M4: voice pipeline (software-only telephony)

- AudioSocket server (asyncio TCP, Asterisk wire protocol) bridging calls
  into the same M2 agent used by chat
- Call session engine: greeting → energy-VAD utterance collection → STT →
  agent turn → TTS playback with barge-in (120ms of caller speech stops
  playback); inactivity + max-duration guards; unintelligible audio reaches
  the agent as '[nerazumljivo]' so the two-attempt rule stays in the prompt
- STTProvider (faster-whisper, lang hint 'sr', GPU/CPU via env) and
  TTSProvider (Azure Neural raw-8k PCM / ElevenLabs Flash) + test fakes
- Recording (mixed caller+agent WAV), transcripts, per-turn latency trace,
  metering via record_agent_call (§12)
- Internal dialplan API: /internal/calls/register (ring targets computed from
  working hours + ring settings §5.2), /answered (human outcome, no minutes),
  /hangup (abandoned → missed-call SMS §5.5); shared-token auth
- Asterisk config generator (pjsip.conf + extensions.conf from DB): worker
  endpoints, per-tenant test-caller endpoint, register→Dial→AudioSocket
  dialplan with h-extension reporting — validated against a real Asterisk 20
  container (modules, dialplan, endpoints all load)
- docker-compose 'voice' profile (voice server + Asterisk), Dockerfile.voice,
  docs/VOICE_TESTING.md softphone runbook
- 16 new tests incl. full fake-call e2e and a real-TCP AudioSocket wire test

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
2026-07-11 11:05:56 +02:00
parent 646917c322
commit 714aa1782b
17 changed files with 1797 additions and 0 deletions

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gogo/voice/__init__.py Normal file
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gogo/voice/audio.py Normal file
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"""Audio helpers for the voice pipeline.
Wire format everywhere: SLIN — signed 16-bit LE mono PCM @ 8 kHz (AudioSocket).
Whisper wants 16 kHz; TTS providers are asked for 8 kHz where possible and
resampled otherwise.
"""
from __future__ import annotations
import audioop
import io
import math
import wave
SAMPLE_RATE = 8000
SAMPLE_WIDTH = 2 # bytes, 16-bit
FRAME_MS = 20
FRAME_BYTES = SAMPLE_RATE * SAMPLE_WIDTH * FRAME_MS // 1000 # 320
def resample(pcm: bytes, from_rate: int, to_rate: int) -> bytes:
if from_rate == to_rate or not pcm:
return pcm
out, _ = audioop.ratecv(pcm, SAMPLE_WIDTH, 1, from_rate, to_rate, None)
return out
def rms(pcm: bytes) -> int:
return audioop.rms(pcm, SAMPLE_WIDTH) if pcm else 0
def duration_s(pcm: bytes, rate: int = SAMPLE_RATE) -> float:
return len(pcm) / (rate * SAMPLE_WIDTH)
def silence(ms: int, rate: int = SAMPLE_RATE) -> bytes:
return b"\x00" * (rate * SAMPLE_WIDTH * ms // 1000)
def tone(freq: int, ms: int, rate: int = SAMPLE_RATE, amplitude: int = 12000) -> bytes:
"""Test helper: sine tone (registers as speech for the energy VAD)."""
n = rate * ms // 1000
return b"".join(
int(amplitude * math.sin(2 * math.pi * freq * i / rate)).to_bytes(
2, "little", signed=True
)
for i in range(n)
)
def pcm_to_wav(pcm: bytes, rate: int = SAMPLE_RATE) -> bytes:
buf = io.BytesIO()
with wave.open(buf, "wb") as w:
w.setnchannels(1)
w.setsampwidth(SAMPLE_WIDTH)
w.setframerate(rate)
w.writeframes(pcm)
return buf.getvalue()
def mix(a: bytes, b: bytes) -> bytes:
"""Mix two PCM streams (unequal lengths ok)."""
if len(a) < len(b):
a, b = b, a
if not b:
return a
mixed = audioop.add(a[: len(b)], b, SAMPLE_WIDTH)
return mixed + a[len(b):]
class CallRecorder:
"""Accumulates caller + agent audio on a shared timeline and writes a WAV."""
