How to set workflow env variables depending on branch

Question

I currently have two GitHub actions workflow files that are pretty much identical, only one is configured to react to push/pull_requests on branch master the ot

Answer 1

It is not possible to set workflow-level environment variables from a job. Each job runs in its own machine and setting an env variable there only affects all of the later steps in that job.

There are currently two ways to share data between jobs; either you create an artifact and use that, or you declare and set job outputs. The latter works for string values.

Here's an example:

name: "Main"

on:
  push:
    branches:
      - master
      - production
  pull_request:
    branches:
      - master
      - production

jobs:
  init:
    runs-on: ubuntu-latest
    outputs:
      gcloud_project: ${{ steps.setvars.outputs.gcloud_project }}
      phase: ${{ steps.setvars.outputs.phase }}

    steps:
      - name: Cancel previous workflow
        uses: styfle/cancel-workflow-action@0.4.0
        with:
          access_token: ${{ github.token }}

      - name: Set variables
        id: setvars
        run: |
          if [[ "${{github.base_ref}}" == "master" || "${{github.ref}}" == "refs/heads/master" ]]; then
            echo "::set-output name=gcloud_project::my-project-dev"
            echo "::set-output name=phase::staging"
          fi

          if [[ "${{github.base_ref}}" == "production" || "${{github.ref}}" == "refs/heads/production" ]]; then
            echo "::set-output name=gcloud_project::my-project-prd"
            echo "::set-output name=phase::production"
          fi

  print:
    runs-on: ubuntu-latest
    needs: init
    steps:
      - name: Print
        run: echo "gcloud_project=${{needs.init.outputs.gcloud_project}}"
       

Answer 2

You can drop the global env statement, combine the event triggers to

on:
  push:
    branches:
      - master
      - production
  pull_request:
    branches:
      - master
      - production

and then add a first step that checks which branch the workflow is running on and set the environment there:

      - name: Set environment for branch
        run: |
          if [[ $GITHUB_REF == 'refs/heads/master' ]]; then
              echo "GLCOUD_PROJECT=my-project-stg" >> "$GITHUB_ENV"
              echo "VERCEL_TARGET=staging" >> "$GITHUB_ENV"
          else
              echo "GLCOUD_PROJECT=my-project-prd" >> "$GITHUB_ENV"
              echo "VERCEL_TARGET=production" >> "$GITHUB_ENV"
          fi