fix(gas): fix batch listen, fix history for graceful signal send in workflows

engine/packages/api-peer/src/actors/delete.rs

@@ -67,20 +67,14 @@ pub async fn delete(ctx: ApiCtx, path: DeletePath, query: DeleteQuery) -> Result
 		.signal(pegboard::workflows::actor::Destroy {})
 		.to_workflow::<pegboard::workflows::actor::Workflow>()
 		.tag("actor_id", path.actor_id)
+		.graceful_not_found()
 		.send()
-		.await;
-
-	if let Some(WorkflowError::WorkflowNotFound) = res
-		.as_ref()
-		.err()
-		.and_then(|x| x.chain().find_map(|x| x.downcast_ref::<WorkflowError>()))
-	{
+		.await?;
+	if res.is_none() {
 		tracing::warn!(
 			actor_id=?path.actor_id,
 			"actor workflow not found, likely already stopped"
 		);
-	} else {
-		res?;
 	}
 
 	Ok(DeleteResponse {})

engine/packages/engine/src/util/wf/mod.rs

@@ -468,22 +468,19 @@ pub async fn print_history(
 				}
 			}
 			EventData::Signals(data) => {
-				// Indent
-				print!("{}{c} ", "  ".repeat(indent));
-
 				for ((signal_id, name), body) in
 					data.signal_ids.iter().zip(&data.names).zip(&data.bodies)
 				{
 					// Indent
-					print!("{}{c}   - ", "  ".repeat(indent));
+					print!("{}{c} - ", "  ".repeat(indent));
 					println!("{}", event_style.apply_to(name));
 
-					print!("{}{c}   ", "  ".repeat(indent));
+					print!("{}{c}     ", "  ".repeat(indent));
 					println!("id {}", style(signal_id).green());
 
 					if !exclude_json {
 						// Indent
-						print!("{}{c}   ", "  ".repeat(indent));
+						print!("{}{c}     ", "  ".repeat(indent));
 
 						println!(
 							"body {}",
@@ -590,7 +587,7 @@ pub fn print_event_name(event: &Event) {
 		),
 		EventData::Signal(signal) => print!(
 			"{} {}",
-			style.apply_to("signal receive").bold(),
+			style.apply_to("signal").bold(),
 			style.apply_to(&signal.name)
 		),
 		EventData::SignalSend(signal_send) => print!(
@@ -626,7 +623,7 @@ pub fn print_event_name(event: &Event) {
 		EventData::Branch => print!("{}", style.apply_to("branch").bold()),
 		EventData::Signals(signal) => print!(
 			"{} {}",
-			style.apply_to("signal receive").bold(),
+			style.apply_to("signal recv").bold(),
 			style.apply_to(&signal.names.len())
 		),
 	}

engine/packages/gasoline/src/builder/common/signal.rs

@@ -18,6 +18,7 @@ pub struct SignalBuilder<T: Signal + Serialize> {
 	to_workflow_name: Option<&'static str>,
 	to_workflow_id: Option<Id>,
 	tags: serde_json::Map<String, serde_json::Value>,
+	graceful_not_found: bool,
 	error: Option<BuilderError>,
 }
 
@@ -37,6 +38,7 @@ impl<T: Signal + Serialize> SignalBuilder<T> {
 			to_workflow_name: None,
 			to_workflow_id: None,
 			tags: serde_json::Map::new(),
+			graceful_not_found: false,
 			error: from_workflow.then_some(BuilderError::CannotDispatchFromOpInWorkflow),
 		}
 	}
@@ -102,8 +104,21 @@ impl<T: Signal + Serialize> SignalBuilder<T> {
 		self
 	}
 
+	/// Does not throw an error when the signal target is not found and instead returns `Ok(None)`.
+	pub fn graceful_not_found(mut self) -> Self {
+		if self.error.is_some() {
+			return self;
+		}
+
+		self.graceful_not_found = true;
+
+		self
+	}
+
+	/// Returns the signal id that was just sent. Unless `graceful_not_found` is set and the workflow does not
+	/// exist, will always return `Some`.
 	#[tracing::instrument(skip_all, fields(signal_name=T::NAME, signal_id))]
-	pub async fn send(self) -> Result<Id> {
+	pub async fn send(self) -> Result<Option<Id>> {
 		if let Some(err) = self.error {
 			return Err(err.into());
 		}
@@ -132,8 +147,18 @@ impl<T: Signal + Serialize> SignalBuilder<T> {
 				let workflow_id = self
 					.db
 					.find_workflow(workflow_name, &serde_json::Value::Object(self.tags))
-					.await?
-					.ok_or(WorkflowError::WorkflowNotFound)?;
+					.await?;
+
+				let Some(workflow_id) = workflow_id else {
+					// Handle signal target not found gracefully
+					if self.graceful_not_found {
+						tracing::debug!("signal target not found");
+
+						return Ok(None);
+					} else {
+						return Err(WorkflowError::WorkflowNotFound.into());
+					}
+				};
 
 				self.db
 					.publish_signal(self.ray_id, workflow_id, signal_id, T::NAME, &input_val)
@@ -188,6 +213,6 @@ impl<T: Signal + Serialize> SignalBuilder<T> {
 			],
 		);
 
