that this job will run on the latest version of Ubuntu (runs-on: ubuntu-latest).
We’re declaring two steps. In the first step, we’re reusing the checkout action available on GitHub Marketplace. This allows our GitHub Actions workflow to checkout our repository. In the second step, we’re running an Azure CLI command to build any files with a .bicep file extension within the .azure/bicep directory. If any of these files fail to build, our GitHub Actions workflow will report a failure, otherwise it will succeed.

Altogether, our .github/workflows/bicep.yml file looks like this:

name: Validate Bicep files

on: pull_request

jobs:
  validate:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - run: az bicep build --file .azure/bicep/*.bicep

Once merged into the repository, any future pull requests raised will trigger this GitHub Actions workflow to be run.

Stuart McColl