ci fixup

Dockerfile

@@ -31,12 +31,17 @@ WORKDIR /workspace
 # Run this with docker build --build-arg goproxy=$(go env GOPROXY) to override the goproxy
 ARG goproxy=https://proxy.golang.org
 # Run this with docker build --build-arg package=./controlplane/kubeadm or --build-arg package=./bootstrap/kubeadm
-ENV GOPROXY=$goproxy
+ENV GOPROXY=direct
 
 # Copy the Go Modules manifests
 COPY go.mod go.mod
 COPY go.sum go.sum
 
+# Cache deps before building and copying source so that we don't need to re-download as much
+# and so that source changes don't invalidate our downloaded layer
+RUN --mount=type=cache,target=/go/pkg/mod \
+    go mod download
+
 # Copy the sources
 COPY ./ ./
 
@@ -45,7 +50,10 @@ ARG package=.
 ARG ARCH
 ARG ldflags
 
-Run CGO_ENABLED=0 GOOS=linux GOARCH=${ARCH} \
+# Do not force rebuild of up-to-date packages (do not use -a) and use the compiler cache folder
+RUN --mount=type=cache,target=/root/.cache/go-build \
+    --mount=type=cache,target=/go/pkg/mod \
+    CGO_ENABLED=0 GOOS=linux GOARCH=${ARCH} \
     go build -trimpath -ldflags "${ldflags} -extldflags '-static'" \
     -o manager ${package}