Grpcio: communicating through long-lived bidirectional stream

help
1

I am using the grpcio crate to set up a grpc server. One of the calls I support is a long-lived bidirectional stream. I would like my main thread to be able to broadcast a message through this bidirectional stream to all clients currently connected to the server. I would also like my main thread to get messages from any of these "handler" threads (though for my use case I don't need to know which client the request came from).

I've included the approach I'm currently using below. As you can see, my previous thought was to use futures::sync::mpsc::channels, but I don't think this approach will work (certainly not for broadcasting to multiple clients), and I am open to other approaches to having my main thread communicate with my "handler" threads. Thanks for your help!

foo.proto

syntax = "proto3";

message FooInbound {
  uint32 val = 1;
}

message FooOutbound {
  uint32 val = 1;
}

service FooService {
  rpc BidiFoo(stream FooInbound) returns (stream FooOutbound);
}

lib.rs

extern crate grpcio;

use foo::*
use foo_grpc::*;
use grpcio::*;

#[derive(Clone, Debug)]
pub struct InboundMsg {
  val: u32,
}

#[derive(Clone, Debug)]
pub struct OutboundMsg {
  val: u32,
}

#[derive(Clone)]
pub struct FooServiceImpl {
  rx: Arc<Mutex<Receiver<OutboundMsg>>>,
  tx: Sender<InboundMsg>,
}

impl FooService for FooServiceImpl {
  fn bidi_foo(
    &mut self,
    ctx: RpcContext,
    stream: RequestStream<FooInbound>,
    sink: DuplexSink<FooOutbound>,
  ) {
    // Here I would like to put code that will transform `FooInbound` to `InboundMsg`
    // and pass it on to my main thread.
    // I also want to listen for `OutboundMsg`s from my main thread and transform them
    // to `FooOutbound` before sending them to the client.
  }
}