Merge pull request #2344 from polarathene/refactor/dockerfile-to-opensuse

refactor(dockerfile): Change base Alpine (3.17) => openSUSE Leap (15.4)

Dockerfile

@@ -1,18 +1,39 @@
-FROM alpine:3.17
+# syntax=docker.io/docker/dockerfile:1
 
-RUN apk update && \
-    apk upgrade && \
-    apk add bash procps drill git coreutils libidn curl socat openssl xxd && \
-    rm -rf /var/cache/apk/* && \
-    adduser -D -s /bin/bash testssl && \
-    ln -s /home/testssl/testssl.sh /usr/local/bin/ 
+ARG LEAP_VERSION=15.4
+ARG INSTALL_ROOT=/rootfs
 
-USER testssl
-WORKDIR /home/testssl/
+FROM opensuse/leap:${LEAP_VERSION} as builder
+ARG CACHE_ZYPPER=/tmp/cache/zypper
+ARG INSTALL_ROOT
+# /etc/os-release provides $VERSION_ID
+RUN source /etc/os-release \
+  && export ZYPPER_OPTIONS=( --releasever "${VERSION_ID}" --installroot "${INSTALL_ROOT}" --cache-dir "${CACHE_ZYPPER}" ) \
+  && zypper "${ZYPPER_OPTIONS[@]}" --gpg-auto-import-keys refresh \
+  && zypper "${ZYPPER_OPTIONS[@]}" --non-interactive install --download-in-advance --no-recommends \
+       bash procps grep gawk sed coreutils busybox-util-linux busybox-vi ldns libidn2-0 socat openssl curl \
+  && zypper "${ZYPPER_OPTIONS[@]}" clean --all
+## Cleanup (reclaim approx 13 MiB):
+# None of this content should be relevant to the container:
+RUN  rm -r "${INSTALL_ROOT}/usr/share/"{licenses,man,locale,doc,help,info}
+# Functionality that the container doesn't need:
+RUN  rm    "${INSTALL_ROOT}/usr/share/misc/termcap" \
+  && rm -r "${INSTALL_ROOT}/usr/lib/sysimage/rpm"
+
+
+# Create a new image with the contents of $INSTALL_ROOT
+FROM scratch
+ARG INSTALL_ROOT
+COPY --link --from=builder ${INSTALL_ROOT} /
+# Create user + (home with SGID set):
+RUN  echo 'testssl:x:1000:1000::/home/testssl:/bin/bash' >> /etc/passwd \
+  && echo 'testssl:x:1000:' >> /etc/group \
+  && echo 'testssl:!::0:::::' >> /etc/shadow \
+  && install --mode 2755 --owner testssl --group testssl --directory /home/testssl \
+  && ln -s /home/testssl/testssl.sh /usr/local/bin/
 
 # Copy over build context (after filtered by .dockerignore): bin/ etc/ testssl.sh
 COPY --chown=testssl:testssl . /home/testssl/
-
+USER testssl
 ENTRYPOINT ["testssl.sh"]
-
 CMD ["--help"]