The transcriber ships with the daemon that starts it (V-486)

serve.py lived only on workpc, which was fine while systemd launched it and is not fine now that mavgpud does. Two endpoints and no framework: /health answers 503 until the model is loaded, /transcribe takes raw PCM and returns {"text","confidence"}. The unit carries CW2_TOKEN through EnvironmentFile and the child inherits it, so the token is never a flag value. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013ptwopxyo3Z2kwFckHkLvN
2026-08-09 01:07:55 +04:00
parent b975716759
commit 1456336652
3 changed files with 176 additions and 2 deletions
@@ -0,0 +1,156 @@
+"""CrisperWhisper 2.0 turbo as an HTTP service, for Maven's stt.Pair.
+
+Two endpoints and no framework.
+
+  GET  /health      200 once the model is loaded, 503 while it is loading.
+  POST /transcribe  raw 16kHz mono PCM in, {"text","confidence"} out.
+
+The body is the PCM itself rather than JSON. A minute of 16kHz mono is under
+2MB raw and about 2.6MB base64, and the format is fixed at the Maven seam, so
+headers carry it more cheaply than an envelope.
+
+Why this exists at all: whisper.cpp cannot load CW2. It derives its language
+count from the vocabulary size, and CW2's 51897 tokens shift seven special
+token ids. So mavsttd stays whisper.cpp on homesrv and this runs beside the
+model on workpc, where it scores 10.4% WER in Russian against the floor's 27.5%
+(docs/evals/2026-08-09-crisperwhisper2-russian-wer.md in the Maven repo).
+
+Intended mode, not verbatim. The owner asked for what he meant to say, not
+every stutter on the way there.
+"""
+
+import hmac
+import json
+import logging
+import os
+import sys
+import threading
+import time
+from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
+
+import numpy as np
+
+HOST = os.environ.get("CW2_HOST", "0.0.0.0")
+PORT = int(os.environ.get("CW2_PORT", "8081"))
+SIZE = os.environ.get("CW2_SIZE", "turbo")
+MODE = os.environ.get("CW2_MODE", "intended")
+TOKEN = os.environ.get("CW2_TOKEN", "")
+# 25MB is about thirteen minutes of 16kHz mono. Longer than any utterance and
+# short enough that a wrong caller cannot exhaust memory.
+MAX_BODY = int(os.environ.get("CW2_MAX_BODY", str(25 * 1024 * 1024)))
+
+logging.basicConfig(
+    level=logging.INFO, format="%(asctime)s cw2: %(message)s", stream=sys.stderr
+)
+log = logging.getLogger("cw2")
+
+_model = None
+# The card holds one model and transcribes one utterance at a time. The lock is
+# what makes a second caller wait rather than corrupt the first.
+_lock = threading.Lock()
+
+
+def load_model():
+    global _model
+    from crisperwhisper import CrisperWhisperModel
+
+    t0 = time.perf_counter()
+    # backend is forced. With ctranslate2 importable, "auto" picks ct2, which is
+    # CUDA-only and this card is AMD.
+    m = CrisperWhisperModel(
+        SIZE, backend="transformers", compute_type="float16", device="cuda"
+    )
+    _model = m
+    log.info("loaded %s in %.1fs, mode=%s", SIZE, time.perf_counter() - t0, MODE)
+
+
+def authorised(headers):
+    if not TOKEN:
+        return True
+    got = headers.get("Authorization", "")
+    return hmac.compare_digest(got, "Bearer " + TOKEN)
+
+
+class Handler(BaseHTTPRequestHandler):
+    protocol_version = "HTTP/1.1"
+
+    def log_message(self, fmt, *args):
+        log.info(fmt, *args)
+
+    def _send(self, code, payload):
+        body = json.dumps(payload, ensure_ascii=False).encode("utf-8")
+        self.send_response(code)
+        self.send_header("Content-Type", "application/json; charset=utf-8")
+        self.send_header("Content-Length", str(len(body)))
+        self.end_headers()
+        self.wfile.write(body)
+
+    def do_GET(self):
+        if self.path.rstrip("/") != "/health":
+            self._send(404, {"error": "not found"})
+            return
+        if _model is None:
+            self._send(503, {"status": "loading"})
+            return
+        self._send(200, {"status": "ok", "model": SIZE, "mode": MODE})
+
+    def do_POST(self):
+        if self.path.rstrip("/") != "/transcribe":
+            self._send(404, {"error": "not found"})
+            return
+        if not authorised(self.headers):
+            self._send(401, {"error": "unauthorised"})
+            return
+        if _model is None:
+            self._send(503, {"error": "loading"})
+            return
+
+        length = int(self.headers.get("Content-Length", "0"))
+        if length <= 0 or length > MAX_BODY:
+            self._send(413, {"error": "bad body length"})
+            return
+        raw = self.rfile.read(length)
+
+        rate = int(self.headers.get("X-Sample-Rate", "16000"))
+        channels = int(self.headers.get("X-Channels", "1"))
+        bits = int(self.headers.get("X-Sample-Bits", "16"))
+        lang = self.headers.get("X-Language", "ru") or "ru"
+        if channels != 1 or bits != 16:
+            self._send(400, {"error": "want 16-bit mono pcm"})
+            return
+
+        # int16 little-endian to the float32 the encoder wants.
+        wav = np.frombuffer(raw, dtype="<i2").astype(np.float32) / 32768.0
+        if wav.size == 0:
+            self._send(200, {"text": "", "confidence": 0.0})
+            return
+
+        t0 = time.perf_counter()
+        try:
+            with _lock:
+                res = _model.transcribe(wav, sr=rate, language=lang, mode=MODE)
+        except Exception as exc:  # noqa: BLE001 - the caller falls back to mavsttd
+            log.exception("transcribe failed")
+            self._send(500, {"error": str(exc)})
+            return
+        elapsed = time.perf_counter() - t0
+        text = (res.text or "").strip()
+        log.info("%.2fs audio in %.2fs: %r", wav.size / rate, elapsed, text[:60])
+        # The model reports no calibrated score. 1.0 would be a claim, and the
+        # Maven side reads confidence only to log it.
+        self._send(200, {"text": text, "confidence": 0.0})
+
+
+def main():
+    if not TOKEN:
+        log.warning("no CW2_TOKEN set: anything on the LAN can post audio here")
+    # Bind before loading, so a restart answers 503 rather than refusing the
+    # connection. Both make Maven fall back, but only one of them says why.
+    srv = ThreadingHTTPServer((HOST, PORT), Handler)
+    threading.Thread(target=load_model, daemon=True).start()
+    log.info("listening on %s:%d", HOST, PORT)
+    srv.serve_forever()
+
+
+if __name__ == "__main__":
+    main()
@@ -20,6 +20,19 @@
    "--spec-draft-n-max", "2"
  ],

