zarvox: when I run the command from inside the grain using nodeJS' execFile (https://nodejs.org/api/child_process.html#child_process_child_process_execfile_file_args_options_callback) I get:

/opt/app/sandstorm-integration/bin/getPublicId 1
error { [Error: spawn /opt/app/sandstorm-integration/bin/getPublicId ENOENT]
  code: 'ENOENT',
  errno: 'ENOENT',
  syscall: 'spawn /opt/app/sandstorm-integration/bin/getPublicId',
  path: '/opt/app/sandstorm-integration/bin/getPublicId',
  spawnargs: [ '1' ],
  cmd: '/opt/app/sandstorm-integration/bin/getPublicId 1' }