From Zero to Live: Containerise a Python App, Deploy It to Azure Container Apps and Automate It with GitHub Actions

Introduction

I recently completed the ShipIt Weekend: Deploy Your First App to Azure lab. It has three missions:

1. Build it: write a small web app, package it in a Docker image and run it locally.
2. Ship it: publish the image to GitHub Container Registry (GHCR) and run it on Azure Container Apps with a public HTTPS URL.
3. Automate it: add a GitHub Actions pipeline that builds, pushes and deploys on every push to main.

I worked through everything from a Linux terminal (Ubuntu on WSL, on a Windows laptop). This is not a polished "everything worked first time" tutorial. I made a few mistakes along the way: I named my repository differently from what the lab expected, my pipeline failed on its first run, and my first credential claim was rejected. I've kept those moments in, because that is where most of the learning happens.

What you'll need:

• A GitHub account
• An Azure account with an active subscription
• Docker, Git and the Azure CLI installed in a Linux-style terminal (WSL works well on Windows)

A note on screenshots: I blurred subscription IDs, tenant IDs and secrets in the images below. I also deleted the token, the service principal and the Azure resources after finishing, so nothing shown here can be used. Do the same, and never publish real credentials.

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Mission 1: Build it, containerise a web app

Step 1: Create the project and a Git repository

mkdir -p ~/shipit-app && cd ~/shipit-app
git init -b main

• mkdir -p creates the folder (and doesn't complain if it already exists), and && runs cd only if that succeeded.
• git init -b main turns the folder into a Git repository and names the first branch main.

Step 2: Write the web app

The app uses only Python's standard library, so there is nothing to install and less that can break.

cat > app.py << 'EOF'
import os
from http.server import BaseHTTPRequestHandler, HTTPServer

MESSAGE = "Hello from ShipIt Weekend!"


class Handler(BaseHTTPRequestHandler):
    def do_GET(self):
        body = f"<h1>{MESSAGE}</h1><p>Built with Docker, shipped to Azure, automated with GitHub Actions.</p>".encode()
        self.send_response(200)
        self.send_header("Content-Type", "text/html; charset=utf-8")
        self.send_header("Content-Length", str(len(body)))
        self.end_headers()
        self.wfile.write(body)


HTTPServer(("0.0.0.0", int(os.environ.get("PORT", "8080"))), Handler).serve_forever()
EOF

The cat > app.py << 'EOF' pattern is a here-document: everything up to the EOF line is written into app.py. The quotes around 'EOF' stop the shell from interpreting anything inside. The server listens on port 8080 (or whatever PORT says) and answers every request with a small HTML page.

Step 3: Write the Dockerfile

cat > Dockerfile << 'EOF'
FROM python:3.12-slim
WORKDIR /app
COPY app.py .
ENV PORT=8080
EXPOSE 8080
USER nobody
CMD ["python", "app.py"]
EOF

• FROM python:3.12-slim starts from a small official Python image.
• WORKDIR /app and COPY app.py . put the app in the container.
• ENV PORT=8080 and EXPOSE 8080 set and document the port.
• USER nobody runs the app as an unprivileged user instead of root. This is a small but important security habit.
• CMD is the command that runs when the container starts.

Step 4: Build and run it locally

docker build -t shipit-app .

docker build reads the Dockerfile in the current folder (the .) and -t shipit-app names the image. The first build downloads the Python base image, so it took about 16 seconds for me.

docker run -d --rm -p 8080:8080 --name shipit shipit-app
curl http://localhost:8080
docker stop shipit

• -d runs the container in the background, --rm deletes it when it stops, -p 8080:8080 maps the port to your machine, and --name shipit gives it a name.
• curl fetches the page, and docker stop shuts the container down.

The app answered with the HTML heading, so the container worked.

Step 5: Commit, create a GitHub repository and push

git add app.py Dockerfile
git commit -m "feat: containerised web app"

Before pushing, I created an empty repository on GitHub. This is where I made my first mistake: I named it shipit, but the lab expects shipit-app. I didn't notice until much later, and it caused a confusing problem at the end (more on that in Mission 3). I connected my local repo to it like this:

git remote add origin [e-mail]:rahimahisah17/shipit.git
git push -u origin main

• git remote add origin <url> registers the GitHub repo under the nickname origin. I used the SSH URL because I already had SSH keys set up.
• git push -u origin main uploads the main branch and links it to origin/main, so a plain git push works from now on.

