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fix: include http_request_id in request-wise priming event IDs (#799)

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* fix: include http_request_id in request-wise priming event IDs

* refactor: use Option::into_iter and usize::from for priming

* fix: retain event cache for completed request-wise channels

* fix: track completed_at for cache eviction and resume

* fix: log resume failures at warn level

* test: add completed_cache_ttl eviction test

* fix: return empty stream on failed resume

* test: add resume after completion test
This commit is contained in:
Dale Seo 2026-04-16 12:02:35 -04:00 • committed by GitHub
commit 3e56d52764
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1 changed files with 467 additions and 89 deletions
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84
crates/rmcp/src/transport/streamable_http_server/tower.rs
View file

@ -478,40 +478,52 @@ where
.and_then(|v| v.to_str().ok())
.map(|s| s.to_owned());
if let Some(last_event_id) = last_event_id {
// check if session has this event id
let stream = self
match self
.session_manager
.resume(&session_id, last_event_id)
.await
.map_err(internal_error_response("resume session"))?;
// Resume doesn't need priming - client already has the event ID
Ok(sse_stream_response(
stream,
self.config.sse_keep_alive,
self.config.cancellation_token.child_token(),
))
} else {
// create standalone stream
let stream = self
.session_manager
.create_standalone_stream(&session_id)
.await
.map_err(internal_error_response("create standalone stream"))?;
// Prepend priming event if sse_retry configured
let stream = if let Some(retry) = self.config.sse_retry {
let priming = ServerSseMessage::priming("0", retry);
futures::stream::once(async move { priming })
.chain(stream)
.left_stream()
} else {
stream.right_stream()
};
Ok(sse_stream_response(
stream,
self.config.sse_keep_alive,
self.config.cancellation_token.child_token(),
))
{
Ok(stream) => {
return Ok(sse_stream_response(
stream,
self.config.sse_keep_alive,
self.config.cancellation_token.child_token(),
));
}
Err(e) => {
// Return 200 with an immediately-closed empty stream.
// Returning an HTTP error would cause EventSource to retry
// with the same Last-Event-ID in an infinite loop. An empty
// 200 cleanly terminates the EventSource without delivering
// events from a different stream.
tracing::warn!("Resume failed ({e}), returning empty stream");
return Ok(sse_stream_response(
futures::stream::empty(),
None,
self.config.cancellation_token.child_token(),
));
}
}
}
// No Last-Event-ID — create standalone stream
let stream = self
.session_manager
.create_standalone_stream(&session_id)
.await
.map_err(internal_error_response("create standalone stream"))?;
let stream = if let Some(retry) = self.config.sse_retry {
let priming = ServerSseMessage::priming("0", retry);
futures::stream::once(async move { priming })
.chain(stream)
.left_stream()
} else {
stream.right_stream()
};
Ok(sse_stream_response(
stream,
self.config.sse_keep_alive,
self.config.cancellation_token.child_token(),
))
}
async fn handle_post<B>(&self, request: Request<B>) -> Result<BoxResponse, BoxResponse>
@ -598,20 +610,14 @@ where
match message {
ClientJsonRpcMessage::Request(_) => {
// Priming for request-wise streams is handled by the
// session layer (SessionManager::create_stream) which
// has access to the http_request_id for correct event IDs.
let stream = self
.session_manager
.create_stream(&session_id, message)
.await
.map_err(internal_error_response("get session"))?;
// Prepend priming event if sse_retry configured
let stream = if let Some(retry) = self.config.sse_retry {
let priming = ServerSseMessage::priming("0", retry);
futures::stream::once(async move { priming })
.chain(stream)
.left_stream()
} else {
stream.right_stream()
};
Ok(sse_stream_response(
stream,
self.config.sse_keep_alive,