put ruby installation to Dockerfile for caching

followup of Merge pull request sameersbn#2429
image size : 2.83GB / 14.4.1 is 2.69GB
I will try to make smaller ..

Dockerfile

@@ -55,6 +55,32 @@ RUN set -ex && \
  && DEBIAN_FRONTEND=noninteractive dpkg-reconfigure locales \
  && rm -rf /var/lib/apt/lists/*
 
+# install build dependencies for ruby
+RUN set -ex \
+ && apt-get update \
+ && DEBIAN_FRONTEND=noninteractive apt-get install --no-install-recommends -y \
+      gcc libc6-dev make \
+      zlib1g-dev libssl-dev libgdbm-dev libreadline-dev \
+ && rm -rf /var/lib/apt/lists/*
+
+# build ruby from source
+RUN set -ex \
+ && RUBY_SRC_URL=https://cache.ruby-lang.org/pub/ruby/${RUBY_VERSION%.*}/ruby-${RUBY_VERSION}.tar.gz \
+ && echo "Building ruby v${RUBY_VERSION} from source..." \
+ && PWD_ORG="$PWD" \
+ && mkdir /tmp/ruby && cd /tmp/ruby \
+ && curl --remote-name -Ss "${RUBY_SRC_URL}" \
+ && printf '%s ruby-%s.tar.gz' "${RUBY_SOURCE_SHA256SUM}" "${RUBY_VERSION}" | sha256sum -c - \
+ && tar xzf ruby-"${RUBY_VERSION}".tar.gz && cd ruby-"${RUBY_VERSION}" \
+ &&./configure --disable-install-rdoc --enable-shared \
+ && make -j"$(nproc)" \
+ && make install \
+ && cd "$PWD_ORG" && rm -rf /tmp/ruby
+
+# RUN DEBIAN_FRONTEND=noninteractive apt-get purge -y --auto-remove \
+#     gcc libc6-dev make \
+#     zlib1g-dev libssl-dev libgdbm-dev libreadline-dev
+
 COPY assets/build/ ${GITLAB_BUILD_DIR}/
 RUN bash ${GITLAB_BUILD_DIR}/install.sh
 

assets/build/install.sh

@@ -10,8 +10,6 @@ GITLAB_WORKHORSE_BUILD_DIR=${GITLAB_INSTALL_DIR}/workhorse
 GITLAB_PAGES_BUILD_DIR=/tmp/gitlab-pages
 GITLAB_GITALY_BUILD_DIR=/tmp/gitaly
 
-RUBY_SRC_URL=https://cache.ruby-lang.org/pub/ruby/${RUBY_VERSION%.*}/ruby-${RUBY_VERSION}.tar.gz
-
 GEM_CACHE_DIR="${GITLAB_BUILD_DIR}/cache"
 
 GOROOT=/tmp/go
@@ -20,9 +18,8 @@ PATH=${GOROOT}/bin:$PATH
 export GOROOT PATH
 
 BUILD_DEPENDENCIES="gcc g++ make patch pkg-config cmake paxctl \
-  libc6-dev \
-  libpq-dev zlib1g-dev libyaml-dev libssl-dev \
-  libgdbm-dev libreadline-dev libncurses5-dev libffi-dev \
+  libpq-dev libyaml-dev \
+  libncurses5-dev libffi-dev \
   libxml2-dev libxslt-dev libcurl4-openssl-dev libicu-dev \
   gettext libkrb5-dev"
 
@@ -39,18 +36,6 @@ exec_as_git() {
 apt-get update
 DEBIAN_FRONTEND=noninteractive apt-get install --no-install-recommends -y ${BUILD_DEPENDENCIES}
 
-# build ruby from source
-echo "Building ruby v${RUBY_VERSION} from source..."
-PWD_ORG="$PWD"
-mkdir /tmp/ruby && cd /tmp/ruby
-curl --remote-name -Ss "${RUBY_SRC_URL}"
-printf '%s ruby-%s.tar.gz' "${RUBY_SOURCE_SHA256SUM}" "${RUBY_VERSION}" | sha256sum -c -
-tar xzf ruby-"${RUBY_VERSION}".tar.gz && cd ruby-"${RUBY_VERSION}"
-./configure --disable-install-rdoc --enable-shared
-make -j"$(nproc)"
-make install
-cd "$PWD_ORG" && rm -rf /tmp/ruby
-
 # PaX-mark ruby
 # Applying the mark late here does make the build usable on PaX kernels, but
 # still the build itself must be executed on a non-PaX kernel. It's done here