+  "//stt": [
+    "CrisperWhisper 2.0 turbo, which Maven reaches directly on port 8081.",
+    "mavgpud runs it because it is a ROCm process on this card: under its own",
+    "systemd unit it registered on the KFD and the supervisor evicted",
+    "llama-server every few seconds. CW2_TOKEN comes from the unit's",
+    "EnvironmentFile and is never a flag value."
+  ],
+  "stt": {
+    "addr": "127.0.0.1:8081",
+    "bin": "/home/kami/Programs/cw2-eval/.venv/bin/python",
+    "args": ["/home/kami/Programs/cw2-service/serve.py"]
+  },
+
  "kfd_root": "/sys/class/kfd/kfd/proc",
  "drm_device": "/sys/class/drm/card1/device",

@@ -1,5 +1,5 @@
 [Unit]
-# Runs on the workstation (bugmachine), not on homesrv. Install as a systemd
+# Runs on the workstation (workpc), not on homesrv. Install as a systemd
 # user unit and turn on lingering, so the card is supervised after a reboot
 # with nobody logged in:
 #
@@ -8,10 +8,15 @@
 #   scp deploy/mavgpud.service workpc:~/.config/systemd/user/mavgpud.service
 #   ssh workpc 'systemctl --user daemon-reload && systemctl --user enable --now mavgpud'
 #   sudo loginctl enable-linger kami
-Description=Maven GPU supervisor (holds llama-server while the card is free)
+Description=Maven GPU supervisor (holds llama-server and CW2 while the card is free)
 After=network.target

 [Service]
+# CW2_TOKEN for the transcriber child, which inherits this environment. The
+# token is read from a file and never appears as a flag value, the rule
+# mavpoll and mavmaild follow. Missing file, no transcriber auth, so keep the
+# dash off: a mavgpud that cannot read it must fail loudly.
+EnvironmentFile=%h/Programs/cw2-service/cw2.env
 ExecStart=%h/.local/bin/mavgpud -config %h/.config/mavgpud.json
 Restart=always
 RestartSec=5