fix(codec): Enforce encoders/decoders are Sync

tonic-build/src/server.rs

@@ -146,7 +146,7 @@ fn generate_trait_methods(service: &Service, proto_path: &str) -> TokenStream {
 
                 quote! {
                     #stream_doc
-                    type #stream: Stream<Item = Result<#res_message, tonic::Status>>  + Send + 'static;
+                    type #stream: Stream<Item = Result<#res_message, tonic::Status>> + Send + Sync + 'static;
 
                     #method_doc
                     async fn #name(&self, request: tonic::Request<#req_message>)
@@ -164,7 +164,7 @@ fn generate_trait_methods(service: &Service, proto_path: &str) -> TokenStream {
 
                 quote! {
                     #stream_doc
-                    type #stream: Stream<Item = Result<#res_message, tonic::Status>> + Send + 'static;
+                    type #stream: Stream<Item = Result<#res_message, tonic::Status>> + Send + Sync + 'static;
 
                     #method_doc
                     async fn #name(&self, request: tonic::Request<tonic::Streaming<#req_message>>)

tonic-examples/src/routeguide/server.rs

@@ -108,7 +108,8 @@ impl server::RouteGuide for RouteGuide {
         Ok(Response::new(summary))
     }
 
-    type RouteChatStream = Pin<Box<dyn Stream<Item = Result<RouteNote, Status>> + Send + 'static>>;
+    type RouteChatStream =
+        Pin<Box<dyn Stream<Item = Result<RouteNote, Status>> + Send + Sync + 'static>>;
 
     async fn route_chat(
         &self,
@@ -138,7 +139,7 @@ impl server::RouteGuide for RouteGuide {
 
         Ok(Response::new(Box::pin(output)
             as Pin<
-                Box<dyn Stream<Item = Result<RouteNote, Status>> + Send + 'static>,
+                Box<dyn Stream<Item = Result<RouteNote, Status>> + Send + Sync + 'static>,
             >))
     }
 }

tonic-interop/src/server.rs

@@ -12,8 +12,9 @@ pub struct TestService;
 
 type Result<T> = std::result::Result<Response<T>, Status>;
 type Streaming<T> = Request<tonic::Streaming<T>>;
-type Stream<T> =
-    Pin<Box<dyn futures_core::Stream<Item = std::result::Result<T, Status>> + Send + 'static>>;
+type Stream<T> = Pin<
+    Box<dyn futures_core::Stream<Item = std::result::Result<T, Status>> + Send + Sync + 'static>,
+>;
 
 #[tonic::async_trait]
 impl pb::server::TestService for TestService {

tonic/Cargo.toml

@@ -41,10 +41,6 @@ tls = []
 name = "bench_main"
 harness = false
 
-[dev-dependencies]
-rand = "0.7.2"
-criterion = "0.3"
-
 [dependencies]
 bytes = "0.4"
 futures-core-preview = "=0.3.0-alpha.19"
@@ -83,6 +79,11 @@ openssl1 = { package = "openssl", version = "0.10", optional = true }
 # rustls
 tokio-rustls = { version = "=0.12.0-alpha.4", optional = true }
 
+[dev-dependencies]
+static_assertions = "1.0"
+rand = "0.7.2"
+criterion = "0.3"
+
 [package.metadata.docs.rs]
 all-features = true
 rustdoc-args = ["--cfg", "docsrs"]

tonic/src/body.rs

@@ -15,7 +15,7 @@ use std::{
 pub(crate) type BytesBuf = <Bytes as IntoBuf>::Buf;
 
 /// A trait alias for [`http_body::Body`].
-pub trait Body: sealed::Sealed {
+pub trait Body: sealed::Sealed + Send + Sync {
     /// The body data type.
     type Data: Buf;
     /// The errors produced from the body.
@@ -45,7 +45,7 @@ pub trait Body: sealed::Sealed {
 
 impl<T> Body for T
 where
-    T: HttpBody,
+    T: HttpBody + Send + Sync + 'static,
     T::Error: Into<Error>,
 {
     type Data = T::Data;
@@ -83,7 +83,7 @@ mod sealed {
 