-		Ok(signal_id)
+		Ok(Some(signal_id))
 	}
 }

engine/packages/gasoline/src/builder/workflow/signal.rs

@@ -6,8 +6,13 @@ use rivet_util::Id;
 use serde::Serialize;
 
 use crate::{
-	builder::BuilderError, ctx::WorkflowCtx, error::WorkflowError, history::cursor::HistoryResult,
-	metrics, signal::Signal, workflow::Workflow,
+	builder::BuilderError,
+	ctx::WorkflowCtx,
+	error::WorkflowError,
+	history::{cursor::HistoryResult, event::EventType, removed::Signal as RemovedSignal},
+	metrics,
+	signal::Signal,
+	workflow::Workflow,
 };
 
 pub struct SignalBuilder<'a, T: Signal + Serialize> {
@@ -18,6 +23,7 @@ pub struct SignalBuilder<'a, T: Signal + Serialize> {
 	to_workflow_name: Option<&'static str>,
 	to_workflow_id: Option<Id>,
 	tags: serde_json::Map<String, serde_json::Value>,
+	graceful_not_found: bool,
 	error: Option<BuilderError>,
 }
 
@@ -31,6 +37,7 @@ impl<'a, T: Signal + Serialize> SignalBuilder<'a, T> {
 			to_workflow_name: None,
 			to_workflow_id: None,
 			tags: serde_json::Map::new(),
+			graceful_not_found: false,
 			error: None,
 		}
 	}
@@ -85,14 +92,39 @@ impl<'a, T: Signal + Serialize> SignalBuilder<'a, T> {
 		self
 	}
 
+	/// Does not throw an error when the signal target is not found and instead returns `Ok(None)`.
+	pub fn graceful_not_found(mut self) -> Self {
+		if self.error.is_some() {
+			return self;
+		}
+
+		self.graceful_not_found = true;
+
+		self
+	}
+
+	/// Returns the signal id that was just sent. Unless `graceful_not_found` is set and the workflow does not
+	/// exist, will always return `Some`.
 	#[tracing::instrument(skip_all, fields(signal_name=T::NAME, signal_id))]
-	pub async fn send(self) -> Result<Id> {
+	pub async fn send(self) -> Result<Option<Id>> {
 		self.ctx.check_stop()?;
 
 		if let Some(err) = self.error {
 			return Err(err.into());
 		}
 
+		// Check if this signal is being replayed and previously had no target (will have a removed event)
+		if self.graceful_not_found && self.ctx.cursor().is_removed() {
+			self.ctx.cursor().compare_removed::<RemovedSignal<T>>()?;
+
+			tracing::debug!("replaying gracefully not found signal dispatch");
+
+			// Move to next event
+			self.ctx.cursor_mut().inc();
+
+			return Ok(None);
+		}
+
 		// Error for version mismatch. This is done in the builder instead of in `VersionedWorkflowCtx` to
 		// defer the error.
 		self.ctx.compare_version("signal", self.version)?;
@@ -105,7 +137,7 @@ impl<'a, T: Signal + Serialize> SignalBuilder<'a, T> {
 
 		// Signal sent before
 		let signal_id = if let HistoryResult::Event(signal) = history_res {
-			tracing::debug!("replaying signal dispatch",);
+			tracing::debug!("replaying signal dispatch");
 
 			signal.signal_id
 		}
@@ -133,8 +165,33 @@ impl<'a, T: Signal + Serialize> SignalBuilder<'a, T> {
 						.ctx
 						.db()
 						.find_workflow(workflow_name, &serde_json::Value::Object(self.tags))
-						.await?
-						.ok_or(WorkflowError::WorkflowNotFound)?;
+						.await?;
+
+					let Some(workflow_id) = workflow_id else {
+						// Handle signal target not found gracefully
+						if self.graceful_not_found {
+							tracing::debug!("signal target not found");
+
+							// Insert removed event
+							self.ctx
+								.db()
+								.commit_workflow_removed_event(
+									self.ctx.workflow_id(),
+									&location,
+									EventType::SignalSend,
+									Some(T::NAME),
+									self.ctx.loop_location(),
+								)
+								.await?;
+
+							// Move to next event
+							self.ctx.cursor_mut().update(&location);
+
+							return Ok(None);
+						} else {
+							return Err(WorkflowError::WorkflowNotFound.into());
+						}
+					};
 
 					self.ctx
 						.db()
@@ -222,6 +279,6 @@ impl<'a, T: Signal + Serialize> SignalBuilder<'a, T> {
 		// Move to next event
 		self.ctx.cursor_mut().update(&location);
 
-		Ok(signal_id)
+		Ok(Some(signal_id))
 	}
 }

engine/packages/gasoline/src/ctx/workflow.rs

@@ -819,7 +819,7 @@ impl WorkflowCtx {
 		let loop_location = self.cursor.current_location_for(&history_res);
 
