|
| 1 | +""" |
| 2 | +lid_provider.py — Language Identification (LID) via Sarvam saaras:v3. |
| 3 | +
|
| 4 | +Opens a dedicated WebSocket to Sarvam with language-code=unknown so the |
| 5 | +server auto-detects the spoken language and returns language_code in each |
| 6 | +data payload alongside the transcript. Audio is forwarded in real-time |
| 7 | +from the TranscriberPool audio router — zero added latency to the ASR path. |
| 8 | +
|
| 9 | +Usage (in TranscriberPool): |
| 10 | + lid = SarvamLID(on_language=callback, config={...}) |
| 11 | + await lid.start() |
| 12 | + lid.feed(audio_chunk_bytes) # called for every incoming audio packet |
| 13 | + await lid.stop() |
| 14 | +""" |
| 15 | + |
| 16 | +from __future__ import annotations |
| 17 | + |
| 18 | +import asyncio |
| 19 | +import base64 |
| 20 | +import io |
| 21 | +import json |
| 22 | +import os |
| 23 | +import wave |
| 24 | +from typing import Awaitable, Callable, Optional |
| 25 | + |
| 26 | +from bolna.helpers.logger_config import configure_logger |
| 27 | + |
| 28 | +logger = configure_logger(__name__) |
| 29 | + |
| 30 | +# Signature: async def on_language(lang: str, confidence: float) -> None |
| 31 | +OnLanguageCallback = Callable[[str, float], Awaitable[None]] |
| 32 | + |
| 33 | + |
| 34 | +class SarvamLID: |
| 35 | + """ |
| 36 | + LID via Sarvam saaras:v3 with language_code=unknown. |
| 37 | +
|
| 38 | + Config keys (all optional, fall back to env vars): |
| 39 | + sarvam_api_key — SARVAM_API_KEY env var |
| 40 | + sarvam_host — api.sarvam.ai |
| 41 | + telephony_provider — "twilio" | "plivo" | other |
| 42 | + sampling_rate — 16000 |
| 43 | + """ |
| 44 | + |
| 45 | + _WS_BASE = "wss://{host}/speech-to-text/ws" |
| 46 | + |
| 47 | + def __init__(self, on_language: OnLanguageCallback, config: dict): |
| 48 | + self.on_language = on_language |
| 49 | + self.config = config |
| 50 | + self._api_key = config.get("sarvam_api_key") or os.getenv("SARVAM_API_KEY", "") |
| 51 | + self._host = config.get("sarvam_host") or os.getenv("SARVAM_HOST", "api.sarvam.ai") |
| 52 | + self._telephony = config.get("telephony_provider", "") |
| 53 | + self._sr = int(config.get("sampling_rate", 16000)) |
| 54 | + self._input_sr = 8000 if self._telephony in ("twilio", "plivo") else self._sr |
| 55 | + self._encoding = "mulaw" if self._telephony == "twilio" else "linear16" |
| 56 | + |
| 57 | + # Bounded queue: LID is best-effort. If the Sarvam WS stalls, we drop |
| 58 | + # chunks rather than buffering unboundedly for the entire call duration. |
| 59 | + self._queue: asyncio.Queue = asyncio.Queue(maxsize=200) |
| 60 | + self._ws = None |
| 61 | + self._sender_task: Optional[asyncio.Task] = None |
| 62 | + self._receiver_task: Optional[asyncio.Task] = None |
| 63 | + # Set to True if the receiver loop exits abnormally (WS drop / error). |
| 64 | + # feed() will log a warning when dead so silent stat bias is visible. |
| 65 | + self._dead: bool = False |
| 66 | + |
| 67 | + def _build_url(self) -> str: |
| 68 | + params = { |
| 69 | + "model": "saaras:v3", |
| 70 | + "mode": "transcribe", |
| 71 | + "language-code": "unknown", |
| 72 | + "high_vad_sensitivity": "true", |
| 73 | + } |
| 74 | + qs = "&".join(f"{k}={v}" for k, v in params.items()) |
| 75 | + return f"{self._WS_BASE.format(host=self._host)}?{qs}" |
| 76 | + |
| 77 | + def _convert_to_wav_b64(self, raw: bytes) -> Optional[str]: |
| 78 | + """Convert telephony audio to 16kHz WAV base64 for Sarvam.""" |
| 79 | + import audioop |
| 80 | + try: |
| 81 | + if self._encoding == "mulaw": |
| 82 | + raw = audioop.ulaw2lin(raw, 2) |
| 83 | + if self._input_sr != self._sr: |
| 84 | + raw, _ = audioop.ratecv(raw, 2, 1, self._input_sr, self._sr, None) |
| 85 | + buf = io.BytesIO() |
| 86 | + with wave.open(buf, "wb") as wf: |
| 87 | + wf.setnchannels(1) |
| 88 | + wf.setsampwidth(2) |
| 89 | + wf.setframerate(self._sr) |
| 90 | + wf.writeframes(raw) |
| 91 | + return base64.b64encode(buf.getvalue()).decode() |
| 92 | + except Exception as e: |
| 93 | + logger.warning(f"SarvamLID audio convert error: {e}") |