def __init__(self) -> None:
self._caller = bytearray()
self._agent = bytearray()
def add_caller(self, pcm: bytes) -> None:
self._caller.extend(pcm)
# keep agent track in sync (silence while caller talks)
if len(self._agent) < len(self._caller):
self._agent.extend(b"\x00" * (len(self._caller) - len(self._agent)))
def add_agent(self, pcm: bytes) -> None:
self._agent.extend(pcm)
if len(self._caller) < len(self._agent):
self._caller.extend(b"\x00" * (len(self._agent) - len(self._caller)))
def to_wav(self) -> bytes:
return pcm_to_wav(mix(bytes(self._caller), bytes(self._agent)))
@property
def seconds(self) -> float:
return duration_s(bytes(self._caller))

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"""One agent-handled phone call: audio loop, barge-in, recording, metering (M4).
The transport hands us paced 20 ms SLIN frames from Asterisk (AudioSocket) and
accepts frames to play back. Flow per §6.2: greeting → collect utterance (VAD)
→ STT → agent turn (M2 loop, same tools as chat) → TTS → play, with barge-in
(caller speech stops playback). Unintelligible audio reaches the agent as
'[nerazumljivo]' so the two-attempts rule (§6.4/A.6) lives in the prompt.
"""
from __future__ import annotations
import asyncio
import logging
import os
import time
import uuid
from dataclasses import dataclass
from sqlalchemy import select
from gogo.agent.loop import AgentConversation
from gogo.config import get_settings
from gogo.db import get_sessionmaker
from gogo.metering import record_agent_call
from gogo.models import Call, CallRegistration, Tenant, utcnow
from gogo.voice.audio import FRAME_BYTES, FRAME_MS, CallRecorder
from gogo.voice.stt import get_stt
from gogo.voice.tts import get_tts
from gogo.voice.vad import UtteranceCollector
log = logging.getLogger("gogo.voice.call")
UNCLEAR_MARKER = "[nerazumljivo]"
GOODBYE_TIMEOUT = (
"Izgleda da veza ne radi. Salon će vidjeti vaš broj i javiti vam se. Prijatno!"
)
BARGE_IN_FRAMES = 6 # 120 ms of speech during playback stops it
@dataclass
class CallLimits:
inactivity_s: float = 30.0
max_call_s: float = 600.0
max_turns: int = 30
class Transport:
"""What CallSession needs from the wire (implemented by AudioSocket + fakes)."""
async def read_frame(self) -> bytes | None:
"""Next inbound 20 ms frame, or None on hangup."""
raise NotImplementedError
async def send_audio(self, pcm: bytes) -> None:
raise NotImplementedError
async def hangup(self) -> None:
raise NotImplementedError
class CallSession:
def __init__(
self,
transport: Transport,
registration_id: uuid.UUID,
*,
limits: CallLimits | None = None,
pace: float = FRAME_MS / 1000,
):
self.transport = transport
self.registration_id = registration_id
self.limits = limits or CallLimits()
self.pace = pace
self.recorder = CallRecorder()
self.collector = UtteranceCollector()
self._started = time.monotonic()
async def run(self) -> None:
async with get_sessionmaker()() as session:
reg = (
await session.execute(
select(CallRegistration).where(CallRegistration.id == self.registration_id)
)
).scalar_one_or_none()
if reg is None:
log.error("no registration for call %s — hanging up", self.registration_id)
await self.transport.hangup()
return
tenant = (
await session.execute(select(Tenant).where(Tenant.id == reg.tenant_id))
).scalar_one()
reg.handled_by_agent = True
call = Call(
tenant_id=tenant.id,
caller_msisdn=reg.caller_msisdn,
started_at=utcnow(),
)
session.add(call)
await session.flush()
convo = AgentConversation(
session,
tenant,
channel="voice",
caller_phone=reg.caller_msisdn,
call_id=call.id,
)
tts, voice = get_tts(tenant.tts_voice)
stt = get_stt()
try:
greeting = await convo.greeting()
await session.commit()
await self._speak(tts, voice, greeting)
for _turn in range(self.limits.max_turns):
if time.monotonic() - self._started > self.limits.max_call_s:
log.warning("max call duration hit (tenant %s)", tenant.slug)
break