 /// A type erased http body.
 pub struct BoxBody {
-    inner: Pin<Box<dyn Body<Data = BytesBuf, Error = Status> + Send + 'static>>,
+    inner: Pin<Box<dyn Body<Data = BytesBuf, Error = Status> + Send + Sync + 'static>>,
 }
 
 struct MapBody<B>(B);
@@ -92,7 +92,7 @@ impl BoxBody {
     /// Create a new `BoxBody` mapping item and error to the default types.
     pub fn new<B>(inner: B) -> Self
     where
-        B: Body<Data = BytesBuf, Error = Status> + Send + 'static,
+        B: Body<Data = BytesBuf, Error = Status> + Send + Sync + 'static,
     {
         BoxBody {
             inner: Box::pin(inner),
@@ -102,7 +102,7 @@ impl BoxBody {
     /// Create a new `BoxBody` mapping item and error to the default types.
     pub fn map_from<B>(inner: B) -> Self
     where
-        B: Body + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
     {

tonic/src/client/grpc.rs

@@ -62,8 +62,8 @@ impl<T> Grpc<T> {
         <T::ResponseBody as HttpBody>::Error: Into<crate::Error>,
         <T::ResponseBody as HttpBody>::Data: Into<Bytes>,
         C: Codec<Encode = M1, Decode = M2>,
-        M1: Send + 'static,
-        M2: Send + 'static,
+        M1: Send + Sync + 'static,
+        M2: Send + Sync + 'static,
     {
         let request = request.map(|m| stream::once(future::ready(m)));
         self.client_streaming(request, path, codec).await
@@ -81,10 +81,10 @@ impl<T> Grpc<T> {
         T::ResponseBody: Body + HttpBody + Send + 'static,
         <T::ResponseBody as HttpBody>::Error: Into<crate::Error>,
         <T::ResponseBody as HttpBody>::Data: Into<Bytes>,
-        S: Stream<Item = M1> + Send + 'static,
+        S: Stream<Item = M1> + Send + Sync + 'static,
         C: Codec<Encode = M1, Decode = M2>,
-        M1: Send + 'static,
-        M2: Send + 'static,
+        M1: Send + Sync + 'static,
+        M2: Send + Sync + 'static,
     {
         let (mut parts, body) = self.streaming(request, path, codec).await?.into_parts();
 
@@ -115,8 +115,8 @@ impl<T> Grpc<T> {
         <T::ResponseBody as HttpBody>::Error: Into<crate::Error>,
         <T::ResponseBody as HttpBody>::Data: Into<Bytes>,
         C: Codec<Encode = M1, Decode = M2>,
-        M1: Send + 'static,
-        M2: Send + 'static,
+        M1: Send + Sync + 'static,
+        M2: Send + Sync + 'static,
     {
         let request = request.map(|m| stream::once(future::ready(m)));
         self.streaming(request, path, codec).await
@@ -134,10 +134,10 @@ impl<T> Grpc<T> {
         T::ResponseBody: Body + HttpBody + Send + 'static,
         <T::ResponseBody as HttpBody>::Data: Into<Bytes>,
         <T::ResponseBody as HttpBody>::Error: Into<crate::Error>,
-        S: Stream<Item = M1> + Send + 'static,
+        S: Stream<Item = M1> + Send + Sync + 'static,
         C: Codec<Encode = M1, Decode = M2>,
-        M1: Send + 'static,
-        M2: Send + 'static,
+        M1: Send + Sync + 'static,
+        M2: Send + Sync + 'static,
     {
         let mut parts = Parts::default();
         parts.path_and_query = Some(path);

