Dockerfile

FROM golang:1.23.2-alpine3.20 AS builder

RUN apk add --no-cache --no-progress ca-certificates gcc git make musl-dev

COPY . /src
ARG BININFO_BUILD_DATE BININFO_COMMIT_HASH BININFO_VERSION # provided to 'make install'
RUN make -C /src install PREFIX=/pkg GOTOOLCHAIN=local GO_BUILDFLAGS='-mod vendor'

################################################################################

FROM alpine:3.20

RUN addgroup -g 4200 appgroup \
  && adduser -h /home/appuser -s /sbin/nologin -G appgroup -D -u 4200 appuser

# upgrade all installed packages to fix potential CVEs in advance
# also remove apk package manager to hopefully remove dependency on OpenSSL 🤞
RUN apk upgrade --no-cache --no-progress \
  && apk del --no-cache --no-progress apk-tools alpine-keys

COPY --from=builder /etc/ssl/certs/ /etc/ssl/certs/
COPY --from=builder /etc/ssl/cert.pem /etc/ssl/cert.pem
COPY --from=builder /pkg/ /usr/
# make sure all binaries can be executed
RUN ntp_exporter --version 2>/dev/null

ARG BININFO_BUILD_DATE BININFO_COMMIT_HASH BININFO_VERSION
LABEL source_repository="https://github.com/sapcc/ntp_exporter" \
  org.opencontainers.image.url="https://github.com/sapcc/ntp_exporter" \
  org.opencontainers.image.created=${BININFO_BUILD_DATE} \
  org.opencontainers.image.revision=${BININFO_COMMIT_HASH} \
  org.opencontainers.image.version=${BININFO_VERSION}

USER 4200:4200
WORKDIR /home/appuser
ENTRYPOINT [ "/usr/bin/ntp_exporter" ]