| 94 | + return None |
| 95 | + |
| 96 | + async def start(self) -> None: |
| 97 | + import websockets as ws_lib |
| 98 | + url = self._build_url() |
| 99 | + headers = {"api-subscription-key": self._api_key} |
| 100 | + logger.info(f"SarvamLID: connecting to {url}") |
| 101 | + self._ws = await ws_lib.connect(url, additional_headers=headers) |
| 102 | + self._sender_task = asyncio.create_task(self._sender_loop()) |
| 103 | + self._receiver_task = asyncio.create_task(self._receiver_loop()) |
| 104 | + logger.info("SarvamLID: connected") |
| 105 | + |
| 106 | + def feed(self, audio_bytes: bytes) -> None: |
| 107 | + if self._dead: |
| 108 | + logger.warning("SarvamLID: feed() called but WS is dead — chunk dropped (LID inactive)") |
| 109 | + return |
| 110 | + try: |
| 111 | + self._queue.put_nowait(audio_bytes) |
| 112 | + except asyncio.QueueFull: |
| 113 | + logger.debug("SarvamLID: audio queue full — chunk dropped (backpressure)") |
| 114 | + |
| 115 | + async def _sender_loop(self) -> None: |
| 116 | + try: |
| 117 | + while True: |
| 118 | + chunk = await self._queue.get() |
| 119 | + if chunk is None: |
| 120 | + break |
| 121 | + b64 = self._convert_to_wav_b64(chunk) |
| 122 | + if b64: |
| 123 | + msg = {"audio": {"data": b64, "encoding": "audio/wav", "sample_rate": self._sr}} |
| 124 | + await self._ws.send(json.dumps(msg)) |
| 125 | + except asyncio.CancelledError: |
| 126 | + pass |
| 127 | + except Exception as e: |
| 128 | + logger.error(f"SarvamLID sender error: {e}") |
| 129 | + self._dead = True |
| 130 | + logger.warning("SarvamLID: sender loop exited abnormally — LID inactive for remainder of call") |
| 131 | + |
| 132 | + async def _receiver_loop(self) -> None: |
| 133 | + try: |
| 134 | + async for raw in self._ws: |
| 135 | + try: |
| 136 | + data = json.loads(raw) if isinstance(raw, str) else {} |
| 137 | + if data.get("type") == "data": |
| 138 | + payload = data.get("data", {}) |
| 139 | + lang = payload.get("language_code", "") |
| 140 | + # Sarvam returns language_probability=None when operating in |
| 141 | + # unknown-language mode — the language_code is the signal. |
| 142 | + # conf is passed through for API compatibility but the pool's |
| 143 | + # confidence gate is skipped for Sarvam (see _handle_lid_signal). |
| 144 | + conf = float(payload.get("language_probability") or 0.0) |
| 145 | + if lang and lang != "unknown": |
| 146 | + short = lang.split("-")[0].lower() |
| 147 | + logger.info(f"SarvamLID: detected {lang!r} (short={short!r}, conf={conf:.2f})") |
| 148 | + await self.on_language(short, conf) |
| 149 | + except Exception as e: |
| 150 | + logger.error(f"SarvamLID receiver parse error: {e}") |
| 151 | + except asyncio.CancelledError: |
| 152 | + pass |
| 153 | + except Exception as e: |
| 154 | + logger.error(f"SarvamLID receiver error: {e}") |
| 155 | + self._dead = True |
| 156 | + logger.warning("SarvamLID: receiver loop exited abnormally — LID inactive for remainder of call") |
| 157 | + |
| 158 | + async def stop(self) -> None: |
| 159 | + self._queue.put_nowait(None) |
| 160 | + for task in (self._sender_task, self._receiver_task): |
| 161 | + if task and not task.done(): |
| 162 | + task.cancel() |
| 163 | + try: |
| 164 | + await task |
| 165 | + except asyncio.CancelledError: |
| 166 | + pass |
| 167 | + if self._ws: |
| 168 | + try: |
| 169 | + await self._ws.close() |
| 170 | + except Exception: |
| 171 | + pass |
| 172 | + logger.info("SarvamLID: stopped") |
| 173 | + |
| 174 | + |
| 175 | +# Thin factory shim for backward compatibility |
| 176 | +class LIDProvider: |
| 177 | + @classmethod |
| 178 | + def create(cls, provider: str, on_language: OnLanguageCallback, config: dict) -> SarvamLID: |
| 179 | + if provider.lower() != "sarvam": |
| 180 | + logger.warning(f"LIDProvider: unknown provider '{provider}', falling back to sarvam") |
| 181 | + return SarvamLID(on_language=on_language, config=config) |
![github-actions[bot]](https://avatars.githubusercontent.com/in/15368?v=4&size=40){kind=avatar}
0 commit comments