UNIX domain socket support

[trustin]

From @huydx

I have a use case which uses nginx as a sidecar proxy and it may be better to use domain sockets instead of network sockets.

[max904-github]

I do have a similar use case! It should be feasible to do as Netty fully supports this.

[trustin]

Yeah, would be nice to have this feature to work nicely with sidecars such as Envoy, Linkerd, nginx, etc.

[chris-ryan-square]

Any news on this?

For now, for my purposes, I've written a proxy server listening on the domain socket transferring everything to the Armeria port (based off the netty proxy server example: https://netty.io/4.1/xref/io/netty/example/proxy/package-summary.html).

Works, but obviously it's not ideal to have an extra step there.

[trustin]

Sorry for not following up on this issue yet. Still need to find some time for implementing this.

[ikhoon]

Thanks to @trustin, it is fixed by #4846.