text: #! /bin/bash
  
  repo_root=$(dirname "$0")/../..
  node_version=$(jq -r .engines.node "${repo_root}/package.json")
  if [ -z "${node_version}" ]; then
      echo "Could not determine node version from top-level package.json"
      exit 1
  fi
  
  
  tmpdir=$(mktemp -d)
  trap "cd /; rm -rf ${tmpdir}" EXIT
  cat > ${tmpdir}/Dockerfile <<EOF
  FROM node:${node_version}-stretch
  RUN apt-get update && apt-get install -y firefox-esr xvfb
  EOF
  
  docker build -t "taskcluster/browser-test:${node_version}" ${tmpdir}
  [ -n "$DOCKER_PUSH" ] && docker push "taskcluster/browser-test:${node_version}"
  