Update container image to run as non root (#352)

.gitlab/build-scripts/docker-entrypoint.sh

 #!/bin/bash
 set -e
 
-chmod a+x /app/*.sh
-
 if [[ "$1" = 'run' ]]; then
-      exec gosu plausibleuser /app/bin/plausible start
+      /app/bin/plausible start
 
 elif [[ "$1" = 'db' ]]; then
-      exec gosu plausibleuser /app/"$2".sh
- else
-      exec "$@"
-
+      /app/"$2".sh
 fi
 
 exec "$@"

Dockerfile

@@ -6,7 +6,6 @@ FROM elixir:1.10.3 as buildcontainer
 
 # preparation
 ARG APP_VER=0.0.1
-ENV GOSU_VERSION 1.11
 ENV MIX_ENV=prod
 ENV NODE_ENV=production
 ENV APP_VERSION=$APP_VER
@@ -23,20 +22,6 @@ RUN apt-get update  && \
 RUN apt-get install -y --no-install-recommends ca-certificates wget \
     && apt-get install -y --install-recommends gnupg2 dirmngr
 
-# grab gosu for easy step-down from root
-RUN set -x \
-    && dpkgArch="$(dpkg --print-architecture | awk -F- '{ print $NF }')" \
-    && wget -O /usr/local/bin/gosu "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-$dpkgArch" \
-    && wget -O /usr/local/bin/gosu.asc "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-$dpkgArch.asc" \
-    && export GNUPGHOME="$(mktemp -d)" \
-    && gpg --keyserver ha.pool.sks-keyservers.net --recv-keys B42F6819007F00F88E364FD4036A9C25BF357DD4 \
-    && gpg --batch --verify /usr/local/bin/gosu.asc /usr/local/bin/gosu \
-    && command -v gpgconf && gpgconf --kill all || : \
-    && rm -r "$GNUPGHOME" /usr/local/bin/gosu.asc \
-    && chmod +x /usr/local/bin/gosu \
-    && gosu --version \
-    && gosu nobody true
-
 COPY mix.exs ./
 COPY mix.lock ./
 RUN mix local.hex --force && \
@@ -82,9 +67,9 @@ COPY .gitlab/build-scripts/docker-entrypoint.sh /entrypoint.sh
 RUN chmod a+x /entrypoint.sh && \
     useradd -d /app -u 1000 -s /bin/bash -m plausibleuser
 
-COPY --from=buildcontainer /usr/local/bin/gosu /usr/local/bin/gosu
 COPY --from=buildcontainer /app/_build/prod/rel/plausible /app
 RUN chown -R plausibleuser:plausibleuser /app
+USER plausibleuser
 WORKDIR /app
 ENTRYPOINT ["/entrypoint.sh"]
 CMD ["run"]