nodejs

function install_node_deps() {
  local cwd=$(pwd)
  local target="$1"

  if [ ! -f "$target/package.json" ]; then
      return 0
  fi

  status "NODE (package.json) app detected"

  compile_node $BUILD_DIR $CACHE_DIR

  local node_path='vendor/node'

  # Symlink node to /app/vendor/node so node and its modules are runnable.

  ln -s ${BUILD_DIR}/${node_path}/ /app/${node_path}
  ln -s ${BUILD_DIR}/node_modules /app/node_modules

  echo "Node " `node -v` | indent
}

function compile_node() {
  # Configure directories
  build_dir=$1
  cache_basedir=$2
  bp_dir=$(cd $(dirname $0); cd ..; pwd)

  # Load some convenience functions like status() echo(), indent()
  source $bp_dir/bin/common.sh

  # Output npm debug info on error
  trap cat_npm_debug_log ERR

  # Look in package.json's engines.node field for a semver range
  semver_range=$(cat $build_dir/package.json | jq -r .engines.node)

  # Resolve node version using semver.io
  semver_url=https://semver.io/node/resolve/$semver_range
  node_version=$(curl --silent $semver_url)

  # Recommend using semver ranges in a safe manner
  if [ "$semver_range" == "null" ]; then
    protip "Specify a node version in package.json"
    semver_range=""
  elif [ "$semver_range" == "*" ]; then
    protip "Avoid using semver ranges like '*' in engines.node"
  elif [ ${semver_range:0:1} == ">" ]; then
    protip "Avoid using semver ranges starting with '>' in engines.node"
  fi

  # Output info about requested range and resolved node version
  if [ "$semver_range" == "" ]; then
    status "Defaulting to latest stable node: $node_version"
  else
    status "Requested node range:  $semver_range"
    status "Resolved node version: $node_version"
  fi

  # Download node from Heroku's S3 mirror of nodejs.org/dist
  status "Downloading and installing node"
  node_url="https://s3pository.heroku.com/node/v$node_version/node-v$node_version-linux-x64.tar.gz"
  curl $node_url --location -s -o - | tar xzf - -C $build_dir

  # Move node into ./vendor and make it executable
  mkdir -p $build_dir/vendor
  mv $build_dir/node-v$node_version-linux-x64 $build_dir/vendor/node
  chmod +x $build_dir/vendor/node/bin/*
  PATH=$PATH:$build_dir/vendor/node/bin

  # Run subsequent node/npm commands from the build path
  cd $build_dir

  if test -f $build_dir/npm-shrinkwrap.json; then
    # Use npm-shrinkwrap.json's checksum as the cachebuster
    status "Found npm-shrinkwrap.json"
    shrinkwrap_checksum=$(cat $build_dir/npm-shrinkwrap.json | md5sum | awk '{print $1}')
    cache_dir="$cache_basedir/$shrinkwrap_checksum"
    test -d $cache_dir && status "npm-shrinkwrap.json unchanged since last build"
  else
    # Fall back to package.json as the cachebuster.
    protip "Use npm shrinkwrap to lock down dependency versions"
    package_json_checksum=$(cat $build_dir/package.json | md5sum | awk '{print $1}')
    cache_dir="$cache_basedir/$package_json_checksum"
    test -d $cache_dir && status "package.json unchanged since last build"
  fi

  if test -d $cache_dir; then
    status "Restoring node_modules from cache"
    test -d $cache_dir/node_modules && cp -r $cache_dir/node_modules $build_dir/
  fi

  status "Installing dependencies"
  npm install --production 2>&1 | indent

  status "Pruning unused dependencies"
  npm prune 2>&1 | indent

  status "Caching node_modules for future builds"
  rm -rf $cache_dir
  mkdir -p $cache_dir
  test -d $build_dir/node_modules && cp -r $build_dir/node_modules $cache_dir/

  status "Cleaning up node-gyp and npm artifacts"
  rm -rf "$build_dir/.node-gyp"
  rm -rf "$build_dir/.npm"

  # Update the PATH
  status "Building runtime environment"
  mkdir -p $build_dir/.profile.d
  echo "export PATH=\"\$HOME/vendor/node/bin:\$HOME/bin:\$HOME/node_modules/.bin:\$PATH\"" > $build_dir/.profile.d/nodejs.sh
}