Tip: If you follow the lab, name your GitHub repository shipit-app from the start. The final credential check expects that name.

---

Mission 2: Ship it, GHCR and Azure Container Apps

Step 1: Set your GitHub username and link the image to the repo

export GH_USER=rahimahisah17
echo "LABEL org.opencontainers.image.source=https://github.com/$GH_USER/shipit" >> Dockerfile
git commit -am "chore: link image to repository" && git push

• export GH_USER=... stores your username in a variable, so later commands don't need it typed out. It must be lowercase.
• The LABEL line adds the repo's URL to the image as metadata, so GitHub can link the package to the repository. >> appends to the file (a single > would overwrite it).
• git commit -am stages and commits changes to tracked files in one step.

Small mistake #1: When I first ran echo $GH_USER it printed nothing. I had opened a new terminal session, and environment variables don't survive that. I ran export again and it was fine. If a command suddenly produces strange image names or URLs, check that your variables are still set.

Step 2: Log in to GitHub Container Registry

GHCR is free for public images. Docker needs a personal access token to log in:

1. GitHub → Settings → Developer settings → Personal access tokens → Tokens (classic)
2. Generate a token with only the write:packages scope and a short expiry.

echo YOUR_TOKEN | docker login ghcr.io -u $GH_USER --password-stdin

--password-stdin makes Docker read the token from the pipe instead of from the command line, which is safer. I got Login Succeeded.

Security note: Treat the token like a password. Don't share it, don't screenshot it unblurred, and delete it when you've finished.

Step 3: Build, tag and push the image

docker build -t ghcr.io/$GH_USER/shipit-app:v1 .
docker push ghcr.io/$GH_USER/shipit-app:v1

The tag has four parts: the registry (ghcr.io), the owner (your username), the image name (shipit-app) and the version (v1). Because the layers were cached, the build took 2.6 seconds.

The push uploaded each layer and ended with the image digest.

Step 4: Make the package public

A new GHCR package is private by default, as the badge on its page shows.

Azure has to pull the image without a password, so it must be public. In the package's Package settings, go to the Danger Zone, click Change visibility, choose Public and type the package name to confirm.

Afterwards the Danger Zone says "This package is currently public."

Step 5: Sign in to Azure and prepare the subscription

az login --use-device-code

--use-device-code gives you a code and a URL to open in a browser, which works well in WSL, where a browser often can't open automatically. You'll see a couple of yellow warnings ("Attempted too soon" and a note about a tenant without subscriptions). They look alarming but are harmless: the login still completes and lists your subscription.

az extension add --name containerapp --upgrade
az provider register --namespace Microsoft.App --wait
az provider register --namespace Microsoft.OperationalInsights --wait

• The first command installs the CLI extension that provides the az containerapp commands. Mine was already installed and up to date, which is fine.
• The provider register commands switch on the services Container Apps needs (the Container Apps service itself and Log Analytics for logs). A new subscription must do this once. With --wait they print nothing when they succeed, and the prompt simply returns.

Step 6: Create a resource group

az group create --name shipit-rg --location westeurope

A resource group is a folder-like container for everything in this lab, which makes cleanup easy at the end. The JSON output showed "provisioningState": "Succeeded".

Step 7: Deploy to Azure Container Apps

az containerapp up \
  --name shipit-app \
  --resource-group shipit-rg \
  --location westeurope \
  --image ghcr.io/$GH_USER/shipit-app:v1 \
  --ingress external \
  --target-port 8080

This one command creates a Container Apps environment, a Log Analytics workspace and the app itself.

• --image points at the image in GHCR (this works because the package is public).
• --ingress external gives the app a public address.
• --target-port 8080 tells Azure which port inside the container receives traffic.

It's slow. Mine ran for over five minutes on a spinner while Azure created the environment and workspace. Don't press Ctrl+C: stopping halfway can leave half-created resources behind. When it finished, it printed the public URL.

Step 8: Test the live app

export APP_URL=https://$(az containerapp show --name shipit-app --resource-group shipit-rg --query properties.configuration.ingress.fqdn -o tsv)
echo $APP_URL
curl $APP_URL

• az containerapp show fetches the app's details, and --query ... -o tsv picks out only the hostname as plain text.
• $(...) drops that result into the variable.

