Dockerfile

# Build stage
FROM golang:1.23.12-alpine AS builder

# Install build dependencies for CGo (required by go-sqlite3)
RUN apk add --no-cache gcc musl-dev

WORKDIR /app

# Download dependencies first (layer caching)
COPY go.mod go.sum ./
RUN go mod download

# Copy source code and build
COPY . .
RUN CGO_ENABLED=1 go build -o relay-server -ldflags="-s -w" ./cmd/relay

# Runtime stage
FROM alpine:3.20

# OCI labels — required by GHCR to link the package to the repository and
# display metadata on the package page.
# Ref: https://docs.github.com/en/packages/working-with-a-github-packages-registry/working-with-the-container-registry#labelling-container-images
LABEL org.opencontainers.image.source="https://github.com/AOSSIE-Org/ThruBox-Server" \
      org.opencontainers.image.description="Lightweight, self-hosted relay server for ephemeral message passing" \
      org.opencontainers.image.licenses="GPL-3.0" \
      org.opencontainers.image.title="ThruBox-Server" \
      org.opencontainers.image.vendor="AOSSIE"

RUN apk add --no-cache ca-certificates

RUN addgroup -S relay && adduser -S -G relay relay

COPY --from=builder /app/relay-server /usr/local/bin/relay-server
COPY --from=builder /app/config.yaml /etc/relay/config.yaml

# Create data directory for SQLite and set ownership
RUN mkdir -p /data && chown -R relay:relay /data

# Set default storage path to the mounted volume
ENV RELAY_STORAGE_PATH=/data/relay.db

# Point the binary at the config file copied in above. Without this the
# process starts from / and silently falls back to built-in defaults,
# ignoring the bundled config.yaml entirely.
ENV RELAY_CONFIG_PATH=/etc/relay/config.yaml

USER relay

EXPOSE 3000

VOLUME ["/data"]

CMD ["relay-server"]