init

backend/core/progress_bus.py

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+"""
+progress_bus.py - 07 May 2025
+"""
+from __future__ import annotations
+import asyncio, json, time
+from typing import Dict, Any
+
+# in-mem state
+_progress: Dict[str, Dict[str, Any]] = {}
+_watchers: Dict[str, list[asyncio.Queue[str]]] = {}
+_TTL = 60 * 60        # keep finished/error records 1 h
+
+def _now() -> float: return time.time()
+
+def register(sid: str) -> None:
+    _progress[sid] = dict(pct=0, progress="", status="running", ts=_now())
+    _broadcast(sid)
+
+def update(sid: str, *, pct: float | None = None,
+           progress: str | None = None, status: str | None = None) -> None:
+    if sid not in _progress:
+        register(sid)
+    p = _progress[sid]
+    if pct is not None:      p["pct"] = pct
+    if progress is not None: p["progress"] = progress
+    if status is not None:   p["status"] = status
+    p["ts"] = _now()
+    _broadcast(sid)
+
+def get(sid: str) -> Dict[str, Any]:
+    _gc()
+    return _progress.get(sid, {"status": "idle"})
+
+def clear(sid: str) -> None:
+    _progress.pop(sid, None)
+    _watchers.pop(sid, None)
+
+#  SSE integration
+def subscribe(sid: str) -> asyncio.Queue[str]:
+    q: asyncio.Queue[str] = asyncio.Queue(maxsize=16)
+    _watchers.setdefault(sid, []).append(q)
+    # immediately push current state
+    q.put_nowait(json.dumps({"sid": sid, **get(sid)}))
+    return q
+
+def _broadcast(sid: str) -> None:
+    if sid not in _watchers:
+        return
+    payload = json.dumps({"sid": sid, **_progress[sid]})
+    for q in list(_watchers[sid]):
+        try:
+            q.put_nowait(payload)
+        except asyncio.QueueFull:
+            pass  # drop frame
+
+# garbage collector
+def _gc() -> None:
+    now = _now()
+    stale = [k for k, v in _progress.items()
+             if v["status"] in ("finished", "error") and now - v["ts"] > _TTL]
+    for k in stale:
+        clear(k)