The warning about the extension altering the command's behaviour is harmless. curl returned my page from the public internet.

---

Mission 3: Automate it, CI/CD with GitHub Actions

Step 1: Give GitHub Actions access, with least privilege

The pipeline needs permission to update the app, but only that app's resource group.

export SUB_ID=$(az account show --query id -o tsv)
az ad sp create-for-rbac --name shipit-github --role contributor \
  --scopes /subscriptions/$SUB_ID/resourceGroups/shipit-rg --json-auth

• az ad sp create-for-rbac creates a service principal, an identity for automation (like a robot account).
• --role contributor lets it create and update resources.
• --scopes ... limits that to the shipit-rg resource group only. This is the least-privilege idea in practice.
• --json-auth prints the credentials in the JSON format the GitHub login action expects.

The output contains a clientSecret. You'll see a warning about it, plus a deprecation notice for --json-auth (it still worked for me).

Copy the whole JSON and save it as a GitHub secret: your repo → Settings → Secrets and variables → Actions → New repository secret, with the name AZURE_CREDENTIALS.

Step 2: Write the pipeline

mkdir -p .github/workflows

The folder must be named exactly .github/workflows, because that's where GitHub looks for workflows.

cat > .github/workflows/deploy.yml << 'EOF'
name: deploy

on:
  push:
    branches: [main]
  workflow_dispatch:

permissions:
  contents: read
  packages: write

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Log in to GitHub Container Registry
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Build and push the image
        run: |
          IMAGE=ghcr.io/${GITHUB_REPOSITORY_OWNER,,}/shipit-app:${GITHUB_SHA::7}
          docker build -t "$IMAGE" .
          docker push "$IMAGE"
          echo "IMAGE=$IMAGE" >> "$GITHUB_ENV"

      - name: Log in to Azure
        uses: azure/login@v2
        with:
          creds: ${{ secrets.AZURE_CREDENTIALS }}

      - name: Deploy to Azure Container Apps
        run: az containerapp update --name shipit-app --resource-group shipit-rg --image "$IMAGE"
EOF

What the workflow does:

• on: runs it on every push to main, and lets you start it manually (workflow_dispatch).
• permissions: lets it read the code and write packages.
• Log in to GHCR: uses a temporary built-in token, GITHUB_TOKEN, so no personal token is needed in the pipeline.
• Build and push: tags the image with the first 7 characters of the commit ID, so every deployment is traceable to a commit.
• Log in to Azure: uses the AZURE_CREDENTIALS secret.
• Deploy: az containerapp update points the app at the new image.

The terminal in this screenshot looks jumbled because of how it displayed my paste, but the file itself was fine, as the workflow runs below prove.

Step 3: Change the app and push

I changed the app's message so the pipeline had something new to deploy:

sed -i.bak 's/Hello from ShipIt Weekend!/Shipped automatically by GitHub Actions!/' app.py && rm app.py.bak
grep MESSAGE app.py
git add .github/workflows/deploy.yml app.py
git commit -m "ci: deploy to Azure on every push"
git push

• sed -i.bak 's/old/new/' does an in-place find-and-replace and keeps a backup, which rm then deletes.
• grep MESSAGE app.py confirms the change before I committed.

Step 4: The first pipeline run fails

I opened the Actions tab and the run had failed after just 19 seconds.

I opened the failing job and found the red step: Build and push the image. The image had built fine, but the log ended with:

denied: permission_denied: write_package
Error: Process completed with exit code 1.

Why it happened: I had first pushed the shipit-app image from my laptop using my personal token, so the package belongs to my account. The workflow's built-in GITHUB_TOKEN is a different identity, and it had no permission to write to that existing package.

Step 5: The fix, give the repository write access to the package

In the package's Package settings → Manage Actions access, I clicked Add Repository, chose my repo and gave it the Write role. That grants only this one repository permission to push to this one package.

Then I clicked Re-run all jobs on the failed run, and this time it passed in 45 seconds.

Step 6: Verify the deployment

curl $APP_URL

The response now showed the new heading, "Shipped automatically by GitHub Actions!", which proves the pipeline built, pushed and deployed the change without me touching Azure.

