无法启动googleappengine launcer .format（module_configuration.env，_ALLOWED_RUNTIMES_ENV_FLEX

Question

按照本教程https://cloud.google.com/php/tutorials/wordpress-app-engine-flexible

一切顺利。当我开始运行googleAppEngineLauncer时，它会在最后一行日志中抛出此错误。

.format(module_configuration.env, _ALLOWED_RUNTIMES_ENV_FLEX)) google.appengine.tools.devappserver2.errors.InvalidAppConfigError: In env: flex, only the following runtimes are allowed: ('python-compat', 'java', 'java7', 'go', 'custom')

我的app.yml看起来像这样

runtime: php
env: flex

beta_settings:
cloud_sql_instances: myproject-id:europe-west1:wp

runtime_config:
document_root: wordpress

env_variables:
WHITELIST_FUNCTIONS: escapeshellarg,escapeshellcmd,exec,pclose,popen,shell_exec,phpversion,php_uname

我尝试使用custom和php55，但仍然出错。