Cookbook

These are some additional recipes you can implement in Github Actions!

Debugging Github Actions

Given that steps in a job can be a script, you can actually perform logging as steps in a job:

- name: Logging
  run: |
    echo ${{ github.repository }}
    echo 'Hello!'

These will add a step to the job that logs these echos.

Conditional steps

You can also run steps based on certain conditions (using expressions). This is particularly useful when you want to only run a step when certain conditions are met.

- name: Only run on Windows
  if: ${{ runner.os == 'windows' }}
  run: |
    Write-Output "test output"

The above step only runs when the runner OS is Windows.

It is very important to note that there are several limitations to what expressions might work in the if key. These are dependent on what contexts are available to each part of a step. More information about contexts can be found here and the contexts available to if are: github, needs, vars, inputs

Adding environment variables

Given that virtual machine runners run an OS, you will have access to environment variables from within the job through the env context. To add to the env context, you can use a step:

- name: Export environment variables
  run: |
    echo "START=$(date +'%Y-%m-%dT%H:%M:%S')" >> $GITHUB_ENV

The above exports a new environment variable START into env . This can be then accessed via ${{ env.START }}.

Matrix strategies

Suppose that you want to verify that a set of changes are not susceptible to backward compatibility issues in a Node.js environment (version 20), while ensuring that the latest Node.js version is supported as well (version 23).

You can actually use matrix strategies to verify this information by running the same job across different parameters.

jobs:
  example_matrix:
    strategy:
      matrix:
        version: [20, 23]
    steps:
      - uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.version }}

So using the above, we are able to then run the same job example_matrix twice with two different node versions: 20 and 23.