bootstrap_node

#!/usr/bin/env bash

# Copyright 2017 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License

# fail fast
set -e

function usage() {
  echo "Usage: $(basename $0) [--ignore-verification-failure] [--direct] [--help] version"
  echo ""
  echo "Verifies and installs the specified version of Node.js."
  echo ""
  echo "Options:"
  echo "  --ignore-verification-failure  If the binary verification fails,"
  echo "                                 still continue with the installation."
  echo "                                 By default, if binary verification"
  echo "                                 fails, the installation is aborted."
  echo "  --direct                       Download and install directly from"
  echo "                                 nodejs.org instead of from"
  echo "                                 https://storage.googleapis.com/gcp-node-packages"
  echo "  --help                         Prints this help message"
  echo ""
  echo "  version                        The version of Node.js to install."
  echo "                                 The version number is expected to be"
  echo "                                 of the form 'v#.#.#'."
  exit 1
}

ignore_verification_failure="false"
direct="false"

# The node version to install expected to be of the form 'v#.#.#'
node_version=

# Parse the command line arguments
while [ $# -gt 0 ]; do
  case "${1}" in
    --ignore-verification-failure)
      ignore_verification_failure="true"
      shift
      ;;
    --direct)
      direct="true"
      shift
      ;;
    --help)
      shift
      usage
      ;;
    *)
      # If the argument with any -- prefix removed is equal to the
      # argument itself, then the argument does not start with --.
      # Thus, interpret it as specifying the version.
      if [ "${1#--}" == "${1}" ]; then
        if [ -z "${node_version}" ]; then
          node_version="${1}"
        else
          echo "Note: Exactly one version must be specified and"
          echo "      \"${node_version}\" was already specified as the version."
          usage
        fi
      else
        echo "Unexpected argument ${1}"
        usage
      fi
      shift
      ;;
  esac
done

if [ -z "${node_version}" ]; then
  echo "A version must be specified."
  usage
fi

if [ "${direct}" == "true" ]; then
  # The URL of the location from which the specified Node.js file
  # and checksum file can be downloaded
  base_url="https://nodejs.org/dist/${node_version}"
  # The name of the checksum file found in ${base_url} that is used to
  # verify the Node.js binary
  checksum_file="SHASUMS256.txt.asc"
else
  base_url="https://storage.googleapis.com/gcp-node-packages"
  checksum_file="${node_version}-SHASUMS256.txt.asc"
fi

# The location where the Node will be installed
install_dir="/nodejs"

# The name of the Node.js binary to install
node_filename="node-${node_version}-linux-x64.tar.gz"

# The temporary location where the downloaded files are stored while being
# verified.  The script will ensure that this directory is removed before
# the script exits.
script_name=$(basename ${0})
tmp_dir=$(mktemp -d /tmp/${script_name}.XXXXXX) || exit 1

# Used to issue warnings to the user, directing the message to standard error
function warn {
  echo ${1} 1>&2;
}

# Used to cleanup any temporary directories
function cleanUp {
  rm -Rf "${tmp_dir}"
}

# Used to cleanup any temporary directories and immediately exit this
# script with an error code indicating failure
function exitAsFailure {
  cleanUp
  exit 1
}

# Used to handle a failure by either aborting the installation or issuing a
# warning depending on the options passed to this script.
function handleFailure {
  if [ "${ignore_verification_failure}" == "true" ]; then
    warn "The installation will continue because the --ignore-verification-failure"
    warn "flag was specified, but it is strongly recommended that you install"
    warn "a version of Node.js that can been verified."
    warn ""
  else
    warn "Aborting the installation."
    warn ""
    warn "The installation can be forced using the --ignore-verification-failure"
    warn "flag.  However, it is strongly recommended that you install a version"
    warn "of Node.js that can be verified."
    warn ""
    exitAsFailure
  fi
}

# Used to handle not being able to download the checksum file needed to
# verify the Node.js binary.
function handleFailedChecksumDownload {
  warn "The files required to verify the requested Node.js binary could not be"
  warn "downloaded."
  warn ""
  handleFailure
}

# Used to handle a failure in verifying the specified Node.js binary.
function handleFailedVerification {
  warn "The Node.js binary could not be verified."
  warn "This means it may not be an officially released Node.js binary"
  warn "or may have been tampered with."
  warn ""
  handleFailure
}

# Make sure we are in the correct place in the fs and it is pristine
cleanUp
mkdir -p "${tmp_dir}"
cd "${tmp_dir}"

# Use the --fail option so that a non-zero exit code is produced if a
# 404 error is encountered
curl --fail -O ${base_url}/${node_filename} || exitAsFailure
curl --fail -O ${base_url}/${checksum_file} || handleFailedChecksumDownload

# The verify node script has a non-zero exit code on failure
/opt/gcp/runtime/verify_node ${node_filename} ${checksum_file} \
  || handleFailedVerification

# Proceed to install Node
# First, remove the installation directory to prepare for a fresh install
# Note: The -f option is used with rm so that rm will still succeed if
#       the installation directory doesn't exist.
(rm -Rf "${install_dir}") || exitAsFailure
(mkdir -p "${install_dir}") || exitAsFailure

# Do the actual installation
(tar xzf "${tmp_dir}/${node_filename}" -C "${install_dir}" --strip-components=1) \
  || exitAsFailure

# Remove any temporary directories
cleanUp