Add graceful shutdown for recorder worker

cmd/sdrd/main.go

@@ -102,6 +102,7 @@ func main() {
 		ClassFilter: cfg.Recorder.ClassFilter,
 		RingSeconds: cfg.Recorder.RingSeconds,
 	}, cfg.CenterHz, decodeMap)
+	defer recMgr.Close()
 
 	sigSnap := &signalSnapshot{}
 

internal/recorder/recorder.go

@@ -39,6 +39,9 @@ type Manager struct {
 	decodeCommands map[string]string
 	queue          chan detector.Event
 	gpuDemod       *gpudemod.Engine
+	closed         bool
+	closeOnce      sync.Once
+	workerWG       sync.WaitGroup
 }
 
 func New(sampleRate int, blockSize int, policy Policy, centerHz float64, decodeCommands map[string]string) *Manager {
@@ -50,6 +53,7 @@ func New(sampleRate int, blockSize int, policy Policy, centerHz float64, decodeC
 	}
 	m := &Manager{policy: policy, ring: NewRing(sampleRate, blockSize, policy.RingSeconds), sampleRate: sampleRate, blockSize: blockSize, centerHz: centerHz, decodeCommands: decodeCommands, queue: make(chan detector.Event, 64)}
 	m.initGPUDemod(sampleRate, blockSize)
+	m.workerWG.Add(1)
 	go m.worker()
 	return m
 }
@@ -89,8 +93,9 @@ func (m *Manager) OnEvents(events []detector.Event) {
 	}
 	m.mu.RLock()
 	enabled := m.policy.Enabled
+	closed := m.closed
 	m.mu.RUnlock()
-	if !enabled {
+	if !enabled || closed {
 		return
 	}
 	for _, ev := range events {
@@ -103,6 +108,7 @@ func (m *Manager) OnEvents(events []detector.Event) {
 }
 
 func (m *Manager) worker() {
+	defer m.workerWG.Done()
 	for ev := range m.queue {
 		_ = m.recordEvent(ev)
 	}
@@ -129,6 +135,26 @@ func (m *Manager) initGPUDemodLocked(sampleRate int, blockSize int) {
 	m.gpuDemod = eng
 }
 
+func (m *Manager) Close() {
+	if m == nil {
+		return
+	}
+	m.closeOnce.Do(func() {
+		m.mu.Lock()
+		m.closed = true
+		if m.queue != nil {
+			close(m.queue)
+		}
+		gpu := m.gpuDemod
+		m.gpuDemod = nil
+		m.mu.Unlock()
+		m.workerWG.Wait()
+		if gpu != nil {
+			gpu.Close()
+		}
+	})
+}
+
 func (m *Manager) recordEvent(ev detector.Event) error {
 	m.mu.RLock()
 	policy := m.policy