runner.go

cmd/mxl-pattern/main.go

@@ -19,6 +19,7 @@ import (
 	"github.com/qvest-digital/go-mxl/mxl"
 	"github.com/spf13/pflag"
 
+	"mxl-pattern-generator/internal/app"
 	"mxl-pattern-generator/internal/audio"
 	"mxl-pattern-generator/internal/flowdef"
 	"mxl-pattern-generator/internal/video"
@@ -59,16 +60,6 @@ type parseResult struct {
 	shouldRun bool
 }
 
-type namedRunner struct {
-	name string
-	run  func(context.Context) error
-}
-
-type runnerResult struct {
-	name string
-	err  error
-}
-
 var frameRates = map[string]mxl.Rational{
 	"23.97": {Num: 24000, Den: 1001},
 	"24":    {Num: 24, Den: 1},
@@ -464,48 +455,22 @@ func run(ctx context.Context, args appArgs) (runErr error) {
 		}
 	}()
 
-	runners := []namedRunner{
+	runners := []app.Runner{
 		{
-			name: "video",
+			Name: "video",
-			run: func(ctx context.Context) error {
+			Run: func(ctx context.Context) error {
 				return video.Run(ctx, inst, videoCfg)
 			},
 		},
 	}
 	if audioCfg != nil {
-		runners = append(runners, namedRunner{
+		runners = append(runners, app.Runner{
-			name: "audio",
+			Name: "audio",
-			run: func(ctx context.Context) error {
+			Run: func(ctx context.Context) error {
 				return audio.Run(ctx, inst, *audioCfg)
 			},
 		})
 	}
 
-	return runConcurrent(ctx, runners...)
+	return app.RunConcurrent(ctx, runners...)
-}
-
-func runConcurrent(ctx context.Context, runners ...namedRunner) error {
-	if len(runners) == 0 {
-		return nil
-	}
-
-	ctx, cancel := context.WithCancel(ctx)
-	defer cancel()
-	results := make(chan runnerResult, len(runners))
-	for _, runner := range runners {
-		runner := runner
-		go func() {
-			results <- runnerResult{name: runner.name, err: runner.run(ctx)}
-		}()
-	}
-
-	var resultErr error
-	for range runners {
-		result := <-results
-		if result.err != nil {
-			resultErr = errors.Join(resultErr, fmt.Errorf("%s flow: %w", result.name, result.err))
-			cancel()
-		}
-	}
-	return resultErr
 }

cmd/mxl-pattern/main_test.go

@@ -2,13 +2,10 @@ package main
 
 import (
 	"bytes"
-	"context"
 	"encoding/json"
-	"errors"
 	"os"
 	"strings"
 	"testing"
-	"time"
 
 	"mxl-pattern-generator/internal/audio"
 	"mxl-pattern-generator/internal/flowdef"
@@ -253,67 +250,3 @@ func TestValidateAudioArgsRejectsUnknownLevelForFlowDefinition(t *testing.T) {
 		t.Fatalf("error = %v, want unsupported audio level error", err)
 	}
 }
-
-func TestRunConcurrentCancelsSiblingAndWaitsForCleanup(t *testing.T) {
-	wantErr := errors.New("writer failed")
-	peerStarted := make(chan struct{})
-	peerStopped := make(chan struct{})
-
-	err := runConcurrent(context.Background(),
-		namedRunner{
-			name: "video",
-			run: func(ctx context.Context) error {
-				<-peerStarted
-				return wantErr
-			},
-		},
-		namedRunner{
-			name: "audio",
-			run: func(ctx context.Context) error {
-				close(peerStarted)
-				<-ctx.Done()
-				close(peerStopped)
-				return nil
-			},
-		},
-	)
-
-	if !errors.Is(err, wantErr) {
-		t.Fatalf("error = %v, want wrapped %v", err, wantErr)
-	}
-	if !strings.Contains(err.Error(), "video flow") {
-		t.Fatalf("error = %q, want runner name", err)
-	}
-	select {
-	case <-peerStopped:
-	default:
-		t.Fatal("runConcurrent returned before the sibling completed cleanup")
-	}
-}
-
-func TestRunConcurrentParentCancellationIsGraceful(t *testing.T) {
-	ctx, cancel := context.WithCancel(context.Background())
-	started := make(chan struct{})
-	done := make(chan error, 1)
-	go func() {
-		done <- runConcurrent(ctx, namedRunner{
-			name: "video",
-			run: func(ctx context.Context) error {
-				close(started)
-				<-ctx.Done()
-				return nil
-			},
-		})
-	}()
-
-	<-started
-	cancel()
-	select {
-	case err := <-done:
-		if err != nil {
-			t.Fatalf("runConcurrent: %v", err)
-		}
-	case <-time.After(time.Second):
-		t.Fatal("runConcurrent did not stop after parent cancellation")
-	}
-}

internal/app/runner.go

@@ -0,0 +1,43 @@
+package app
+
+import (
+	"context"
+	"errors"
+	"fmt"
+)
+
+type Runner struct {
+	Name string
+	Run  func(context.Context) error
+}
+
+type runnerResult struct {
+	name string
+	err  error
+}
+
+func RunConcurrent(ctx context.Context, runners ...Runner) error {
+	if len(runners) == 0 {
+		return nil
+	}
+
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+	results := make(chan runnerResult, len(runners))
+	for _, runner := range runners {
+		runner := runner
+		go func() {
+			results <- runnerResult{name: runner.Name, err: runner.Run(ctx)}
+		}()
+	}
+
+	var resultErr error
+	for range runners {
+		result := <-results
+		if result.err != nil {
+			resultErr = errors.Join(resultErr, fmt.Errorf("%s flow: %w", result.name, result.err))
+			cancel()
+		}
+	}
+	return resultErr
+}

internal/app/runner_test.go

@@ -0,0 +1,74 @@
+package app_test
+
+import (
+	"context"
+	"errors"
+	"mxl-pattern-generator/internal/app"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestRunConcurrentCancelsSiblingAndWaitsForCleanup(t *testing.T) {
+	wantErr := errors.New("writer failed")
+	peerStarted := make(chan struct{})
+	peerStopped := make(chan struct{})
+
+	err := app.RunConcurrent(context.Background(),
+		app.Runner{
+			Name: "video",
+			Run: func(ctx context.Context) error {
+				<-peerStarted
+				return wantErr
+			},
+		},
+		app.Runner{
+			Name: "audio",
+			Run: func(ctx context.Context) error {
+				close(peerStarted)
+				<-ctx.Done()
+				close(peerStopped)
+				return nil
+			},
+		},
+	)
+
+	if !errors.Is(err, wantErr) {
+		t.Fatalf("error = %v, want wrapped %v", err, wantErr)
+	}
+	if !strings.Contains(err.Error(), "video flow") {
+		t.Fatalf("error = %q, want runner name", err)
+	}
+	select {
+	case <-peerStopped:
+	default:
+		t.Fatal("runConcurrent returned before the sibling completed cleanup")
+	}
+}
+
+func TestRunConcurrentParentCancellationIsGraceful(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	started := make(chan struct{})
+	done := make(chan error, 1)
+	go func() {
+		done <- app.RunConcurrent(ctx, app.Runner{
+			Name: "video",
+			Run: func(ctx context.Context) error {
+				close(started)
+				<-ctx.Done()
+				return nil
+			},
+		})
+	}()
+
+	<-started
+	cancel()
+	select {
+	case err := <-done:
+		if err != nil {
+			t.Fatalf("runConcurrent: %v", err)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("runConcurrent did not stop after parent cancellation")
+	}
+}