vidforward: getPipeline handles revid creation and start

It simplifies things if getPipeline handles creation and starting
of the revid pipeline. We don't need to be doing this in multiple
places.

Approved-by: Trek Hopton

cmd/vidforward/file.go

@@ -77,16 +77,6 @@ func (b *Broadcast) UnmarshalJSON(data []byte) error {
 	b.urls = bm.URLs
 	b.status = bm.Status
 
-	b.rv, err = newRevid(global.GetLogger(), b.urls)
-	if err != nil {
-		return fmt.Errorf("could not populate RV field: %w", err)
-	}
-
-	err = b.rv.Start()
-	if err != nil {
-		return fmt.Errorf("could not start revid pipeline: %w", err)
-	}
-
 	return nil
 }
 
@@ -119,9 +109,9 @@ func (m *broadcastManager) UnmarshalJSON(data []byte) error {
 		if b.status == statusSlate {
 			sigCh := make(chan struct{})
 			m.slateExitSignals[mac] = sigCh
-			rv := m.getPipeline(mac)
-			if rv == nil {
-				panic("no pipeline for MAC")
+			rv, err := m.getPipeline(mac)
+			if err != nil {
+				return fmt.Errorf("could not get revid pipeline: %v",err)
 			}
 			if !inTest {
 				err := writeSlateAndCheckErrors(rv, sigCh, m.log)

cmd/vidforward/main.go

@@ -261,9 +261,10 @@ func (m *broadcastManager) recv(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	rv := m.getPipeline(ma)
-	if r == nil {
-		panic(fmt.Sprintf("no revid pipeline for mac address: %s", ma))
+	rv, err := m.getPipeline(ma)
+	if err != nil {
+		m.errorLogWrite(m.log, w, "could not get revid pipeline","mac",ma,"error",err)
+		return
 	}
 
 	for i, frame := range h264Clip.Frames() {
@@ -363,14 +364,32 @@ func (m *broadcastManager) processRequest(w http.ResponseWriter, r *http.Request
 }
 
 // getPipeline gets the revid pipeline corresponding to a provided device MAC.
-func (m *broadcastManager) getPipeline(ma MAC) *revid.Revid {
+// If it hasn't been created yet, it's created, and if it hasn't been started yet
+// (or just created) then it is started.
+func (m *broadcastManager) getPipeline(ma MAC) (*revid.Revid, error) {
 	m.mu.Lock()
 	defer m.mu.Unlock()
-	v, ok := m.broadcasts[ma]
+	b, ok := m.broadcasts[ma]
 	if !ok {
-		return nil
+		panic("shouldn't be getting pipeline if this mac isn't registered")
 	}
-	return v.rv
+
+	var err error
+	if b.rv == nil {
+		b.rv, err = newRevid(m.log, b.urls)
+		if err != nil {
+			return nil, fmt.Errorf("could not create new revid: %v",err)
+		}
+	}
+
+	if !b.rv.Running() {
+		err = b.rv.Start()
+		if err != nil {
+			return nil, fmt.Errorf("could not start revid pipeline: %v",err)
+		}
+	}
+
+	return b.rv, nil
 }
 
 // getStatus gets the broadcast's status corresponding to the provided MAC.