fixup! wip: refactor: API

go.mod

@@ -11,7 +11,11 @@ require (
 	github.com/rivo/tview v0.0.0-20250330220935-949945f8d922
 	github.com/stretchr/testify v1.10.0
 	github.com/testcontainers/testcontainers-go v0.35.0
+	github.com/urfave/cli/v2 v2.27.6
 	golang.design/x/clipboard v0.7.0
+	golang.org/x/sync v0.13.0
+	google.golang.org/grpc v1.69.4
+	google.golang.org/protobuf v1.36.3
 	gopkg.in/yaml.v3 v3.0.1
 )
 
@@ -24,6 +28,7 @@ require (
 	github.com/containerd/log v0.1.0 // indirect
 	github.com/containerd/platforms v0.2.1 // indirect
 	github.com/cpuguy83/dockercfg v0.3.2 // indirect
+	github.com/cpuguy83/go-md2man/v2 v2.0.5 // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
 	github.com/distribution/reference v0.6.0 // indirect
 	github.com/docker/go-units v0.5.0 // indirect
@@ -65,6 +70,7 @@ require (
 	github.com/power-devops/perfstat v0.0.0-20210106213030-5aafc221ea8c // indirect
 	github.com/rivo/uniseg v0.4.7 // indirect
 	github.com/rs/zerolog v1.33.0 // indirect
+	github.com/russross/blackfriday/v2 v2.1.0 // indirect
 	github.com/sagikazarmark/locafero v0.7.0 // indirect
 	github.com/sagikazarmark/slog-shim v0.1.0 // indirect
 	github.com/shirou/gopsutil/v3 v3.23.12 // indirect
@@ -81,6 +87,7 @@ require (
 	github.com/tklauser/go-sysconf v0.3.12 // indirect
 	github.com/tklauser/numcpus v0.6.1 // indirect
 	github.com/vektra/mockery/v2 v2.52.2 // indirect
+	github.com/xrash/smetrics v0.0.0-20240521201337-686a1a2994c1 // indirect
 	github.com/yusufpapurcu/wmi v1.2.3 // indirect
 	go.opentelemetry.io/auto/sdk v1.1.0 // indirect
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.60.0 // indirect
@@ -95,12 +102,13 @@ require (
 	golang.org/x/image v0.26.0 // indirect
 	golang.org/x/mobile v0.0.0-20250408133729-978277e7eaf7 // indirect
 	golang.org/x/mod v0.24.0 // indirect
-	golang.org/x/sync v0.13.0 // indirect
+	golang.org/x/net v0.39.0 // indirect
 	golang.org/x/sys v0.32.0 // indirect
 	golang.org/x/term v0.31.0 // indirect
 	golang.org/x/text v0.24.0 // indirect
 	golang.org/x/time v0.9.0 // indirect
 	golang.org/x/tools v0.32.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20250115164207-1a7da9e5054f // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect
 )
 

go.sum

@@ -18,6 +18,8 @@ github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSV
 github.com/cpuguy83/dockercfg v0.3.2 h1:DlJTyZGBDlXqUZ2Dk2Q3xHs/FtnooJJVaad2S9GKorA=
 github.com/cpuguy83/dockercfg v0.3.2/go.mod h1:sugsbF4//dDlL/i+S+rtpIWp+5h0BHJHfjj5/jFyUJc=
 github.com/cpuguy83/go-md2man/v2 v2.0.4/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
+github.com/cpuguy83/go-md2man/v2 v2.0.5 h1:ZtcqGrnekaHpVLArFSe4HK5DoKx1T0rq2DwVB0alcyc=
+github.com/cpuguy83/go-md2man/v2 v2.0.5/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/creack/pty v1.1.18 h1:n56/Zwd5o6whRC5PMGretI4IdRLlmBXYNjScPaBgsbY=
 github.com/creack/pty v1.1.18/go.mod h1:MOBLtS5ELjhRRrroQr9kyvTxUAFNvYEK993ew/Vr4O4=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -52,6 +54,8 @@ github.com/go-ole/go-ole v1.2.6/go.mod h1:pprOEPIfldk/42T2oK7lQ4v4JSDwmV0As9GaiU
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/gogo/protobuf v1.3.2 h1:Ov1cvc58UF3b5XjBnZv7+opcTcQFZebYjWzi34vdm4Q=
 github.com/gogo/protobuf v1.3.2/go.mod h1:P1XiOD3dCwIKUDQYPy72D8LYyHL2YPYrpS2s69NZV8Q=
+github.com/golang/protobuf v1.5.4 h1:i7eJL8qZTpSEXOPTxNKhASYpMn+8e5Q6AdndVa1dWek=
+github.com/golang/protobuf v1.5.4/go.mod h1:lnTiLA8Wa4RWRcIUkrtSVa5nRhsEGBg48fD6rSs7xps=
 github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
@@ -140,6 +144,7 @@ github.com/rogpeppe/go-internal v1.13.1/go.mod h1:uMEvuHeurkdAXX61udpOXGD/AzZDWN
 github.com/rs/xid v1.5.0/go.mod h1:trrq9SKmegXys3aeAKXMUTdJsYXVwGY3RLcfgqegfbg=
 github.com/rs/zerolog v1.33.0 h1:1cU2KZkvPxNyfgEmhHAz/1A9Bz+llsdYzklWFzgp0r8=
 github.com/rs/zerolog v1.33.0/go.mod h1:/7mN4D5sKwJLZQ2b/znpjC3/GQWY/xaDXUM0kKWRHss=
+github.com/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf35Ld67mk=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/sagikazarmark/locafero v0.7.0 h1:5MqpDsTGNDhY8sGp0Aowyf0qKsPrhewaLSsFaodPcyo=
 github.com/sagikazarmark/locafero v0.7.0/go.mod h1:2za3Cg5rMaTMoG/2Ulr9AwtFaIppKXTRYnozin4aB5k=
@@ -185,8 +190,12 @@ github.com/tklauser/go-sysconf v0.3.12 h1:0QaGUFOdQaIVdPgfITYzaTegZvdCjmYO52cSFA
 github.com/tklauser/go-sysconf v0.3.12/go.mod h1:Ho14jnntGE1fpdOqQEEaiKRpvIavV0hSfmBq8nJbHYI=
 github.com/tklauser/numcpus v0.6.1 h1:ng9scYS7az0Bk4OZLvrNXNSAO2Pxr1XXRAPyjhIx+Fk=
 github.com/tklauser/numcpus v0.6.1/go.mod h1:1XfjsgE2zo8GVw7POkMbHENHzVg3GzmoZ9fESEdAacY=
+github.com/urfave/cli/v2 v2.27.6 h1:VdRdS98FNhKZ8/Az8B7MTyGQmpIr36O1EHybx/LaZ4g=
+github.com/urfave/cli/v2 v2.27.6/go.mod h1:3Sevf16NykTbInEnD0yKkjDAeZDS0A6bzhBH5hrMvTQ=
 github.com/vektra/mockery/v2 v2.52.2 h1:8QfPKUIrq8P3Cs7G79Iu4Byd5wdhGCE0quIS27x7rQo=
 github.com/vektra/mockery/v2 v2.52.2/go.mod h1:zGDY/f6bip0Yh13GQ5j7xa43fuEoYBa4ICHEaihisHw=
+github.com/xrash/smetrics v0.0.0-20240521201337-686a1a2994c1 h1:gEOO8jv9F4OT7lGCjxCBTO/36wtF6j2nSip77qHd4x4=
+github.com/xrash/smetrics v0.0.0-20240521201337-686a1a2994c1/go.mod h1:Ohn+xnUBiLI6FVj/9LpzZWtj1/D6lUovWYBkxHVV3aM=
 github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=

internal/client/clientapp.go

@@ -0,0 +1,131 @@
+package client
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+
+	"git.netflux.io/rob/octoplex/internal/domain"
+	"git.netflux.io/rob/octoplex/internal/event"
+	pb "git.netflux.io/rob/octoplex/internal/generated/grpc"
+	"git.netflux.io/rob/octoplex/internal/protocol"
+	"git.netflux.io/rob/octoplex/internal/terminal"
+	"golang.org/x/sync/errgroup"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+)
+
+// App is the client application.
+type App struct {
+	bus                *event.Bus
+	clipboardAvailable bool
+	buildInfo          domain.BuildInfo
+	screen             *terminal.Screen
+	logger             *slog.Logger
+}
+
+// NewParams contains the parameters for the App.
+type NewParams struct {
+	ClipboardAvailable bool
+	BuildInfo          domain.BuildInfo
+	Screen             *terminal.Screen
+	Logger             *slog.Logger
+}
+
+// New creates a new App instance.
+func New(params NewParams) *App {
+	return &App{
+		bus:                event.NewBus(params.Logger),
+		clipboardAvailable: params.ClipboardAvailable,
+		buildInfo:          params.BuildInfo,
+		screen:             params.Screen,
+		logger:             params.Logger,
+	}
+}
+
+// Run starts the application, and blocks until it is closed.
+//
+// It returns nil if the application was closed by the user, or an error if it
+// closed for any other reason.
+func (a *App) Run(ctx context.Context) error {
+	g, ctx := errgroup.WithContext(ctx)
+
+	conn, err := grpc.NewClient("localhost:50051", grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		return fmt.Errorf("connect to gRPC server: %w", err)
+	}
+	apiClient := pb.NewInternalAPIClient(conn)
+	stream, err := apiClient.Communicate(ctx)
+	if err != nil {
+		return fmt.Errorf("create gRPC stream: %w", err)
+	}
+
+	ui, err := terminal.NewUI(ctx, terminal.Params{
+		EventBus: a.bus,
+		Dispatcher: func(cmd event.Command) {
+			a.logger.Info("Command dispatched", "cmd", cmd.Name())
+			if sendErr := stream.Send(&pb.Envelope{Payload: &pb.Envelope_Command{Command: protocol.CommandToProto(cmd)}}); sendErr != nil {
+				a.logger.Error("Error sending command to gRPC API", "err", sendErr)
+			}
+		},
+		ClipboardAvailable: a.clipboardAvailable,
+		BuildInfo:          a.buildInfo,
+		Screen:             a.screen,
+		Logger:             a.logger.With("component", "ui"),
+	})
+	if err != nil {
+		return fmt.Errorf("start terminal user interface: %w", err)
+	}
+	defer ui.Close()
+
+	g.Go(func() error { return ui.Run(ctx) })
+
+	// After the UI is available, perform a handshake with the server.
+	// Ordering is important here. We want to ensure that the UI is ready to
+	// react to events received from the server. Performing the handshake ensures
+	// the client has received at least one event.
+	if err := a.doHandshake(stream); err != nil {
+		return fmt.Errorf("do handshake: %w", err)
+	}
+
+	g.Go(func() error {
+		for {
+			envelope, recErr := stream.Recv()
+			if recErr != nil {
+				return fmt.Errorf("receive envelope: %w", recErr)
+			}
+
+			pbEvt := envelope.GetEvent()
+			if pbEvt == nil {
+				a.logger.Error("Received envelope without event")
+				continue
+			}
+
+			evt := protocol.EventFromProto(pbEvt)
+			a.logger.Debug("Received event from gRPC stream", "event", evt.EventName(), "payload", evt)
+			a.bus.Send(evt)
+		}
+	})
+
+	if err := g.Wait(); err == terminal.ErrUserClosed {
+		return nil
+	} else {
+		return fmt.Errorf("errgroup.Wait: %w", err)
+	}
+}
+
+func (a *App) doHandshake(stream pb.InternalAPI_CommunicateClient) error {
+	if err := stream.Send(&pb.Envelope{Payload: &pb.Envelope_Command{Command: &pb.Command{CommandType: &pb.Command_StartHandshake{}}}}); err != nil {
+		return fmt.Errorf("send start handshake command: %w", err)
+	}
+
+	env, err := stream.Recv()
+	if err != nil {
+		return fmt.Errorf("receive handshake completed event: %w", err)
+	}
+	if evt := env.GetEvent(); evt == nil || evt.GetHandshakeCompleted() == nil {
+		return fmt.Errorf("expected handshake completed event but got: %T", env)
+	}
+
+	return nil
+}

internal/client/integration_helpers_test.go

@@ -1,9 +1,11 @@
 //go:build integration
 
-package app_test
+package client_test
 
 import (
+	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"log/slog"
@@ -14,39 +16,79 @@ import (
 	"testing"
 	"time"
 
