jenkins: create PRs in the stack repos upon deployment.

pr.sh

# COMMIT_TO_REPO is a boolean parameter
# STACK is a choice parameter
if [ "${COMMIT_TO_REPO}" == "true" ]; then
  # commit, push and create PR to the stack repo
  REPONAME=XXX-stack
  BRANCH=${STACK}-$(date +%Y%m%d-%H%M%S)
  FILE_TO_COMMIT=$(readlink -f $PROJDIR/.env | sed "s|${BASEDIR}/${REPONAME}/||")
  # don't care about possible wonky private files; we only care about that .env file
  rsync -a ${BASEDIR}/${REPONAME} ${WORKSPACE}/ 2>/dev/null || echo -en ""
  cd ${WORKSPACE}/${REPONAME}
  git checkout -q -b ${BRANCH}
  git diff-index --quiet HEAD ${FILE_TO_COMMIT}
  if [ "$?" == "0" ]; then
  	echo -en "\nNo tag changes detected. Skip PR Creation.\n\n"
    exit 0
  fi
  if [ "$?" != "1" ]; then
  	echo -en "\nAn error has occured. Failing the job.\n\n"
    exit 1
  fi
  git commit -m "New ${SERVICE} deployment on ${STACK} stack, tag ${IMAGE_TAG}" --  ${FILE_TO_COMMIT}
  echo -e "\n"
  git push -u origin ${BRANCH}
  echo -e "\nThe following PR has been created in ${REPONAME} stack repository:\n"
  /usr/local/bin/hub pull-request -m "deployed ${SERVICE}:${IMAGE_TAG} on ${STACK}"
  echo -e "\n"
  # cleaning up workspace is left to post-build.
else
  echo -en "\n\nSkip PR creation.\n\n"
fi