message: Push new Docker images if anything under bazel/ changes.
diff: set -e
  # push the envoy image on merge to master
  -want_push='false'
  +branch_want_push='false'
  for branch in "master"
  do
  if [ "$CIRCLE_BRANCH" == "$branch" ]
  then
  - want_push='true'
  + branch_want_push='true'
  fi
  done
  -if [ -z "$CIRCLE_PULL_REQUEST" ] && [ "$want_push" == "true" ]
  +if [ -z "$CIRCLE_PULL_REQUEST" ] && [ "$branch_want_push" == "true" ]
  then
  + diff_want_push='false'
  if [[ $(git diff HEAD^ ci/build_container/) ]]; then
  echo "There are changes in the ci/build_container directory"
  + diff_want_push='true'
  + elif [[ $(git diff HEAD^ bazel/) ]]; then
  + echo "There are changes in the bazel directory"
  + diff_want_push='true'
  + fi
  + if [ "$diff_want_push" == "true" ]; then
  cd ci/build_container
  docker login -u "$DOCKERHUB_USERNAME" -p "$DOCKERHUB_PASSWORD"
  