utterance = await self._collect_utterance()
if utterance is None: # hangup
break
if utterance == b"": # inactivity
await self._speak(tts, voice, GOODBYE_TIMEOUT)
break
t0 = time.monotonic()
text = await stt.transcribe(utterance)
stt_ms = int((time.monotonic() - t0) * 1000)
t0 = time.monotonic()
reply = await convo.user_turn(text or UNCLEAR_MARKER)
llm_ms = int((time.monotonic() - t0) * 1000)
await session.commit()
t0 = time.monotonic()
interrupted = await self._speak(tts, voice, reply)
tts_ms = int((time.monotonic() - t0) * 1000)
trace = call.trace or {}
turns = trace.setdefault("turns", [])
turns.append(
{"stt_ms": stt_ms, "llm_ms": llm_ms, "speak_ms": tts_ms,
"interrupted": interrupted, "chars": len(reply)}
)
call.trace = dict(trace)
if self._agent_closed(convo):
break
except Exception: # noqa: BLE001 — a crash must still finalize the call
log.exception("call session error (tenant %s)", tenant.slug)
finally:
await self._finalize(session, tenant, call, convo, reg)
await self.transport.hangup()
# -- audio helpers ------------------------------------------------------
async def _speak(self, tts, voice: str, text: str) -> bool:
"""Synthesize and play; returns True if the caller barged in."""
if not text:
return False
try:
pcm = await tts.synthesize(text, voice)
except Exception: # noqa: BLE001
log.exception("TTS failed — continuing without audio")
return False
voiced_streak = 0
for i in range(0, len(pcm), FRAME_BYTES):
frame = pcm[i : i + FRAME_BYTES]
await self.transport.send_audio(frame)
self.recorder.add_agent(frame)
if self.pace:
await asyncio.sleep(self.pace)
# barge-in: watch inbound audio while we play
inbound = await self._poll_frame()
if inbound is not None:
self.recorder.add_caller(inbound)
if self.collector.is_speech(inbound):
voiced_streak += 1
if voiced_streak >= BARGE_IN_FRAMES:
self.collector.reset()
self.collector.feed(inbound)
return True
else:
voiced_streak = 0
return False
async def _poll_frame(self) -> bytes | None:
try:
return await asyncio.wait_for(self.transport.read_frame(), timeout=0.001)
except TimeoutError:
return None
async def _collect_utterance(self) -> bytes | None:
"""None = hangup, b'' = inactivity timeout, else utterance PCM."""
deadline = time.monotonic() + self.limits.inactivity_s
while True:
timeout = deadline - time.monotonic()
if timeout <= 0:
return b""
try:
frame = await asyncio.wait_for(self.transport.read_frame(), timeout=timeout)
except TimeoutError:
return b""
if frame is None:
return None
self.recorder.add_caller(frame)
utterance = self.collector.feed(frame)
if utterance is not None:
return utterance
def _agent_closed(self, convo: AgentConversation) -> bool:
"""The closing line ends the call from our side (short calls §2.5)."""
last = next((t.text for t in reversed(convo.turns) if t.role == "assistant"), "")
lowered = last.lower()
return ("prijatno" in lowered or "doviđenja" in lowered) and bool(
convo.executor.created_request_id or convo.executor.took_message
)
async def _finalize(self, session, tenant, call, convo, reg) -> None:
try:
call.duration_s = int(time.monotonic() - self._started)
call.agent_seconds_charged = call.duration_s
call.outcome = convo.outcome
call.transcript = convo.transcript
rec_dir = get_settings().recordings_dir
os.makedirs(rec_dir, exist_ok=True)
path = os.path.join(rec_dir, f"{call.id}.wav")
with open(path, "wb") as f:
f.write(self.recorder.to_wav())
call.recording_path = path
reg.finalized = True
await record_agent_call(session, tenant, call.agent_seconds_charged)
await session.commit()
log.info(
"call %s finalized: %ss outcome=%s tenant=%s",
call.id, call.duration_s, call.outcome, tenant.slug,
)
except Exception: # noqa: BLE001
log.exception("failed to finalize call %s", call.id)
await session.rollback()

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"""AudioSocket server — Asterisk connects here per agent-handled call (M4).
