fix(dashboard): keep session DB reads off event loop

hermes_cli/web_server.py

@@ -1910,6 +1910,22 @@ async def fs_default_cwd():
     return {"cwd": cwd, "branch": _fs_git_branch(cwd)}
 
 
+def _count_active_sessions() -> int:
+    from hermes_state import SessionDB
+
+    db = SessionDB()
+    try:
+        sessions = db.list_sessions_rich(limit=50)
+        now = time.time()
+        return sum(
+            1 for s in sessions
+            if s.get("ended_at") is None
+            and (now - s.get("last_active", s.get("started_at", 0))) < 300
+        )
+    finally:
+        db.close()
+
+
 @app.get("/api/status")
 async def get_status(profile: Optional[str] = None):
     status_scope = None
@@ -2008,18 +2024,7 @@ async def get_status(profile: Optional[str] = None):
 
         active_sessions = 0
         try:
-            from hermes_state import SessionDB
-            db = SessionDB()
-            try:
-                sessions = db.list_sessions_rich(limit=50)
-                now = time.time()
-                active_sessions = sum(
-                    1 for s in sessions
-                    if s.get("ended_at") is None
-                    and (now - s.get("last_active", s.get("started_at", 0))) < 300
-                )
-            finally:
-                db.close()
+            active_sessions = await asyncio.to_thread(_count_active_sessions)
         except Exception:
             pass
 
@@ -3137,7 +3142,7 @@ async def get_action_status(name: str, lines: int = 200):
 
 
 @app.get("/api/sessions")
-async def get_sessions(
+def get_sessions(
     limit: int = 20,
     offset: int = 0,
     min_messages: int = 0,
@@ -3226,7 +3231,7 @@ async def get_sessions(
 
 
 @app.get("/api/profiles/sessions")
-async def get_profiles_sessions(
+def get_profiles_sessions(
     limit: int = 20,
     offset: int = 0,
     min_messages: int = 0,

tests/hermes_cli/test_web_server_boot_handshake.py

@@ -29,6 +29,7 @@ from unittest.mock import patch
 import pytest
 
 import hermes_cli.web_server as web_server_mod
+import hermes_state
 
 SLOW_SECONDS = 3  # represents the Defender worst-case (scaled down for CI speed)
 
@@ -186,3 +187,46 @@ def test_concurrent_status_probes_all_respond():
         f"{len(failed)}/{PROBES} probes failed (codes: {responses}). "
         f"This would cause WinError 10054 and orphan accumulation on desktop."
     )
+
+
+def test_status_session_count_does_not_block_event_loop(monkeypatch):
+    import httpx
+
+    class SlowSessionDB:
+        def list_sessions_rich(self, limit: int = 50):
+            time.sleep(SLOW_SECONDS)
+            return []
+
+        def close(self):
+            pass
+
+    monkeypatch.setattr(hermes_state, "SessionDB", SlowSessionDB)
+    results: dict[str, float | int] = {}
+
+    async def _run():
+        transport = httpx.ASGITransport(app=web_server_mod.app)
+        async with httpx.AsyncClient(transport=transport, base_url="http://test") as client:
+            scenario_started = time.perf_counter()
+            async with asyncio.TaskGroup() as tg:
+                async def _status():
+                    t = time.perf_counter()
+                    r = await client.get("/api/status", timeout=SLOW_SECONDS + 5)
+                    results["status_ms"] = (time.perf_counter() - t) * 1000
+                    results["status_code"] = r.status_code
+
+                async def _version():
+                    await asyncio.sleep(0.1)
+                    t = time.perf_counter()
+                    r = await client.get("/api/version", timeout=5)
+                    results["version_ms"] = (time.perf_counter() - t) * 1000
+                    results["version_elapsed_ms"] = (time.perf_counter() - scenario_started) * 1000
+                    results["version_code"] = r.status_code
+
+                tg.create_task(_status())
+                tg.create_task(_version())
+
+    asyncio.run(_run())
+
+    assert results.get("version_code") in {200, 401}
+    assert results.get("status_code") == 200
+    assert results["version_elapsed_ms"] < SLOW_SECONDS * 1000