Add transcription jobs to AI service

internal/transcription/client.go

@@ -0,0 +1,168 @@
+package transcription
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"mime/multipart"
+	"net/http"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+type Client struct {
+	baseURL string
+	http    *http.Client
+}
+
+type Input struct {
+	AudioURL    string `json:"audio_url"`
+	Filename    string `json:"filename,omitempty"`
+	Language    string `json:"language,omitempty"`
+	Diarize     bool   `json:"diarize"`
+	MinSpeakers int    `json:"min_speakers,omitempty"`
+	MaxSpeakers int    `json:"max_speakers,omitempty"`
+}
+
+type Segment struct {
+	Start   float64 `json:"start"`
+	End     float64 `json:"end"`
+	Text    string  `json:"text"`
+	Speaker string  `json:"speaker,omitempty"`
+}
+
+type Result struct {
+	Language     string    `json:"language"`
+	Segments     []Segment `json:"segments"`
+	DiarizeError *string   `json:"diarize_error,omitempty"`
+	AlignError   *string   `json:"align_error,omitempty"`
+	DurationMS   int64     `json:"duration_ms"`
+}
+
+type whisperResponse struct {
+	Language     string    `json:"language"`
+	Segments     []Segment `json:"segments"`
+	DiarizeError *string   `json:"diarize_error,omitempty"`
+	AlignError   *string   `json:"align_error,omitempty"`
+}
+
+func New(baseURL string, timeout time.Duration) *Client {
+	baseURL = strings.TrimRight(strings.TrimSpace(baseURL), "/")
+	if baseURL == "" {
+		return nil
+	}
+	if timeout <= 0 {
+		timeout = 10 * time.Minute
+	}
+	return &Client{
+		baseURL: baseURL,
+		http:    &http.Client{Timeout: timeout},
+	}
+}
+
+func (c *Client) Transcribe(ctx context.Context, in Input) (*Result, error) {
+	if c == nil || c.baseURL == "" {
+		return nil, fmt.Errorf("whisperx not configured")
+	}
+	if strings.TrimSpace(in.AudioURL) == "" {
+		return nil, fmt.Errorf("audio_url is required")
+	}
+	audio, filename, err := c.downloadAudio(ctx, in)
+	if err != nil {
+		return nil, err
+	}
+	resp, duration, err := c.transcribeAudio(ctx, audio, filename, in)
+	if err != nil {
+		return nil, err
+	}
+	return &Result{
+		Language:     resp.Language,
+		Segments:     resp.Segments,
+		DiarizeError: resp.DiarizeError,
+		AlignError:   resp.AlignError,
+		DurationMS:   duration.Milliseconds(),
+	}, nil
+}
+
+func (c *Client) downloadAudio(ctx context.Context, in Input) ([]byte, string, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, in.AudioURL, nil)
+	if err != nil {
+		return nil, "", fmt.Errorf("audio request: %w", err)
+	}
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return nil, "", fmt.Errorf("audio download: %w", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode >= 300 {
+		body, _ := io.ReadAll(io.LimitReader(resp.Body, 4096))
+		return nil, "", fmt.Errorf("audio HTTP %d: %s", resp.StatusCode, strings.TrimSpace(string(body)))
+	}
+	audio, err := io.ReadAll(io.LimitReader(resp.Body, 512<<20))
+	if err != nil {
+		return nil, "", fmt.Errorf("audio read: %w", err)
+	}
+	if len(audio) == 0 {
+		return nil, "", fmt.Errorf("audio is empty")
+	}
+	filename := filepath.Base(strings.TrimSpace(in.Filename))
+	if filename == "." || filename == "/" || filename == "" {
+		filename = "audio.mp3"
+	}
+	return audio, filename, nil
+}
+
+func (c *Client) transcribeAudio(ctx context.Context, audio []byte, filename string, in Input) (*whisperResponse, time.Duration, error) {
+	body := &bytes.Buffer{}
+	mw := multipart.NewWriter(body)
+	fw, err := mw.CreateFormFile("file", filename)
+	if err != nil {
+		return nil, 0, fmt.Errorf("create form file: %w", err)
+	}
+	if _, err := fw.Write(audio); err != nil {
+		return nil, 0, fmt.Errorf("copy audio: %w", err)
+	}
+	if in.Language != "" {
+		_ = mw.WriteField("language", in.Language)
+	}
+	if in.Diarize {
+		_ = mw.WriteField("diarize", "true")
+		if in.MinSpeakers > 0 {
+			_ = mw.WriteField("min_speakers", fmt.Sprintf("%d", in.MinSpeakers))
+		}
+		if in.MaxSpeakers > 0 {
+			_ = mw.WriteField("max_speakers", fmt.Sprintf("%d", in.MaxSpeakers))
+		}
+	} else {
+		_ = mw.WriteField("diarize", "false")
+	}
+	if err := mw.Close(); err != nil {
+		return nil, 0, fmt.Errorf("close form: %w", err)
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.baseURL+"/transcribe", body)
+	if err != nil {
+		return nil, 0, fmt.Errorf("whisperx request: %w", err)
+	}
+	req.Header.Set("Content-Type", mw.FormDataContentType())
+
+	start := time.Now()
+	resp, err := c.http.Do(req)
+	duration := time.Since(start)
+	if err != nil {
+		return nil, duration, fmt.Errorf("whisperx do: %w", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode >= 300 {
+		body, _ := io.ReadAll(io.LimitReader(resp.Body, 4096))
+		return nil, duration, fmt.Errorf("whisperx HTTP %d: %s", resp.StatusCode, strings.TrimSpace(string(body)))
+	}
+	var out whisperResponse
+	if err := json.NewDecoder(resp.Body).Decode(&out); err != nil {
+		return nil, duration, fmt.Errorf("whisperx decode: %w", err)
+	}
+	return &out, duration, nil
+}