Suya OCR API — vLLM-backed, OpenAI-compatible OCR service

FastAPI service wrapping the Surya-OCR-2 model (datalab-to) served through vLLM:
legacy /v1/api/ai/* endpoints, an OpenAI-compatible /v1/chat/completions endpoint,
a coalescing request batcher, a local OCR CLI, Docker packaging, multilingual
example outputs, and quantization/concurrency benchmarks.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

scripts/poll_vllm_metrics.py

@@ -0,0 +1,54 @@
+"""Sample a vLLM server's Prometheus /metrics and report peak in-flight sequences.
+
+vLLM exposes `vllm:num_requests_running` (currently executing on GPU) and
+`vllm:num_requests_waiting` (queued). Peak running vs VLLM_MAX_NUM_SEQS tells us
+whether we are saturating or overflowing the GPU's sequence slots.
+
+Run this in the background during a benchmark, then read its printed summary.
+
+Usage:
+    python scripts/poll_vllm_metrics.py \
+        --url http://127.0.0.1:8000/metrics --interval 0.25 --duration 120
+"""
+from __future__ import annotations
+
+import argparse
+import re
+import time
+
+import requests
+
+_RUNNING_RE = re.compile(r"^vllm:num_requests_running\S*\s+([0-9.]+)", re.MULTILINE)
+_WAITING_RE = re.compile(r"^vllm:num_requests_waiting\S*\s+([0-9.]+)", re.MULTILINE)
+
+
+def _scrape(url: str) -> tuple[float, float]:
+    text = requests.get(url, timeout=5).text
+    running = max((float(m) for m in _RUNNING_RE.findall(text)), default=0.0)
+    waiting = max((float(m) for m in _WAITING_RE.findall(text)), default=0.0)
+    return running, waiting
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description="Poll vLLM /metrics for peak in-flight sequences.")
+    parser.add_argument("--url", default="http://127.0.0.1:8000/metrics")
+    parser.add_argument("--interval", type=float, default=0.25)
+    parser.add_argument("--duration", type=float, default=120)
+    args = parser.parse_args()
+
+    peak_running = 0.0
+    peak_waiting = 0.0
+    deadline = time.perf_counter() + args.duration
+    while time.perf_counter() < deadline:
+        try:
+            running, waiting = _scrape(args.url)
+            peak_running = max(peak_running, running)
+            peak_waiting = max(peak_waiting, waiting)
+        except Exception:
+            pass
+        time.sleep(args.interval)
+    print(f"peak_running={peak_running} peak_waiting={peak_waiting}")
+
+
+if __name__ == "__main__":
+    main()