KEP-2170: Bind repository into the build environment instead of filec…

…opy (#2222)

Signed-off-by: Yuki Iwai <yuki.iwai.tz@gmail.com>

cmd/training-operator.v2alpha1/Dockerfile

@@ -1,23 +1,20 @@
 # Build the manager binary
-FROM golang:1.22 as builder
+FROM golang:1.22 AS builder
 
 WORKDIR /workspace
-# 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 go mod download
-
-# Copy the go source
-COPY . .
 
 # Build
-RUN CGO_ENABLED=0 GOOS=linux GO111MODULE=on go build -a -o manager cmd/training-operator.v2alpha1/main.go
+RUN --mount=type=cache,target=/go/pkg/mod/,sharing=locked \
+    --mount=type=bind,source=go.sum,target=go.sum \
+    --mount=type=bind,source=go.mod,target=go.mod \
+    go mod download
+RUN --mount=type=cache,target=/go/pkg/mod/ \
+    --mount=type=bind,target=. \
+    CGO_ENABLED=0 GOOS=linux GO111MODULE=on go build -a -o /bin/manager cmd/training-operator.v2alpha1/main.go
 
 # Use distroless as minimal base image to package the manager binary
 # Refer to https://github.com/GoogleContainerTools/distroless for more details
 FROM gcr.io/distroless/static:nonroot
 WORKDIR /
-COPY --from=builder /workspace/manager .
+COPY --from=builder /bin/manager .
 ENTRYPOINT ["/manager"]