Dockerfile

# Build stage
FROM golang:1.21-alpine AS builder

# Install build dependencies
RUN apk add --no-cache git make

# Set working directory
WORKDIR /app

# Copy go mod files first for better caching
COPY go.mod go.sum ./
RUN go mod download

# Copy source code
COPY . .

# Build the binary
RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build \
    -ldflags="-w -s -X main.Version=$(git describe --tags --always --dirty 2>/dev/null || echo 'dev')" \
    -o /broker .

# Runtime stage
FROM alpine:3.19

# Install runtime dependencies
RUN apk add --no-cache ca-certificates tzdata

# Create non-root user for security
RUN addgroup -g 1000 broker && \
    adduser -u 1000 -G broker -s /bin/sh -D broker

# Create data directory
RUN mkdir -p /data && chown -R broker:broker /data

# Copy binary from builder
COPY --from=builder /broker /usr/local/bin/broker

# Set ownership
RUN chown broker:broker /usr/local/bin/broker

# Switch to non-root user
USER broker

# Expose ports
# 8080: gRPC client API
# 9080: Raft controller communication
# 9180: Inter-broker replication
# 9090: Prometheus metrics
EXPOSE 8080 9080 9180 9090

# Health check
HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
    CMD wget -qO- http://localhost:9090/health || exit 1

# Data volume
VOLUME ["/data"]

# Default environment variables
ENV BROKER_DATA_DIR=/data \
    BROKER_LOG_LEVEL=info

# Entry point
ENTRYPOINT ["/usr/local/bin/broker"]

# Default arguments (can be overridden)
CMD ["-id", "broker-1"]