 		// Loop existed before
-		let (mut iteration, mut state, output, mut loop_event_commit_fut) =
+		let (mut iteration, mut state, output, mut loop_event_init_fut) =
 			if let HistoryResult::Event(loop_event) = history_res {
 				let state = loop_event.parse_state()?;
 				let output = loop_event.parse_output()?;
@@ -838,7 +838,7 @@ impl WorkflowCtx {
 				let nested_loop_location = self.loop_location().cloned();
 
 				// This future is deferred until later for parallelization
-				let loop_event_commit_fut = async move {
+				let loop_event_init_fut = async move {
 					db2.upsert_workflow_loop_event(
 						workflow_id,
 						&name,
@@ -852,7 +852,7 @@ impl WorkflowCtx {
 					.await
 				};
 
-				(0, state, None, Some(loop_event_commit_fut))
+				(0, state, None, Some(loop_event_init_fut))
 			};
 
 		// Create a branch for the loop event
@@ -869,6 +869,9 @@ impl WorkflowCtx {
 		else {
 			tracing::debug!("running loop");
 
+			// Used to defer loop upsertion for parallelization
+			let mut loop_event_upsert_fut = None;
+
 			loop {
 				self.check_stop()?;
 
@@ -898,14 +901,23 @@ impl WorkflowCtx {
 					// NOTE: Great care has been taken to optimize this function. This join allows multiple
 					// txns to run simultaneously instead of in series but is hard to read.
 					//
-					// 1. First, but not necessarily chronologically first because its parallelized, we
+					// 1. First (but not necessarily chronologically first because its parallelized), we
 					//    commit the loop event. This only happens on the first iteration of the loop
 					// 2. Second, we commit the branch event for the current iteration
-					// 3. Last, we run the user's loop code
-					let (loop_event_commit_res, branch_commit_res, loop_res) = tokio::join!(
+					// 3. Third, we run the user's loop code
+					// 4. Last, if we have to upsert the loop event, we save the future and process it in the
+					//    next iteration of the loop as part of this join
+					let (loop_event_commit_res, loop_event_upsert_res, branch_commit_res, loop_res) = tokio::join!(
 						async {
-							if let Some(loop_event_commit_fut) = loop_event_commit_fut.take() {
-								loop_event_commit_fut.await
+							if let Some(loop_event_init_fut) = loop_event_init_fut.take() {
+								loop_event_init_fut.await
+							} else {
+								Ok(())
+							}
+						},
+						async {
+							if let Some(loop_event_upsert_fut) = loop_event_upsert_fut.take() {
+								loop_event_upsert_fut.await
 							} else {
 								Ok(())
 							}
@@ -928,6 +940,7 @@ impl WorkflowCtx {
 					);
 
 					loop_event_commit_res?;
+					loop_event_upsert_res?;
 					branch_commit_res?;
 
 					// Run loop
@@ -936,23 +949,33 @@ impl WorkflowCtx {
 							let dt2 = start_instant2.elapsed().as_secs_f64();
 							iteration += 1;
 
-							let state_val = serde_json::value::to_raw_value(&state)
-								.map_err(WorkflowError::SerializeLoopOutput)?;
-
 							// Commit workflow state to db
 							if iteration % LOOP_ITERS_PER_COMMIT == 0 {
-								self.db
-									.upsert_workflow_loop_event(
-										self.workflow_id,
-										&self.name,
+								let state_val = serde_json::value::to_raw_value(&state)
+									.map_err(WorkflowError::SerializeLoopOutput)?;
+
+								// Clone data to move into future
+								let loop_location = loop_location.clone();
+								let db2 = self.db.clone();
+								let workflow_id = self.workflow_id;
+								let name = self.name.clone();
+								let version = self.version;
+								let nested_loop_location = self.loop_location().cloned();
+
+								// Defer upsertion to next iteration so it runs in parallel
+								loop_event_upsert_fut = Some(async move {
+									db2.upsert_workflow_loop_event(
+										workflow_id,
+										&name,
 										&loop_location,
-										self.version,
+										version,
 										iteration,
 										&state_val,
 										None,
-										self.loop_location(),
+										nested_loop_location.as_ref(),
 									)
-									.await?;
+									.await
+								});
 							}
 
 							anyhow::Ok((dt2, None))
@@ -966,7 +989,8 @@ impl WorkflowCtx {
 							let output_val = serde_json::value::to_raw_value(&res)
 								.map_err(WorkflowError::SerializeLoopOutput)?;
 
-							// Commit loop output and final state to db
+							// Commit loop output and final state to db. Note that we don't defer this because
+							// there will be no more loop iterations afterwards.
 							self.db
 								.upsert_workflow_loop_event(
 									self.workflow_id,
@@ -1338,7 +1362,7 @@ impl WorkflowCtx {
 
 		// Existing event
 		if self.cursor.compare_removed::<T>()? {
-			tracing::debug!("skipping removed step",);
+			tracing::debug!("skipping removed step");
 		}
 		// New "removed" event
 		else {