fix(transport): Improve Error type (#217)

tonic/src/transport/channel/endpoint.rs

@@ -4,7 +4,7 @@ use super::Channel;
 use super::ClientTlsConfig;
 #[cfg(feature = "tls")]
 use crate::transport::service::TlsConnector;
-use crate::transport::{Error, ErrorKind};
+use crate::transport::Error;
 use bytes::Bytes;
 use http::uri::{InvalidUri, Uri};
 use std::{
@@ -44,9 +44,7 @@ impl Endpoint {
  D: TryInto<Self>,
  D::Error: Into<crate::Error>,
  {
- let me = dst
- .try_into()
- .map_err(|e| Error::from_source(ErrorKind::Client, e.into()))?;
+ let me = dst.try_into().map_err(|e| Error::from_source(e.into()))?;
  Ok(me)
  }
 

tonic/src/transport/channel/mod.rs

@@ -136,7 +136,7 @@ impl Channel {
 
  let svc = Connection::new(connector, endpoint)
  .await
- .map_err(|e| super::Error::from_source(super::ErrorKind::Client, e))?;
+ .map_err(|e| super::Error::from_source(e))?;
 
  let svc = Buffer::new(Either::A(svc), buffer_size);
 
@@ -174,8 +174,7 @@ impl GrpcService<BoxBody> for Channel {
  type Future = ResponseFuture;
 
  fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
- GrpcService::poll_ready(&mut self.svc, cx)
- .map_err(|e| super::Error::from_source(super::ErrorKind::Client, e))
+ GrpcService::poll_ready(&mut self.svc, cx).map_err(|e| super::Error::from_source(e))
  }
 
  fn call(&mut self, mut request: Request<BoxBody>) -> Self::Future {
@@ -193,7 +192,7 @@ impl Future for ResponseFuture {
 
  fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
  let val = futures_util::ready!(Pin::new(&mut self.inner).poll(cx))
- .map_err(|e| super::Error::from_source(super::ErrorKind::Client, e))?;
+ .map_err(|e| super::Error::from_source(e))?;
  Ok(val).into()
  }
 }

tonic/src/transport/error.rs

@@ -1,57 +1,23 @@
 use std::{error, fmt};
 
 /// Error's that originate from the client or server;
-pub struct Error {
- kind: ErrorKind,
- source: Option<crate::Error>,
-}
-
-impl Error {
- pub(crate) fn from_source(kind: ErrorKind, source: crate::Error) -> Self {
- Self {
- kind,
- source: Some(source),
- }
- }
-}
-
 #[derive(Debug)]
-pub(crate) enum ErrorKind {
- Client,
- Server,
-}
+pub struct Error(crate::Error);
 
-impl fmt::Debug for Error {
- fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- let mut f = f.debug_tuple("Error");
- f.field(&self.kind);
- if let Some(source) = &self.source {
- f.field(source);
- }
- f.finish()
+impl Error {
+ pub(crate) fn from_source(source: impl Into<crate::Error>) -> Self {
+ Self(source.into())
  }
 }
 
 impl fmt::Display for Error {
  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- if let Some(source) = &self.source {
- write!(f, "{}: {}", self.kind, source)
- } else {
- write!(f, "{}", self.kind)
- }
+ self.0.fmt(f)
  }
 }
 
 impl error::Error for Error {
  fn source(&self) -> Option<&(dyn error::Error + 'static)> {
- self.source
- .as_ref()
- .map(|e| &**e as &(dyn error::Error + 'static))
- }
-}
-
-impl fmt::Display for ErrorKind {
- fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- write!(f, "{:?}", self)
+ self.0.source()
  }
 }

tonic/src/transport/mod.rs

@@ -112,5 +112,3 @@ pub use self::channel::ClientTlsConfig;
 #[cfg(feature = "tls")]
 #[cfg_attr(docsrs, doc(cfg(feature = "tls")))]
 pub use self::server::ServerTlsConfig;
-
-pub(crate) use self::error::ErrorKind;

tonic/src/transport/server/mod.rs

@@ -300,9 +300,9 @@ impl Server {
  .serve(svc)
  .with_graceful_shutdown(signal)
  .await
- .map_err(map_err)?
+ .map_err(super::Error::from_source)?
  } else {
- server.serve(svc).await.map_err(map_err)?;
+ server.serve(svc).await.map_err(super::Error::from_source)?;
  }
 
  Ok(())
@@ -374,7 +374,7 @@ where
  /// [`Server`]: struct.Server.html
  pub async fn serve(self, addr: SocketAddr) -> Result<(), super::Error> {
  let incoming = TcpIncoming::new(addr, self.server.tcp_nodelay, self.server.tcp_keepalive)
- .map_err(map_err)?;
+ .map_err(super::Error::from_source)?;
  self.server
  .serve_with_shutdown::<_, _, future::Ready<()>, _, _>(self.routes, incoming, None)
  .await
@@ -391,7 +391,7 @@ where
  f: F,
  ) -> Result<(), super::Error> {
  let incoming = TcpIncoming::new(addr, self.server.tcp_nodelay, self.server.tcp_keepalive)
- .map_err(map_err)?;
+ .map_err(super::Error::from_source)?;
  self.server
  .serve_with_shutdown(self.routes, incoming, Some(f))
  .await
@@ -413,10 +413,6 @@ where
  }
 }
 
-fn map_err(e: impl Into<crate::Error>) -> super::Error {
- super::Error::from_source(super::ErrorKind::Server, e.into())
-}
-
 impl fmt::Debug for Server {
  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  f.debug_struct("Builder").finish()