feat: error handling

internal/app/app.go

@@ -106,7 +106,12 @@ func Run(ctx context.Context, params RunParams) error {
 			applyServerState(serverState, state)
 			updateUI()
 		case mpState := <-mp.C():
-			applyMultiplexerState(mpState, state)
+			destErrors := applyMultiplexerState(mpState, state)
+
+			for _, destError := range destErrors {
+				handleDestError(destError, mp, ui)
+			}
+
 			updateUI()
 		}
 	}
@@ -117,18 +122,49 @@ func applyServerState(serverState domain.Source, appState *domain.AppState) {
 	appState.Source = serverState
 }
 
+// destinationError holds the information needed to display a destination
+// error.
+type destinationError struct {
+	name string
+	url  string
+	err  error
+}
+
 // applyMultiplexerState applies the current multiplexer state to the app state.
-func applyMultiplexerState(mpState multiplexer.State, appState *domain.AppState) {
+//
-	for i, dest := range appState.Destinations {
+// It returns a list of destination errors that should be displayed to the user.
+func applyMultiplexerState(mpState multiplexer.State, appState *domain.AppState) []destinationError {
+	var errorsToDisplay []destinationError
+
+	for i := range appState.Destinations {
+		dest := &appState.Destinations[i]
+
 		if dest.URL != mpState.URL {
 			continue
 		}
 
-		appState.Destinations[i].Container = mpState.Container
+		if dest.Container.Err == nil && mpState.Container.Err != nil {
-		appState.Destinations[i].Status = mpState.Status
+			errorsToDisplay = append(errorsToDisplay, destinationError{
+				name: dest.Name,
+				url:  dest.URL,
+				err:  mpState.Container.Err,
+			})
+		}
+
+		dest.Container = mpState.Container
+		dest.Status = mpState.Status
 
 		break
 	}
+
+	return errorsToDisplay
+}
+
+// handleDestError displays a modal to the user, and stops the destination.
+func handleDestError(destError destinationError, mp *multiplexer.Actor, ui *terminal.UI) {
+	ui.ShowDestinationErrorModal(destError.name, destError.err)
+
+	mp.StopDestination(destError.url)
 }
 
 // newStateFromRunParams creates a new app state from the run parameters.

internal/container/container.go

@@ -263,11 +263,8 @@ func (a *Client) runContainerLoop(
 			case resp := <-respC:
 				// Check if the container is restarting. If it is not then we don't
 				// want to wait for it again and can return early.
-				//
-				// Low priority: is the API call necessary?
 				ctr, err := a.apiClient.ContainerInspect(ctx, containerID)
 				if err != nil {
-					// TODO: error handling?
 					a.logger.Error("Error inspecting container", "err", err, "id", shortID(containerID))
 					containerErrC <- err
 					return
@@ -282,7 +279,6 @@ func (a *Client) runContainerLoop(
 				}
 			case err := <-errC:
 				// Otherwise, this is probably unexpected and we need to handle it.
-				// TODO: improve handling
 				containerErrC <- err
 				return
 			case <-ctx.Done():

internal/domain/types.go

@@ -39,6 +39,7 @@ type Source struct {
 	ExitReason      string
 }
 
+// DestinationStatus reflects the high-level status of a single destination.
 type DestinationStatus int
 
 const (
@@ -81,4 +82,5 @@ type Container struct {
 	RxSince          time.Time
 	RestartCount     int
 	ExitCode         *int
+	Err              error // Err is set if any error was received from the container client.
 }

internal/mediaserver/actor.go

@@ -234,6 +234,7 @@ func (s *Actor) actorLoop(containerStateC <-chan domain.Container, errC <-chan e
 	}
 }
 
+// TODO: refactor to use container.Err?
 func (s *Actor) handleContainerExit(err error) {
 	if s.state.Container.ExitCode != nil {
 		s.state.ExitReason = fmt.Sprintf("Server process exited with code %d.", *s.state.Container.ExitCode)

internal/multiplexer/multiplexer.go

@@ -84,6 +84,9 @@ func (a *Actor) StartDestination(url string) {
 			return
 		}
 
+		a.nextIndex++
+		a.currURLs[url] = struct{}{}
+
 		a.logger.Info("Starting live stream", "url", url)
 
 		containerStateC, errC := a.containerClient.RunContainer(a.ctx, container.RunContainerParams{
@@ -108,9 +111,6 @@ func (a *Actor) StartDestination(url string) {
 			NetworkCountConfig: container.NetworkCountConfig{Rx: "eth1", Tx: "eth0"},
 		})
 
-		a.nextIndex++
-		a.currURLs[url] = struct{}{}
-
 		a.wg.Add(1)
 		go func() {
 			defer a.wg.Done()
@@ -146,12 +146,6 @@ func (a *Actor) StopDestination(url string) {
 
 // destLoop is the actor loop for a destination stream.
 func (a *Actor) destLoop(url string, containerStateC <-chan domain.Container, errC <-chan error) {
-	defer func() {
-		a.actorC <- func() {
-			delete(a.currURLs, url)
-		}
-	}()
-
 	state := &State{URL: url}
 	sendState := func() { a.stateC <- *state }
 
@@ -171,10 +165,11 @@ func (a *Actor) destLoop(url string, containerStateC <-chan domain.Container, er
 			}
 			sendState()
 		case err := <-errC:
-			// TODO: error handling
 			if err != nil {
 				a.logger.Error("Error from container client", "err", err)
 			}
+			state.Container.Err = err
+			sendState()
 			return
 		}
 	}

internal/terminal/terminal.go

@@ -251,7 +251,6 @@ func (ui *UI) ShowStartupCheckModal() bool {
 			[]string{"Continue", "Exit"},
 			func(buttonIndex int, _ string) {
 				if buttonIndex == 0 {
-					ui.pages.RemovePage("modal")
 					ui.app.SetFocus(ui.destView)
 					done <- true
 				} else {
@@ -264,6 +263,27 @@ func (ui *UI) ShowStartupCheckModal() bool {
 	return <-done
 }
 
+func (ui *UI) ShowDestinationErrorModal(name string, err error) {
+	done := make(chan struct{})
+
+	ui.app.QueueUpdateDraw(func() {
+		ui.showModal(
+			modalGroupStartupCheck,
+			fmt.Sprintf(
+				"Streaming to %s failed:\n\n%s",
+				cmp.Or(name, "this destination"),
+				err,
+			),
+			[]string{"Ok"},
+			func(int, string) {
+				done <- struct{}{}
+			},
+		)
+	})
+
+	<-done
+}
+
 // AllowQuit enables the quit action.
 func (ui *UI) AllowQuit() {
 	ui.mu.Lock()
@@ -580,7 +600,6 @@ func (ui *UI) confirmQuit() {
 		[]string{"Quit", "Cancel"},
 		func(buttonIndex int, _ string) {
 			if buttonIndex == 0 {
-				ui.logger.Info("quitting")
 				ui.commandCh <- CommandQuit{}
 				return
 			}