in lib/google/serverless/exec.rb [771:781]
def deploy_temp_app app_yaml_file
temp_version = "appengine-exec-#{@timestamp_suffix}"
Exec::Gcloud.execute [
"app", "deploy", app_yaml_file,
"--project", @project,
"--version", temp_version,
"--no-promote", "--quiet"
]
temp_version
end