-	"git.netflux.io/rob/octoplex/internal/app"
+	"git.netflux.io/rob/octoplex/internal/client"
 	"git.netflux.io/rob/octoplex/internal/config"
 	"git.netflux.io/rob/octoplex/internal/container"
 	"git.netflux.io/rob/octoplex/internal/domain"
+	"git.netflux.io/rob/octoplex/internal/server"
 	"git.netflux.io/rob/octoplex/internal/terminal"
 	"github.com/gdamore/tcell/v2"
 	"github.com/stretchr/testify/require"
 	"github.com/testcontainers/testcontainers-go"
+	"golang.org/x/sync/errgroup"
 )
 
-func buildAppParams(
-	t *testing.T,
+func buildClientServer(
 	configService *config.Service,
 	dockerClient container.DockerClient,
 	screen tcell.SimulationScreen,
 	screenCaptureC chan<- terminal.ScreenCapture,
 	logger *slog.Logger,
-) app.Params {
-	t.Helper()
-
-	return app.Params{
-		ConfigService: configService,
-		DockerClient:  dockerClient,
+) (*client.App, *server.App) {
+	client := client.New(client.NewParams{
+		BuildInfo: domain.BuildInfo{Version: "0.0.1", GoVersion: "go1.16.3"},
 		Screen: &terminal.Screen{
 			Screen:   screen,
 			Width:    180,
 			Height:   25,
 			CaptureC: screenCaptureC,
 		},
-		ClipboardAvailable: false,
-		BuildInfo:          domain.BuildInfo{Version: "0.0.1", GoVersion: "go1.16.3"},
-		Logger:             logger,
-	}
+		Logger: logger,
+	})
+
+	server := server.New(server.Params{
+		ConfigService: configService,
+		DockerClient:  dockerClient,
+		WaitForClient: true,
+		Logger:        logger,
+	})
+
+	return client, server
+}
+
+type clientServerResult struct {
+	errClient error
+	errServer error
+}
+
+func runClientServer(
+	ctx context.Context,
+	_ *testing.T,
+	clientApp *client.App,
+	serverApp *server.App,
+) <-chan clientServerResult {
+	ch := make(chan clientServerResult, 1)
+
+	g, ctx := errgroup.WithContext(ctx)
+	var clientErr, srvErr error
+
+	g.Go(func() error {
+		srvErr = serverApp.Run(ctx)
+		return errors.New("server closed")
+	})
+
+	g.Go(func() error {
+		clientErr = clientApp.Run(ctx)
+		return errors.New("client closed")
+	})
+
+	go func() {
+		_ = g.Wait()
+
+		ch <- clientServerResult{errClient: clientErr, errServer: srvErr}
+	}()
+
+	return ch
 }
 
 func setupSimulationScreen(t *testing.T) (tcell.SimulationScreen, chan<- terminal.ScreenCapture, func() []string) {

internal/client/integration_test.go

@@ -1,6 +1,6 @@
 //go:build integration
 
-package app_test
+package client_test
 
 import (
 	"cmp"
@@ -15,12 +15,10 @@ import (
 	"testing"
 	"time"
 
-	"git.netflux.io/rob/octoplex/internal/app"
 	"git.netflux.io/rob/octoplex/internal/config"
 	"git.netflux.io/rob/octoplex/internal/container"
 	"git.netflux.io/rob/octoplex/internal/container/mocks"
 	"git.netflux.io/rob/octoplex/internal/domain"
-	"git.netflux.io/rob/octoplex/internal/terminal"
 	"git.netflux.io/rob/octoplex/internal/testhelpers"
 	"github.com/docker/docker/api/types/network"
 	dockerclient "github.com/docker/docker/client"
@@ -126,26 +124,8 @@ func testIntegration(t *testing.T, mediaServerConfig config.MediaServerSource) {
 		Destinations: []config.Destination{{Name: "Local server 1", URL: destURL1}},
 	})
 
-	done := make(chan struct{})
-	go func() {
-		defer func() {
-			done <- struct{}{}
-		}()
-
-		require.Equal(t, context.Canceled, app.New(app.Params{
-			ConfigService: configService,
-			DockerClient:  dockerClient,
-			Screen: &terminal.Screen{
-				Screen:   screen,
-				Width:    160,
-				Height:   25,
-				CaptureC: screenCaptureC,
-			},
-			ClipboardAvailable: false,
-			BuildInfo:          domain.BuildInfo{Version: "0.0.1", GoVersion: "go1.16.3"},
-			Logger:             logger,
-		}).Run(ctx))
-	}()
+	client, server := buildClientServer(configService, dockerClient, screen, screenCaptureC, logger)
+	ch := runClientServer(ctx, t, client, server)
 
 	require.EventuallyWithT(
 		t,
@@ -286,13 +266,12 @@ func testIntegration(t *testing.T, mediaServerConfig config.MediaServerSource) {
 
 	printScreen(t, getContents, "After stopping the first destination")
 
-	// TODO:
-	// - Source error
-	// - Additional features (copy URL, etc.)
-
 	cancel()
 
-	<-done
+	result := <-ch
+	// May be a gRPC error, not context.Canceled:
+	assert.ErrorContains(t, result.errClient, "context canceled")
+	assert.ErrorIs(t, result.errServer, context.Canceled)
 }
 
 func TestIntegrationCustomHost(t *testing.T) {
@@ -313,14 +292,8 @@ func TestIntegrationCustomHost(t *testing.T) {
 	})
 	screen, screenCaptureC, getContents := setupSimulationScreen(t)
 
-	done := make(chan struct{})
-	go func() {
-		defer func() {
-			done <- struct{}{}
-		}()
-
-		require.Equal(t, context.Canceled, app.New(buildAppParams(t, configService, dockerClient, screen, screenCaptureC, logger)).Run(ctx))
-	}()
+	client, server := buildClientServer(configService, dockerClient, screen, screenCaptureC, logger)
+	ch := runClientServer(ctx, t, client, server)
 
 	time.Sleep(time.Second)
 	sendKey(t, screen, tcell.KeyF1, ' ')
@@ -360,7 +333,10 @@ func TestIntegrationCustomHost(t *testing.T) {
 
 	cancel()
 
-	<-done
+	result := <-ch
+	// May be a gRPC error, not context.Canceled:
+	assert.ErrorContains(t, result.errClient, "context canceled")
+	assert.ErrorIs(t, result.errServer, context.Canceled)
 }
 
 func TestIntegrationCustomTLSCerts(t *testing.T) {
@@ -384,14 +360,8 @@ func TestIntegrationCustomTLSCerts(t *testing.T) {
 	})
 	screen, screenCaptureC, getContents := setupSimulationScreen(t)
 
-	done := make(chan struct{})
-	go func() {
-		defer func() {
-			done <- struct{}{}
-		}()
-
-		require.Equal(t, context.Canceled, app.New(buildAppParams(t, configService, dockerClient, screen, screenCaptureC, logger)).Run(ctx))
-	}()
+	client, server := buildClientServer(configService, dockerClient, screen, screenCaptureC, logger)
+	ch := runClientServer(ctx, t, client, server)
 
 	require.EventuallyWithT(
 		t,
@@ -426,7 +396,9 @@ func TestIntegrationCustomTLSCerts(t *testing.T) {
 
 	cancel()
 
-	<-done
+	result := <-ch
+	assert.ErrorContains(t, result.errClient, "context canceled")
+	assert.ErrorIs(t, result.errServer, context.Canceled)
 }
 
 func TestIntegrationRestartDestination(t *testing.T) {
@@ -465,14 +437,8 @@ func TestIntegrationRestartDestination(t *testing.T) {
 		}},
 	})
 
-	done := make(chan struct{})
-	go func() {
-		defer func() {
-			done <- struct{}{}
-		}()
-
-		require.Equal(t, context.Canceled, app.New(buildAppParams(t, configService, dockerClient, screen, screenCaptureC, logger)).Run(ctx))
-	}()
+	client, server := buildClientServer(configService, dockerClient, screen, screenCaptureC, logger)
+	ch := runClientServer(ctx, t, client, server)
 
 	require.EventuallyWithT(
 		t,
@@ -584,7 +550,9 @@ func TestIntegrationRestartDestination(t *testing.T) {
 
 	cancel()
 
-	<-done
+	result := <-ch
+	assert.ErrorContains(t, result.errClient, "context canceled")
+	assert.ErrorIs(t, result.errServer, context.Canceled)
 }
 
 func TestIntegrationStartDestinationFailed(t *testing.T) {
@@ -602,14 +570,8 @@ func TestIntegrationStartDestinationFailed(t *testing.T) {
 		Destinations: []config.Destination{{Name: "Example server", URL: "rtmp://rtmp.example.com/live"}},
 	})
 
-	done := make(chan struct{})
-	go func() {
-		defer func() {
-			done <- struct{}{}
-		}()
-
-		require.Equal(t, context.Canceled, app.New(buildAppParams(t, configService, dockerClient, screen, screenCaptureC, logger)).Run(ctx))
-	}()
+	client, server := buildClientServer(configService, dockerClient, screen, screenCaptureC, logger)
+	ch := runClientServer(ctx, t, client, server)
 
 	require.EventuallyWithT(
 		t,
@@ -658,7 +620,9 @@ func TestIntegrationStartDestinationFailed(t *testing.T) {
 
 	cancel()
 
-	<-done
+	result := <-ch
+	assert.ErrorContains(t, result.errClient, "context canceled")
+	assert.ErrorIs(t, result.errServer, context.Canceled)
 }
 
 func TestIntegrationDestinationValidations(t *testing.T) {
@@ -675,14 +639,8 @@ func TestIntegrationDestinationValidations(t *testing.T) {
 		Sources: config.Sources{MediaServer: config.MediaServerSource{StreamKey: "live", RTMP: config.RTMPSource{Enabled: true}}},
 	})
 
-	done := make(chan struct{})
-	go func() {
-		defer func() {
-			done <- struct{}{}
-		}()
-
-		require.Equal(t, context.Canceled, app.New(buildAppParams(t, configService, dockerClient, screen, screenCaptureC, logger)).Run(ctx))
-	}()
+	client, server := buildClientServer(configService, dockerClient, screen, screenCaptureC, logger)
+	ch := runClientServer(ctx, t, client, server)
 
 	require.EventuallyWithT(
 		t,
@@ -786,7 +744,9 @@ func TestIntegrationDestinationValidations(t *testing.T) {
 	printScreen(t, getContents, "After entering a duplicate destination URL")
 	cancel()
 
-	<-done
+	result := <-ch
+	assert.ErrorContains(t, result.errClient, "context canceled")
+	assert.ErrorIs(t, result.errServer, context.Canceled)
 }
 
 func TestIntegrationStartupCheck(t *testing.T) {
@@ -817,14 +777,8 @@ func TestIntegrationStartupCheck(t *testing.T) {
 	configService := setupConfigService(t, config.Config{Sources: config.Sources{MediaServer: config.MediaServerSource{RTMP: config.RTMPSource{Enabled: true}}}})
 	screen, screenCaptureC, getContents := setupSimulationScreen(t)
 
-	done := make(chan struct{})
-	go func() {
-		defer func() {
-			done <- struct{}{}
-		}()
-
-		require.Equal(t, context.Canceled, app.New(buildAppParams(t, configService, dockerClient, screen, screenCaptureC, logger)).Run(ctx))
-	}()
+	client, server := buildClientServer(configService, dockerClient, screen, screenCaptureC, logger)
+	ch := runClientServer(ctx, t, client, server)
 
 	require.EventuallyWithT(
 		t,
@@ -868,7 +822,9 @@ func TestIntegrationStartupCheck(t *testing.T) {
 	printScreen(t, getContents, "After starting the mediaserver")
 	cancel()
 