AudioSocket wire protocol (Asterisk `AudioSocket()` app):
1 byte kind | 2 bytes big-endian payload length | payload
kind 0x00 = terminate, 0x01 = UUID (16 raw bytes), 0x10 = SLIN audio,
0xff = error. Audio is 16-bit LE mono PCM @ 8 kHz, ~20 ms per message.
Run: python -m gogo.voice.server
"""
from __future__ import annotations
import asyncio
import logging
import uuid
from gogo.config import get_settings
from gogo.voice.call import CallSession, Transport
log = logging.getLogger("gogo.voice.server")
KIND_TERMINATE = 0x00
KIND_UUID = 0x01
KIND_AUDIO = 0x10
KIND_ERROR = 0xFF
class AudioSocketTransport(Transport):
def __init__(self, reader: asyncio.StreamReader, writer: asyncio.StreamWriter):
self.reader = reader
self.writer = writer
self._closed = False
async def read_message(self) -> tuple[int, bytes] | None:
try:
header = await self.reader.readexactly(3)
except (asyncio.IncompleteReadError, ConnectionResetError):
return None
kind = header[0]
length = int.from_bytes(header[1:3], "big")
payload = b""
if length:
try:
payload = await self.reader.readexactly(length)
except (asyncio.IncompleteReadError, ConnectionResetError):
return None
return kind, payload
async def read_frame(self) -> bytes | None:
"""Next audio frame; skips non-audio messages; None on hangup/close."""
while True:
msg = await self.read_message()
if msg is None:
return None
kind, payload = msg
if kind == KIND_AUDIO:
return payload
if kind == KIND_TERMINATE:
return None
if kind == KIND_ERROR:
log.warning("audiosocket error frame: %s", payload[:64])
async def send_audio(self, pcm: bytes) -> None:
if self._closed:
return
try:
self.writer.write(bytes([KIND_AUDIO]) + len(pcm).to_bytes(2, "big") + pcm)
await self.writer.drain()
except (ConnectionResetError, BrokenPipeError):
self._closed = True
async def hangup(self) -> None:
if self._closed:
return
self._closed = True
try:
self.writer.write(bytes([KIND_TERMINATE, 0, 0]))
await self.writer.drain()
self.writer.close()
except (ConnectionResetError, BrokenPipeError):
pass
async def handle_connection(reader: asyncio.StreamReader, writer: asyncio.StreamWriter) -> None:
transport = AudioSocketTransport(reader, writer)
msg = await transport.read_message()
if msg is None or msg[0] != KIND_UUID or len(msg[1]) != 16:
log.warning("connection without UUID handshake — dropping")
await transport.hangup()
return
registration_id = uuid.UUID(bytes=msg[1])
log.info("call connected: %s", registration_id)
session = CallSession(transport, registration_id)
await session.run()
async def serve() -> None:
s = get_settings()
server = await asyncio.start_server(handle_connection, s.voice_host, s.voice_port)
addrs = ", ".join(str(sock.getsockname()) for sock in server.sockets)
log.info("AudioSocket server listening on %s", addrs)
# health heartbeat file for the admin panel / monitoring (M6)
async with server:
await server.serve_forever()
def main() -> None:
logging.basicConfig(level=logging.INFO, format="%(asctime)s %(levelname)s %(name)s %(message)s")
asyncio.run(serve())
if __name__ == "__main__":
main()

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"""STTProvider interface — faster-whisper implementation + test fake (§4).
Language hint 'sr' covers spoken Bosnian/Serbian/Croatian (§6.1). The model
runs on GPU in the founder's DC (large-v3); CPU with a small model for dev.
"""
from __future__ import annotations
import asyncio
import logging
import os
from typing import Protocol
from gogo.voice.audio import SAMPLE_RATE, resample
log = logging.getLogger("gogo.voice.stt")
class STTProvider(Protocol):
async def transcribe(self, pcm_8k: bytes) -> str:
"""SLIN 8 kHz PCM → text (empty string when nothing intelligible)."""
