feat: server RAM via Prometheus /metrics in benchmark (v2.03.09)

Probe remote engines' /metrics for process_resident_memory_bytes or
container_memory_rss; show actual server-side MB in RAM column.
Falls back to "server" when the endpoint is not exposed.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

linux/CHANGELOG.md

@@ -9,6 +9,15 @@ The version is defined in [`blitztext/__init__.py`](blitztext/__init__.py).
 
 ## [Unreleased]
 
+## [2.03.09] - 2026-06-09
+
+### Added
+- **Server RAM in benchmark.** For remote/Docker STT engines the benchmark now
+  probes the server's Prometheus `/metrics` endpoint for
+  `process_resident_memory_bytes` (standard Python/Go exporter) or
+  `container_memory_rss` (cAdvisor) and shows the server-side RSS in MB in the
+  RAM column. Falls back to `server` when the endpoint is not exposed.
+
 ## [2.03.08] - 2026-06-09
 
 ### Fixed

linux/blitztext/__init__.py

@@ -6,4 +6,4 @@ counterpart to the macOS Blitztext menu bar app: it runs natively on the host
 (not in a container) so it can type into any application via xdotool.
 """
 
-__version__ = "2.03.08"
+__version__ = "2.03.09"

linux/blitztext/benchmark.py

@@ -41,7 +41,8 @@ class BenchRow:
     wer: float
     accuracy: float   # percent, max(0, 1-wer)*100
     text: str
-    ram_mb: float = 0.0  # RSS delta in MB; >0 means model loaded during this run
+    ram_mb: float = 0.0          # local RSS delta in MB
+    srv_ram_mb: float | None = None  # server /metrics RSS in MB, None = not available
     error: str = ""
 
 
@@ -126,6 +127,7 @@ def run(engines, wav_path: Path, reference: str, *, language: str = "",
 
     device_cache: dict = {}
     meta_cache: dict = {}   # url → list[ModelMeta]
+    server_ram_cache: dict = {}   # url → float | None (MB from /metrics)
 
     def _get_langs(e) -> list[str]:
         if e.is_local:
@@ -141,10 +143,21 @@ def run(engines, wav_path: Path, reference: str, *, language: str = "",
     rows: list[BenchRow] = []
     for e in run_list:
         tr = get_local_transcriber(e) if (e.is_local and get_local_transcriber) else None
+        # Snapshot server RAM before (if Prometheus metrics available)
+        if not e.is_local and e.url not in server_ram_cache:
+            server_ram_cache[e.url] = None  # sentinel — probe once per URL
+        srv_before: float | None = None
+        if not e.is_local:
+            srv_before = stt.probe_server_ram_mb(e.url)
         rss_before = _rss_mb()
         res = stt.benchmark(e, wav_path, language=language, local_transcriber=tr)
         rss_after = _rss_mb()
         ram_delta = max(0.0, rss_after - rss_before)
+        srv_ram: float | None = None
+        if not e.is_local:
+            srv_after = stt.probe_server_ram_mb(e.url)
+            if srv_before is not None and srv_after is not None:
+                srv_ram = srv_after  # report current RSS, not delta (server may not unload)
         w = wer(reference, res.text, case_sensitive=case_sensitive) if res.ok else 1.0
         row = BenchRow(
             engine=e.name,
@@ -159,6 +172,7 @@ def run(engines, wav_path: Path, reference: str, *, language: str = "",
             accuracy=max(0.0, 1.0 - w) * 100.0,
             text=res.text,
             ram_mb=ram_delta,
+            srv_ram_mb=srv_ram,
             error=res.error,
         )
         rows.append(row)

linux/blitztext/gtksettings.py

@@ -2104,8 +2104,10 @@ notebook.bt-nb tab:checked label {
                 col.set_max_width(max_w)
             if i == 8:
                 col.set_widget(Gtk.Label(label="RAM (MB)", tooltip_text=
-                    "RAM loaded by this engine during the benchmark run (local engines only).\n"
-                    "'server' = model runs in a container or remote server — memory is not visible here.\n"
+                    "RAM used by the engine during the benchmark.\n"
+                    "Local engines: RSS delta measured on this machine.\n"
+                    "Remote engines: current RSS read from the server's Prometheus /metrics endpoint.\n"
+                    "'server' = server does not expose /metrics — RAM not measurable.\n"
                     "'—' = local model was already loaded, no delta to measure."))
                 col.get_widget().show()
             tree.append_column(col)
@@ -2265,9 +2267,12 @@ notebook.bt-nb tab:checked label {
         if row.ram_mb >= 1.0:
             ram_display = f"{row.ram_mb:.0f}"
         elif row.url:
-            ram_display = "server"  # model runs remotely — RAM not measurable here
+            if row.srv_ram_mb is not None:
+                ram_display = f"{row.srv_ram_mb:.0f}"  # from server /metrics
+            else:
+                ram_display = "server"  # metrics not exposed
         else:
-            ram_display = "—"       # local model already loaded, no delta
+            ram_display = "—"  # local model already loaded, no delta
         self.bench_store.append([row.engine, url_display, row.model, row.device, row.best_for,
                                  lang_display, f"{row.seconds:.2f}", acc, ram_display, out_friendly, tooltip])
         # Persist result so Engines tab can show it

linux/blitztext/stt.py

@@ -148,6 +148,42 @@ def list_models_meta(base_url: str, api_key_env: str = "", timeout: float = 5.0)
     return []
 
 
+def probe_server_ram_mb(base_url: str, timeout: float = 3.0) -> float | None:
+    """Probe a remote server's Prometheus /metrics endpoint for RSS memory.
+
+    Returns RSS in MB if the server exposes Prometheus metrics with either
+    ``process_resident_memory_bytes`` (standard Python/Go exporter) or
+    ``container_memory_rss`` (cAdvisor). Returns None if not available.
+    """
+    if not base_url:
+        return None
+    base = _api_base(base_url)
+    try:
+        req = urllib.request.Request(base + "/metrics")
+        with urllib.request.urlopen(req, timeout=timeout) as resp:
+            text = resp.read().decode("utf-8", "replace")
+    except Exception:
+        return None
+
+    # Parse Prometheus text format — we only need two specific metric names.
+    # Lines look like:  process_resident_memory_bytes 1.23456e+08
+    best: float | None = None
+    for line in text.splitlines():
+        line = line.strip()
+        if line.startswith("#"):
+            continue
+        for metric in ("process_resident_memory_bytes", "container_memory_rss"):
+            if line.startswith(metric):
+                parts = line.split()
+                if len(parts) >= 2:
+                    try:
+                        best = float(parts[-1]) / (1024 * 1024)  # bytes → MB
+                        return best
+                    except ValueError:
+                        pass
+    return best
+
+
 def detect_remote_device(base_url: str, timeout: float = 3.0) -> str:
     """Best-effort GPU/CPU detection for a remote STT server.