Dockerfile

# Stage 1: Build the Go binary
FROM golang:1.21-alpine AS builder

WORKDIR /app

# Copy source code and mod files
COPY go.mod ./
COPY main.go .

# Download dependencies
# Note: main.go must be present for 'go mod tidy' to detect imports correctly
RUN go mod tidy

# Build the application
# CGO_ENABLED=0 ensures a static binary
RUN CGO_ENABLED=0 GOOS=linux go build -o ctf-server main.go

# Stage 2: Create the runtime image
FROM alpine:latest

WORKDIR /root/

# Copy the binary from the builder stage
COPY --from=builder /app/ctf-server .

# CRITICAL: Copy the source code so /source endpoint can serve it
COPY --from=builder /app/main.go .

# Expose the port Hugging Face Spaces expects (7860)
EXPOSE 7860

# Run the binary
CMD ["./ctf-server"]