Add gRPC Web support

[everflux]

Feature Request

Proposal

Support gRPC Web to HTTP translation as part of maesh/traefik. Currently an additional envoy proxy instance is required.
This is related to traefik/traefik#4210

Background

For web clients a translation between http-grpc and grpc is required. Since most frameworks do not support this as in-process an external proxy must provide the protocol translation.
See https://github.com/grpc/grpc-web

Workarounds

Use envoy in addition to maesh.

[dtomcej]

I'm curious why you would choose to use gRPC-Web as a protocol for inter-service communication.

It seems like gRPC-Web is designed to solve some issues that browsers face, and provide external-facing features.

Wouldn't just using base gRPC requests be simpler in a clustered environment?

[everflux]

You are right that gRPC is for inter-service communication, but I don't want to manually expose a different protocol (http/json). That is what gRPC-Web solves, but there needs to be a translating proxy. This could be at the edge with traefik or as part of the mesh in maesh. (So I thought)

The reason for translating as part of the mesh is that for load balancing of the long lived http2-stream the protocol needs to be converted to discrete requests anyway.

[dtomcej]

Ah that makes sense. Thx for the explanation.

[einali]

Is there any update for this feature? What is time schedule for implementing it?

[jspdown]

@einali Thanks for you interest in Maesh.

As Maesh depends on Traefik we can't give you any ETA until this feature gets implemented on their side.

[zs-dima]

@jspdown any update or related issue are welcome

[jspdown]

@zs-dima the GrpcWeb middleware has been merged very recently on Traefik traefik/traefik#9451. Once this get released we will be able to unblock this issue.

In the meantime, if anyone wants to start working on this, I would be happy to help 😃