Add clonable wrapper around TryRecvError

zebrad/src/components/inbound.rs

@@ -10,6 +10,7 @@ use futures::{
     future::{FutureExt, TryFutureExt},
     stream::Stream,
 };
+use oneshot::error::TryRecvError;
 use tokio::sync::oneshot;
 use tower::{buffer::Buffer, timeout::Timeout, util::BoxService, Service, ServiceExt};
 
@@ -72,9 +73,17 @@ pub enum Setup {
     ///
     /// We keep hold of the closed oneshot, so we can use it to create a
     /// new error for each `poll_ready` call.
-    FailedRecv {
-        failed_setup: oneshot::Receiver<NetworkSetupData>,
-    },
+    FailedRecv { error: SharedRecvError },
+}
+
+#[derive(thiserror::Error, Debug, Clone)]
+#[error(transparent)]
+pub struct SharedRecvError(Arc<TryRecvError>);
+
+impl From<TryRecvError> for SharedRecvError {
+    fn from(source: TryRecvError) -> Self {
+        Self(Arc::new(source))
+    }
 }
 
 /// Uses the node state to respond to inbound peer requests.
@@ -131,8 +140,6 @@ impl Service<zn::Request> for Inbound {
         Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send + 'static>>;
 
     fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
-        use oneshot::error::TryRecvError;
-
         // Check whether the network setup is finished, but don't wait for it to
         // become ready before reporting readiness. We expect to get it "soon",
         // and reporting unreadiness might cause unwanted load-shedding, since
@@ -169,8 +176,9 @@ impl Service<zn::Request> for Inbound {
                     Err(error @ TryRecvError::Closed) => {
                         // Mark the service as failed, because network setup failed
                         error!(?error, "inbound network setup failed");
+                        let error: SharedRecvError = error.into();
                         self.network = Setup::FailedRecv {
-                            failed_setup: network_setup,
+                            error: error.clone(),
                         };
                         return Poll::Ready(Err(error.into()));
                     }
@@ -187,27 +195,8 @@ impl Service<zn::Request> for Inbound {
         }
 
         // If network setup failed, report service failure
-        if let Setup::FailedRecv { failed_setup } = &mut self.network {
-            // TryRecvError is not cloneable, so we have to generate a new error from the oneshot,
-            // rather than re-using a clone of the original error
-            let failed_response = failed_setup.try_recv();
-            match failed_response {
-                Err(error @ TryRecvError::Closed) => {
-                    return Poll::Ready(Err(error.into()));
-                }
-                Err(error) => {
-                    unreachable!(
-                        "unexpected error kind from failed Inbound network setup oneshot: {:?}",
-                        error
-                    );
-                }
-                Ok(_) => {
-                    // we can't log the response, because it doesn't impl Debug
-                    unreachable!(
-                        "unexpected success response from failed Inbound network setup oneshot"
-                    );
-                }
-            }
+        if let Setup::FailedRecv { error } = &mut self.network {
+            return Poll::Ready(Err(error.clone().into()));
         }
 
         // Clean up completed download tasks, ignoring their results