Adding proxy caching for faster and more resilient CI

Signed-off-by: apostasie <spam_blackhole@farcloser.world>

.github/config/daemon.json

@@ -0,0 +1,4 @@
+{
+  "registry-mirrors": ["http://localhost:5000"],
+  "debug": true
+}

.github/config/hosts.toml

@@ -0,0 +1,4 @@
+server = "https://registry-1.docker.io"
+
+[host."http://localhost:5000"]
+  capabilities = ["pull", "resolve"]

.github/workflows/test.yml

@@ -91,6 +91,52 @@ jobs:
       - uses: actions/checkout@v4.1.6
         with:
           fetch-depth: 1
+      - name: "Cache for Docker Hub images"
+        id: registry-cache
+        uses: actions/cache@v4
+        with:
+          path: |
+            "$GITHUB_WORKSPACE"/registry-proxy-cache
+          key: ${{ matrix.os }}-registry
+      - name: "Configure and start proxy cache"
+        run: |
+          # Configure docker to use the proxy cache
+          mkdir -p ~/.config/docker
+          cp .github/config/daemon.json ~/.config/docker/
+          sudo cp .github/config/daemon.json /etc/docker/
+          # Configure containerd to use the proxy cache
+          sudo mkdir -p /etc/containerd/certs.d/docker.io
+          sudo cp .github/config/hosts.toml /etc/containerd/certs.d/docker.io/
+          # Restart services
+          sudo systemctl restart docker
+          sudo systemctl restart containerd
+          # Start the proxy cache (FIXME: workaround github secret protection - should be a secret - though it does not matter, it is a readonly token on a test account)
+          docker run -d --net bridge --restart always --name registry-proxy-cache \
+            -e REGISTRY_PROXY_REMOTEURL=https://registry-1.docker.io \
+            -e REGISTRY_PROXY_USERNAME=dubogus \
+            -e REGISTRY_PROXY_PASSWORD="$(echo ZGNrcl9wYXRfUk8zdzV6UFdhWDdVWk1yRFh2NDRRYjU4ZVhnCg== | base64 -d)" \
+            --volume "$GITHUB_WORKSPACE"/registry-proxy-cache:/var/lib/registry -p 5000:5000 registry:2
+          # Get curl
+          sudo apt-get update -qq
+          sudo apt-get install -qq curl
+          # Wait until it is ready
+          attempts=0
+          while ! curl localhost:5000 && [ "$attempts" -lt 10 ] 1>/dev/null 2>&1 ; do
+            sleep 0.5
+            attempts=$((attempts + 1))
+          done
+          [ "$attempts" -lt 10 ] || {
+            >&2 printf "Failed contacting proxy server in less than five seconds. Giving up"
+            exit 1
+          }
+          # We are ready
+          echo "===== TESTING ===="
+          ls -lA "$GITHUB_WORKSPACE"/registry-proxy-cache
+          echo "===== Was there some cache already? SHOULD BE ^ ===="
+          time docker pull alpine || true
+          docker logs registry-proxy-cache
+          ls -lA "$GITHUB_WORKSPACE"/registry-proxy-cache
+          exit 1
       - name: "Prepare integration test environment"
         run: DOCKER_BUILDKIT=1 docker build -t test-integration --target test-integration --build-arg UBUNTU_VERSION=${UBUNTU_VERSION} --build-arg CONTAINERD_VERSION=${CONTAINERD_VERSION} .
       - name: "Remove snap loopback devices (conflicts with our loopback devices in TestRunDevice)"