Use environment variable in github action if

Question

I'm trying to use an environment variable in an if condition in github actions like so:

name: Worfklow
on:
  push

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v1

      - name: EXIT step
        if: $GITHUB_REF == 'specific-branch'
        run: exit 1

I want to exit if the current branch is equal to a specific branch.

Unfortunately, the github actions console displays an error:

Unexpected symbol: '$GITHUB_REF'

I can use $GITHUB_REF in a run: (where it contains the current branch), but not in an if:. What am I doing wrong?

Cement

Answer 1

do it like this:

if: github.ref == 'specific-branch'

reference branch conditional

Negligence

A word of warning: github.ref will store either the current branch or tag ref. This depends on the action that caused the workflow. Source: help.github.com/en/actions/… – Cement

This does not answer the actual question asked though which is how to access an environmental variable from if:... how is this done if it's truly an environnmental variable and not something you can just go fetch from the magic github context? – Gamesome

Answer 2

Though the original problem had been solved without environment vars, I'd like to share how it can be used with if conditions.

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:

      - name: Set env BRANCH
        run: echo "BRANCH=$(echo $GITHUB_REF | cut -d'/' -f 3)" >> $GITHUB_ENV

      - name: Set env NEED
        run: |
          if [[ $BRANCH == 'master' && $GITHUB_EVENT_NAME == 'push' ]]; then
              echo "NEED=true" >> "$GITHUB_ENV"
          else
              echo "NEED=false" >> "$GITHUB_ENV"
          fi

      - name: Skip Deploy?
        if: env.NEED != 'true'
        run: echo "Only pushing to 'master' causes automatic deployment"

     ...

The first two steps set 2 env variables, the third step demonstrates what syntax you need to follow to use these vars in if conditions.

Frolic

This solution works for any environment variable needed on any step, which is more complete than other solutions. This is why I think it should be marked as the correct answer. – Ia

This is the correct answer, but it could be clearer. The point being: Use env.MYVAR instead of $MYVAR. – Alister

for more info on environment variables: docs.github.com/en/actions/learn-github-actions/… – Wehrmacht

I needed to use secrets in if statements: if: ${{ env.super_secret != '' }} docs.github.com/en/actions/using-workflows/… – Wehrmacht

You can only use the env variables you set on the next step, not in the same step – Middlebrooks

`if: env.NEED == 'true' gives me an invalid workflow file: Unrecognized named-value: 'env'. Located at position 1 within expression: env.VALID_LABELS == 'true' – Lollard

^As I've later learned that env is not available in the jobs.<job_id>.if context. 🫥 – Lollard

Thanks for taking the time to document this answer even though you didn't need it – Licko

Answer 3

If you want to check an environment variable on job-level (refer to Github context), you can do like this:

env:
  MY_VAR: Dummy

jobs:
  build:
    name: Build
    runs-on: ubuntu-latest         
    outputs:
      myVar: ${{ steps.init.outputs.myVar }}
    
    steps:        
      - name: Environment variables to output 
        id: init
        run: |
          echo "myVar=${{ env.MY_VAR }}" >> $GITHUB_OUTPUT

And use it in another job:

  second_job:
    name: Second Job
    needs: build
    if: needs.build.outputs.myVar == 'Dummy'

Ioved

sad one can't use the env variable directly without all that overhead...in my case, I just wanted to pull a condition into an env var, but it's not worth it with that solution. – Pirali

@MarianKlühspies It's by design. Maybe GitHub changes it in the future.. :) – Ioved

This has worked for me, thanks @BakedInhalf There's further explanation in the docs: docs.github.com/en/actions/using-jobs/defining-outputs-for-jobs – Proverbial

Answer 4

As @Claudio noted, the solution is to use env.MYVAR. For reference, I am sharing an example from my own use case: the presence of GitHub secrets will trigger docker publishing.

name: docker-image

on:
  push:
    branches: [ "main" ]
    paths: ["Dockerfile",".github/workflows/docker-image.yaml"]
  workflow_dispatch:


jobs:
  build-and-publish:
    runs-on: ubuntu-latest
    # Docker tags and credentials for DockerHub/GitHub Containers, customize!
    env:
      IMAGE_NAME: plantuml-docker
      IMAGE_VERSION: latest
      DOCKER_USER: ${{ secrets.DOCKER_USER }}
      DOCKER_PASSWORD: ${{ secrets.DOCKER_PASSWORD }}
      GITHUB_TOKEN: ${{ secrets.PAT }}
      GITHUB_USER: ${{ github.actor }}
    steps:
    - uses: actions/checkout@v3
    - name: Build and tag the image
      run: |
        docker build . \
        --tag $DOCKER_USER/$IMAGE_NAME:$IMAGE_VERSION \
        --tag ghcr.io/$GITHUB_USER/$IMAGE_NAME:$IMAGE_VERSION
    - name: Publish to DockerHub
      if: env.DOCKER_PASSWORD != ''
      run: |
        docker login -u $DOCKER_USER -p $DOCKER_PASSWORD
        docker push $DOCKER_USER/$IMAGE_NAME:$IMAGE_VERSION
    - name: Publish to GitHub Container registry
      if: env.GITHUB_TOKEN != ''
      run: |
        docker login ghcr.io -u $GITHUB_USER -p $GITHUB_TOKEN 
        docker push ghcr.io/$GITHUB_USER/$IMAGE_NAME:$IMAGE_VERSION

Plimsoll

Answer 5

You can use some restrictions on the push section of the action

on:
  push:
    branches:    
      - '*'         # matches every branch that doesn't contain a '/'
      - '*/*'       # matches every branch containing a single '/'
      - '**'        # matches every branch
      - '!master'   # excludes master

This answer was taken from this stack overflow question

Nous