[feature] Allow S3 bucket name to be blank to better support CDN with S3 buckets

[joelghill]

Is your feature request related to a problem ?

I have configured an S3 storage bucket for server media. I also configured a CDN for said bucket at a subdomain.

When configuring the server, there do not appear to be any settings to allow for the CDN to function correctly. I can set the S3 host to the CDN url, but GTS inserts the bucket name in the media urls and this is inappropriate for the CDN.

Describe the solution you'd like.

Allow the S3 bucket name to be blank and document this use case in the config file. This should produce correct URLs

Describe alternatives you've considered.

None

Additional context.

I can provide my current server config, hostname, S3 bucket, CDN url, etc, if any of that will help.

[joelghill]

Did a little bit of research here and it looks like allowing a blank bucket name is probably not going to work, reading and writing to S3 needs a bucket name.

I think the solution here might be to add a new setting for a CDN endpoint. The S3 config would all be the same, however if a CDN is configured creating URLs to read media the CDN endpoint should be used instead of the S3 URL + bucket name.

[daenney]

I'm going to close this in favour of #2574 where we've got the generic solution and different use cases documented. If you're still interested in this feature, feel free to subscribe to that issue.