First pass at full fork pretty much complete.

diskwriter/diskwriter.go

@@ -34,6 +34,8 @@ const (
 
 var Directory string
 
+var activeRecordings sync.Map
+
 type Client struct {
 	hall *hall.Hall
 	id   string
@@ -250,6 +252,7 @@ func newRecorder(client *Client, directory string) (*recorder, error) {
 		done:    make(chan error, 1),
 		sources: make(map[*diskTrack]chan []byte),
 	}
+	activeRecordings.Store(path, struct{}{})
 	go r.mix()
 	return r, nil
 }
@@ -358,6 +361,7 @@ func (r *recorder) Close() error {
 	err := <-r.done
 	stdinErr := r.stdin.Close()
 	waitErr := r.cmd.Wait()
+	activeRecordings.Delete(r.path)
 
 	if err != nil {
 		return err
@@ -368,6 +372,10 @@ func (r *recorder) Close() error {
 	if waitErr != nil {
 		return waitErr
 	}
+	now := time.Now()
+	if err := os.Chtimes(r.path, now, now); err != nil {
+		return err
+	}
 	return nil
 }
 
@@ -658,6 +666,49 @@ func openDiskFile(directory, extension string) (*os.File, error) {
 	return nil, errors.New("couldn't create file")
 }
 
+func CleanupOldRecordings(retention time.Duration) error {
+	if retention <= 0 {
+		return nil
+	}
+	cutoff := time.Now().Add(-retention)
+	err := filepath.WalkDir(
+		Directory,
+		func(path string, d os.DirEntry, err error) error {
+			if err != nil {
+				log.Printf("Recording cleanup %v: %v", path, err)
+				return nil
+			}
+			if d.IsDir() {
+				return nil
+			}
+			name := d.Name()
+			if !strings.HasPrefix(name, "skald-recording-") ||
+				filepath.Ext(name) != ".ogg" {
+				return nil
+			}
+			if _, ok := activeRecordings.Load(path); ok {
+				return nil
+			}
+			info, err := d.Info()
+			if err != nil {
+				log.Printf("Recording cleanup %v: %v", path, err)
+				return nil
+			}
+			if info.ModTime().After(cutoff) {
+				return nil
+			}
+			if err := os.Remove(path); err != nil {
+				log.Printf("Recording cleanup %v: %v", path, err)
+			}
+			return nil
+		},
+	)
+	if errors.Is(err, os.ErrNotExist) {
+		return nil
+	}
+	return err
+}
+
 func drainStderr(prefix string, r io.Reader) {
 	buf := make([]byte, 1024)
 	for {

diskwriter/diskwriter_test.go

@@ -46,6 +46,63 @@ func TestOpenDiskFileUsesSkaldOggName(t *testing.T) {
 	}
 }
 
+func TestCleanupOldRecordings(t *testing.T) {
+	oldDirectory := Directory
+	defer func() {
+		Directory = oldDirectory
+	}()
+
+	Directory = t.TempDir()
+	hallDir := filepath.Join(Directory, "test")
+	if err := os.MkdirAll(hallDir, 0700); err != nil {
+		t.Fatal(err)
+	}
+
+	oldRecording := filepath.Join(hallDir, "skald-recording-20000101-000000.ogg")
+	activeRecording := filepath.Join(hallDir, "skald-recording-20000101-010000.ogg")
+	newRecording := filepath.Join(hallDir, "skald-recording-29990101-000000.ogg")
+	otherFile := filepath.Join(hallDir, "notes.txt")
+	for _, name := range []string{oldRecording, activeRecording, newRecording, otherFile} {
+		if err := os.WriteFile(name, []byte("test"), 0600); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	oldTime := time.Now().Add(-48 * time.Hour)
+	newTime := time.Now()
+	if err := os.Chtimes(oldRecording, oldTime, oldTime); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Chtimes(activeRecording, oldTime, oldTime); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Chtimes(newRecording, newTime, newTime); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Chtimes(otherFile, oldTime, oldTime); err != nil {
+		t.Fatal(err)
+	}
+
+	activeRecordings.Store(activeRecording, struct{}{})
+	defer activeRecordings.Delete(activeRecording)
+
+	if err := CleanupOldRecordings(24 * time.Hour); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := os.Stat(oldRecording); !os.IsNotExist(err) {
+		t.Fatalf("old recording still exists or stat failed unexpectedly: %v", err)
+	}
+	if _, err := os.Stat(newRecording); err != nil {
+		t.Fatalf("new recording was removed: %v", err)
+	}
+	if _, err := os.Stat(activeRecording); err != nil {
+		t.Fatalf("active recording was removed: %v", err)
+	}
+	if _, err := os.Stat(otherFile); err != nil {
+		t.Fatalf("non-recording file was removed: %v", err)
+	}
+}
+
 func TestMixFrameClipsAndSumsSources(t *testing.T) {
 	a := make(chan []byte, 1)
 	b := make(chan []byte, 1)