GoogleAppEngine Application
https://developers.google.com/analytics/solutions/articles/hello-analytics-api#environment
を参考に、
/client_secrets.json
が必要です。
{
"installed": {
"client_id": "INSERT CLIENT ID HERE",
"client_secret": "INSERT CLIENT SECRET HERE",
"redirect_uris": ["INSERT REDIRECT URI"],
"auth_uri": "https://accounts.google.com/o/oauth2/auth",
"token_uri": "https://accounts.google.com/o/oauth2/token"
}
}