Ways to get last commit author in Github Actions workflow - github

Question

I am working on converting a Jenkins Pipeline into a Github Actions workflow and need a way of storing the commit author as an environment variable for later use in node.js code.
I have read the documentation and this seems to be the only way I can get it working:
name: Feature Branch PR
on:
pull_request:
types: [opened, edited, synchronize]
push:
branches:
- '**'
Then in the Env section:
env:
AUTHOR: ${{ github.event.pusher.name }}
The problem is this only works for Push triggers. So if i remove the on: push section from top of yml workflow (so it only triggers on PRs) the AUTHOR info becomes empty.
I cannot find a way to get it for commits. Does anyone know of of a way? We do not want this workflow to trigger on pushes.
I also tried
AUTHOR: $(jq '.commits.committer.name' $GITHUB_EVENT_PATH)
I think this was syntactically incorrect though.

Answer 1

For anyone who struggles with this in future, I managed to work it out.
In the node code (not yml) you can obtain an Actions event.json file with all info available. To get the author of a previous commit:
const ev = JSON.parse(fs.readFileSync(process.env.GITHUB_EVENT_PATH, 'utf8'));
return ev.pull_request.user.login;

Answer 2

As YakovL mentioned,
env:
${{ github.event.pull_request.user.login }}
Works fine in a Github action.

Answer 3

To answer the question that was originally asked, you can do the following to get the author of the last commit in a GitHub action:
github.event.commits[0].author.name
For example (to prevent a loop in an action using a personal access token):
name: Version and Package Repo
on:
push:
branches: [ master, main ]
jobs:
build:
if: github.event.commits[0].author.name != 'GitHubActions'
runs-on: ubuntu-18.04
steps:
- name: Checkout repo
uses: actions/checkout#v2
with:
fetch-depth: 0
token: ${{ secrets.PAT }}
- name: Configure git
run: |
git config user.name "GitHubActions"
git config user.email "<>"
- name: Version and Package
run: npm version patch --force
env:
NODE_AUTH_TOKEN: $\{{ secrets.PAT }}
- name: Update git
run: |
git push
git push --tags
You can use this in the interpolation format too:
${github.event.commits[0].author.name}
And if you need to use different github context variables, they are documented at:
https://docs.github.com/en/actions/learn-github-actions/environment-variables
https://docs.github.com/en/developers/webhooks-and-events/webhooks/webhook-events-and-payloads#push
Annoyingly, the user details are in different formats for different event types, but in addition to example above (for push), you could try github.event.head.user.login or github.event.base.user.login too