-	<-done
+	result := <-ch
+	assert.ErrorContains(t, result.errClient, "context canceled")
+	assert.ErrorIs(t, result.errServer, context.Canceled)
 }
 
 func TestIntegrationMediaServerError(t *testing.T) {
@@ -886,18 +842,8 @@ func TestIntegrationMediaServerError(t *testing.T) {
 	configService := setupConfigService(t, config.Config{Sources: config.Sources{MediaServer: config.MediaServerSource{RTMP: config.RTMPSource{Enabled: true}}}})
 	screen, screenCaptureC, getContents := setupSimulationScreen(t)
 
-	done := make(chan struct{})
-	go func() {
-		defer func() {
-			done <- struct{}{}
-		}()
-
-		require.EqualError(
-			t,
-			app.New(buildAppParams(t, configService, dockerClient, screen, screenCaptureC, logger)).Run(ctx),
-			"media server exited",
-		)
-	}()
+	client, server := buildClientServer(configService, dockerClient, screen, screenCaptureC, logger)
+	ch := runClientServer(ctx, t, client, server)
 
 	require.EventuallyWithT(
 		t,
@@ -911,10 +857,12 @@ func TestIntegrationMediaServerError(t *testing.T) {
 	)
 	printScreen(t, getContents, "Ater displaying the media server error modal")
 
-	// Quit the app, this should cause the done channel to receive.
+	// Quit the app:
 	sendKey(t, screen, tcell.KeyEnter, ' ')
 
-	<-done
+	result := <-ch
+	assert.ErrorContains(t, result.errClient, "context canceled")
+	assert.ErrorContains(t, result.errServer, "media server exited")
 }
 
 func TestIntegrationDockerClientError(t *testing.T) {
@@ -929,18 +877,8 @@ func TestIntegrationDockerClientError(t *testing.T) {
 	configService := setupConfigService(t, config.Config{Sources: config.Sources{MediaServer: config.MediaServerSource{RTMP: config.RTMPSource{Enabled: true}}}})
 	screen, screenCaptureC, getContents := setupSimulationScreen(t)
 
-	done := make(chan struct{})
-	go func() {
-		defer func() {
-			done <- struct{}{}
-		}()
-
-		require.EqualError(
-			t,
-			app.New(buildAppParams(t, configService, &dockerClient, screen, screenCaptureC, logger)).Run(ctx),
-			"create container client: network create: boom",
-		)
-	}()
+	client, server := buildClientServer(configService, &dockerClient, screen, screenCaptureC, logger)
+	ch := runClientServer(ctx, t, client, server)
 
 	require.EventuallyWithT(
 		t,
@@ -954,10 +892,12 @@ func TestIntegrationDockerClientError(t *testing.T) {
 	)
 	printScreen(t, getContents, "Ater displaying the fatal error modal")
 
-	// Quit the app, this should cause the done channel to receive.
+	// Quit the app:
 	sendKey(t, screen, tcell.KeyEnter, ' ')
 
-	<-done
+	result := <-ch
+	assert.ErrorContains(t, result.errClient, "context canceled")
+	assert.EqualError(t, result.errServer, "create container client: network create: boom")
 }
 
 func TestIntegrationDockerConnectionError(t *testing.T) {
@@ -971,16 +911,8 @@ func TestIntegrationDockerConnectionError(t *testing.T) {
 	configService := setupConfigService(t, config.Config{Sources: config.Sources{MediaServer: config.MediaServerSource{RTMP: config.RTMPSource{Enabled: true}}}})
 	screen, screenCaptureC, getContents := setupSimulationScreen(t)
 
-	done := make(chan struct{})
-	go func() {
-		defer func() {
-			done <- struct{}{}
-		}()
-
-		err := app.New(buildAppParams(t, configService, dockerClient, screen, screenCaptureC, logger)).Run(ctx)
-		require.ErrorContains(t, err, "dial tcp: lookup docker.example.com")
-		require.ErrorContains(t, err, "no such host")
-	}()
+	client, server := buildClientServer(configService, dockerClient, screen, screenCaptureC, logger)
+	ch := runClientServer(ctx, t, client, server)
 
 	require.EventuallyWithT(
 		t,
@@ -994,10 +926,13 @@ func TestIntegrationDockerConnectionError(t *testing.T) {
 	)
 	printScreen(t, getContents, "Ater displaying the fatal error modal")
 
-	// Quit the app, this should cause the done channel to receive.
+	// Quit the app:
 	sendKey(t, screen, tcell.KeyEnter, ' ')
 
-	<-done
+	result := <-ch
+	assert.ErrorContains(t, result.errClient, "context canceled")
+	assert.ErrorContains(t, result.errServer, "dial tcp: lookup docker.example.com")
+	assert.ErrorContains(t, result.errServer, "no such host")
 }
 
 func TestIntegrationCopyURLs(t *testing.T) {
@@ -1067,14 +1002,8 @@ func TestIntegrationCopyURLs(t *testing.T) {
 			configService := setupConfigService(t, config.Config{Sources: config.Sources{MediaServer: tc.mediaServerConfig}})
 			screen, screenCaptureC, getContents := setupSimulationScreen(t)
 
-			done := make(chan struct{})
-			go func() {
-				defer func() {
-					done <- struct{}{}
-				}()
-
-				require.Equal(t, context.Canceled, app.New(buildAppParams(t, configService, dockerClient, screen, screenCaptureC, logger)).Run(ctx))
-			}()
+			client, server := buildClientServer(configService, dockerClient, screen, screenCaptureC, logger)
+			ch := runClientServer(ctx, t, client, server)
 
 			time.Sleep(3 * time.Second)
 			printScreen(t, getContents, "Ater loading the app")
@@ -1095,7 +1024,9 @@ func TestIntegrationCopyURLs(t *testing.T) {
 
 			cancel()
 
-			<-done
+			result := <-ch
+			assert.ErrorContains(t, result.errClient, "context canceled")
+			assert.ErrorIs(t, result.errServer, context.Canceled)
 		})
 	}
 }

internal/event/bus.go

@@ -2,6 +2,7 @@ package event
 
 import (
 	"log/slog"
+	"slices"
 	"sync"
 )
 
@@ -31,6 +32,21 @@ func (b *Bus) Register() <-chan Event {
 	return ch
 }
 
+// Deregister deregisters a consumer for all events.
+func (b *Bus) Deregister(ch <-chan Event) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	b.consumers = slices.DeleteFunc(b.consumers, func(other chan Event) bool {
+		if ch == other {
+			close(other)
+			return true
+		}
+
+		return false
+	})
+}
+
 // Send sends an event to all registered consumers.
 func (b *Bus) Send(evt Event) {
 	// The mutex is needed to ensure the backing array of b.consumers cannot be
@@ -43,7 +59,7 @@ func (b *Bus) Send(evt Event) {
 		select {
 		case ch <- evt:
 		default:
-			b.logger.Warn("Event dropped", "name", evt.name())
+			b.logger.Warn("Event dropped", "name", evt.EventName())
 		}
 	}
 }

internal/event/bus_test.go

@@ -6,6 +6,7 @@ import (
 	"git.netflux.io/rob/octoplex/internal/event"
 	"git.netflux.io/rob/octoplex/internal/testhelpers"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestBus(t *testing.T) {
@@ -25,5 +26,19 @@ func TestBus(t *testing.T) {
 	}()
 
 	assert.Equal(t, evt, (<-ch1).(event.MediaServerStartedEvent))
+	assert.Equal(t, evt, (<-ch1).(event.MediaServerStartedEvent))
+
 	assert.Equal(t, evt, (<-ch2).(event.MediaServerStartedEvent))
+	assert.Equal(t, evt, (<-ch2).(event.MediaServerStartedEvent))
+
+	bus.Deregister(ch1)
+
+	_, ok := <-ch1
+	assert.False(t, ok)
+
+	select {
+	case <-ch2:
+		require.Fail(t, "ch2 should be blocking")
+	default:
+	}
 }

internal/event/command.go

@@ -50,6 +50,8 @@ func (c CommandCloseOtherInstance) Name() string {
 }
 
 // CommandQuit quits the app.
+//
+// TODO: consider how this should look in a client/server architecture.
 type CommandQuit struct{}
 
 // Name implements the Command interface.

internal/event/events.go

@@ -19,7 +19,7 @@ const (
 
 // Event represents something which happened in the appllication.
 type Event interface {
-	name() Name
+	EventName() Name
 }
 
 // AppStateChangedEvent is emitted when the application state changes.
@@ -27,7 +27,7 @@ type AppStateChangedEvent struct {
 	State domain.AppState
 }
 
-func (e AppStateChangedEvent) name() Name {
+func (e AppStateChangedEvent) EventName() Name {
 	return EventNameAppStateChanged
 }
 
@@ -36,16 +36,17 @@ type DestinationAddedEvent struct {
 	URL string
 }
 
-func (e DestinationAddedEvent) name() Name {
+func (e DestinationAddedEvent) EventName() Name {
 	return EventNameDestinationAdded
 }
 
 // AddDestinationFailedEvent is emitted when a destination fails to be added.
 type AddDestinationFailedEvent struct {
+	URL string
 	Err error
 }
 
-func (e AddDestinationFailedEvent) name() Name {
+func (e AddDestinationFailedEvent) EventName() Name {
 	return EventNameAddDestinationFailed
 }
 
@@ -55,14 +56,17 @@ type DestinationStreamExitedEvent struct {
 	Err  error
 }
 
-func (e DestinationStreamExitedEvent) name() Name {
+func (e DestinationStreamExitedEvent) EventName() Name {
 	return EventNameDestinationStreamExited
 }
 
 // StartDestinationFailedEvent is emitted when a destination fails to start.
-type StartDestinationFailedEvent struct{}
+type StartDestinationFailedEvent struct {
+	URL     string
+	Message string
+}
 
-func (e StartDestinationFailedEvent) name() Name {
+func (e StartDestinationFailedEvent) EventName() Name {
 	return EventNameStartDestinationFailed
 }
 
@@ -72,17 +76,18 @@ type DestinationRemovedEvent struct {
 	URL string
 }
 
-func (e DestinationRemovedEvent) name() Name {
+func (e DestinationRemovedEvent) EventName() Name {
 	return EventNameDestinationRemoved
 }
 
 // RemoveDestinationFailedEvent is emitted when a destination fails to be
 // removed.
 type RemoveDestinationFailedEvent struct {
+	URL string
 	Err error
 }
 
-func (e RemoveDestinationFailedEvent) name() Name {
+func (e RemoveDestinationFailedEvent) EventName() Name {
 	return EventNameRemoveDestinationFailed
 }
 
@@ -95,11 +100,11 @@ type FatalErrorOccurredEvent struct {
 // OtherInstanceDetectedEvent is emitted when the app launches and detects another instance.
 type OtherInstanceDetectedEvent struct{}
 
-func (e OtherInstanceDetectedEvent) name() Name {
+func (e OtherInstanceDetectedEvent) EventName() Name {
 	return EventNameOtherInstanceDetected
 }
 
-func (e FatalErrorOccurredEvent) name() Name {
+func (e FatalErrorOccurredEvent) EventName() Name {
 	return "fatal_error_occurred"
 }
 
