FROM golang:1.22-bookworm AS builder
WORKDIR /app
COPY go.mod ./
# Download deps before copying source so layer is cached separately
ENV GONOSUMDB=*
ENV GOFLAGS=-mod=mod
RUN go mod download
COPY main.go ./
RUN CGO_ENABLED=0 GOOS=linux go build -trimpath -o spnego-proxy .

FROM debian:bookworm-slim
RUN apt-get update && \
    apt-get install -y --no-install-recommends ca-certificates && \
    rm -rf /var/lib/apt/lists/*
COPY --from=builder /app/spnego-proxy /usr/local/bin/spnego-proxy
EXPOSE 4000
ENTRYPOINT ["/usr/local/bin/spnego-proxy"]