Many functions have a lot of return points due to having many error checks -- does the database exist, the table exist, is the token string empty, does the user exist, is the token already registered to a different user, etc. etc. -- so figure out good places to log. A function calling that function could do it, but there might be additional error checks in the calling function as well.
There's also the issue that log_action() is expecting either a wp_error or a string, so that could make it hard to add additional details to a wp_error for example whether associating a token with a user had happened via a WordPress dashboard submenu page or the API.
Many functions have a lot of return points due to having many error checks -- does the database exist, the table exist, is the token string empty, does the user exist, is the token already registered to a different user, etc. etc. -- so figure out good places to log. A function calling that function could do it, but there might be additional error checks in the calling function as well.
There's also the issue that log_action() is expecting either a wp_error or a string, so that could make it hard to add additional details to a wp_error for example whether associating a token with a user had happened via a WordPress dashboard submenu page or the API.