And in the browser:

Step 7: The repository name problem and claiming the credential

The lab ends by asking you to claim a verified credential, using your live URL and the repository https://github.com/<your-username>/shipit-app.

My repository was called shipit, not shipit-app. My first claim attempt failed with the message "We couldn't reach your live URL". The app was up and curl returned the page, so I first suspected Azure had scaled the app to zero while idle and the checker gave up before it woke. I checked the app with curl and got a successful response.

The real problem turned out to be the repository name. The form still contained .../shipit. After I renamed the repository to shipit-app and submitted the matching URL, the claim worked. The error message pointed at the wrong thing, so the lesson is: when a validation message doesn't make sense, re-check every input against the instructions, not just the one the message mentions.

[Screenshot placeholder: the failed claim showing "We couldn't reach your live URL"]

To rename the repo, I went to the repo's Settings → General → Repository name, entered shipit-app and clicked Rename. GitHub redirects the old name, and the secret, workflow and Actions history all move with the repo. Then I updated my local remote:

git remote set-url origin [e-mail]:rahimahisah17/shipit-app.git

git remote set-url changes the address stored for origin, so future pushes go to the renamed repo.

Step 8: Clean up

Deleting what you no longer need is how you make sure nothing is ever charged:

az group delete --name shipit-rg --yes --no-wait
az ad sp delete --id $(az ad sp list --display-name shipit-github --query "[0].id" -o tsv)
az group exists --name shipit-rg

• az group delete removes the resource group and everything in it: the app, its environment and the logs. --yes skips the prompt and --no-wait returns immediately while Azure deletes in the background.
• az ad sp delete removes the service principal. Deleting the resource group does not remove it.
• az group exists prints true while the group is still there and false once it's gone.

Deletion takes a few minutes. I got true twice, then Deleting from az group show, then finally false. I also deleted the AZURE_CREDENTIALS secret and the personal access token.

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Troubleshooting summary

What happened	Cause	Fix
echo $GH_USER printed nothing	I opened a new terminal, and variables don't persist between sessions	Run export GH_USER=... again
Package couldn't be pulled by Azure	GHCR packages are private by default	Set the package visibility to Public
az containerapp up seemed stuck	Creating the environment and Log Analytics workspace takes several minutes	Wait, and don't press Ctrl+C
Pipeline failed with permission_denied: write_package	The package was first pushed with my personal token, so the workflow's GITHUB_TOKEN couldn't write to it	Add the repo under Manage Actions access with the Write role, then re-run
Credential claim said "couldn't reach your live URL"	My repo was named shipit, not shipit-app	Rename the repo to shipit-app and use the matching URL

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Lessons learned

• Follow naming conventions in guided labs. My shipit vs shipit-app mismatch caused the longest detour.
• Read the failing step, not just the red X. The Actions log told me exactly what was wrong: write_package.
• Least privilege pays off. The service principal can only touch one resource group, and the repo has write access to only one package.
• No secrets in code. The Azure credentials live in an encrypted GitHub secret, and the pipeline's registry login uses a temporary token.
• Clean up. Deleting the resource group, the service principal, the secret and the token means nothing keeps running or stays exposed.

One thing I'd still tidy up: my Dockerfile's LABEL line still points at the old repository name (shipit). GitHub redirects the old name, so nothing broke, but updating it would be cleaner.

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Summary

In one weekend-sized lab I went from an empty folder to a live HTTPS app on Azure with a working CI/CD pipeline:

1. I wrote a tiny Python web server and packaged it in a Docker image that runs as a non-root user.
2. I pushed the image to GitHub Container Registry, made it public, and deployed it to Azure Container Apps with the Azure CLI.
3. I created a least-privilege service principal and a GitHub Actions workflow, so every push to main builds, pushes and deploys automatically.
4. I debugged a package permission error and a repository naming mismatch, then cleaned up all the Azure resources.

The app itself is simple, but the workflow behind it is the real thing: containers, a registry, cloud hosting, least-privilege access and automated deployment. If you're learning DevOps or cloud, I'd recommend trying it yourself, mistakes included.

The code is on GitHub: rahimahisah17/shipit-app

Thanks for reading! If you've hit similar errors in your own pipelines, I'd love to hear how you solved them in the comments.