@@ -109,6 +114,6 @@ type MediaServerStartedEvent struct {
 	RTMPSURL string
 }
 
-func (e MediaServerStartedEvent) name() Name {
+func (e MediaServerStartedEvent) EventName() Name {
 	return "media_server_started"
 }

internal/generated/grpc/api_grpc.pb.go

@@ -0,0 +1,137 @@
+// Code generated by protoc-gen-go-grpc. DO NOT EDIT.
+// versions:
+// - protoc-gen-go-grpc v1.2.0
+// - protoc             v6.30.1
+// source: api.proto
+
+package grpc
+
+import (
+	context "context"
+	grpc "google.golang.org/grpc"
+	codes "google.golang.org/grpc/codes"
+	status "google.golang.org/grpc/status"
+)
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the grpc package it is being compiled against.
+// Requires gRPC-Go v1.32.0 or later.
+const _ = grpc.SupportPackageIsVersion7
+
+// InternalAPIClient is the client API for InternalAPI service.
+//
+// For semantics around ctx use and closing/ending streaming RPCs, please refer to https://pkg.go.dev/google.golang.org/grpc/?tab=doc#ClientConn.NewStream.
+type InternalAPIClient interface {
+	Communicate(ctx context.Context, opts ...grpc.CallOption) (InternalAPI_CommunicateClient, error)
+}
+
+type internalAPIClient struct {
+	cc grpc.ClientConnInterface
+}
+
+func NewInternalAPIClient(cc grpc.ClientConnInterface) InternalAPIClient {
+	return &internalAPIClient{cc}
+}
+
+func (c *internalAPIClient) Communicate(ctx context.Context, opts ...grpc.CallOption) (InternalAPI_CommunicateClient, error) {
+	stream, err := c.cc.NewStream(ctx, &InternalAPI_ServiceDesc.Streams[0], "/api.InternalAPI/Communicate", opts...)
+	if err != nil {
+		return nil, err
+	}
+	x := &internalAPICommunicateClient{stream}
+	return x, nil
+}
+
+type InternalAPI_CommunicateClient interface {
+	Send(*Envelope) error
+	Recv() (*Envelope, error)
+	grpc.ClientStream
+}
+
+type internalAPICommunicateClient struct {
+	grpc.ClientStream
+}
+
+func (x *internalAPICommunicateClient) Send(m *Envelope) error {
+	return x.ClientStream.SendMsg(m)
+}
+
+func (x *internalAPICommunicateClient) Recv() (*Envelope, error) {
+	m := new(Envelope)
+	if err := x.ClientStream.RecvMsg(m); err != nil {
+		return nil, err
+	}
+	return m, nil
+}
+
+// InternalAPIServer is the server API for InternalAPI service.
+// All implementations must embed UnimplementedInternalAPIServer
+// for forward compatibility
+type InternalAPIServer interface {
+	Communicate(InternalAPI_CommunicateServer) error
+	mustEmbedUnimplementedInternalAPIServer()
+}
+
+// UnimplementedInternalAPIServer must be embedded to have forward compatible implementations.
+type UnimplementedInternalAPIServer struct {
+}
+
+func (UnimplementedInternalAPIServer) Communicate(InternalAPI_CommunicateServer) error {
+	return status.Errorf(codes.Unimplemented, "method Communicate not implemented")
+}
+func (UnimplementedInternalAPIServer) mustEmbedUnimplementedInternalAPIServer() {}
+
+// UnsafeInternalAPIServer may be embedded to opt out of forward compatibility for this service.
+// Use of this interface is not recommended, as added methods to InternalAPIServer will
+// result in compilation errors.
+type UnsafeInternalAPIServer interface {
+	mustEmbedUnimplementedInternalAPIServer()
+}
+
+func RegisterInternalAPIServer(s grpc.ServiceRegistrar, srv InternalAPIServer) {
+	s.RegisterService(&InternalAPI_ServiceDesc, srv)
+}
+
+func _InternalAPI_Communicate_Handler(srv interface{}, stream grpc.ServerStream) error {
+	return srv.(InternalAPIServer).Communicate(&internalAPICommunicateServer{stream})
+}
+
+type InternalAPI_CommunicateServer interface {
+	Send(*Envelope) error
+	Recv() (*Envelope, error)
+	grpc.ServerStream
+}
+
+type internalAPICommunicateServer struct {
+	grpc.ServerStream
+}
+
+func (x *internalAPICommunicateServer) Send(m *Envelope) error {
+	return x.ServerStream.SendMsg(m)
+}
+
+func (x *internalAPICommunicateServer) Recv() (*Envelope, error) {
+	m := new(Envelope)
+	if err := x.ServerStream.RecvMsg(m); err != nil {
+		return nil, err
+	}
+	return m, nil
+}
+
+// InternalAPI_ServiceDesc is the grpc.ServiceDesc for InternalAPI service.
+// It's only intended for direct use with grpc.RegisterService,
+// and not to be introspected or modified (even as a copy)
+var InternalAPI_ServiceDesc = grpc.ServiceDesc{
+	ServiceName: "api.InternalAPI",
+	HandlerType: (*InternalAPIServer)(nil),
+	Methods:     []grpc.MethodDesc{},
+	Streams: []grpc.StreamDesc{
+		{
+			StreamName:    "Communicate",
+			Handler:       _InternalAPI_Communicate_Handler,
+			ServerStreams: true,
+			ClientStreams: true,
+		},
+	},
+	Metadata: "api.proto",
+}

internal/protocol/command.go

@@ -0,0 +1,110 @@
+package protocol
+
+import (
+	"git.netflux.io/rob/octoplex/internal/event"
+	pb "git.netflux.io/rob/octoplex/internal/generated/grpc"
+)
+
+// CommandToProto converts a command to a protobuf message.
+func CommandToProto(command event.Command) *pb.Command {
+	switch evt := command.(type) {
+	case event.CommandAddDestination:
+		return buildAddDestinationCommand(evt)
+	case event.CommandRemoveDestination:
+		return buildRemoveDestinationCommand(evt)
+	case event.CommandStartDestination:
+		return buildStartDestinationCommand(evt)
+	case event.CommandStopDestination:
+		return buildStopDestinationCommand(evt)
+	case event.CommandCloseOtherInstance:
+		return buildCloseOtherInstanceCommand(evt)
+	case event.CommandQuit:
+		return buildQuitCommand(evt)
+	default:
+		panic("unknown command type")
+	}
+}
+
+func buildAddDestinationCommand(cmd event.CommandAddDestination) *pb.Command {
+	return &pb.Command{CommandType: &pb.Command_AddDestination{AddDestination: &pb.AddDestinationCommand{Name: cmd.DestinationName, Url: cmd.URL}}}
+}
+
+func buildRemoveDestinationCommand(cmd event.CommandRemoveDestination) *pb.Command {
+	return &pb.Command{CommandType: &pb.Command_RemoveDestination{RemoveDestination: &pb.RemoveDestinationCommand{Url: cmd.URL}}}
+}
+
+func buildStartDestinationCommand(cmd event.CommandStartDestination) *pb.Command {
+	return &pb.Command{CommandType: &pb.Command_StartDestination{StartDestination: &pb.StartDestinationCommand{Url: cmd.URL}}}
+}
+
+func buildStopDestinationCommand(cmd event.CommandStopDestination) *pb.Command {
+	return &pb.Command{CommandType: &pb.Command_StopDestination{StopDestination: &pb.StopDestinationCommand{Url: cmd.URL}}}
+}
+
+func buildCloseOtherInstanceCommand(event.CommandCloseOtherInstance) *pb.Command {
+	return &pb.Command{CommandType: &pb.Command_CloseOtherInstances{CloseOtherInstances: &pb.CloseOtherInstancesCommand{}}}
+}
+
+func buildQuitCommand(event.CommandQuit) *pb.Command {
+	return &pb.Command{CommandType: &pb.Command_Quit{Quit: &pb.QuitCommand{}}}
+}
+
+// CommandFromProto converts a protobuf message to a command.
+func CommandFromProto(pbCmd *pb.Command) event.Command {
+	if pbCmd == nil || pbCmd.CommandType == nil {
+		panic("invalid or nil pb.Command")
+	}
+
+	switch cmd := pbCmd.CommandType.(type) {
+	case *pb.Command_AddDestination:
+		return parseAddDestinationCommand(cmd.AddDestination)
+	case *pb.Command_RemoveDestination:
+		return parseRemoveDestinationCommand(cmd.RemoveDestination)
+	case *pb.Command_StartDestination:
+		return parseStartDestinationCommand(cmd.StartDestination)
+	case *pb.Command_StopDestination:
+		return parseStopDestinationCommand(cmd.StopDestination)
+	case *pb.Command_CloseOtherInstances:
+		return parseCloseOtherInstanceCommand(cmd.CloseOtherInstances)
+	case *pb.Command_Quit:
+		return parseQuitCommand(cmd.Quit)
+	default:
+		panic("unknown pb.Command type")
+	}
+}
+
+func parseAddDestinationCommand(cmd *pb.AddDestinationCommand) event.Command {
+	if cmd == nil {
+		panic("nil AddDestinationCommand")
+	}
+	return event.CommandAddDestination{DestinationName: cmd.Name, URL: cmd.Url}
+}
+
+func parseRemoveDestinationCommand(cmd *pb.RemoveDestinationCommand) event.Command {
+	if cmd == nil {
+		panic("nil RemoveDestinationCommand")
+	}
+	return event.CommandRemoveDestination{URL: cmd.Url}
+}
+
+func parseStartDestinationCommand(cmd *pb.StartDestinationCommand) event.Command {
+	if cmd == nil {
+		panic("nil StartDestinationCommand")
+	}
+	return event.CommandStartDestination{URL: cmd.Url}
+}
+
+func parseStopDestinationCommand(cmd *pb.StopDestinationCommand) event.Command {
+	if cmd == nil {
+		panic("nil StopDestinationCommand")
+	}
+	return event.CommandStopDestination{URL: cmd.Url}
+}
+
+func parseCloseOtherInstanceCommand(_ *pb.CloseOtherInstancesCommand) event.Command {
+	return event.CommandCloseOtherInstance{}
+}
+
+func parseQuitCommand(_ *pb.QuitCommand) event.Command {
+	return event.CommandQuit{}
+}

internal/protocol/domain.go

@@ -0,0 +1,121 @@
+package protocol
+
+import (
+	"errors"
+
+	"git.netflux.io/rob/octoplex/internal/domain"
+	pb "git.netflux.io/rob/octoplex/internal/generated/grpc"
+	"google.golang.org/protobuf/types/known/timestamppb"
+)
+
+func containerToProto(c domain.Container) *pb.Container {
+	var errString string
+	if c.Err != nil {
+		errString = c.Err.Error()
+	}
+
+	var exitCode *int32
+	if c.ExitCode != nil {
+		code := int32(*c.ExitCode)
+		exitCode = &code
+	}
+
+	return &pb.Container{
+		Id:               c.ID,
+		Status:           c.Status,
+		HealthState:      c.HealthState,
+		CpuPercent:       c.CPUPercent,
+		MemoryUsageBytes: c.MemoryUsageBytes,
+		RxRate:           int32(c.RxRate),
+		TxRate:           int32(c.TxRate),
+		RxSince:          timestamppb.New(c.RxSince),
+		ImageName:        c.ImageName,
+		PullStatus:       c.PullStatus,
+		PullProgress:     c.PullProgress,
+		PullPercent:      int32(c.PullPercent),
+		RestartCount:     int32(c.RestartCount),
+		ExitCode:         exitCode,
+		Err:              errString,
+	}
+}
+func protoToContainer(pbCont *pb.Container) domain.Container {
+	if pbCont == nil {
+		return domain.Container{}
+	}
+
+	var exitCode *int
+	if pbCont.ExitCode != nil {
+		val := int(*pbCont.ExitCode)
+		exitCode = &val
+	}
+
+	var err error
+	if pbCont.Err != "" {
+		err = errors.New(pbCont.Err)
+	}
+
+	return domain.Container{
+		ID:               pbCont.Id,
+		Status:           pbCont.Status,
+		HealthState:      pbCont.HealthState,
+		CPUPercent:       pbCont.CpuPercent,
+		MemoryUsageBytes: pbCont.MemoryUsageBytes,
+		RxRate:           int(pbCont.RxRate),
+		TxRate:           int(pbCont.TxRate),
+		RxSince:          pbCont.RxSince.AsTime(),
+		ImageName:        pbCont.ImageName,
+		PullStatus:       pbCont.PullStatus,
+		PullProgress:     pbCont.PullProgress,
+		PullPercent:      int(pbCont.PullPercent),
+		RestartCount:     int(pbCont.RestartCount),
+		ExitCode:         exitCode,
+		Err:              err,
+	}
+}
+
+func destinationsToProto(inDests []domain.Destination) []*pb.Destination {
+	destinations := make([]*pb.Destination, 0, len(inDests))
+	for _, d := range inDests {
+		destinations = append(destinations, destinationToProto(d))
+	}
+	return destinations
+}
+
+func destinationToProto(d domain.Destination) *pb.Destination {
+	return &pb.Destination{
+		Container: containerToProto(d.Container),
+		Status:    destinationStatusToProto(d.Status),
+		Name:      d.Name,
+		Url:       d.URL,
+	}
+}
+
+func protoToDestinations(pbDests []*pb.Destination) []domain.Destination {
+	if pbDests == nil {
+		return nil
+	}
+
+	dests := make([]domain.Destination, 0, len(pbDests))
+	for _, pbDest := range pbDests {
+		if pbDest == nil {
+			continue
+		}
+		dests = append(dests, domain.Destination{
+			Container: protoToContainer(pbDest.Container),
+			Status:    domain.DestinationStatus(pbDest.Status), // direct cast, same underlying int
+			Name:      pbDest.Name,
+			URL:       pbDest.Url,
+		})
+	}
+	return dests
+}
+func destinationStatusToProto(s domain.DestinationStatus) pb.Destination_Status {
+	switch s {
+	case domain.DestinationStatusStarting:
+		return pb.Destination_STATUS_STARTING
+	case domain.DestinationStatusLive:
+		return pb.Destination_STATUS_LIVE
+	default:
+		return pb.Destination_STATUS_OFF_AIR
+	}
+}

