Different S3 serving endpoint (e.g. CDN support)

[mattdsteele]

DigitalOcean supports a built-in CDN when using their S3-compatible Spaces storage. After enabling, use of the CDN just requires changing the endpoint; e.g.:

• Origin: https://bucket.region.digitaloceanspaces.com
• Edge: https://bucket.region.cdn.digitaloceanspaces.com

It's also possible to configure a custom domain (using a subdomain you own, for example).

I can try to add a new configuration parameter to support this (something like s3.servingHostname), but wanted to get your thoughts before making the change.

Simplest approach would be to just generate and return the custom URL within s3Storage.Save, but if you think there's value in pulling this up more generally, we could probably move it into monitor.go. This would potentially let other storage providers use the same param. I don't think this would be valuable for local serving, but maybe for other providers in the future? I dunno.

[gabek]

AWS also offers a feature to change the host to get a CDN'ized version of it, not to mention just having control over where the video segments are in general would be useful across the board.

So as it stands the Segment type (in playlist.go) knows the relative path (via RelativeUploadPath like 1/stream-1595834191.ts) and the absolute remote URL (RemoteID, not a great name, https://gabevideo.us-east-1.linodeobjects.com/gabevideo/hls/0/stream-1595814948.ts)

So in GenerateRemotePlaylist it seems like instead of using just the RemoteID if the config has a servingHostname it could instead piece together its own absolute URL using the overriden host in the config + the relative path. And then if an overridden host doesn't exist in the config then GenerateRemotePlaylist would just do what it already does now and use the RemoteID.

I think? :)

If you want to take a stab at this, go for it! Otherwise I can probably get to it this week.

[gabek]

Just noticed you already looked at it! So the only thought I had that's different is instead of rewriting the URL in Save we rewrite it in GenerateRemotePlaylist, only because that URL returned from save is technically correct, but we just want to reference it differently in the playlist.

[mattdsteele]

Yup, I was just mucking around to see if I could get something working. I'll update the branch and open a PR