tonic/src/codec/decode.rs

@@ -19,7 +19,7 @@ const BUFFER_SIZE: usize = 8 * 1024;
 /// This will wrap some inner [`Body`] and [`Decoder`] and provide an interface
 /// to fetch the message stream and trailing metadata
 pub struct Streaming<T> {
-    decoder: Box<dyn Decoder<Item = T, Error = Status> + Send + 'static>,
+    decoder: Box<dyn Decoder<Item = T, Error = Status> + Send + Sync + 'static>,
     body: BoxBody,
     state: State,
     direction: Direction,
@@ -45,40 +45,40 @@ enum Direction {
 impl<T> Streaming<T> {
     pub(crate) fn new_response<B, D>(decoder: D, body: B, status_code: StatusCode) -> Self
     where
-        B: Body + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
-        D: Decoder<Item = T, Error = Status> + Send + 'static,
+        D: Decoder<Item = T, Error = Status> + Send + Sync + 'static,
     {
         Self::new(decoder, body, Direction::Response(status_code))
     }
 
     pub(crate) fn new_empty<B, D>(decoder: D, body: B) -> Self
     where
-        B: Body + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
-        D: Decoder<Item = T, Error = Status> + Send + 'static,
+        D: Decoder<Item = T, Error = Status> + Send + Sync + 'static,
     {
         Self::new(decoder, body, Direction::EmptyResponse)
     }
 
     pub(crate) fn new_request<B, D>(decoder: D, body: B) -> Self
     where
-        B: Body + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
-        D: Decoder<Item = T, Error = Status> + Send + 'static,
+        D: Decoder<Item = T, Error = Status> + Send + Sync + 'static,
     {
         Self::new(decoder, body, Direction::Request)
     }
 
     fn new<B, D>(decoder: D, body: B, direction: Direction) -> Self
     where
-        B: Body + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes>,
         B::Error: Into<crate::Error>,
-        D: Decoder<Item = T, Error = Status> + Send + 'static,
+        D: Decoder<Item = T, Error = Status> + Send + Sync + 'static,
     {
         Self {
             decoder: Box::new(decoder),
@@ -291,3 +291,6 @@ impl<T> fmt::Debug for Streaming<T> {
         f.debug_struct("Streaming").finish()
     }
 }
+
+#[cfg(test)]
+static_assertions::assert_impl_all!(Streaming<()>: Send, Sync);

tonic/src/codec/encode.rs

@@ -16,8 +16,9 @@ pub(crate) fn encode_server<T, U>(
     source: U,
 ) -> EncodeBody<impl Stream<Item = Result<BytesBuf, Status>>>
 where
-    T: Encoder<Error = Status>,
-    U: Stream<Item = Result<T::Item, Status>>,
+    T: Encoder<Error = Status> + Send + Sync + 'static,
+    T::Item: Send + Sync,
+    U: Stream<Item = Result<T::Item, Status>> + Send + Sync + 'static,
 {
     let stream = encode(encoder, source).into_stream();
     EncodeBody::new_server(stream)
@@ -28,8 +29,9 @@ pub(crate) fn encode_client<T, U>(
     source: U,
 ) -> EncodeBody<impl Stream<Item = Result<BytesBuf, Status>>>
 where
-    T: Encoder<Error = Status>,
-    U: Stream<Item = T::Item>,
+    T: Encoder<Error = Status> + Send + Sync + 'static,
+    T::Item: Send + Sync,
+    U: Stream<Item = T::Item> + Send + Sync + 'static,
 {
     let stream = encode(encoder, source.map(|x| Ok(x))).into_stream();
     EncodeBody::new_client(stream)
@@ -88,7 +90,7 @@ pub(crate) struct EncodeBody<S> {
 
 impl<S> EncodeBody<S>
 where
-    S: Stream<Item = Result<crate::body::BytesBuf, Status>>,
+    S: Stream<Item = Result<crate::body::BytesBuf, Status>> + Send + Sync + 'static,
 {
     pub(crate) fn new_client(inner: S) -> Self {
         Self {

tonic/src/codec/mod.rs

@@ -28,9 +28,9 @@ pub trait Codec: Default {
     type Decode: Send + 'static;
 