internal/protocol/event.go

@@ -0,0 +1,252 @@
+package protocol
+
+import (
+	"errors"
+
+	"git.netflux.io/rob/octoplex/internal/domain"
+	"git.netflux.io/rob/octoplex/internal/event"
+	pb "git.netflux.io/rob/octoplex/internal/generated/grpc"
+	"google.golang.org/protobuf/types/known/timestamppb"
+)
+
+// EventToProto converts an event to a protobuf message.
+func EventToProto(ev event.Event) *pb.Event {
+	switch evt := ev.(type) {
+	case event.AppStateChangedEvent:
+		return buildAppStateChangeEvent(evt)
+	case event.DestinationAddedEvent:
+		return buildDestinationAddedEvent(evt)
+	case event.AddDestinationFailedEvent:
+		return buildAddDestinationFailedEvent(evt)
+	case event.DestinationStreamExitedEvent:
+		return buildDestinationStreamExitedEvent(evt)
+	case event.StartDestinationFailedEvent:
+		return buildStartDestinationFailedEvent(evt)
+	case event.DestinationRemovedEvent:
+		return buildDestinationRemovedEvent(evt)
+	case event.RemoveDestinationFailedEvent:
+		return buildRemoveDestinationFailedEvent(evt)
+	case event.FatalErrorOccurredEvent:
+		return buildFatalErrorOccurredEvent(evt)
+	case event.OtherInstanceDetectedEvent:
+		return buildOtherInstanceDetectedEvent(evt)
+	case event.MediaServerStartedEvent:
+		return buildMediaServerStartedEvent(evt)
+	default:
+		panic("unknown event type")
+	}
+}
+
+func buildAppStateChangeEvent(evt event.AppStateChangedEvent) *pb.Event {
+	return &pb.Event{
+		EventType: &pb.Event_AppStateChanged{
+			AppStateChanged: &pb.AppStateChangedEvent{
+				AppState: &pb.AppState{
+					Source: &pb.Source{
+						Container:     containerToProto(evt.State.Source.Container),
+						Live:          evt.State.Source.Live,
+						LiveChangedAt: timestamppb.New(evt.State.Source.LiveChangedAt),
+						Tracks:        evt.State.Source.Tracks,
+						ExitReason:    evt.State.Source.ExitReason,
+					},
+					Destinations: destinationsToProto(evt.State.Destinations),
+					BuildInfo: &pb.BuildInfo{
+						GoVersion: evt.State.BuildInfo.GoVersion,
+						Version:   evt.State.BuildInfo.Version,
+						Commit:    evt.State.BuildInfo.Commit,
+						Date:      evt.State.BuildInfo.Date,
+					},
+				},
+			},
+		},
+	}
+}
+
+func buildDestinationAddedEvent(evt event.DestinationAddedEvent) *pb.Event {
+	return &pb.Event{
+		EventType: &pb.Event_DestinationAdded{
+			DestinationAdded: &pb.DestinationAddedEvent{Url: evt.URL},
+		},
+	}
+}
+
+func buildAddDestinationFailedEvent(evt event.AddDestinationFailedEvent) *pb.Event {
+	return &pb.Event{
+		EventType: &pb.Event_AddDestinationFailed{
+			AddDestinationFailed: &pb.AddDestinationFailedEvent{Url: evt.URL, Error: evt.Err.Error()},
+		},
+	}
+}
+
+func buildDestinationStreamExitedEvent(evt event.DestinationStreamExitedEvent) *pb.Event {
+	return &pb.Event{
+		EventType: &pb.Event_DestinationStreamExited{
+			DestinationStreamExited: &pb.DestinationStreamExitedEvent{Name: evt.Name, Error: evt.Err.Error()},
+		},
+	}
+}
+
+func buildStartDestinationFailedEvent(evt event.StartDestinationFailedEvent) *pb.Event {
+	return &pb.Event{
+		EventType: &pb.Event_StartDestinationFailed{
+			StartDestinationFailed: &pb.StartDestinationFailedEvent{Url: evt.URL, Message: evt.Message},
+		},
+	}
+}
+
+func buildDestinationRemovedEvent(evt event.DestinationRemovedEvent) *pb.Event {
+	return &pb.Event{
+		EventType: &pb.Event_DestinationRemoved{
+			DestinationRemoved: &pb.DestinationRemovedEvent{Url: evt.URL},
+		},
+	}
+}
+
+func buildRemoveDestinationFailedEvent(evt event.RemoveDestinationFailedEvent) *pb.Event {
+	return &pb.Event{
+		EventType: &pb.Event_RemoveDestinationFailed{
+			RemoveDestinationFailed: &pb.RemoveDestinationFailedEvent{Url: evt.URL, Error: evt.Err.Error()},
+		},
+	}
+}
+
+func buildFatalErrorOccurredEvent(evt event.FatalErrorOccurredEvent) *pb.Event {
+	return &pb.Event{
+		EventType: &pb.Event_FatalError{
+			FatalError: &pb.FatalErrorEvent{Message: evt.Message},
+		},
+	}
+}
+
+func buildOtherInstanceDetectedEvent(_ event.OtherInstanceDetectedEvent) *pb.Event {
+	return &pb.Event{
+		EventType: &pb.Event_OtherInstanceDetected{
+			OtherInstanceDetected: &pb.OtherInstanceDetectedEvent{},
+		},
+	}
+}
+
+func buildMediaServerStartedEvent(evt event.MediaServerStartedEvent) *pb.Event {
+	return &pb.Event{
+		EventType: &pb.Event_MediaServerStarted{
+			MediaServerStarted: &pb.MediaServerStartedEvent{RtmpUrl: evt.RTMPURL, RtmpsUrl: evt.RTMPSURL},
+		},
+	}
+}
+
+// EventFromProto converts a protobuf message to an event.
+func EventFromProto(pbEv *pb.Event) event.Event {
+	if pbEv == nil || pbEv.EventType == nil {
+		panic("invalid or nil pb.Event")
+	}
+
+	switch evt := pbEv.EventType.(type) {
+	case *pb.Event_AppStateChanged:
+		return parseAppStateChangedEvent(evt.AppStateChanged)
+	case *pb.Event_DestinationAdded:
+		return parseDestinationAddedEvent(evt.DestinationAdded)
+	case *pb.Event_AddDestinationFailed:
+		return parseAddDestinationFailedEvent(evt.AddDestinationFailed)
+	case *pb.Event_DestinationStreamExited:
+		return parseDestinationStreamExitedEvent(evt.DestinationStreamExited)
+	case *pb.Event_StartDestinationFailed:
+		return parseStartDestinationFailedEvent(evt.StartDestinationFailed)
+	case *pb.Event_DestinationRemoved:
+		return parseDestinationRemovedEvent(evt.DestinationRemoved)
+	case *pb.Event_RemoveDestinationFailed:
+		return parseRemoveDestinationFailedEvent(evt.RemoveDestinationFailed)
+	case *pb.Event_FatalError:
+		return parseFatalErrorOccurredEvent(evt.FatalError)
+	case *pb.Event_OtherInstanceDetected:
+		return parseOtherInstanceDetectedEvent(evt.OtherInstanceDetected)
+	case *pb.Event_MediaServerStarted:
+		return parseMediaServerStartedEvent(evt.MediaServerStarted)
+	default:
+		panic("unknown pb.Event type")
+	}
+}
+
+func parseAppStateChangedEvent(evt *pb.AppStateChangedEvent) event.Event {
+	if evt == nil || evt.AppState == nil || evt.AppState.Source == nil {
+		panic("invalid AppStateChangedEvent")
+	}
+
+	return event.AppStateChangedEvent{
+		State: domain.AppState{
+			Source: domain.Source{
+				Container:     protoToContainer(evt.AppState.Source.Container),
+				Live:          evt.AppState.Source.Live,
+				LiveChangedAt: evt.AppState.Source.LiveChangedAt.AsTime(),
+				Tracks:        evt.AppState.Source.Tracks,
+				ExitReason:    evt.AppState.Source.ExitReason,
+			},
+			Destinations: protoToDestinations(evt.AppState.Destinations),
+			BuildInfo: domain.BuildInfo{
+				GoVersion: evt.AppState.BuildInfo.GoVersion,
+				Version:   evt.AppState.BuildInfo.Version,
+				Commit:    evt.AppState.BuildInfo.Commit,
+				Date:      evt.AppState.BuildInfo.Date,
+			},
+		},
+	}
+}
+
+func parseDestinationAddedEvent(evt *pb.DestinationAddedEvent) event.Event {
+	if evt == nil {
+		panic("nil DestinationAddedEvent")
+	}
+	return event.DestinationAddedEvent{URL: evt.Url}
+}
+
+func parseAddDestinationFailedEvent(evt *pb.AddDestinationFailedEvent) event.Event {
+	if evt == nil {
+		panic("nil AddDestinationFailedEvent")
+	}
+	return event.AddDestinationFailedEvent{URL: evt.Url, Err: errors.New(evt.Error)}
+}
+
+func parseDestinationStreamExitedEvent(evt *pb.DestinationStreamExitedEvent) event.Event {
+	if evt == nil {
+		panic("nil DestinationStreamExitedEvent")
+	}
+	return event.DestinationStreamExitedEvent{Name: evt.Name, Err: errors.New(evt.Error)}
+}
+
+func parseStartDestinationFailedEvent(evt *pb.StartDestinationFailedEvent) event.Event {
+	if evt == nil {
+		panic("nil StartDestinationFailedEvent")
+	}
+	return event.StartDestinationFailedEvent{URL: evt.Url, Message: evt.Message}
+}
+
+func parseDestinationRemovedEvent(evt *pb.DestinationRemovedEvent) event.Event {
+	if evt == nil {
+		panic("nil DestinationRemovedEvent")
+	}
+	return event.DestinationRemovedEvent{URL: evt.Url}
+}
+
+func parseRemoveDestinationFailedEvent(evt *pb.RemoveDestinationFailedEvent) event.Event {
+	if evt == nil {
+		panic("nil RemoveDestinationFailedEvent")
+	}
+	return event.RemoveDestinationFailedEvent{URL: evt.Url, Err: errors.New(evt.Error)}
+}
+
+func parseFatalErrorOccurredEvent(evt *pb.FatalErrorEvent) event.Event {
+	if evt == nil {
+		panic("nil FatalErrorEvent")
+	}
+	return event.FatalErrorOccurredEvent{Message: evt.Message}
+}
+
+func parseOtherInstanceDetectedEvent(_ *pb.OtherInstanceDetectedEvent) event.Event {
+	return event.OtherInstanceDetectedEvent{}
+}
+
+func parseMediaServerStartedEvent(evt *pb.MediaServerStartedEvent) event.Event {
+	if evt == nil {
+		panic("nil MediaServerStartedEvent")
+	}
+	return event.MediaServerStartedEvent{RTMPURL: evt.RtmpUrl, RTMPSURL: evt.RtmpsUrl}
+}

