feat(api): introduce FastAPI app that boots SerialManager and exposes GET /status

- Add benchmesh_service.api FastAPI module
- Add dependencies (fastapi, uvicorn) to pyproject
- README_FASTAPI with run instructions

Co-authored-by: openhands <openhands@all-hands.dev>

Author: openhands-agent

benchmesh-serial-service/README_FASTAPI.md

@@ -0,0 +1,18 @@
+# BenchMesh Serial Service - FastAPI mode
+
+Two ways to run the service:
+
+1) Standalone SerialManager (legacy/debug)
+   - poetry run python -m benchmesh_service.main --config ./config.yaml
+
+2) FastAPI application
+   - ENV: BENCHMESH_CONFIG=./config.yaml
+   - poetry run uvicorn benchmesh_service.api:app --host 0.0.0.0 --port 52892
+
+API
+- GET /status -> { "devices_total": N, "connected": M, "disconnected": N-M }
+
+Notes
+- The FastAPI app starts/stops SerialManager on app startup/shutdown.
+- Keep BENCHMESH_CONFIG environment variable pointing to your config.yaml.
+- To enable console DEBUG logs, adjust logger configuration if desired.

benchmesh-serial-service/pyproject.toml

@@ -15,6 +15,8 @@ pyserial = "^3.5"
 pydantic = "^1.8"
 loguru = "^0.5.3"
 pyyaml = "^6.0.3"
+fastapi = "^0.111.0"
+uvicorn = {version = "^0.30.0", extras=["standard"]}
 
 [build-system]
 requires = ["poetry-core>=1.0.0"]

benchmesh-serial-service/src/benchmesh_service/api.py

@@ -0,0 +1,40 @@
+import os
+from fastapi import FastAPI
+from .serial_manager import SerialManager
+from .config import load_config
+
+app = FastAPI(title="BenchMesh Serial Service", version="0.1.0")
+
+_manager: SerialManager | None = None
+
+
+def _make_manager() -> SerialManager:
+    cfg_path = os.getenv("BENCHMESH_CONFIG", "config.yaml")
+    cfg = load_config(cfg_path)
+    return SerialManager(cfg.get('devices', []))
+
+
+@app.on_event("startup")
+def on_startup():
+    global _manager
+    _manager = _make_manager()
+    _manager.start()
+
+
+@app.on_event("shutdown")
+def on_shutdown():
+    global _manager
+    if _manager:
+        _manager.stop()
+        _manager = None
+
+
+@app.get("/status", summary="Service status", response_model=dict)
+def get_status():
+    global _manager
+    if not _manager:
+        return {"devices_total": 0, "connected": 0, "disconnected": 0}
+    device_ids = [d.get('id') for d in _manager.devices if d.get('id')]
+    total = len(device_ids)
+    connected = sum(1 for did in device_ids if _manager.connections.get(did))
+    return {"devices_total": total, "connected": connected, "disconnected": total - connected}