Discoveries event channels are now created when start sync is called

Author: silvanocerza

arduino/discovery/discovery.go

@@ -390,44 +390,38 @@ func (disc *PluggableDiscovery) List() ([]*Port, error) {
 	}
 }
 
-// EventChannel creates a channel used to receive events from the pluggable discovery.
-// The event channel must be consumed as quickly as possible since it may block the
-// discovery if it becomes full. The channel size is configurable.
-func (disc *PluggableDiscovery) EventChannel(size int) <-chan *Event {
-	disc.statusMutex.Lock()
-	defer disc.statusMutex.Unlock()
-	if disc.eventChan != nil {
-		// In case there is already an existing event channel in use we close it
-		// before creating a new one.
-		close(disc.eventChan)
-	}
-	c := make(chan *Event, size)
-	disc.eventChan = c
-	return c
-}
-
 // StartSync puts the discovery in "events" mode: the discovery will send "add"
 // and "remove" events each time a new port is detected or removed respectively.
 // After calling StartSync an initial burst of "add" events may be generated to
 // report all the ports available at the moment of the start.
-func (disc *PluggableDiscovery) StartSync() error {
+// It also creates a channel used to receive events from the pluggable discovery.
+// The event channel must be consumed as quickly as possible since it may block the
+// discovery if it becomes full. The channel size is configurable.
+func (disc *PluggableDiscovery) StartSync(size int) (<-chan *Event, error) {
 	if err := disc.sendCommand("START_SYNC\n"); err != nil {
-		return err
+		return nil, err
 	}
 
 	if msg, err := disc.waitMessage(time.Second * 10); err != nil {
-		return fmt.Errorf("calling START_SYNC: %w", err)
+		return nil, fmt.Errorf("calling START_SYNC: %w", err)
 	} else if msg.EventType != "start_sync" {
-		return errors.Errorf(tr("communication out of sync, expected 'start_sync', received '%s'"), msg.EventType)
+		return nil, errors.Errorf(tr("communication out of sync, expected 'start_sync', received '%s'"), msg.EventType)
 	} else if msg.Message != "OK" || msg.Error {
-		return errors.Errorf(tr("command failed: %s"), msg.Message)
+		return nil, errors.Errorf(tr("command failed: %s"), msg.Message)
 	}
 
 	disc.statusMutex.Lock()
 	defer disc.statusMutex.Unlock()
 	disc.state = Syncing
 	disc.cachedPorts = map[string]*Port{}
-	return nil
+	if disc.eventChan != nil {
+		// In case there is already an existing event channel in use we close it
+		// before creating a new one.
+		close(disc.eventChan)
+	}
+	c := make(chan *Event, size)
+	disc.eventChan = c
+	return c, nil
 }
 
 // ListSync returns a list of the available ports. The list is a cache of all the

arduino/discovery/discoverymanager/discoverymanager.go

@@ -141,8 +141,8 @@ func (dm *DiscoveryManager) StartSyncAll() (<-chan *discovery.Event, []error) {
 			return nil
 		}
 
-		eventCh := d.EventChannel(5)
-		if err := d.StartSync(); err != nil {
+		eventCh, err := d.StartSync(5)
+		if err != nil {
 			return fmt.Errorf("start syncing discovery %s: %w", d.GetID(), err)
 		}
 		go func() {