Files
beer_data/.gitea/workflows/build_push.yml
T
hermes ce6f5b7962
Build and Push Image / Unit tests (push) Successful in 46s
Build and Push Image / Build and push image (push) Skipped
Build and Push Image / Deploy to the cluster (push) Skipped
fix(ci): pin the cluster CA fingerprint instead of trusting a fetched CA
The review was right on both counts, and both are fixed.

1. MITM. Fetching the CA over an unverified connection (`curl -sk`) and then
   trusting it is a privilege-escalation hole: the runner holds cluster-admin
   credentials, so an attacker able to intercept the fetch could hand us a CA
   of their choosing and then read everything sent over the connection.

   The CA is now PINNED. It is still fetched over an insecure connection, but
   it is only USED if its SHA-256 fingerprint matches
   `KUBE_SERVER_CA_FINGERPRINT`. An intercepted CA will not hash to the
   pinned value, so it is refused. If the secret is not set, the job fails
   rather than trusting an unverified CA.

2. The hardcoded cluster name. `kubectl config set-cluster default` creates a
   NEW cluster entry when the kubeconfig's entry is called something else,
   leaving the original (and its stale CA) in use. The name is now read from
   the kubeconfig: `{.clusters[0].name}`.

The bash is also moved out of the YAML into `scripts/kube-ca-refresh.sh`, so
it can be read, reviewed and tested on its own rather than as a wall of
shell inside a workflow file.

All three paths are tested against the live API server:

- no fingerprint supplied   -> refuses, exit 1
- wrong fingerprint        -> refuses, exit 1
- correct fingerprint      -> refreshes the CA, exit 0, kubectl then works
2026-11-09 12:11:56 +10:00

