# Multi-stage build for the WebRTC signaling server.
# Stage 1: compile signal.c statically against musl so the runtime image
# doesn't need libc at all.
FROM docker.io/library/alpine:3.20 AS build
RUN apk add --no-cache gcc musl-dev
WORKDIR /src
COPY server/signal.c ./
RUN cc -O3 -Wall -Wextra -Werror -static signal.c -o signal

# Stage 2: minimal runtime. Keep alpine (instead of scratch) so the
# entrypoint can use /bin/sh + cp to publish index.html into the bind-
# mounted /static directory on startup.
FROM docker.io/library/alpine:3.20
RUN apk add --no-cache curl
COPY --from=build /src/signal /usr/local/bin/signal
COPY index.html /opt/static/index.html
COPY entrypoint.sh /usr/local/bin/entrypoint.sh
RUN chmod +x /usr/local/bin/entrypoint.sh
EXPOSE 8080
ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]