chore: Reorganize examples and interop crates (#180)

* chore: Reorganize examples and interop crates

* fix interop tests

examples/src/load_balance/client.rs

@@ -0,0 +1,29 @@
+pub mod pb {
+    tonic::include_proto!("grpc.examples.echo");
+}
+
+use pb::{echo_client::EchoClient, EchoRequest};
+use tonic::transport::Channel;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let endpoints = ["http://[::1]:50051", "http://[::1]:50052"]
+        .into_iter()
+        .map(|a| Channel::from_static(a));
+
+    let channel = Channel::balance_list(endpoints);
+
+    let mut client = EchoClient::new(channel);
+
+    for _ in 0..12usize {
+        let request = tonic::Request::new(EchoRequest {
+            message: "hello".into(),
+        });
+
+        let response = client.unary_echo(request).await?;
+
+        println!("RESPONSE={:?}", response);
+    }
+
+    Ok(())
+}

examples/src/load_balance/server.rs

@@ -0,0 +1,82 @@
+pub mod pb {
+    tonic::include_proto!("grpc.examples.echo");
+}
+
+use futures::Stream;
+use std::net::SocketAddr;
+use std::pin::Pin;
+use tokio::sync::mpsc;
+use tonic::{transport::Server, Request, Response, Status, Streaming};
+
+use pb::{EchoRequest, EchoResponse};
+
+type EchoResult<T> = Result<Response<T>, Status>;
+type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send + Sync>>;
+
+#[derive(Debug)]
+pub struct EchoServer {
+    addr: SocketAddr,
+}
+
+#[tonic::async_trait]
+impl pb::echo_server::Echo for EchoServer {
+    async fn unary_echo(&self, request: Request<EchoRequest>) -> EchoResult<EchoResponse> {
+        let message = format!("{} (from {})", request.into_inner().message, self.addr);
+
+        Ok(Response::new(EchoResponse { message }))
+    }
+
+    type ServerStreamingEchoStream = ResponseStream;
+
+    async fn server_streaming_echo(
+        &self,
+        _: Request<EchoRequest>,
+    ) -> EchoResult<Self::ServerStreamingEchoStream> {
+        Err(Status::unimplemented("not implemented"))
+    }
+
+    async fn client_streaming_echo(
+        &self,
+        _: Request<Streaming<EchoRequest>>,
+    ) -> EchoResult<EchoResponse> {
+        Err(Status::unimplemented("not implemented"))
+    }
+
+    type BidirectionalStreamingEchoStream = ResponseStream;
+
+    async fn bidirectional_streaming_echo(
+        &self,
+        _: Request<Streaming<EchoRequest>>,
+    ) -> EchoResult<Self::BidirectionalStreamingEchoStream> {
+        Err(Status::unimplemented("not implemented"))
+    }
+}
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let addrs = ["[::1]:50051", "[::1]:50052"];
+
+    let (tx, mut rx) = mpsc::unbounded_channel();
+
+    for addr in &addrs {
+        let addr = addr.parse()?;
+        let tx = tx.clone();
+
+        let server = EchoServer { addr };
+        let serve = Server::builder()
+            .add_service(pb::echo_server::EchoServer::new(server))
+            .serve(addr);
+
+        tokio::spawn(async move {
+            if let Err(e) = serve.await {
+                eprintln!("Error = {:?}", e);
+            }
+
+            tx.send(()).unwrap();
+        });
+    }
+
+    rx.recv().await;
+
+    Ok(())
+}