How to use API key?

[arsduo]

Hi! Hope you have all been doing well over these last few terrible years.

We are trying to make an API request for public Youtube data. I've tried authenticating multiple ways, but even when following the documentation here for accessing a a service account, the API errors out because of a lack of an API key:

Google::Apis::ClientError: forbidden: The request is missing a valid API key.

The google-api-ruby-client library specifically says it integrates with google-auth-library-ruby "for authentication using OAuth, API keys, and service accounts"; however, I can't find any information on how to include the API key in the documentation for this library.

What's the right way to do that? And should that be documented here, since the other Google library points to this one for API keys? (Or should that reference be removed from the other readme?)

[AlexWayfer]

No progression in this? I see type: docs Improvement to the documentation for an API. label, but I found no code for this. Is there an implementation at all? Maybe you can give a hint before docs completion?