install_node_on_heroku

#!/usr/bin/env bash

# Installs the requested version of node on Heroku
# Example: source install_node_on_heroku '0.10.15'
# For use as part of a post_compile step

set -eo pipefail

# Pretty printing functions
[ $(uname) == "Darwin" ] && SED_FLAG='-l' || SED_FLAG='-u'

indent() {
  RE="s/^/       /"
  sed $SED_FLAG "$RE"
}

function puts-step (){
  echo "-----> $@"
}

node_version="$1"
if [ -z "$node_version" ]; then
  puts-step "No node verson specified, skipping"
  exit
fi

node_dir="$BUILD_DIR/.heroku/node"
node_version_file="$node_dir/node-version.txt"
# Check existing installed version and remove if necessary
puts-step "Checking for Node version $node_version"
skip_install=false
if [ -f "$node_version_file" ]; then
  if [ ! $(cat "$node_version_file") = $node_version ]; then
    puts-step "Found Node version $(cat "$node_version_file"), removing."
    rm -fr "$node_dir"
  else
    skip_install=true
  fi
fi

if ! $skip_install; then
  # Grab Heroku's bundled node
  puts-step "Installing Node version $node_version"
  mkdir -p "$node_dir"
  package_url="http://heroku-buildpack-nodejs.s3.amazonaws.com/nodejs-${node_version}.tgz"
  curl "$package_url" -s -o - | tar xzf - -C "$node_dir"
  # Record node version for future reference
  echo "$node_version" > "$node_version_file"
fi

# Add node/bin to path for future sessions
profile_file="$BUILD_DIR/.profile.d/node.sh"
mkdir -p $(dirname "$profile_file")
echo 'export PATH="$HOME/.heroku/node/bin:$PATH"' > "$profile_file"
export PATH="$node_dir/bin:$PATH"