internal/server/grpc.go

@@ -0,0 +1,151 @@
+package server
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"log/slog"
+	"sync"
+	"time"
+
+	"git.netflux.io/rob/octoplex/internal/event"
+	pb "git.netflux.io/rob/octoplex/internal/generated/grpc"
+	"git.netflux.io/rob/octoplex/internal/protocol"
+	"golang.org/x/sync/errgroup"
+)
+
+// APIListenerCountDeltaFunc is a function that is called when the number of
+// API clients increments or decrements.
+type APIClientCountDeltaFunc func(delta int)
+
+// Server is the gRPC server that handles incoming commands and outgoing
+// events.
+type Server struct {
+	pb.UnimplementedInternalAPIServer
+
+	dispatcher func(event.Command)
+	bus        *event.Bus
+	logger     *slog.Logger
+
+	mu          sync.Mutex
+	clientCount int
+	clientC     chan struct{}
+}
+
+// newServer creates a new gRPC server.
+func newServer(
+	dispatcher func(event.Command),
+	bus *event.Bus,
+	logger *slog.Logger,
+) *Server {
+	return &Server{
+		dispatcher: dispatcher,
+		bus:        bus,
+		clientC:    make(chan struct{}, 1),
+		logger:     logger.With("component", "server"),
+	}
+}
+
+func (s *Server) Communicate(stream pb.InternalAPI_CommunicateServer) error {
+	g, ctx := errgroup.WithContext(stream.Context())
+
+	// perform handshake:
+	startHandshakeCmd, err := stream.Recv()
+	if err != nil {
+		return fmt.Errorf("receive start handshake command: %w", err)
+	}
+	if startHandshakeCmd.GetCommand() == nil || startHandshakeCmd.GetCommand().GetStartHandshake() == nil {
+		return fmt.Errorf("expected start handshake command but got: %T", startHandshakeCmd)
+	}
+	if err := stream.Send(&pb.Envelope{Payload: &pb.Envelope_Event{Event: &pb.Event{EventType: &pb.Event_HandshakeCompleted{}}}}); err != nil {
+		return fmt.Errorf("send handshake completed event: %w", err)
+	}
+
+	// Notify that a client has connected and completed the handshake.
+	select {
+	case s.clientC <- struct{}{}:
+	default:
+	}
+
+	g.Go(func() error {
+		eventsC := s.bus.Register()
+		defer s.bus.Deregister(eventsC)
+
+		for {
+			select {
+			case evt := <-eventsC:
+				if err := stream.Send(&pb.Envelope{Payload: &pb.Envelope_Event{Event: protocol.EventToProto(evt)}}); err != nil {
+					return fmt.Errorf("send event: %w", err)
+				}
+			case <-ctx.Done():
+				return ctx.Err()
+			}
+		}
+	})
+
+	g.Go(func() error {
+		s.mu.Lock()
+		s.clientCount++
+		s.mu.Unlock()
+
+		defer func() {
+			s.mu.Lock()
+			s.clientCount--
+			s.mu.Unlock()
+		}()
+
+		for {
+			in, err := stream.Recv()
+			if err == io.EOF {
+				s.logger.Info("Client disconnected")
+				return err
+			}
+
+			if err != nil {
+				return fmt.Errorf("receive message: %w", err)
+			}
+
+			switch pbCmd := in.Payload.(type) {
+			case *pb.Envelope_Command:
+				cmd := protocol.CommandFromProto(pbCmd.Command)
+				s.logger.Info("Received command", "command", cmd.Name())
+				s.dispatcher(cmd)
+			default:
+				return fmt.Errorf("expected command but got: %T", pbCmd)
+			}
+		}
+	})
+
+	if err := g.Wait(); err != nil && !errors.Is(err, io.EOF) && !errors.Is(err, context.Canceled) {
+		s.logger.Error("Client stream closed with error", "err", err)
+		return fmt.Errorf("errgroup.Wait: %w", err)
+	}
+
+	s.logger.Info("Client stream closed")
+
+	return nil
+}
+
+// GetClientCount returns the number of connected clients.
+func (s *Server) GetClientCount() int {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	return s.clientCount
+}
+
+const waitForClientTimeout = 10 * time.Second
+
+// WaitForClient waits for _any_ client to connect and complete the handshake.
+// It times out if no client has connected after 10 seconds.
+func (s *Server) WaitForClient(ctx context.Context) error {
+	select {
+	case <-s.clientC:
+		return nil
+	case <-time.After(waitForClientTimeout):
+		return errors.New("timeout")
+	case <-ctx.Done():
+		return ctx.Err()
+	}
+}

internal/server/serverapp.go

@@ -1,11 +1,13 @@
-package app
+package server
 
 import (
 	"cmp"
 	"context"
 	"errors"
 	"fmt"
+	"log"
 	"log/slog"
+	"net"
 	"slices"
 	"time"
 
@@ -13,38 +15,32 @@ import (
 	"git.netflux.io/rob/octoplex/internal/container"
 	"git.netflux.io/rob/octoplex/internal/domain"
 	"git.netflux.io/rob/octoplex/internal/event"
+	pb "git.netflux.io/rob/octoplex/internal/generated/grpc"
 	"git.netflux.io/rob/octoplex/internal/mediaserver"
 	"git.netflux.io/rob/octoplex/internal/replicator"
-	"git.netflux.io/rob/octoplex/internal/terminal"
 	"github.com/docker/docker/client"
+	"google.golang.org/grpc"
 )
 
 // App is an instance of the app.
 type App struct {
-	cfg                config.Config
-	configService      *config.Service
-	eventBus           *event.Bus
-	dispatchC          chan event.Command
-	dockerClient       container.DockerClient
-	screen             *terminal.Screen // Screen may be nil.
-	headless           bool
-	clipboardAvailable bool
-	configFilePath     string
-	buildInfo          domain.BuildInfo
-	logger             *slog.Logger
+	cfg           config.Config
+	configService *config.Service
+	eventBus      *event.Bus
+	dispatchC     chan event.Command
+	dockerClient  container.DockerClient
+	waitForClient bool
+	logger        *slog.Logger
 }
 
 // Params holds the parameters for running the application.
 type Params struct {
-	ConfigService      *config.Service
-	DockerClient       container.DockerClient
-	ChanSize           int
-	Screen             *terminal.Screen // Screen may be nil.
-	Headless           bool
-	ClipboardAvailable bool
-	ConfigFilePath     string
-	BuildInfo          domain.BuildInfo
-	Logger             *slog.Logger
+	ConfigService  *config.Service
+	DockerClient   container.DockerClient
+	ChanSize       int
+	ConfigFilePath string
+	WaitForClient  bool
+	Logger         *slog.Logger
 }
 
 // defaultChanSize is the default size of the dispatch channel.
@@ -53,17 +49,13 @@ const defaultChanSize = 64
 // New creates a new application instance.
 func New(params Params) *App {
 	return &App{
-		cfg:                params.ConfigService.Current(),
-		configService:      params.ConfigService,
-		eventBus:           event.NewBus(params.Logger.With("component", "event_bus")),
-		dispatchC:          make(chan event.Command, cmp.Or(params.ChanSize, defaultChanSize)),
-		dockerClient:       params.DockerClient,
-		screen:             params.Screen,
-		headless:           params.Headless,
-		clipboardAvailable: params.ClipboardAvailable,
-		configFilePath:     params.ConfigFilePath,
-		buildInfo:          params.BuildInfo,
-		logger:             params.Logger,
+		cfg:           params.ConfigService.Current(),
+		configService: params.ConfigService,
+		eventBus:      event.NewBus(params.Logger.With("component", "event_bus")),
+		dispatchC:     make(chan event.Command, cmp.Or(params.ChanSize, defaultChanSize)),
+		dockerClient:  params.DockerClient,
+		waitForClient: params.WaitForClient,
+		logger:        params.Logger,
 	}
 }
 
@@ -78,20 +70,26 @@ func (a *App) Run(ctx context.Context) error {
 		return errors.New("config: either sources.mediaServer.rtmp.enabled or sources.mediaServer.rtmps.enabled must be set")
 	}
 
-	if !a.headless {
-		ui, err := terminal.StartUI(ctx, terminal.StartParams{
-			EventBus:           a.eventBus,
-			Dispatcher:         func(cmd event.Command) { a.dispatchC <- cmd },
-			Screen:             a.screen,
-			ClipboardAvailable: a.clipboardAvailable,
-			ConfigFilePath:     a.configFilePath,
-			BuildInfo:          a.buildInfo,
-			Logger:             a.logger.With("component", "ui"),
-		})
-		if err != nil {
-			return fmt.Errorf("start terminal user interface: %w", err)
+	const grpcAddr = ":50051"
+	lis, err := net.Listen("tcp", grpcAddr)
+	if err != nil {
+		log.Fatalf("failed to listen: %v", err)
+	}
+	defer lis.Close()
+
+	grpcServer := grpc.NewServer()
+	grpcDone := make(chan error, 1)
+	internalAPI := newServer(a.DispatchAsync, a.eventBus, a.logger)
+	pb.RegisterInternalAPIServer(grpcServer, internalAPI)
+	go func() {
+		a.logger.Info("gRPC server started", "addr", grpcAddr)
+		grpcDone <- grpcServer.Serve(lis)
+	}()
+
+	if a.waitForClient {
+		if err = internalAPI.WaitForClient(ctx); err != nil {
+			return fmt.Errorf("wait for client: %w", err)
 		}
-		defer ui.Close()
 	}
 
 	// emptyUI is a dummy function that sets the UI state to an empty state, and
@@ -107,12 +105,13 @@ func (a *App) Run(ctx context.Context) error {
 		a.eventBus.Send(event.AppStateChangedEvent{State: domain.AppState{}})
 	}
 
-	// doFatalError publishes a fatal error to the event bus, waiting for the
-	// user to acknowledge it if not in headless mode.
+	// doFatalError publishes a fatal error to the event bus. It will block until
+	// the user acknowledges it if there is 1 or more clients connected to the
+	// internal API.
 	doFatalError := func(msg string) {
 		a.eventBus.Send(event.FatalErrorOccurredEvent{Message: msg})
 
-		if a.headless {
+		if internalAPI.GetClientCount() == 0 {
 			return
 		}
 
@@ -177,21 +176,20 @@ func (a *App) Run(ctx context.Context) error {
 	defer uiUpdateT.Stop()
 
 	startMediaServerC := make(chan struct{}, 1)
-	if a.headless { // disable startup check in headless mode for now
+	if ok, startupErr := doStartupCheck(ctx, containerClient, a.eventBus); startupErr != nil {
+		doFatalError(startupErr.Error())
+		return startupErr
+	} else if ok {
 		startMediaServerC <- struct{}{}
-	} else {
-		if ok, startupErr := doStartupCheck(ctx, containerClient, a.eventBus); startupErr != nil {
-			doFatalError(startupErr.Error())
-			return startupErr
-		} else if ok {
-			startMediaServerC <- struct{}{}
-		}
 	}
 
 	for {
 		select {
 		case <-ctx.Done():
 			return ctx.Err()
+		case grpcErr := <-grpcDone:
+			a.logger.Error("gRPC server exited", "err", grpcErr)
+			return grpcErr
 		case <-startMediaServerC:
 			if err = srv.Start(ctx); err != nil {
 				return fmt.Errorf("start mediaserver: %w", err)
@@ -245,6 +243,11 @@ func (a *App) Dispatch(cmd event.Command) event.Event {
 	return <-ch
 }
 
+// DispatchAsync dispatches a command to be executed synchronously.
+func (a *App) DispatchAsync(cmd event.Command) {
+	a.dispatchC <- cmd
+}
+
 // errExit is an error that indicates the app should exit.
 var errExit = errors.New("exit")
 
@@ -272,6 +275,10 @@ func (a *App) handleCommand(
 		}
 	}()
 