...
class WhisperSTT:
"""faster-whisper; model size/device via env (GOGO_WHISPER_MODEL, GOGO_WHISPER_DEVICE)."""
def __init__(self, model_name: str | None = None, device: str | None = None):
from faster_whisper import WhisperModel # heavy import, voice extra
model_name = model_name or os.environ.get("GOGO_WHISPER_MODEL", "small")
device = device or os.environ.get("GOGO_WHISPER_DEVICE", "auto")
compute = "float16" if device == "cuda" else "int8"
log.info("loading whisper model=%s device=%s", model_name, device)
self._model = WhisperModel(model_name, device=device, compute_type=compute)
self._lock = asyncio.Lock()
async def transcribe(self, pcm_8k: bytes) -> str:
import numpy as np
pcm_16k = resample(pcm_8k, SAMPLE_RATE, 16000)
audio = np.frombuffer(pcm_16k, dtype=np.int16).astype(np.float32) / 32768.0
def run() -> str:
segments, _info = self._model.transcribe(
audio,
language="sr", # covers bs/sr/hr as one spoken language (§6.1)
beam_size=5,
vad_filter=True,
)
return " ".join(s.text.strip() for s in segments).strip()
async with self._lock: # one decode at a time per worker process
return await asyncio.get_running_loop().run_in_executor(None, run)
class FakeSTT:
"""Test fake: returns queued texts, one per transcribe() call."""
def __init__(self, texts: list[str] | None = None):
self.texts = list(texts or [])
self.received: list[bytes] = []
async def transcribe(self, pcm_8k: bytes) -> str:
self.received.append(pcm_8k)
return self.texts.pop(0) if self.texts else ""
_stt: STTProvider | None = None
def get_stt() -> STTProvider:
global _stt
if _stt is None:
_stt = WhisperSTT()
return _stt
def set_stt(provider: STTProvider | None) -> None:
global _stt
_stt = provider

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"""TTSProvider interface (§4): Azure Neural + ElevenLabs Flash + test fake.
Both return SLIN 8 kHz PCM ready for AudioSocket. Default provider/voice comes
from settings; per-tenant voice ids look like "azure:sr-RS-SophieNeural" or
"elevenlabs:<voice_id>".
"""
from __future__ import annotations
import logging
from typing import Protocol
from xml.sax.saxutils import escape
import httpx
from gogo.config import get_settings
from gogo.voice.audio import SAMPLE_RATE, resample, tone
log = logging.getLogger("gogo.voice.tts")
DEFAULT_AZURE_VOICE = "sr-RS-SophieNeural"
class TTSProvider(Protocol):
async def synthesize(self, text: str, voice: str = "") -> bytes:
"""Text → SLIN 8 kHz PCM."""
...
class AzureTTS:
async def synthesize(self, text: str, voice: str = "") -> bytes:
s = get_settings()
voice = voice or DEFAULT_AZURE_VOICE
ssml = (
f"<speak version='1.0' xml:lang='sr-RS'>"
f"<voice name='{voice}'>{escape(text)}</voice></speak>"
)
url = (
f"https://{s.azure_speech_region}.tts.speech.microsoft.com/"
"cognitiveservices/v1"
)
async with httpx.AsyncClient(timeout=15) as client:
resp = await client.post(
url,
content=ssml.encode(),
headers={
"Ocp-Apim-Subscription-Key": s.azure_speech_key,
"Content-Type": "application/ssml+xml",
"X-Microsoft-OutputFormat": "raw-8khz-16bit-mono-pcm",
"User-Agent": "gogotelefon",
},
)
resp.raise_for_status()
return resp.content
class ElevenLabsTTS:
async def synthesize(self, text: str, voice: str = "") -> bytes:
s = get_settings()
voice_id = voice or "JBFqnCBsd6RMkjVDRZzb"
async with httpx.AsyncClient(timeout=20) as client:
resp = await client.post(
f"https://api.elevenlabs.io/v1/text-to-speech/{voice_id}",
params={"output_format": "pcm_16000"},
headers={"xi-api-key": s.elevenlabs_api_key},
json={"text": text, "model_id": "eleven_flash_v2_5"},
)
resp.raise_for_status()
return resample(resp.content, 16000, SAMPLE_RATE)
class FakeTTS:
"""Test fake: N ms of tone per character (deterministic, VAD-audible)."""
