feat: Add metadata to error responses (#348)

tests/integration_tests/tests/status.rs

@@ -3,6 +3,7 @@ use futures_util::FutureExt;
 use integration_tests::pb::{test_client, test_server, Input, Output};
 use std::time::Duration;
 use tokio::sync::oneshot;
+use tonic::metadata::{MetadataMap, MetadataValue};
 use tonic::{transport::Server, Code, Request, Response, Status};
 
 #[tokio::test]
@@ -50,3 +51,69 @@ async fn status_with_details() {
 
     jh.await.unwrap();
 }
+
+#[tokio::test]
+async fn status_with_metadata() {
+    const MESSAGE: &str = "Internal error, see metadata for details";
+
+    const ASCII_NAME: &str = "x-host-ip";
+    const ASCII_VALUE: &str = "127.0.0.1";
+
+    const BINARY_NAME: &str = "x-host-name-bin";
+    const BINARY_VALUE: &[u8] = b"localhost";
+
+    struct Svc;
+
+    #[tonic::async_trait]
+    impl test_server::Test for Svc {
+        async fn unary_call(&self, _: Request<Input>) -> Result<Response<Output>, Status> {
+            let mut metadata = MetadataMap::new();
+            metadata.insert(ASCII_NAME, ASCII_VALUE.parse().unwrap());
+            metadata.insert_bin(BINARY_NAME, MetadataValue::from_bytes(BINARY_VALUE));
+
+            Err(Status::with_metadata(Code::Internal, MESSAGE, metadata))
+        }
+    }
+
+    let svc = test_server::TestServer::new(Svc);
+
+    let (tx, rx) = oneshot::channel::<()>();
+
+    let jh = tokio::spawn(async move {
+        Server::builder()
+            .add_service(svc)
+            .serve_with_shutdown("127.0.0.1:1338".parse().unwrap(), rx.map(drop))
+            .await
+            .unwrap();
+    });
+
+    tokio::time::delay_for(Duration::from_millis(100)).await;
+
+    let mut channel = test_client::TestClient::connect("http://127.0.0.1:1338")
+        .await
+        .unwrap();
+
+    let err = channel
+        .unary_call(Request::new(Input {}))
+        .await
+        .unwrap_err();
+
+    assert_eq!(err.code(), Code::Internal);
+    assert_eq!(err.message(), MESSAGE);
+
+    let metadata = err.metadata();
+
+    assert_eq!(
+        metadata.get(ASCII_NAME).unwrap().to_str().unwrap(),
+        ASCII_VALUE
+    );
+
+    assert_eq!(
+        metadata.get_bin(BINARY_NAME).unwrap().to_bytes().unwrap(),
+        BINARY_VALUE
+    );
+
+    tx.send(()).unwrap();
+
+    jh.await.unwrap();
+}