feat: return streaming errors as an event formatted for openai's client

router/src/server.rs

@@ -1274,7 +1274,8 @@ pub(crate) async fn chat_completions(
             };
             let mut response_as_tool = using_tools;
             while let Some(result) = response_stream.next().await {
-                if let Ok(stream_token) = result {
+                match result {
+                    Ok(stream_token) => {
                         let token_text = &stream_token.token.text.clone();
                         match state {
                             StreamState::Buffering => {
@@ -1353,7 +1354,6 @@ pub(crate) async fn chat_completions(
                                 if skip_close_quote && token_text.contains('"') {
                                     break;
                                 }
-
                                 // send the content
                                 let event = create_event_from_stream_token(
                                     &stream_token,
@@ -1368,6 +1368,15 @@ pub(crate) async fn chat_completions(
                             }
                         }
                     }
+                    Err(err) => {
+                        let error_event: ErrorEvent = err.into();
+                        let event = Event::default().json_data(error_event).unwrap_or_else(|e| {
+                            InferError::StreamSerializationError(e.to_string()).into()
+                        });
+                        yield Ok::<Event, Infallible>(event);
+                        break;
+                    }
+                }
             }
             yield Ok::<Event, Infallible>(Event::default().data("[DONE]"));
         };
@@ -2517,6 +2526,26 @@ impl From<InferError> for Event {
     }
 }
 
+#[derive(serde::Serialize)]
+pub struct ErrorWithMessage {
+    message: String,
+}
+
+#[derive(serde::Serialize)]
+pub struct ErrorEvent {
+    error: ErrorWithMessage,
+}
+
+impl From<InferError> for ErrorEvent {
+    fn from(err: InferError) -> Self {
+        ErrorEvent {
+            error: ErrorWithMessage {
+                message: err.to_string(),
+            },
+        }
+    }
+}
+
 #[derive(Debug, Error)]
 pub enum WebServerError {
     #[error("Axum error: {0}")]