Merge pull request #1575 from srm09/automated-cherry-pick-of-#1574-upstream-release-1.3

Automated cherry pick of #1574: Adds go mod download directive to Dockerfile

Author: k8s-ci-robot

Dockerfile

@@ -23,14 +23,23 @@ WORKDIR /workspace
 ARG goproxy=https://proxy.golang.org
 ENV GOPROXY=${goproxy}
 
+# 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
+
 # Build
 ARG TARGETOS
 ARG TARGETARCH
 ARG ldflags
 RUN --mount=type=bind,target=. \
     --mount=type=cache,target=/root/.cache/go-build \
-    --mount=type=cache,target=/go/pkg \
-    CGO_ENABLED=0 GOOS=linux GOOS=${TARGETOS} GOARCH=${TARGETARCH} \
+    --mount=type=cache,target=/go/pkg/mod \
+    CGO_ENABLED=0 GOOS=${TARGETOS} GOARCH=${TARGETARCH} \
     go build -a -ldflags "${ldflags} -extldflags '-static'" \
     -o /out/manager .