Dockerfile-scratch

## We specify the base image we need for our
## go application
FROM  golang:1.20.5-alpine as builder

RUN apk --no-cache add ca-certificates

# add a user here because addgroup and adduser are not available in scratch
RUN addgroup -S goapp \
    && adduser -S -u 12345 -g goapp goapp

## We specify that we now wish to execute 
## any further commands inside our /app
## directory
WORKDIR /app

## Add this go mod download command to pull in any dependencies
COPY go.* ./
RUN go mod download

COPY *.go ./

## we run go build to compile the binary
## executable of our Go program
RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-s -w" -o /server .

# Deploy the application binary into a lean image
FROM scratch

# Copy the binary to the production image from the builder stage.
COPY --from=builder /server .

# Copy CA certificattes from the builder image
COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
 
# Copy users from builder image
COPY --from=builder /etc/passwd /etc/passwd

USER goapp

# Run the web service on container startup.
ENTRYPOINT ["/server"]