212 lines
9.2 KiB
YAML

name: Build and Push Image
on: [push]
jobs:
test:
name: Unit tests
runs-on: ubuntu-latest
steps:
- name: Checkout
uses: actions/checkout@v4
# NOTE: no actions/setup-python here. That action downloads a Python
# build from GitHub, which this runner cannot reach reliably - the job
# hung on it. The runner image already carries a usable python3, so
# the tests use it directly.
- name: Show the Python version
run: python3 --version
- name: Install dependencies
run: |
python3 -m venv .venv
. .venv/bin/activate
pip install --upgrade pip
pip install -r requirements-dev.txt
- name: Run tests
run: |
. .venv/bin/activate
python -m pytest tests/ -q
# NOTE: the build job deliberately does NOT have a kubeconfig. The
# `KUBEC_CONFIG_BUILDX` secret is cluster-admin-equivalent, and a build step
# that has no need of the cluster should not be able to read it. The deploy
# step, added in a later PR, gets its own job with the kubeconfig - that way
# a compromised dependency in the build cannot reach the cluster.
build:
name: Build and push image
runs-on: ubuntu-latest
container: catthehacker/ubuntu:act-latest
needs: test
if: gitea.ref == 'refs/heads/master'
steps:
- name: Checkout
uses: actions/checkout@v4
- name: Set up Docker Buildx (remote -> persistent buildkit daemon)
uses: docker/setup-buildx-action@v3
with:
# The `kubernetes` driver talks to the cluster API, which needs the
# k3s CA certificate. The job container does not have it, so the
# bootstrap failed with "x509: certificate signed by unknown
# authority".
#
# The `remote` driver talks straight to the buildkit daemon that is
# already running in the cluster, so no cluster API access (and no
# kubeconfig) is needed at all. This is the same pattern the
# wedding-photos workflow uses successfully.
#
# NOTE: `endpoint` must be passed as a top-level key. The action
# appends it as the POSITIONAL argument to
# `buildx create --driver remote <endpoint>`; putting it in
# driver-opts instead yields "ERROR: no remote endpoint provided".
driver: remote
endpoint: tcp://buildkit.gitea-runner.svc:1234
- name: Login to Docker Registry
uses: docker/login-action@v3
with:
registry: git.aridgwayweb.com
username: armistace
password: ${{ secrets.REG_PASSWORD }}
- name: Build Base Image
uses: docker/build-push-action@v5
with:
context: .
push: true
file: base.Dockerfile
# amd64 only. A multi-arch build runs qemu emulation, which crashes
# the buildkit pod on this NUC (exit 255, SandboxChanged) and the
# build then hangs for many minutes. The cluster is amd64.
platforms: linux/amd64
tags: |
git.aridgwayweb.com/armistace/beer_base_image:latest
- name: Build and Push
uses: docker/build-push-action@v5
with:
context: .
push: true
file: flask.Dockerfile
platforms: linux/amd64
tags: |
git.aridgwayweb.com/armistace/beer-data:latest
git.aridgwayweb.com/armistace/beer-data:${{ github.sha }}
# The deploy job is separate from the build job on purpose. The
# `KUBEC_CONFIG_BUILDX` secret is cluster-admin-equivalent, and a build
# step that never talks to the cluster should not be able to read it - a
# compromised dependency in the build would otherwise have a direct path to
# the cluster.
deploy:
name: Deploy to the cluster
runs-on: ubuntu-latest
needs: build
if: gitea.ref == 'refs/heads/master'
timeout-minutes: 10
steps:
- name: Checkout
uses: actions/checkout@v4
- name: Create Kubeconfig
run: |
mkdir -p $HOME/.kube
# Written with restrictive permissions: the kubeconfig is
# cluster-admin-equivalent, so it should not be readable by
# anything else on the runner.
install -m 600 /dev/null $HOME/.kube/config
echo "${{ secrets.KUBEC_CONFIG_BUILDX_NEW_2 }}" > $HOME/.kube/config
chmod 600 $HOME/.kube/config
- name: Verify the cluster is reachable
run: |
# The kubeconfig embeds the k3s server CA. If the cluster's CA has
# been rotated since the secret was created, kubectl cannot verify
# the server. The script refreshes the CA, but only if it matches
# the fingerprint pinned in the secret - see the script for why.
bash scripts/kube-ca-refresh.sh "${{ secrets.KUBE_SERVER_CA_FINGERPRINT }}"
- name: Install kubectl
run: |
# Skip the whole apt dance if the runner already has a kubectl.
if command -v kubectl >/dev/null 2>&1; then
kubectl version --client
exit 0
fi
apt-get update
apt-get install -y apt-transport-https ca-certificates curl gnupg
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.33/deb/Release.key | gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg
chmod 644 /etc/apt/keyrings/kubernetes-apt-keyring.gpg
echo 'deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.33/deb/ /' | tee /etc/apt/sources.list.d/kubernetes.list
apt-get update
apt-get install -y kubectl
- name: Deploy
run: |
# Apply the namespace and the non-secret manifests. The Secrets
# (beer-db, beer-app) are hand-provisioned and are NOT in the repo,
# so they are deliberately not in the apply set.
kubectl apply -f kube/beer_namespace.yaml
kubectl apply -f kube/beer-service.yaml
# The deployment manifest carries a sentinel image tag; the real
# SHA-pinned image is set immediately below. Applying it here
# keeps the rest of the spec (probes, resources, security context)
# in the repo and under review.
kubectl apply -f kube/beer-deployment.yaml
# The image is pinned to the commit SHA rather than `:latest`.
# `kubectl set image` writes the SHA into the pod template, which
# makes the change a real manifest change - the Deployment rolls
# because its pod template changed, not because it was told to.
# That also makes `kubectl rollout undo` meaningful: it can go back
# to the previous SHA.
kubectl -n beer set image deployment/beer-deployment \
beer-data=git.aridgwayweb.com/armistace/beer-data:${{ github.sha }}
kubectl -n beer rollout status deployment/beer-deployment --timeout=180s
- name: Verify the new image is actually running
run: |
# CI green and pods Ready do NOT prove the new code is live. Compare
# the running digest against the registry's :latest.
RUNNING=$(kubectl -n beer get pod -l app=beer-data \
-o jsonpath='{.items[0].status.containerStatuses[0].imageID}')
REGISTRY=$(curl -s -u "armistace:${{ secrets.REG_PASSWORD }}" -I \
"https://git.aridgwayweb.com/v2/armistace/beer-data/manifests/latest" \
-H "Accept: application/vnd.docker.distribution.manifest.v2+json" \
| grep -i docker-content-digest | awk '{print $2}' | tr -d '\r')
echo "running: $RUNNING"
echo "registry: $REGISTRY"
if [ "$RUNNING" != "$REGISTRY" ]; then
echo "ERROR: the running pod is not the image that was just pushed"
exit 1
fi
- name: Remove the kubeconfig
if: always()
run: rm -f $HOME/.kube/config
- name: Smoke test the deployed app
run: |
# Check the app's own port from inside the pod, AND the Service in
# front of it. The pod check alone would pass even if the Service
# selector or the port mapping were wrong, which is exactly the
# kind of breakage a deploy can introduce silently.
for i in $(seq 1 12); do
if kubectl -n beer exec deploy/beer-deployment -- \
python -c "import urllib.request,sys; sys.exit(0 if urllib.request.urlopen('http://127.0.0.1:5000/healthz').status==200 else 1)"; then
echo "healthz OK"
break
fi
echo "waiting for the app to come up ($i/12)"
sleep 5
done
kubectl -n beer exec deploy/beer-deployment -- \
python -c "import urllib.request,sys; r=urllib.request.urlopen('http://127.0.0.1:5000/readyz'); print('readyz:', r.read().decode()); sys.exit(0 if r.status==200 else 1)"
# Through the Service - the path a real client takes.
kubectl -n beer run smoke --rm -i --restart=Never --image=python:3.14-slim -- \
python -c "import urllib.request,sys; r=urllib.request.urlopen('http://beer-service.beer.svc.cluster.local/healthz'); print('service healthz:', r.read().decode()); sys.exit(0 if r.status==200 else 1)"