def __init__(self, ms_per_char: int = 5):
self.ms_per_char = ms_per_char
self.spoken: list[str] = []
async def synthesize(self, text: str, voice: str = "") -> bytes:
self.spoken.append(text)
return tone(440, max(40, self.ms_per_char * len(text)))
def make_tts(provider_and_voice: str = "") -> tuple[TTSProvider, str]:
"""Resolve a tenant voice id 'provider:voice' → (provider instance, voice)."""
s = get_settings()
provider_name, _, voice = (provider_and_voice or "").partition(":")
if not voice:
provider_name, voice = s.tts_provider, ""
if provider_name == "elevenlabs":
return ElevenLabsTTS(), voice
return AzureTTS(), voice or DEFAULT_AZURE_VOICE
_tts: TTSProvider | None = None
def get_tts(tenant_voice: str = "") -> tuple[TTSProvider, str]:
if _tts is not None: # test override
_, _, voice = (tenant_voice or "").partition(":")
return _tts, voice
return make_tts(tenant_voice)
def set_tts(provider: TTSProvider | None) -> None:
global _tts
_tts = provider

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"""Utterance detection: adaptive energy VAD with hangover.
Deliberately simple and dependency-free; swap for silero/webrtcvad later if the
Phase-0 PoC shows it is needed. Operates on 20 ms SLIN frames.
"""
from __future__ import annotations
from dataclasses import dataclass, field
from gogo.voice.audio import FRAME_MS, rms
@dataclass
class VadConfig:
# energy threshold = max(min_threshold, noise_floor * ratio)
min_threshold: int = 500
noise_ratio: float = 3.0
start_ms: int = 120 # this much voiced audio starts an utterance
end_ms: int = 700 # this much silence ends it
max_utterance_ms: int = 15000 # hard cap
pre_roll_ms: int = 200 # audio kept from before the trigger
@dataclass
class UtteranceCollector:
"""Feed 20 ms frames; returns the full utterance PCM when one completes."""
config: VadConfig = field(default_factory=VadConfig)
_noise_floor: float = 200.0
_voiced_ms: int = 0
_silence_ms: int = 0
_in_utterance: bool = False
_buffer: bytearray = field(default_factory=bytearray)
_pre_roll: bytearray = field(default_factory=bytearray)
def is_speech(self, frame: bytes) -> bool:
energy = rms(frame)
threshold = max(self.config.min_threshold, self._noise_floor * self.config.noise_ratio)
speech = energy > threshold
if not speech:
# slowly track the noise floor on non-speech frames
self._noise_floor = 0.95 * self._noise_floor + 0.05 * energy
return speech
def feed(self, frame: bytes) -> bytes | None:
"""Returns utterance PCM when a complete utterance is detected, else None."""
speech = self.is_speech(frame)
if not self._in_utterance:
self._pre_roll.extend(frame)
max_pre = self.config.pre_roll_ms * len(frame) // FRAME_MS
if len(self._pre_roll) > max_pre:
del self._pre_roll[: len(self._pre_roll) - max_pre]
if speech:
self._voiced_ms += FRAME_MS
if self._voiced_ms >= self.config.start_ms:
self._in_utterance = True
self._buffer = bytearray(self._pre_roll)
self._silence_ms = 0
else:
self._voiced_ms = 0
return None
self._buffer.extend(frame)
if speech:
self._silence_ms = 0
else:
self._silence_ms += FRAME_MS
utterance_ms = len(self._buffer) * FRAME_MS // len(frame)
if self._silence_ms >= self.config.end_ms or utterance_ms >= self.config.max_utterance_ms:
utterance = bytes(self._buffer)
self.reset()
return utterance
return None
def reset(self) -> None:
self._in_utterance = False
self._voiced_ms = 0
self._silence_ms = 0
self._buffer = bytearray()
self._pre_roll = bytearray()