How to compare a file changes since last action in github actions

Question

In gitlab we have support for CI_COMMIT_BEFORE_SHA and CI_COMMIT_SHA

Whereas in github we only have support for GITHUB_REF which holds SHA of current commit that triggered this action.

My requirement is to find if a particular file changed since last Action execution

[This answer](https://stackoverflow.com/questions/61860732/how-can-i-get-the-previous-commit-before-a-push-or-merge-in-github-action-workfl/61861763#61861763) may help you. — peterevans, May 22 '20 at 03:06
@RohitReddyAbbadi Were you able to get something implemented? I am trying to do the same thing (seems like there should be a utility), but not sure where to start. Is there anything you could share? — Joseph Carroll, Sep 25 '22 at 01:31

score 1 · Accepted Answer · answered Sep 27 '22 at 07:55

Found a way to solve this using event payload - see push event payload:

in .github/workflows/release.yaml

name: release
on:
  push:
    branches: [ main ]

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
    - name: deploy
      run: sh deploy.sh
      env:
        CI_COMMIT_BEFORE_SHA: ${{ github.event.before }}
        CI_COMMIT_SHA: ${{ github.event.after }}

in bin/deploy.sh

HAS_DESIRED_CHANGES=`git diff --name-only $CI_COMMIT_BEFORE_SHA $CI_COMMIT_SHA | grep -E 'path/to/file1|path/to/dir2'`
echo $HAS_DESIRED_CHANGES
HAS_DESIRED_CHANGES=`echo ${#HAS_DESIRED_CHANGES}`

if ! [ $HAS_DESIRED_CHANGES -eq 0 ]
then
  echo "Has desired changes, proceed performing necessary actions"
else
  echo "No desired changes. Skipping...."
fi

How to compare a file changes since last action in github actions

1 Answers1