+	if c, ok := cmd.(syncCommand); ok {
+		cmd = c.Command
+	}
+
 	switch c := cmd.(type) {
 	case event.CommandAddDestination:
 		newCfg := a.cfg
@@ -281,10 +288,11 @@ func (a *App) handleCommand(
 		})
 		if err := a.configService.SetConfig(newCfg); err != nil {
 			a.logger.Error("Add destination failed", "err", err)
-			return event.AddDestinationFailedEvent{Err: err}, nil
+			return event.AddDestinationFailedEvent{URL: c.URL, Err: err}, nil
 		}
 		a.cfg = newCfg
 		a.handleConfigUpdate(state)
+		a.logger.Info("Destination added", "url", c.URL)
 		a.eventBus.Send(event.DestinationAddedEvent{URL: c.URL})
 	case event.CommandRemoveDestination:
 		repl.StopDestination(c.URL) // no-op if not live
@@ -294,7 +302,7 @@ func (a *App) handleCommand(
 		})
 		if err := a.configService.SetConfig(newCfg); err != nil {
 			a.logger.Error("Remove destination failed", "err", err)
-			a.eventBus.Send(event.RemoveDestinationFailedEvent{Err: err})
+			a.eventBus.Send(event.RemoveDestinationFailedEvent{URL: c.URL, Err: err})
 			break
 		}
 		a.cfg = newCfg
@@ -302,7 +310,7 @@ func (a *App) handleCommand(
 		a.eventBus.Send(event.DestinationRemovedEvent{URL: c.URL}) //nolint:gosimple
 	case event.CommandStartDestination:
 		if !state.Source.Live {
-			a.eventBus.Send(event.StartDestinationFailedEvent{})
+			a.eventBus.Send(event.StartDestinationFailedEvent{URL: c.URL, Message: "source not live"})
 			break
 		}
 

internal/server/serverapp_test.go

@@ -1,4 +1,4 @@
-package app
+package server
 
 import (
 	"testing"

internal/terminal/terminal.go

@@ -3,6 +3,7 @@ package terminal
 import (
 	"cmp"
 	"context"
+	"errors"
 	"fmt"
 	"log/slog"
 	"maps"
@@ -44,9 +45,9 @@ type UI struct {
 	eventBus           *event.Bus
 	dispatch           func(event.Command)
 	clipboardAvailable bool
-	configFilePath     string
 	rtmpURL, rtmpsURL  string
 	buildInfo          domain.BuildInfo
+	appExitC           chan error
 	logger             *slog.Logger
 
 	// tview state
@@ -92,20 +93,20 @@ type ScreenCapture struct {
 	Width, Height int
 }
 
-// StartParams contains the parameters for starting a new terminal user
+// Params contains the parameters for starting a new terminal user
 // interface.
-type StartParams struct {
+type Params struct {
 	EventBus           *event.Bus
 	Dispatcher         func(event.Command)
 	Logger             *slog.Logger
 	ClipboardAvailable bool
-	ConfigFilePath     string
 	BuildInfo          domain.BuildInfo
 	Screen             *Screen // Screen may be nil.
 }
 
-// StartUI starts the terminal user interface.
-func StartUI(ctx context.Context, params StartParams) (*UI, error) {
+// NewUI creates the user interface. Call [Run] on the *UI instance to block
+// until it is completed.
+func NewUI(ctx context.Context, params Params) (*UI, error) {
 	app := tview.NewApplication()
 
 	var screen tcell.Screen
@@ -211,7 +212,7 @@ func StartUI(ctx context.Context, params StartParams) (*UI, error) {
 		eventBus:           params.EventBus,
 		dispatch:           params.Dispatcher,
 		clipboardAvailable: params.ClipboardAvailable,
-		configFilePath:     params.ConfigFilePath,
+		appExitC:           make(chan error, 1),
 		buildInfo:          params.BuildInfo,
 		logger:             params.Logger,
 		app:                app,
@@ -237,8 +238,6 @@ func StartUI(ctx context.Context, params StartParams) (*UI, error) {
 	app.SetInputCapture(ui.inputCaptureHandler)
 	app.SetAfterDrawFunc(ui.afterDrawHandler)
 
-	go ui.run(ctx)
-
 	return ui, nil
 }
 
@@ -262,32 +261,32 @@ func (ui *UI) renderAboutView() {
 		ui.aboutView.AddItem(rtmpsURLView, 1, 0, false)
 	}
 
-	ui.aboutView.AddItem(tview.NewTextView().SetDynamicColors(true).SetText("[grey]c[-]        Copy config file path"), 1, 0, false)
 	ui.aboutView.AddItem(tview.NewTextView().SetDynamicColors(true).SetText("[grey]?[-]        About"), 1, 0, false)
 }
 
-func (ui *UI) run(ctx context.Context) {
-	defer func() {
-		// Ensure the application is stopped when the UI is closed.
-		ui.dispatch(event.CommandQuit{})
-	}()
+var ErrUserClosed = errors.New("user closed UI")
 
+// Run runs the user interface. It always returns a non-nil error, which will
+// be [ErrUserClosed] if the user voluntarily closed the UI.
+func (ui *UI) Run(ctx context.Context) error {
 	eventC := ui.eventBus.Register()
+	defer ui.eventBus.Deregister(eventC)
 
-	uiDone := make(chan struct{})
 	go func() {
-		defer func() {
-			uiDone <- struct{}{}
-		}()
-
-		if err := ui.app.Run(); err != nil {
-			ui.logger.Error("tui application error", "err", err)
+		err := ui.app.Run()
+		if err != nil {
+			ui.logger.Error("Error in UI run loop, exiting", "err", err)
 		}
+		ui.appExitC <- err
 	}()
 
 	for {
 		select {
-		case evt := <-eventC:
+		case evt, ok := <-eventC:
+			if !ok {
+				// should never happen
+				return errors.New("event channel closed")
+			}
 			ui.app.QueueUpdateDraw(func() {
 				switch evt := evt.(type) {
 				case event.AppStateChangedEvent:
@@ -313,12 +312,11 @@ func (ui *UI) run(ctx context.Context) {
 				default:
 					ui.logger.Warn("unhandled event", "event", evt)
 				}
-
 			})
 		case <-ctx.Done():
-			return
-		case <-uiDone:
-			return
+			return ctx.Err()
+		case err := <-ui.appExitC:
+			return cmp.Or(err, ErrUserClosed)
 		}
 	}
 }
@@ -358,8 +356,6 @@ func (ui *UI) inputCaptureHandler(event *tcell.EventKey) *tcell.EventKey {
 			return nil
 		case ' ':
 			ui.toggleDestination()
-		case 'c', 'C':
-			ui.copyConfigFilePathToClipboard(ui.clipboardAvailable, ui.configFilePath)
 		case '?':
 			ui.showAbout()
 		case 'k': // tview vim bindings
@@ -825,6 +821,11 @@ func (ui *UI) Close() {
 	ui.app.Stop()
 }
 
+// Wait waits for the terminal user interface to finish.
+func (ui *UI) Wait() {
+	<-ui.appExitC
+}
+
 func (ui *UI) addDestination() {
 	const (
 		inputLen        = 60
@@ -1006,28 +1007,6 @@ func (ui *UI) copySourceURLToClipboard(url string) {
 	)
 }
 
-func (ui *UI) copyConfigFilePathToClipboard(clipboardAvailable bool, configFilePath string) {
-	var text string
-	if clipboardAvailable {
-		if configFilePath != "" {
-			clipboard.Write(clipboard.FmtText, []byte(configFilePath))
-			text = "Configuration file path copied to clipboard:\n\n" + configFilePath
-		} else {
-			text = "Configuration file path not set"
-		}
-	} else {
-		text = "Copy to clipboard not available"
-	}
-
-	ui.showModal(
-		pageNameModalClipboard,
-		text,
-		[]string{"Ok"},
-		false,
-		nil,
-	)
-}
-
 func (ui *UI) confirmQuit() {
 	ui.showModal(
 		pageNameModalQuit,
@@ -1036,7 +1015,7 @@ func (ui *UI) confirmQuit() {
 		false,
 		func(buttonIndex int, _ string) {
 			if buttonIndex == 0 {
-				ui.dispatch(event.CommandQuit{})
+				ui.app.Stop()
 			}
 		},
 	)

main.go

@@ -4,21 +4,23 @@ import (
 	"cmp"
 	"context"
 	"errors"
-	"flag"
 	"fmt"
 	"io"
 	"log/slog"
 	"os"
-	"os/exec"
 	"os/signal"
+	"runtime"
 	"runtime/debug"
 	"syscall"
 
-	"git.netflux.io/rob/octoplex/internal/app"
+	"git.netflux.io/rob/octoplex/internal/client"
 	"git.netflux.io/rob/octoplex/internal/config"
 	"git.netflux.io/rob/octoplex/internal/domain"
+	"git.netflux.io/rob/octoplex/internal/server"
 	dockerclient "github.com/docker/docker/client"
+	"github.com/urfave/cli/v2"
 	"golang.design/x/clipboard"
+	"golang.org/x/sync/errgroup"
 )
 
 var (
@@ -30,23 +32,108 @@ var (
 	date string
 )
 
-var errShutdown = errors.New("shutdown")
+// errInterrupt is an error type that indicates an interrupt signal was
+// received.
+type errInterrupt struct{}
 
-func main() {
-	var exitStatus int
-
-	if err := run(); errors.Is(err, errShutdown) {
-		exitStatus = 130
-	} else if err != nil {
-		exitStatus = 1
-		_, _ = os.Stderr.WriteString("Error: " + err.Error() + "\n")
-	}
-
-	os.Exit(exitStatus)
+// Error implements the error interface.
+func (e errInterrupt) Error() string {
+	return "interrupt signal received"
 }
 
-func run() error {
-	ctx, cancel := context.WithCancelCause(context.Background())
+// ExitCode implements the ExitCoder interface.
+func (e errInterrupt) ExitCode() int {
+	return 130
+}
+
+func main() {
+	app := &cli.App{
+		Name:  "Octoplex",
+		Usage: "Octoplex is a live video restreamer for Docker.",
+		Commands: []*cli.Command{
+			{
+				Name:  "client",
+				Usage: "Run the client",
+				Action: func(c *cli.Context) error {
+					return runClient(c.Context, c)
+				},
+			},
+			{
+				Name:  "server",
+				Usage: "Run the server",
+				Action: func(c *cli.Context) error {
+					return runServer(c.Context, c, serverConfig{
+						stderrAvailable: true,
+						handleSigInt:    true,
+						waitForClient:   false,
+					})
+				},
+			},
+			{
+				Name:  "run",
+				Usage: "Run server and client together (testing)",
+				Action: func(c *cli.Context) error {
+					return runClientAndServer(c)
+				},
+			},
+		},
+	}
+
+	if err := app.Run(os.Args); err != nil {
+		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+		os.Exit(1)
+	}
+}
+
+func runClient(ctx context.Context, _ *cli.Context) error {
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	// TODO: logger from config
+	fptr, err := os.OpenFile("octoplex.log", os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
+	if err != nil {
+		return fmt.Errorf("open log file: %w", err)
+	}
+	logger := slog.New(slog.NewTextHandler(fptr, nil))
+	logger.Info("Starting client", "version", cmp.Or(version, "devel"), "commit", cmp.Or(commit, "unknown"), "date", cmp.Or(date, "unknown"), "go_version", runtime.Version())
+
+	var clipboardAvailable bool
+	if err = clipboard.Init(); err != nil {
+		logger.Warn("Clipboard not available", "err", err)
+	} else {
+		clipboardAvailable = true
+	}
+
+	buildInfo, ok := debug.ReadBuildInfo()
+	if !ok {
+		return fmt.Errorf("read build info: %w", err)
+	}
+
+	app := client.New(client.NewParams{
+		ClipboardAvailable: clipboardAvailable,
+		BuildInfo: domain.BuildInfo{
+			GoVersion: buildInfo.GoVersion,
+			Version:   version,
+			Commit:    commit,
+			Date:      date,
+		},
+		Logger: logger,
+	})
+	if err := app.Run(ctx); err != nil {
+		return fmt.Errorf("run app: %w", err)
+	}
+
+	return nil
+}
+
+type serverConfig struct {
+	stderrAvailable bool
+	handleSigInt    bool
+	waitForClient   bool
+}
+
+func runServer(ctx context.Context, _ *cli.Context, serverCfg serverConfig) error {
+	ctx, cancel := context.WithCancelCause(ctx)
 	defer cancel(nil)
 
 	configService, err := config.NewDefaultService()
@@ -54,45 +141,35 @@ func run() error {
 		return fmt.Errorf("build config service: %w", err)
 	}
 
