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Fix duplicate task generation (frontport of #5431) #5459

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Merged
ndr-ds merged 1 commit into from
Feb 17, 2026
Merged

Fix duplicate task generation (frontport of #5431) #5459

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64 changes: 45 additions & 19 deletions linera-service/src/task_processor.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,7 @@ use linera_base::{
};
use linera_core::{client::ChainClient, node::NotificationStream, worker::Reason};
use serde_json::json;
use tokio::{io::AsyncWriteExt, process::Command, select, sync::mpsc, task::JoinHandle};
use tokio::{io::AsyncWriteExt, process::Command, select, sync::mpsc};
use tokio_util::sync::CancellationToken;
use tracing::{debug, error, info};

Expand All @@ -43,6 +43,17 @@ pub fn parse_operator(s: &str) -> Result<(String, PathBuf), String> {

type Deadline = Reverse<(Timestamp, Option<ApplicationId>)>;

/// Messages sent from background task execution to the main loop.
enum TaskMessage {
/// A task outcome ready to be submitted.
Outcome {
application_id: ApplicationId,
outcome: TaskOutcome,
},
/// All tasks in a batch have completed and their outcomes (if any) have been sent.
BatchComplete { application_id: ApplicationId },
}

/// A task processor that watches applications and executes off-chain operators.
pub struct TaskProcessor<Env: linera_core::Environment> {
chain_id: ChainId,
Expand All @@ -51,12 +62,12 @@ pub struct TaskProcessor<Env: linera_core::Environment> {
chain_client: ChainClient<Env>,
cancellation_token: CancellationToken,
notifications: NotificationStream,
outcome_sender: mpsc::UnboundedSender<(ApplicationId, TaskOutcome)>,
outcome_receiver: mpsc::UnboundedReceiver<(ApplicationId, TaskOutcome)>,
outcome_sender: mpsc::UnboundedSender<TaskMessage>,
outcome_receiver: mpsc::UnboundedReceiver<TaskMessage>,
update_receiver: mpsc::UnboundedReceiver<Update>,
deadlines: BinaryHeap<Deadline>,
operators: OperatorMap,
last_task_handles: BTreeMap<ApplicationId, JoinHandle<()>>,
in_flight_apps: BTreeSet<ApplicationId>,
}

impl<Env: linera_core::Environment> TaskProcessor<Env> {
Expand Down Expand Up @@ -84,7 +95,7 @@ impl<Env: linera_core::Environment> TaskProcessor<Env> {
update_receiver,
deadlines: BinaryHeap::new(),
operators,
last_task_handles: BTreeMap::new(),
in_flight_apps: BTreeSet::new(),
}
}

Expand All @@ -105,9 +116,17 @@ impl<Env: linera_core::Environment> TaskProcessor<Env> {
let application_ids = self.process_events();
self.process_actions(application_ids).await;
}
Some((application_id, outcome)) = self.outcome_receiver.recv() => {
if let Err(e) = self.submit_task_outcome(application_id, &outcome).await {
error!("Error while processing task outcome {outcome:?}: {e}");
Some(msg) = self.outcome_receiver.recv() => {
match msg {
TaskMessage::Outcome { application_id, outcome } => {
if let Err(e) = self.submit_task_outcome(application_id, &outcome).await {
error!("Error while processing task outcome {outcome:?}: {e}");
}
}
TaskMessage::BatchComplete { application_id } => {
self.in_flight_apps.remove(&application_id);
self.process_actions(vec![application_id]).await;
}
}
}
Some(update) = self.update_receiver.recv() => {
Expand Down Expand Up @@ -138,9 +157,10 @@ impl<Env: linera_core::Environment> TaskProcessor<Env> {
let new_app_set: BTreeSet<_> = update.application_ids.iter().cloned().collect();
let old_app_set: BTreeSet<_> = self.application_ids.iter().cloned().collect();

// Retain only last_requested_callbacks for applications that are still active
self.cursors
.retain(|app_id, _| new_app_set.contains(app_id));
self.in_flight_apps
.retain(|app_id| new_app_set.contains(app_id));

// Update the application_ids
self.application_ids = update.application_ids;
Expand Down Expand Up @@ -176,6 +196,10 @@ impl<Env: linera_core::Environment> TaskProcessor<Env> {

async fn process_actions(&mut self, application_ids: Vec<ApplicationId>) {
for application_id in application_ids {
if self.in_flight_apps.contains(&application_id) {
debug!("Skipping {application_id}: tasks already in flight");
continue;
}
debug!("Processing actions for {application_id}");
let now = Timestamp::now();
let app_cursor = self.cursors.get(&application_id).cloned();
Expand All @@ -199,10 +223,10 @@ impl<Env: linera_core::Environment> TaskProcessor<Env> {
self.cursors.insert(application_id, cursor);
}
if !actions.execute_tasks.is_empty() {
self.in_flight_apps.insert(application_id);
let sender = self.outcome_sender.clone();
let operators = self.operators.clone();
let previous = self.last_task_handles.remove(&application_id);
let handle = tokio::spawn(async move {
tokio::spawn(async move {
// Spawn all tasks concurrently and join them.
let handles: Vec<_> = actions
.execute_tasks
Expand All @@ -218,17 +242,17 @@ impl<Env: linera_core::Environment> TaskProcessor<Env> {
})
.collect();
let results = future::join_all(handles).await;
// Wait for the previous batch to finish sending outcomes first.
if let Some(previous) = previous {
if let Err(error) = previous.await {
error!(%application_id, %error, "Task panicked");
}
}
// Submit outcomes in the original order.
for result in results {
match result {
Ok(Ok(outcome)) => {
if sender.send((application_id, outcome)).is_err() {
if sender
.send(TaskMessage::Outcome {
application_id,
outcome,
})
.is_err()
{
error!("Outcome receiver dropped for {application_id}");
break;
}
Expand All @@ -241,8 +265,10 @@ impl<Env: linera_core::Environment> TaskProcessor<Env> {
}
}
}
// Signal that this batch is done so the main loop can process
// the next batch for this application.
let _ = sender.send(TaskMessage::BatchComplete { application_id });
});
self.last_task_handles.insert(application_id, handle);
}
}
}
Expand Down
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