fix(examples): Remove use of VecDeque as a placeholder type (#143)

tonic-examples/src/authentication/server.rs

@@ -2,13 +2,14 @@ pub mod pb {
     tonic::include_proto!("grpc.examples.echo");
 }
 
+use futures::Stream;
 use pb::{EchoRequest, EchoResponse};
-use std::collections::VecDeque;
+use std::pin::Pin;
 use tonic::{body::BoxBody, transport::Server, Request, Response, Status, Streaming};
 use tower::Service;
 
 type EchoResult<T> = Result<Response<T>, Status>;
-type Stream = VecDeque<Result<EchoResponse, Status>>;
+type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send + Sync>>;
 
 #[derive(Default)]
 pub struct EchoServer;
@@ -20,7 +21,7 @@ impl pb::server::Echo for EchoServer {
         Ok(Response::new(EchoResponse { message }))
     }
 
-    type ServerStreamingEchoStream = Stream;
+    type ServerStreamingEchoStream = ResponseStream;
 
     async fn server_streaming_echo(
         &self,
@@ -36,7 +37,7 @@ impl pb::server::Echo for EchoServer {
         Err(Status::unimplemented("not implemented"))
     }
 
-    type BidirectionalStreamingEchoStream = Stream;
+    type BidirectionalStreamingEchoStream = ResponseStream;
 
     async fn bidirectional_streaming_echo(
         &self,

tonic-examples/src/load_balance/server.rs

@@ -2,13 +2,16 @@ pub mod pb {
     tonic::include_proto!("grpc.examples.echo");
 }
 
-use pb::{EchoRequest, EchoResponse};
-use std::{collections::VecDeque, net::SocketAddr};
+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 Stream = VecDeque<Result<EchoResponse, Status>>;
+type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send + Sync>>;
 
 #[derive(Debug)]
 pub struct EchoServer {
@@ -23,7 +26,7 @@ impl pb::server::Echo for EchoServer {
         Ok(Response::new(EchoResponse { message }))
     }
 
-    type ServerStreamingEchoStream = Stream;
+    type ServerStreamingEchoStream = ResponseStream;
 
     async fn server_streaming_echo(
         &self,
@@ -39,7 +42,7 @@ impl pb::server::Echo for EchoServer {
         Err(Status::unimplemented("not implemented"))
     }
 
-    type BidirectionalStreamingEchoStream = Stream;
+    type BidirectionalStreamingEchoStream = ResponseStream;
 
     async fn bidirectional_streaming_echo(
         &self,

tonic-examples/src/multiplex/server.rs

@@ -1,4 +1,5 @@
-use std::collections::VecDeque;
+use futures::Stream;
+use std::pin::Pin;
 use tonic::{transport::Server, Request, Response, Status};
 
 pub mod hello_world {
@@ -19,6 +20,8 @@ use echo::{
     EchoRequest, EchoResponse,
 };
 
+type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send + Sync>>;
+
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let addr = "[::1]:50051".parse().unwrap();
@@ -64,6 +67,6 @@ impl Echo for MyEcho {
         Ok(Response::new(EchoResponse { message }))
     }
 
-    type ServerStreamingEchoStream = VecDeque<Result<EchoResponse, Status>>;
-    type BidirectionalStreamingEchoStream = VecDeque<Result<EchoResponse, Status>>;
+    type ServerStreamingEchoStream = ResponseStream;
+    type BidirectionalStreamingEchoStream = ResponseStream;
 }

tonic-examples/src/tls/server.rs

@@ -2,15 +2,16 @@ pub mod pb {
     tonic::include_proto!("/grpc.examples.echo");
 }
 
+use futures::Stream;
 use pb::{EchoRequest, EchoResponse};
-use std::collections::VecDeque;
+use std::pin::Pin;
 use tonic::{
     transport::{Identity, Server, ServerTlsConfig},
     Request, Response, Status, Streaming,
 };
 
 type EchoResult<T> = Result<Response<T>, Status>;
-type Stream = VecDeque<Result<EchoResponse, Status>>;
+type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send + Sync>>;
 
 #[derive(Default)]
 pub struct EchoServer;
@@ -22,7 +23,7 @@ impl pb::server::Echo for EchoServer {
         Ok(Response::new(EchoResponse { message }))
     }
 
-    type ServerStreamingEchoStream = Stream;
+    type ServerStreamingEchoStream = ResponseStream;
 
     async fn server_streaming_echo(
         &self,
@@ -38,7 +39,7 @@ impl pb::server::Echo for EchoServer {
         Err(Status::unimplemented("not implemented"))
     }
 
-    type BidirectionalStreamingEchoStream = Stream;
+    type BidirectionalStreamingEchoStream = ResponseStream;
 
     async fn bidirectional_streaming_echo(
         &self,

tonic-examples/src/tls_client_auth/server.rs

@@ -2,14 +2,14 @@ pub mod pb {
     tonic::include_proto!("grpc.examples.echo");
 }
 
-use std::collections::VecDeque;
-
+use futures::Stream;
 use pb::{EchoRequest, EchoResponse};
+use std::pin::Pin;
 use tonic::transport::{Certificate, Identity, Server, ServerTlsConfig};
 use tonic::{Request, Response, Status};
 
 type EchoResult<T> = Result<Response<T>, Status>;
-type Stream = VecDeque<Result<EchoResponse, Status>>;
+type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send + Sync>>;
 
 #[derive(Default)]
 pub struct EchoServer;
@@ -21,8 +21,8 @@ impl pb::server::Echo for EchoServer {
         Ok(Response::new(EchoResponse { message }))
     }
 
-    type ServerStreamingEchoStream = Stream;
-    type BidirectionalStreamingEchoStream = Stream;
+    type ServerStreamingEchoStream = ResponseStream;
+    type BidirectionalStreamingEchoStream = ResponseStream;
 }
 
 #[tokio::main]