Dockerfile

# --- SECTION: Metadata ---
FROM golang:1.25-alpine AS builder

LABEL maintainer="Clovis Mugaruka <clovis.mugaruka@gmail.com>"

# Define build-time arguments (Stage 1)
ARG PORT=4000
ARG TZ=Africa/Nairobi

# --- SECTION: Build Dependencies ---
RUN apk add --no-cache git ca-certificates

WORKDIR /app

# Leverage Docker layer caching for Go modules
COPY go.mod go.sum ./
RUN go mod download

# --- SECTION: Compilation ---
COPY . .

# Build a statically linked binary
# -ldflags="-w -s" strips debug info for a smaller footprint
RUN CGO_ENABLED=0 GOOS=linux go build \
    -buildvcs=true \
    -ldflags="-w -s" \
    -o alice ./cmd/server


# --- SECTION: Final Runtime (Distroless) ---
FROM gcr.io/distroless/static-debian12:latest

# Re-declare ARGs to make them available in this stage
ARG PORT=4000
ARG TZ=Africa/Nairobi

# Set Environment Variables for the application
ENV TZ=${TZ}
ENV PORT=${PORT}

WORKDIR /

# --- SECTION: Asset Transfer ---
# Copy the compiled binary from the builder stage
COPY --from=builder /app/alice .

# Copy configuration and certificates
COPY --from=builder /app/.env ./.env
COPY --from=builder /app/public.cer ./public.cer

# --- SECTION: Execution ---
# Expose the port (now correctly resolving the ARG)
EXPOSE ${PORT}

# Run the binary directly (Distroless has no shell)
ENTRYPOINT ["/alice"]