A wrapper for gar_auth and gar_auth_service
gce_auth(new_user = FALSE, no_auto = FALSE)If TRUE, reauthenticate via Google login screen
Will ignore auto-authentication settings if TRUE
If you have set the environment variable GCE_AUTH_FILE to a valid file location,
the function will look there for authentication details.
Otherwise it will look in the working directory for the `.httr-oauth` file, which if not present
will trigger an authentication flow via Google login screen in your browser.
If GCE_AUTH_FILE is specified, then gce_auth() will be called upon loading the package
via library(googleComputeEngineR),
meaning that calling this function yourself at the start of the session won't be necessary.
GCE_AUTH_FILE can be either a token generated by gar_auth or
service account JSON ending with file extension .json
Invisibly, the token that has been saved to the session