tree.fail
1# Dockerfile
2FROM golang:1.21-alpine AS builder
3
4# Install build dependencies
5RUN apk add --no-cache git ca-certificates tzdata
6
7# Set working directory
8WORKDIR /app
9
10# Copy go mod files
11COPY go.mod go.sum ./
12
13# Download dependencies
14RUN go mod download
15
16# Copy source code
17COPY . .
18
19# Build the application
20RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -ldflags '-extldflags "-static"' -o plcdns .
21
22# Final stage
23FROM scratch
24
25# Copy CA certificates from builder
26COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
27
28# Copy timezone data
29COPY --from=builder /usr/share/zoneinfo /usr/share/zoneinfo
30
31# Copy the binary
32COPY --from=builder /app/plcdns /plcdns
33
34# Expose DNS ports (UDP and TCP)
35EXPOSE 53/udp
36EXPOSE 53/tcp
37
38# Set default environment variables
39ENV DNS_PORT=53
40
41# Run as non-root user (note: for port 53, container must run with --cap-add=NET_BIND_SERVICE)
42USER 65534:65534
43
44# Health check
45HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
46 CMD ["/plcdns", "-h"] || exit 1
47
48# Run the application
49ENTRYPOINT ["/plcdns"]