perf(pipeline): in-memory cache for usv_track (warm: 20ms vs 1.8s cold)

pipeline_runner/main.py

@@ -201,9 +201,14 @@ def _read_usv_track(nav_log_path: Path, max_pts: int = 2000) -> list[dict]:
     return pts
 
 
+_track_cache: dict[str, list[dict]] = {}
+
+
 @app.get("/sorties/{sortie_id:path}/usv_track")
 async def get_usv_track(sortie_id: str):
     """Return USV GPS track [{t_ms, lat, lon, heading, source}] for map polylines."""
+    if sortie_id in _track_cache:
+        return JSONResponse(_track_cache[sortie_id])
     raw_dir = OUTPUT_DIR / sortie_id / "raw"
     nav_logs = list(raw_dir.rglob("*_navigation_log.csv")) if raw_dir.exists() else []
     if not nav_logs:
@@ -212,4 +217,5 @@ async def get_usv_track(sortie_id: str):
     for nav_log in nav_logs:
         pts.extend(await asyncio.to_thread(_read_usv_track, nav_log))
     pts.sort(key=lambda p: p["t_ms"])
+    _track_cache[sortie_id] = pts
     return JSONResponse(pts)