Condititionally set Environmental Variable in GitHub Actions Workflows [duplicate] - github

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 other on production.
The staging workflow starts like this:
env:
GCLOUD_PROJECT: my-project-stg
VERCEL_TARGET: staging
on:
push:
branches: [ master ]
pull_request:
branches: [ master ]
The production workflow starts like:
env:
GCLOUD_PROJECT: my-project-prd
VERCEL_TARGET: production
on:
push:
branches: [ production ]
pull_request:
branches: [ production ]
The rest of the workflow files is the same, so this is clearly not very DRY.
I would like to have 1 single workflow file and somehow switch between two sets of variables based on the branch name. Is there a way to achieve this or am I maybe approach this from the wrong angle?
If it were possible to extend both workflow files on a shared base definition that would also solve it I guess.

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

Answer 3

Things could have changed but for anyone still searching for an answer, there is a way to set a variabe visible for the entire workflow.
jobs:
weekday_job:
runs-on: ubuntu-latest
env:
DAY_OF_WEEK: Mon
Then access by jobs.<job_id>.steps[*].env
More info in the docs

Answer 4

There's now a better way of achieving this using reusable workflows:
https://docs.github.com/en/actions/learn-github-actions/reusing-workflows