fix(managed): bound blocking runtime shutdown

crates/irtt-client/src/managed/blocking.rs

@@ -1,13 +1,54 @@
-use std::thread::{self, JoinHandle};
+use std::{
+    thread::{self, JoinHandle},
+    time::Duration,
+};
 
 use thiserror::Error;
-use tokio::runtime::Builder;
+use tokio::runtime::{Builder, Runtime};
 
 use super::{
     ManagedClient, ManagedClientConfig, ManagedClientHandle, ManagedConfigError, ManagedOutcome,
     ManagedTargetConfig,
 };
 
+const BLOCKING_RUNTIME_SHUTDOWN_TIMEOUT: Duration = Duration::from_millis(100);
+
+/// Owns the runtime used exclusively by the blocking managed worker.
+pub(super) struct WorkerRuntime {
+    runtime: Option<Runtime>,
+}
+
+impl WorkerRuntime {
+    pub(super) fn new(runtime: Runtime) -> Self {
+        Self {
+            runtime: Some(runtime),
+        }
+    }
+
+    fn block_on<F: std::future::Future>(&self, task: F) -> F::Output {
+        self.runtime
+            .as_ref()
+            .expect("worker runtime is available until shutdown")
+            .block_on(task)
+    }
+
+    /// Shut down residual runtime work without delaying managed completion indefinitely.
+    pub(super) fn shutdown(mut self) {
+        self.runtime
+            .take()
+            .expect("worker runtime is available until shutdown")
+            .shutdown_timeout(BLOCKING_RUNTIME_SHUTDOWN_TIMEOUT);
+    }
+}
+
+impl Drop for WorkerRuntime {
+    fn drop(&mut self) {
+        if let Some(runtime) = self.runtime.take() {
+            runtime.shutdown_background();
+        }
+    }
+}
+
 /// Failure to start a blocking managed client owner.
 #[derive(Debug, Error)]
 pub enum BlockingManagedStartError {
@@ -62,9 +103,14 @@ impl BlockingManagedClient {
             .enable_time()
             .build()
             .map_err(|source| BlockingManagedStartError::Runtime { source })?;
+        let runtime = WorkerRuntime::new(runtime);
         let worker = thread::Builder::new()
             .name("irtt-managed".to_owned())
-            .spawn(move || runtime.block_on(task))
+            .spawn(move || {
+                let outcome = runtime.block_on(task);
+                runtime.shutdown();
+                outcome
+            })
             .map_err(|source| BlockingManagedStartError::ThreadSpawn { source })?;
 
         Ok(Self {

crates/irtt-client/src/managed/blocking_tests.rs

@@ -1,8 +1,8 @@
 use std::{
     net::{SocketAddr, UdpSocket},
-    sync::{Arc, Condvar, Mutex},
+    sync::{mpsc::sync_channel, Arc, Condvar, Mutex},
     thread::{self, JoinHandle},
-    time::Duration,
+    time::{Duration, Instant},
 };
 
 use irtt_proto::{
@@ -12,11 +12,11 @@ use irtt_proto::{
 use tokio::{runtime::Builder, time::timeout};
 
 use super::{
-    blocking::join_worker, BlockingManagedClient, BlockingManagedJoinError, ManagedClientConfig,
-    ManagedCompletionPolicy, ManagedEndReason, ManagedLifecycle, ManagedPacing,
-    ManagedTargetConfig, ManagedTargetEndReason,
+    blocking::{join_worker, WorkerRuntime},
+    BlockingManagedClient, BlockingManagedJoinError, ManagedClientConfig, ManagedCompletionPolicy,
+    ManagedEndReason, ManagedLifecycle, ManagedPacing, ManagedTargetConfig, ManagedTargetEndReason,
 };
-use crate::{ClientConfig, ClientEvent};
+use crate::ClientConfig;
 
 const TOKEN: u64 = 0x1234_5678_90ab_cdef;
 
@@ -284,6 +284,44 @@ fn worker_panic_is_a_join_error() {
     );
 }
 
+#[test]
+fn dropping_worker_runtime_inside_async_context_does_not_panic() {
+    test_runtime().block_on(async {
+        let runtime = Builder::new_current_thread()
+            .enable_io()
+            .enable_time()
+            .build()
+            .unwrap();
+        drop(WorkerRuntime::new(runtime));
+    });
+}
+
+#[test]
+fn worker_runtime_shutdown_is_bounded_with_blocking_work() {
+    let runtime = Builder::new_current_thread()
+        .enable_io()
+        .enable_time()
+        .build()
+        .unwrap();
+    let (started_send, started_receive) = sync_channel(0);
+    let (release_send, release_receive) = sync_channel(0);
+
+    runtime.block_on(async move {
+        tokio::task::spawn_blocking(move || {
+            started_send.send(()).unwrap();
+            release_receive.recv().unwrap();
+        });
+    });
+    started_receive
+        .recv_timeout(Duration::from_secs(2))
+        .unwrap();
+
+    let started = Instant::now();
+    WorkerRuntime::new(runtime).shutdown();
+    assert!(started.elapsed() < Duration::from_secs(2));
+    release_send.send(()).unwrap();
+}
+
 #[test]
 fn drop_after_natural_completion_preserves_outcome() {
     let server = EchoServer::start();
@@ -293,34 +331,21 @@ fn drop_after_natural_completion_preserves_outcome() {
     )
     .unwrap();
     let handle = owner.handle();
-    let mut events = handle.subscribe().unwrap();
-
-    test_runtime().block_on(async {
-        loop {
-            if let super::ManagedEvent::Client {
-                event: ClientEvent::EchoSent { .. },
-                ..
-            } = timeout(Duration::from_secs(2), events.recv())
-                .await
-                .unwrap()
-                .unwrap()
-            {
-                break;
-            }
-        }
-        loop {
-            if let super::ManagedEvent::Completed { outcome } =
-                timeout(Duration::from_secs(2), events.recv())
-                    .await
-                    .unwrap()
-                    .unwrap()
-            {
-                assert_eq!(outcome.end_reason, ManagedEndReason::TargetsComplete);
-                break;
-            }
-        }
-    });
+    server.wait_probe();
     server.wait_close();
+    let deadline = Instant::now() + Duration::from_secs(2);
+    let status = loop {
+        let status = handle.status();
+        if status.lifecycle == ManagedLifecycle::Completed && status.final_outcome.is_some() {
+            break status;
+        }
+        assert!(Instant::now() < deadline, "managed worker did not complete");
+        thread::sleep(Duration::from_millis(5));
+    };
+    assert_eq!(
+        status.final_outcome.as_ref().unwrap().end_reason,
+        ManagedEndReason::TargetsComplete
+    );
     drop(owner);
     assert_eq!(
         handle.status().final_outcome.as_ref().unwrap().end_reason,