Docker two stage builder

Dockerfile

FROM alpine:3.9 as builder

ENV VERSION=v12.16.2 NPM_VERSION=6 YARN_VERSION=latest

LABEL maintainer="Thiago Zilli Sarmento <thiago.zilli@gmail.com>"
LABEL builder="builder"

RUN apk upgrade --no-cache -U && \
  apk add --no-cache \
  ca-certificates \
  curl \
  git \
  gnupg \
  openssl-dev \
  openssh-client \
  libstdc++

RUN curl -sfSLO https://unofficial-builds.nodejs.org/download/release/${VERSION}/node-${VERSION}-linux-x64-musl.tar.xz && \
  curl -sfSLO https://unofficial-builds.nodejs.org/download/release/${VERSION}/SHASUMS256.txt && \
  grep " node-${VERSION}-linux-x64-musl.tar.xz\$" SHASUMS256.txt | sha256sum -c | grep ': OK$' && \
  tar -xf node-${VERSION}-linux-x64-musl.tar.xz -C /usr --strip 1 && \
  rm node-${VERSION}-linux-x64-musl.tar.xz

RUN npm install -g npm@${NPM_VERSION} && \
  find /usr/lib/node_modules/npm -type d \( -name test -o -name .bin \) | xargs rm -rf

RUN for server in ipv4.pool.sks-keyservers.net keyserver.pgp.com ha.pool.sks-keyservers.net; do \
  gpg --keyserver $server --recv-keys \
  6A010C5166006599AA17F08146C2130DFD2497F5 && break; \
  done && \
  curl -sfSL -O https://yarnpkg.com/${YARN_VERSION}.tar.gz -O https://yarnpkg.com/${YARN_VERSION}.tar.gz.asc && \
  gpg --batch --verify ${YARN_VERSION}.tar.gz.asc ${YARN_VERSION}.tar.gz && \
  mkdir /usr/local/share/yarn && \
  tar -xf ${YARN_VERSION}.tar.gz -C /usr/local/share/yarn --strip 1 && \
  ln -s /usr/local/share/yarn/bin/yarn /usr/local/bin/ && \
  ln -s /usr/local/share/yarn/bin/yarnpkg /usr/local/bin/ && \
  rm ${YARN_VERSION}.tar.gz*


# Pass the SSH_PRIVATE_KEY as an ARG
ARG SSH_PRIVATE_KEY
RUN mkdir /root/.ssh/ && \
  echo "${SSH_PRIVATE_KEY}" > /root/.ssh/id_rsa && \
  chmod 400 /root/.ssh/id_rsa && \
  touch /root/.ssh/known_hosts && \
  ssh-keyscan gitlab.com >> /root/.ssh/known_hosts


ARG BRANCH
RUN git clone --progress --verbose \
  git@gitlab.com:xxxxx/yyyyy.git \
  --branch ${BRANCH} /app && \
  rm -fr /app/.git && \
  cd /app && \
  yarn install && \
  yarn build
#&& yarn install --silent >/dev/null 2>&1

WORKDIR /app

FROM node:12-alpine

LABEL maintainer="Thiago Zilli Sarmento <thiago.zilli@gmail.com>"

RUN apk upgrade --no-cache -U && \
  apk add --no-cache \
  ca-certificates \
  iputils \
  curl \
  shadow \
  bash \
  tar  

WORKDIR /app

ARG ENV_FILE
COPY --from=builder /app ./
COPY ${ENV_FILE} /app/.env
COPY run.sh /app/run.sh

ARG BRANCH
ENV BRANCH=${BRANCH}

RUN export 

EXPOSE 3000

CMD /app/run.sh