Middleware registration

[rlabrecque]

Feature Request

Currently tonic provides interceptor_fn but this is a little lower level than a lot of other solutions provide.

Ideally I could chain middleware functions without manually building my own stack inside an interceptor_fn.

See: #69, tower-rs/tower-grpc#86, https://github.com/grpc-ecosystem/go-grpc-middleware

[LucioFranco]

Yeah so ideally we would use something like https://docs.rs/tower-layer/0.3.0-alpha.1/tower_layer/trait.Layer.html which achieves this. The issue right now is the extra api's around making these easier to define are not yet done. The interceptor_fn was the first attempt at trying to make an easy api for this. I would love to find a better one.

[mawenqi]

so how could I do this in version 0.1.1? thanks

[LucioFranco]

There is now this https://docs.rs/tonic/0.1.1/tonic/struct.Interceptor.html

[davidpdrsn]

This was solved as part of #651. The API for adding tower middleware to tonic clients and servers has been simplified quite a bit. Interceptors are now also based on tower Service so they are composable in the same way any Service is.