🧪 GitHub Actions and Environment Variables: Static vs. Dynamic Smackdown

Let’s talk about environment variables in GitHub Actions — those little gremlins that either make your CI/CD run silky smooth or throw a wrench in your perfectly crafted YAML.

If you’ve ever squinted at your pipeline and wondered, “Where the heck should I declare this ANSIBLE_CONFIG thing so it doesn’t vanish into the void between steps?”, you’re not alone. I’ve been there. I’ve screamed at $GITHUB_ENV. I’ve misused export. I’ve over-engineered echo. But fear not, dear reader — I’ve distilled it down so you don’t have to.

In this post, we’ll look at the right ways (and a few less right ways) to set environment variables — and more importantly, when to use static vs dynamic approaches.

🧊 Static Variables: Set It and Forget It

Got a variable like ANSIBLE_STDOUT_CALLBACK=yaml that’s the same every time? Congratulations, you’ve got yourself a static variable! These are the boring, predictable, low-maintenance types that make your CI life a dream.

✅ Best Practice: Job-Level env

If your variable is static and used across multiple steps, this is the cleanest, classiest, and least shouty way to do it:

jobs:
  my-job:
    runs-on: ubuntu-latest
    env:
      ANSIBLE_CONFIG: ansible.cfg
      ANSIBLE_STDOUT_CALLBACK: yaml
    steps:
      - name: Use env vars
        run: echo "ANSIBLE_CONFIG is $ANSIBLE_CONFIG"

Why it rocks:

• 👀 Super readable
• 📦 Available in every step of the job
• 🧼 Keeps your YAML clean — no extra echo commands, no nonsense

Unless you have a very specific reason not to, this should be your default.

🎩 Dynamic Variables: Born to Be Wild

Now what if your variables aren’t so chill? Maybe you calculate something in one step and need to pass it to another — a file path, a version number, an API token from a secret backend ritual…

That’s when you reach for the slightly more… creative option:

🔧 $GITHUB_ENV to the rescue

- name: Set dynamic environment vars
  run: |
    echo "BUILD_DATE=$(date +%F)" >> $GITHUB_ENV
    echo "RELEASE_TAG=v1.$(date +%s)" >> $GITHUB_ENV

- name: Use them later
  run: echo "Tag: $RELEASE_TAG built on $BUILD_DATE"

What it does:

• Persists the variables across steps
• Works well when values are calculated during the run
• Makes you feel powerful

🪄 Fancy Bonus: Heredoc Style

If you like your YAML with a side of Bash wizardry:

- name: Set vars with heredoc
  run: |
    cat <<EOF >> $GITHUB_ENV
    FOO=bar
    BAZ=qux
    EOF

Because sometimes, you just want to feel fancy.

😵‍💫 What Not to Do (Unless You Really Mean It)

- name: Set env with export
  run: |
    export FOO=bar
    echo "FOO is $FOO"

This only works within that step. The minute your pipeline moves on, FOO is gone. Poof. Into the void. If that’s what you want, fine. If not, don’t say I didn’t warn you.

🧠 TL;DR – The Cheat Sheet

🧪 My Use Case: Ansible FTW

In my setup, I wanted to use:

ANSIBLE_CONFIG=ansible.cfg
ANSIBLE_STDOUT_CALLBACK=yaml

These are rock-solid, boringly consistent values. So instead of writing this in every step:

- name: Set env
  run: |
    echo "ANSIBLE_CONFIG=ansible.cfg" >> $GITHUB_ENV

I now do this:

jobs:
  deploy:
    runs-on: ubuntu-latest
    env:
      ANSIBLE_CONFIG: ansible.cfg
      ANSIBLE_STDOUT_CALLBACK: yaml
    steps:
      ...

Cleaner. Simpler. One less thing to trip over when I’m debugging at 2am.

💬 Final Thoughts

Environment variables in GitHub Actions aren’t hard — once you know the rules of the game. Use env for the boring stuff. Use $GITHUB_ENV when you need a little dynamism. And remember: if you’re writing export in step after step, something probably smells.

Got questions? Did I miss a clever trick? Want to tell me my heredoc formatting is ugly? Hit me up in the comments or toot at me on Mastodon.

✍️ Posted by Amedee, who loves YAML almost as much as dancing polskas.
💥 Because good CI is like a good dance: smooth, elegant, and nobody falls flat on their face.
🎻 Scheduled to go live on 20 August — just as Boombalfestival kicks off. Because why not celebrate great workflows and great dances at the same time?