add WhisperCppAdapter for local whisper-cpp transcription

This commit is contained in:
leonardotrapani
2026-02-01 01:10:06 +01:00
parent 7a68e6fda9
commit 838edef59b
4 changed files with 253 additions and 1 deletions
+107
View File
@@ -0,0 +1,107 @@
package transcriber
import (
"bytes"
"context"
"fmt"
"log"
"os"
"os/exec"
"path/filepath"
"strings"
"time"
"github.com/leonardotrapani/hyprvoice/internal/language"
)
// WhisperCppAdapter implements BatchAdapter for local whisper-cpp transcription
type WhisperCppAdapter struct {
modelPath string
language string
threads int
}
// NewWhisperCppAdapter creates a new whisper-cpp adapter
// modelPath: full path to the model file (e.g., ~/.local/share/hyprvoice/models/whisper/ggml-base.en.bin)
// lang: canonical language code (will be converted to whisper-cpp format)
// threads: number of CPU threads (0 for auto)
func NewWhisperCppAdapter(modelPath, lang string, threads int) *WhisperCppAdapter {
return &WhisperCppAdapter{
modelPath: modelPath,
language: lang,
threads: threads,
}
}
func (a *WhisperCppAdapter) Transcribe(ctx context.Context, audioData []byte) (string, error) {
if len(audioData) == 0 {
return "", nil
}
// check whisper-cli exists
whisperPath, err := exec.LookPath("whisper-cli")
if err != nil {
return "", fmt.Errorf("whisper-cli not found: install whisper.cpp first")
}
// check model file exists
if _, err := os.Stat(a.modelPath); os.IsNotExist(err) {
return "", fmt.Errorf("model file not found: %s", a.modelPath)
}
// convert raw PCM to WAV
wavData, err := convertToWAV(audioData)
if err != nil {
return "", fmt.Errorf("convert to WAV: %w", err)
}
// write to temp file
tmpDir := os.TempDir()
tmpFile := filepath.Join(tmpDir, fmt.Sprintf("hyprvoice-%d.wav", time.Now().UnixNano()))
if err := os.WriteFile(tmpFile, wavData, 0600); err != nil {
return "", fmt.Errorf("write temp file: %w", err)
}
defer os.Remove(tmpFile)
// convert language to whisper-cpp format
lang := language.ToProviderFormat(a.language, "whisper-cpp")
// build command args
args := []string{
"-m", a.modelPath,
"-l", lang,
"-nt", // no timestamps
"-np", // no progress
"-f", tmpFile,
}
// add threads if specified
if a.threads > 0 {
args = append(args, "-t", fmt.Sprintf("%d", a.threads))
}
// execute whisper-cli
cmd := exec.CommandContext(ctx, whisperPath, args...)
var stdout, stderr bytes.Buffer
cmd.Stdout = &stdout
cmd.Stderr = &stderr
start := time.Now()
err = cmd.Run()
duration := time.Since(start)
if err != nil {
// check if context was cancelled
if ctx.Err() != nil {
return "", ctx.Err()
}
log.Printf("whisper-cpp: command failed after %v: %v\nstderr: %s", duration, err, stderr.String())
return "", fmt.Errorf("whisper-cli failed: %w", err)
}
// parse output - whisper-cli outputs transcription text directly (with -nt flag)
text := strings.TrimSpace(stdout.String())
log.Printf("whisper-cpp: transcribed %d bytes in %v: %q", len(audioData), duration, text)
return text, nil
}
@@ -0,0 +1,125 @@
package transcriber
import (
"context"
"os"
"path/filepath"
"testing"
)
func TestWhisperCppAdapter_ImplementsBatchAdapter(t *testing.T) {
// compile-time check that WhisperCppAdapter implements BatchAdapter
var _ BatchAdapter = (*WhisperCppAdapter)(nil)
}
func TestWhisperCppAdapter_EmptyAudio(t *testing.T) {
adapter := NewWhisperCppAdapter("/nonexistent/model.bin", "en", 4)
text, err := adapter.Transcribe(context.Background(), []byte{})
if err != nil {
t.Errorf("expected no error for empty audio, got: %v", err)
}
if text != "" {
t.Errorf("expected empty text for empty audio, got: %q", text)
}
}
func TestWhisperCppAdapter_MissingModel(t *testing.T) {
adapter := NewWhisperCppAdapter("/nonexistent/path/model.bin", "en", 4)
// create minimal valid PCM data (just zeros)
audioData := make([]byte, 32000) // 1 second at 16kHz 16-bit
_, err := adapter.Transcribe(context.Background(), audioData)
if err == nil {
t.Error("expected error for missing model file")
}
if err != nil && !contains(err.Error(), "model file not found") {
t.Errorf("expected 'model file not found' error, got: %v", err)
}
}
func TestWhisperCppAdapter_LanguageConversion(t *testing.T) {
// verify adapter stores language for later conversion
adapter := NewWhisperCppAdapter("/fake/model.bin", "", 4)
if adapter.language != "" {
t.Errorf("expected empty language for auto, got: %q", adapter.language)
}
adapter = NewWhisperCppAdapter("/fake/model.bin", "en", 4)
if adapter.language != "en" {
t.Errorf("expected 'en' language, got: %q", adapter.language)
}
}
func TestWhisperCppAdapter_ThreadsConfig(t *testing.T) {
adapter := NewWhisperCppAdapter("/fake/model.bin", "en", 0)
if adapter.threads != 0 {
t.Errorf("expected threads=0 (auto), got: %d", adapter.threads)
}
adapter = NewWhisperCppAdapter("/fake/model.bin", "en", 8)
if adapter.threads != 8 {
t.Errorf("expected threads=8, got: %d", adapter.threads)
}
}
func TestWhisperCppAdapter_TempFileCleanup(t *testing.T) {
// this test requires whisper-cli and a model to be installed
// skip if not available
modelPath := os.Getenv("WHISPER_TEST_MODEL")
if modelPath == "" {
t.Skip("WHISPER_TEST_MODEL not set, skipping temp file cleanup test")
}
adapter := NewWhisperCppAdapter(modelPath, "en", 4)
// create minimal audio data
audioData := make([]byte, 32000)
// run transcription
_, _ = adapter.Transcribe(context.Background(), audioData)
// check that temp file was cleaned up
// (we can't easily verify this without modifying the adapter to expose temp path)
// this is more of a visual/log verification
}
func TestWhisperCppAdapter_ContextCancellation(t *testing.T) {
// skip if whisper-cli not installed
if _, err := os.Stat("/usr/local/bin/whisper-cli"); os.IsNotExist(err) {
t.Skip("whisper-cli not installed")
}
// create a fake model file for this test
tmpDir := t.TempDir()
fakeModel := filepath.Join(tmpDir, "fake.bin")
if err := os.WriteFile(fakeModel, []byte("fake"), 0600); err != nil {
t.Fatalf("failed to create fake model: %v", err)
}
adapter := NewWhisperCppAdapter(fakeModel, "en", 4)
ctx, cancel := context.WithCancel(context.Background())
cancel() // cancel immediately
// create minimal audio data
audioData := make([]byte, 32000)
_, err := adapter.Transcribe(ctx, audioData)
if err == nil {
t.Error("expected error for cancelled context")
}
}
func contains(s, substr string) bool {
return len(s) >= len(substr) && (s == substr || len(s) > 0 && containsHelper(s, substr))
}
func containsHelper(s, substr string) bool {
for i := 0; i <= len(s)-len(substr); i++ {
if s[i:i+len(substr)] == substr {
return true
}
}
return false
}