World C3: Release & Deploy

Smoke tests and auto rollback

You will learn: how to taste a deploy right away, and let the pipeline undo a bad one by itself.

Checked with GitHub Actions 2026-10 on 31 Oct 2026

The problem

The deploy goes green. The live site shows an error page. Which station will stop this line? Tap one, then run.

Which station will stop the line? Tap it, then press Run.

What happened on GitHub

Push to main

Workflow file .github/workflows/deploy.yml

1name: Deploy
2on:
3  push:
4    branches: [main]
5permissions:
6  contents: read
7jobs:
8  deploy:
9    runs-on: ubuntu-latest
10    steps:
11      - uses: actions/checkout@v7
12      - run: npm ci
13      - run: npm run deploy
14        env:
15          CLOUDFLARE_API_TOKEN: ${{ secrets.CLOUDFLARE_API_TOKEN }}
16      - run: curl --silent https://shop.example.com/health

The line

Push to main · main

Watch

A is one quick taste right after a deploy. Not the whole menu, one spoon. Good smoke tests, or not?

Swipe right for good, left for needs work. Or use the buttons.

1 / 4

Ask /health and expect 200 OK.

Try it

Fix the check from the first card. Build a curl that fails on an error page.

Tap the pieces in the right order.

…

Watch

Add a job: it runs only if: failure(). Here the canary’s smoke test meets an error. Which station stops the line? Tap, then run.

Which station will stop the line? Tap it, then press Run.

What happened on GitHub

Push tag v1.3.1Run by hand

Workflow file .github/workflows/release.yml

1name: Release
2on:
3  push:
4    tags: ['v*']
5  workflow_dispatch:
6permissions:
7  contents: read
8jobs:
9  canary:
10    runs-on: ubuntu-latest
11    environment: canary
12    steps:
13      - uses: actions/checkout@v7
14      - run: npm ci
15      - run: npm run deploy -- --env canary
16        env:
17          CLOUDFLARE_API_TOKEN: ${{ secrets.CLOUDFLARE_API_TOKEN }}
18      - run: curl --fail --silent https://canary.example.com/health
19  production:
20    needs: canary
21    runs-on: ubuntu-latest
22    environment:
23      name: production
24      url: https://shop.example.com
25    steps:
26      - uses: actions/checkout@v7
27      - run: npm ci
28      - run: npm run deploy
29        env:
30          CLOUDFLARE_API_TOKEN: ${{ secrets.CLOUDFLARE_API_TOKEN }}
31  rollback:
32    needs: canary
33    if: failure()
34    runs-on: ubuntu-latest
35    steps:
36      - uses: actions/checkout@v7
37      - run: npm ci
38      - run: npm run rollback
39        env:
40          CLOUDFLARE_API_TOKEN: ${{ secrets.CLOUDFLARE_API_TOKEN }}

The line

Push tag v1.3.1 · v1.3.1

Try it

Build it yourself: deploy, taste, and roll back on failure.

Tap blocks to add them. Put them in order.

Blocks

Your workflow

Tap a block above to start.

Workflow file .github/workflows/

name: Deploy

What runs

Nothing to run yet.

Predict

Next week, the smoke test passes. What does the rollback job do?

You did it!

You can now catch a bad deploy and undo it automatically.

Go deeper (optional)

wrangler rollback swaps the code, not the data. Databases and other bindings stay as they are. Pair it with expand and contract. Want to taste before any user does? Deploy a version at 0%, then call it with the Cloudflare-Workers-Version-Overrides header.

Real rep (optional): give a test Worker a /health page and a curl check.