-	help := flag.Bool("h", false, "Show help")
-
-	flag.Parse()
-
-	if *help {
-		printUsage()
-		return nil
-	}
-
-	if narg := flag.NArg(); narg > 1 {
-		printUsage()
-		return fmt.Errorf("too many arguments")
-	} else if narg == 1 {
-		switch flag.Arg(0) {
-		case "edit-config":
-			return editConfigFile(configService)
-		case "print-config":
-			return printConfigPath(configService.Path())
-		case "version":
-			return printVersion()
-		case "help":
-			printUsage()
-			return nil
-		}
-	}
-
 	cfg, err := configService.ReadOrCreateConfig()
 	if err != nil {
 		return fmt.Errorf("read or create config: %w", err)
 	}
 
-	headless := os.Getenv("OCTO_HEADLESS") != ""
-	logger, err := buildLogger(cfg.LogFile, headless)
-	if err != nil {
-		return fmt.Errorf("build logger: %w", err)
+	// TODO: improve logger API
+	// Currently it's a bit complicated because we can only use stdout - the
+	// preferred destination - if the client is not running. Otherwise we
+	// fallback to the legacy configuration but this should be bought more
+	// in-line with the client/server split.
+	var w io.Writer
+	if serverCfg.stderrAvailable {
+		w = os.Stdout
+	} else if !cfg.LogFile.Enabled {
+		w = io.Discard
+	} else {
+		w, err = os.OpenFile(cfg.LogFile.GetPath(), os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
+		if err != nil {
+			return fmt.Errorf("error opening log file: %w", err)
+		}
 	}
 
-	if headless {
-		// When running in headless mode tview doesn't handle SIGINT for us.
+	var handlerOpts slog.HandlerOptions
+	if os.Getenv("OCTO_DEBUG") != "" {
+		handlerOpts.Level = slog.LevelDebug
+	}
+	logger := slog.New(slog.NewTextHandler(w, &handlerOpts))
+
+	if serverCfg.handleSigInt {
 		ch := make(chan os.Signal, 1)
 		signal.Notify(ch, syscall.SIGINT, syscall.SIGTERM)
 
@@ -100,17 +177,10 @@ func run() error {
 			<-ch
 			logger.Info("Received interrupt signal, exiting")
 			signal.Stop(ch)
-			cancel(errShutdown)
+			cancel(errInterrupt{})
 		}()
 	}
 
-	var clipboardAvailable bool
-	if err = clipboard.Init(); err != nil {
-		logger.Warn("Clipboard not available", "err", err)
-	} else {
-		clipboardAvailable = true
-	}
-
 	dockerClient, err := dockerclient.NewClientWithOpts(
 		dockerclient.FromEnv,
 		dockerclient.WithAPIVersionNegotiation(),
@@ -119,102 +189,64 @@ func run() error {
 		return fmt.Errorf("new docker client: %w", err)
 	}
 
-	buildInfo, ok := debug.ReadBuildInfo()
-	if !ok {
-		return fmt.Errorf("read build info: %w", err)
-	}
-
-	app := app.New(app.Params{
-		ConfigService:      configService,
-		DockerClient:       dockerClient,
-		Headless:           headless,
-		ClipboardAvailable: clipboardAvailable,
-		ConfigFilePath:     configService.Path(),
-		BuildInfo: domain.BuildInfo{
-			GoVersion: buildInfo.GoVersion,
-			Version:   version,
-			Commit:    commit,
-			Date:      date,
-		},
-		Logger: logger,
+	app := server.New(server.Params{
+		ConfigService:  configService,
+		DockerClient:   dockerClient,
+		ConfigFilePath: configService.Path(),
+		WaitForClient:  serverCfg.waitForClient,
+		Logger:         logger,
 	})
 
-	return app.Run(ctx)
-}
+	logger.Info(
+		"Starting server",
+		"version",
+		cmp.Or(version, "devel"),
+		"commit",
+		cmp.Or(commit, "unknown"),
+		"date",
+		cmp.Or(date, "unknown"),
+		"go_version",
+		runtime.Version(),
+	)
 
-// editConfigFile opens the config file in the user's editor.
-func editConfigFile(configService *config.Service) error {
-	if _, err := configService.ReadOrCreateConfig(); err != nil {
-		return fmt.Errorf("read or create config: %w", err)
-	}
-
-	editor := os.Getenv("EDITOR")
-	if editor == "" {
-		editor = "vi"
-	}
-	binary, err := exec.LookPath(editor)
-	if err != nil {
-		return fmt.Errorf("look path: %w", err)
-	}
-
-	fmt.Fprintf(os.Stderr, "Editing config file: %s\n", configService.Path())
-	fmt.Println(binary)
-
-	if err := syscall.Exec(binary, []string{"--", configService.Path()}, os.Environ()); err != nil {
-		return fmt.Errorf("exec: %w", err)
-	}
-
-	return nil
-}
-
-// printConfigPath prints the path to the config file to stderr.
-func printConfigPath(configPath string) error {
-	fmt.Fprintln(os.Stderr, configPath)
-	return nil
-}
-
-// printVersion prints the version of the application to stderr.
-func printVersion() error {
-	fmt.Fprintf(os.Stderr, "%s version %s\n", domain.AppName, cmp.Or(version, "0.0.0-dev"))
-	return nil
-}
-
-func printUsage() {
-	os.Stderr.WriteString("Usage: octoplex [command]\n\n")
-	os.Stderr.WriteString("Commands:\n\n")
-	os.Stderr.WriteString("  edit-config   Edit the config file\n")
-	os.Stderr.WriteString("  print-config  Print the path to the config file\n")
-	os.Stderr.WriteString("  version       Print the version of the application\n")
-	os.Stderr.WriteString("  help          Print this help message\n")
-	os.Stderr.WriteString("\n")
-	os.Stderr.WriteString("Additionally, Octoplex can be configured with the following environment variables:\n\n")
-	os.Stderr.WriteString("  OCTO_DEBUG    Enables debug logging if set\n")
-	os.Stderr.WriteString("  OCTO_HEADLESS Enables headless mode if set (experimental)\n\n")
-}
-
-// buildLogger builds the logger, which may be a no-op logger.
-func buildLogger(cfg config.LogFile, headless bool) (*slog.Logger, error) {
-	build := func(w io.Writer) *slog.Logger {
-		var handlerOpts slog.HandlerOptions
-		if os.Getenv("OCTO_DEBUG") != "" {
-			handlerOpts.Level = slog.LevelDebug
+	if err := app.Run(ctx); err != nil {
+		if errors.Is(err, context.Canceled) && errors.Is(context.Cause(ctx), errInterrupt{}) {
+			return context.Cause(ctx)
 		}
-		return slog.New(slog.NewTextHandler(w, &handlerOpts))
+		return err
 	}
 
-	// In headless mode, always log to stderr.
-	if headless {
-		return build(os.Stderr), nil
-	}
-
-	if !cfg.Enabled {
-		return slog.New(slog.DiscardHandler), nil
-	}
-
-	fptr, err := os.OpenFile(cfg.GetPath(), os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
-	if err != nil {
-		return nil, fmt.Errorf("error opening log file: %w", err)
-	}
-
-	return build(fptr), nil
+	return nil
+}
+
+func runClientAndServer(c *cli.Context) error {
+	errNoErr := errors.New("no error")
+
+	g, ctx := errgroup.WithContext(c.Context)
+
+	g.Go(func() error {
+		if err := runClient(ctx, c); err != nil {
+			return err
+		}
+
+		return errNoErr
+	})
+
+	g.Go(func() error {
+		if err := runServer(ctx, c, serverConfig{
+			stderrAvailable: false,
+			handleSigInt:    false,
+			waitForClient:   true,
+		}); err != nil {
+			return err
+		}
+
+		return errNoErr
+	})
+
+	if err := g.Wait(); err == errNoErr {
+		return nil
+	} else {
+		return err
+	}
 }

mise/config.toml

@@ -40,3 +40,9 @@ description = "Generate mocks"
 dir = "{{cwd}}"
 run = "go tool mockery"
 alias = "m"
+
+[tasks.generate_proto]
+description = "Generate gRPC files from proto"
+dir = "{{cwd}}"
+run = "protoc -I proto --go_out=paths=source_relative:internal/generated/grpc --go-grpc_out=paths=source_relative:internal/generated/grpc proto/api.proto"
+alias = "p"

proto/api.proto

@@ -0,0 +1,166 @@
+syntax = "proto3";
+
+package api;
+
+import "google/protobuf/timestamp.proto";
+
+option go_package = "git.netflux.io/rob/octoplex/internal/generated/grpc";
+
+service InternalAPI {
+  rpc Communicate(stream Envelope) returns (stream Envelope);
+}
+
+message Envelope {
+  oneof payload {
+    Command command = 1;
+    Event event = 2;
+  }
+}
+
+message Command {
+  oneof command_type {
+    AddDestinationCommand add_destination = 1;
+    RemoveDestinationCommand remove_destination = 2;
+    StartDestinationCommand start_destination = 3;
+    StopDestinationCommand stop_destination = 4;
+    CloseOtherInstancesCommand close_other_instances = 5;
+    QuitCommand quit = 6;
+    StartHandshakeCommand start_handshake = 7;
+  }
+}
+
+message AddDestinationCommand {
+  string name = 1;
+  string url = 2;
+}
+
+message RemoveDestinationCommand {
+  string url= 1;
+}
+
+message StartDestinationCommand {
+  string url = 1;
+}
+
+message StopDestinationCommand {
+  string url = 1;
+}
+
+message CloseOtherInstancesCommand {}
+
+message QuitCommand {}
+
+message StartHandshakeCommand {};
+
+message Event {
+  oneof event_type {
+    AppStateChangedEvent app_state_changed = 1;
+    DestinationStreamExitedEvent destination_stream_exited = 2;
+    DestinationAddedEvent destination_added = 3;
+    AddDestinationFailedEvent add_destination_failed = 4;
+    DestinationRemovedEvent destination_removed = 5;
+    RemoveDestinationFailedEvent remove_destination_failed = 6;
+    StartDestinationFailedEvent start_destination_failed = 7;
+    MediaServerStartedEvent media_server_started = 8;
+    OtherInstanceDetectedEvent other_instance_detected = 9;
+    FatalErrorEvent fatal_error = 10;
+    HandshakeCompletedEvent handshake_completed = 11;
+  }
+}
+
+message Container {
+  string id = 1;
+  string status = 2;
+  string health_state = 3;
+  double cpu_percent = 4;
+  uint64 memory_usage_bytes = 5;
+  int32 rx_rate = 6;
+  int32 tx_rate = 7;
+  google.protobuf.Timestamp rx_since = 8;
+  string image_name = 9;
+  string pull_status = 10; 
+  string pull_progress = 11; 
+  int32 pull_percent = 12;
+  int32 restart_count = 13;
+  optional int32 exit_code = 14;
+  string err = 15;
+}
+
+message Source {
+  Container container = 1;
+  bool live = 2;
+  google.protobuf.Timestamp live_changed_at = 3;
+  repeated string tracks = 4;
+  string exit_reason = 5;
+}
+
+message Destination {
+  enum Status {
+    STATUS_OFF_AIR = 0;
+    STATUS_STARTING = 1;
+    STATUS_LIVE = 2;
+  }
+
+  Container container = 1;
+  Status status = 2;
+  string name = 3;
+  string url = 4;
+}
+
+message BuildInfo {
+  string go_version = 1;
+  string version = 2;
+  string commit = 3;
+  string date = 4;
+}
+
+message AppState {
+  Source source = 1;
+  repeated Destination destinations = 2;
+  BuildInfo build_info = 3;
+}
+
+message AppStateChangedEvent {
+  AppState app_state = 1;
+}
+
+message DestinationStreamExitedEvent {
+  string name = 1;
+  string error = 2;
+}
+
+message DestinationAddedEvent {
+  string url = 1;
+}
+
+message AddDestinationFailedEvent {
+  string url = 1;
+  string error = 2;
+}
+
+message DestinationRemovedEvent {
+  string url = 1;
+}
+
+message RemoveDestinationFailedEvent {
+  string url = 1;
+  string error = 2;
+}
+
+message StartDestinationFailedEvent {
+  string url = 1;
+  string message = 2;
+}
+
+message MediaServerStartedEvent {
+  string rtmp_url = 1;
+  string rtmps_url = 2;
+}
+
+message OtherInstanceDetectedEvent {}
+
+message FatalErrorEvent {
+  string message = 1;
+}
+
+message HandshakeCompletedEvent {}