Created an optimized multi-stage dockerfile

Author: tuukkaviitanen

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.23-bookworm
+FROM golang:1.23-bookworm AS build-stage
 
 WORKDIR /usr/src/app
 
@@ -8,6 +8,13 @@ RUN go mod download
 
 COPY ./src ./src
 
+ENV CGO_ENABLED=0
+ENV GOOS=linux
+
 RUN go build src/cmd/raspy-monitor/main.go
 
+FROM scratch AS final-stage
+
+COPY --from=build-stage /usr/src/app/main .
+
 CMD ["./main"]