     /// The encoder that can encode a message.
-    type Encoder: Encoder<Item = Self::Encode, Error = Status> + Send + 'static;
+    type Encoder: Encoder<Item = Self::Encode, Error = Status> + Send + Sync + 'static;
     /// The encoder that can decode a message.
-    type Decoder: Decoder<Item = Self::Decode, Error = Status> + Send + 'static;
+    type Decoder: Decoder<Item = Self::Decode, Error = Status> + Send + Sync + 'static;
 
     /// Fetch the encoder.
     fn encoder(&mut self) -> Self::Encoder;

tonic/src/request.rs

@@ -77,7 +77,7 @@ pub trait IntoRequest<T>: sealed::Sealed {
 /// ```
 pub trait IntoStreamingRequest: sealed::Sealed {
     /// The RPC request stream type
-    type Stream: Stream<Item = Self::Message> + Send + 'static;
+    type Stream: Stream<Item = Self::Message> + Send + Sync + 'static;
 
     /// The RPC request type
     type Message;
@@ -182,7 +182,7 @@ impl<T> IntoRequest<T> for Request<T> {
 
 impl<T> IntoStreamingRequest for T
 where
-    T: Stream + Send + 'static,
+    T: Stream + Send + Sync + 'static,
 {
     type Stream = T;
     type Message = T::Item;
@@ -194,7 +194,7 @@ where
 
 impl<T> IntoStreamingRequest for Request<T>
 where
-    T: Stream + Send + 'static,
+    T: Stream + Send + Sync + 'static,
 {
     type Stream = T;
     type Message = T::Item;

tonic/src/server/grpc.rs

@@ -26,6 +26,7 @@ pub struct Grpc<T> {
 impl<T> Grpc<T>
 where
     T: Codec,
+    T::Encode: Sync,
 {
     /// Creates a new gRPC client with the provided [`Codec`].
     pub fn new(codec: T) -> Self {
@@ -40,7 +41,7 @@ where
     ) -> http::Response<BoxBody>
     where
         S: UnaryService<T::Decode, Response = T::Encode>,
-        B: Body + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes> + Send,
         B::Error: Into<crate::Error> + Send,
     {
@@ -70,8 +71,8 @@ where
     ) -> http::Response<BoxBody>
     where
         S: ServerStreamingService<T::Decode, Response = T::Encode>,
-        S::ResponseStream: Send + 'static,
-        B: Body + Send + 'static,
+        S::ResponseStream: Send + Sync + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes> + Send,
         B::Error: Into<crate::Error> + Send,
     {
@@ -95,7 +96,7 @@ where
     ) -> http::Response<BoxBody>
     where
         S: ClientStreamingService<T::Decode, Response = T::Encode>,
-        B: Body + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes> + Send + 'static,
         B::Error: Into<crate::Error> + Send + 'static,
     {
@@ -115,8 +116,8 @@ where
     ) -> http::Response<BoxBody>
     where
         S: StreamingService<T::Decode, Response = T::Encode> + Send,
-        S::ResponseStream: Send + 'static,
-        B: Body + Send + 'static,
+        S::ResponseStream: Send + Sync + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes> + Send,
         B::Error: Into<crate::Error> + Send,
     {
@@ -130,7 +131,7 @@ where
         request: http::Request<B>,
     ) -> Result<Request<T::Decode>, Status>
     where
-        B: Body + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes> + Send,
         B::Error: Into<crate::Error> + Send,
     {
@@ -158,7 +159,7 @@ where
         request: http::Request<B>,
     ) -> Request<Streaming<T::Decode>>
     where
-        B: Body + Send + 'static,
+        B: Body + Send + Sync + 'static,
         B::Data: Into<Bytes> + Send,
         B::Error: Into<crate::Error> + Send,
     {
@@ -170,7 +171,7 @@ where
         response: Result<crate::Response<B>, Status>,
     ) -> http::Response<BoxBody>
     where
-        B: TryStream<Ok = T::Encode, Error = Status> + Send + 'static,
+        B: TryStream<Ok = T::Encode, Error = Status> + Send + Sync + 'static,
     {
         match response {
             Ok(r) => {