Improve ProgramRunner task error handling

src/program_runner.rs

@@ -1,5 +1,6 @@
 use crate::model::{ProgramId, ProgramRef, Programs, Sections};
 use crate::section_runner::{SectionEvent, SectionRunHandle, SectionRunner};
+use eyre::WrapErr;
 use std::collections::VecDeque;
 use thiserror::Error;
 use tokio::{
@@ -101,13 +102,13 @@ impl RunnerTask {
         }
     }
 
-    async fn start_program_run(&mut self, run: &mut ProgRun) {
+    async fn start_program_run(&mut self, run: &mut ProgRun) -> eyre::Result<()> {
         if run.state != RunState::Waiting {
             warn!(
                 program_id = run.program.id,
                 "cannot run program which is already running"
             );
-            return;
+            return Ok(());
         }
         run.sec_run_handles.reserve(run.program.sequence.len());
         for item in &run.program.sequence {
@@ -122,14 +123,11 @@ impl RunnerTask {
                     continue;
                 }
             };
-            let handle = match self.section_runner.queue_run(section, item.duration).await {
-                Ok(handle) => handle,
-                Err(_closed) => {
-                    error!("section runner channel closed");
-                    self.running = false;
-                    return;
-                }
-            };
+            let handle = self
+                .section_runner
+                .queue_run(section, item.duration)
+                .await
+                .wrap_err("failed to queue section run")?;
             run.sec_run_handles.push(handle);
         }
         run.state = RunState::Running;
@@ -141,31 +139,36 @@ impl RunnerTask {
         } else {
             debug!(program_id = run.program.id, "started running program");
         }
+        Ok(())
     }
 
-    async fn cancel_program_run(&mut self, run: &mut ProgRun) {
+    async fn cancel_program_run(&mut self, run: &mut ProgRun) -> eyre::Result<()> {
         for handle in run.sec_run_handles.drain(..) {
-            if let Err(_closed) = self.section_runner.cancel_run(handle).await {
-                error!("section runner channel closed");
-                self.running = false;
-                return;
-            }
+            self.section_runner
+                .cancel_run(handle)
+                .await
+                .wrap_err("failed to cancel section run")?;
         }
         debug!(program_id = run.program.id, "program run is cancelled");
         self.send_event(ProgramEvent::RunCancel(run.program.clone()));
+        Ok(())
     }
 
-    async fn process_queue(&mut self, run_queue: &mut RunQueue) {
+    async fn process_queue(&mut self, run_queue: &mut RunQueue) -> eyre::Result<()> {
         while let Some(current_run) = run_queue.front_mut() {
             let run_finished = match current_run.state {
                 RunState::Waiting => {
-                    self.start_program_run(current_run).await;
+                    self.start_program_run(current_run)
+                        .await
+                        .wrap_err("failed to start program run")?;
                     false
                 }
                 RunState::Running => false,
                 RunState::Finished => true,
                 RunState::Cancelled => {
-                    self.cancel_program_run(current_run).await;
+                    self.cancel_program_run(current_run)
+                        .await
+                        .wrap_err("failed to cancel program run")?;
                     true
                 }
             };
@@ -175,6 +178,7 @@ impl RunnerTask {
                 break;
             }
         }
+        Ok(())
     }
 
     fn handle_msg(&mut self, msg: Option<RunnerMsg>, run_queue: &mut RunQueue) {
@@ -239,22 +243,8 @@ impl RunnerTask {
         &mut self,
         sec_event: Result<SectionEvent, broadcast::RecvError>,
         run_queue: &mut RunQueue,
-    ) {
-        let sec_event = match sec_event {
-            Ok(ev) => ev,
-            Err(broadcast::RecvError::Lagged(missed)) => {
-                warn!(
-                    missed,
-                    "missed some section events, increase event channel size"
-                );
-                return;
-            }
-            Err(broadcast::RecvError::Closed) => {
-                error!("section events channel closed");
-                self.running = false;
-                return;
-            }
-        };
+    ) -> eyre::Result<()> {
+        let sec_event = sec_event.wrap_err("failed to receive section event")?;
         #[allow(clippy::single_match)]
         match sec_event {
             SectionEvent::RunFinish(finished_run) => {
@@ -262,28 +252,39 @@ impl RunnerTask {
             }
             _ => {}
         }
+        Ok(())
+    }
+
+    async fn start_impl(&mut self) -> eyre::Result<()> {
+        let mut sec_events = self
+            .section_runner
+            .subscribe()
+            .await
+            .wrap_err("could not subscribe to SectionRunner events")?;
+
+        let mut run_queue: RunQueue = VecDeque::new();
+
+        while self.running {
+            self.process_queue(&mut run_queue)
+                .await
+                .wrap_err("error during queue processing")?;
+            tokio::select! {
+                msg = self.msg_recv.recv() => self.handle_msg(msg, &mut run_queue),
+                sec_event = sec_events.recv() => self.handle_sec_event(sec_event, &mut run_queue)?,
+                // _ = &mut self.delay_future, if self.delay_future.is_some() => delay_done()
+            };
+        }
+
+        Ok(())
     }
 
     async fn start(mut self) {
         let span = trace_span!("runner_task");
         let _enter = span.enter();
 
-        let mut sec_events = self
-            .section_runner
-            .subscribe()
+        self.start_impl()
             .await
-            .expect("could not subscribe to SectionRunner events");
-
-        let mut run_queue: RunQueue = VecDeque::new();
-
-        while self.running {
-            self.process_queue(&mut run_queue).await;
-            tokio::select! {
-                msg = self.msg_recv.recv() => self.handle_msg(msg, &mut run_queue),
-                sec_event = sec_events.recv() => self.handle_sec_event(sec_event, &mut run_queue),
-                // _ = &mut self.delay_future, if self.delay_future.is_some() => delay_done()
-            };
-        }
+            .expect("error in ProgramRunner task");
     }
 }