fix: remove event-loop-blocking cold start; unify profiler to cursor-based incremental

Cold start fetched all logs in one bulk query then processed them in a tight
synchronous loop with no yields, blocking the asyncio event loop for seconds
on datasets of 30K+ rows. This stalled every concurrent await — including the
SSE stream generator's initial DB calls — causing the dashboard to show
INITIALIZING SENSORS indefinitely.

Changes:
- Drop _cold_start() and get_all_logs_raw(); uninitialized state now runs the
  same cursor loop as incremental, starting from last_log_id=0
- Yield to the event loop after every _BATCH_SIZE rows (asyncio.sleep(0))
- Add SSE keepalive comment as first yield so the connection flushes before
  any DB work begins
- Add Cache-Control/X-Accel-Buffering headers to StreamingResponse

decnet/profiler/worker.py

@@ -59,10 +59,7 @@ async def attacker_profile_worker(repo: BaseRepository, *, interval: int = 30) -
 
 
 async def _incremental_update(repo: BaseRepository, state: _WorkerState) -> None:
-    if not state.initialized:
-        await _cold_start(repo, state)
-        return
-
+    was_cold = not state.initialized
     affected_ips: set[str] = set()
 
     while True:
@@ -76,9 +73,13 @@ async def _incremental_update(repo: BaseRepository, state: _WorkerState) -> None
                 affected_ips.add(event.attacker_ip)
             state.last_log_id = row["id"]
 
+        await asyncio.sleep(0)  # yield to event loop after each batch
+
         if len(batch) < _BATCH_SIZE:
             break
 
+    state.initialized = True
+
     if not affected_ips:
         await repo.set_state(_STATE_KEY, {"last_log_id": state.last_log_id})
         return
@@ -86,27 +87,10 @@ async def _incremental_update(repo: BaseRepository, state: _WorkerState) -> None
     await _update_profiles(repo, state, affected_ips)
     await repo.set_state(_STATE_KEY, {"last_log_id": state.last_log_id})
 
-    logger.info("attacker worker: updated %d profiles (incremental)", len(affected_ips))
-
-
-async def _cold_start(repo: BaseRepository, state: _WorkerState) -> None:
-    all_logs = await repo.get_all_logs_raw()
-    if not all_logs:
-        state.last_log_id = await repo.get_max_log_id()
-        state.initialized = True
-        await repo.set_state(_STATE_KEY, {"last_log_id": state.last_log_id})
-        return
-
-    for row in all_logs:
-        state.engine.ingest(row["raw_line"])
-        state.last_log_id = max(state.last_log_id, row["id"])
-
-    all_ips = set(state.engine._events.keys())
-    await _update_profiles(repo, state, all_ips)
-    await repo.set_state(_STATE_KEY, {"last_log_id": state.last_log_id})
-
-    state.initialized = True
-    logger.info("attacker worker: cold start rebuilt %d profiles", len(all_ips))
+    if was_cold:
+        logger.info("attacker worker: cold start rebuilt %d profiles", len(affected_ips))
+    else:
+        logger.info("attacker worker: updated %d profiles (incremental)", len(affected_ips))
 
 
 async def _update_profiles(

decnet/web/db/repository.py

@@ -111,11 +111,6 @@ class BaseRepository(ABC):
         """Store a specific state entry by key."""
         pass
 
-    @abstractmethod
-    async def get_all_logs_raw(self) -> list[dict[str, Any]]:
-        """Retrieve all log rows with fields needed by the attacker profile worker."""
-        pass
-
     @abstractmethod
     async def get_max_log_id(self) -> int:
         """Return the highest log ID, or 0 if the table is empty."""

decnet/web/db/sqlmodel_repo.py

@@ -413,34 +413,6 @@ class SQLModelRepository(BaseRepository):
 
     # ----------------------------------------------------------- attackers
 
-    async def get_all_logs_raw(self) -> List[dict[str, Any]]:
-        async with self.session_factory() as session:
-            result = await session.execute(
-                select(
-                    Log.id,
-                    Log.raw_line,
-                    Log.attacker_ip,
-                    Log.service,
-                    Log.event_type,
-                    Log.decky,
-                    Log.timestamp,
-                    Log.fields,
-                )
-            )
-            return [
-                {
-                    "id": r.id,
-                    "raw_line": r.raw_line,
-                    "attacker_ip": r.attacker_ip,
-                    "service": r.service,
-                    "event_type": r.event_type,
-                    "decky": r.decky,
-                    "timestamp": r.timestamp,
-                    "fields": r.fields,
-                }
-                for r in result.all()
-            ]
-
     async def get_all_bounties_by_ip(self) -> dict[str, List[dict[str, Any]]]:
         from collections import defaultdict
         async with self.session_factory() as session:

decnet/web/router/stream/api_stream_events.py

@@ -40,6 +40,8 @@ async def stream_events(
         loops_since_stats = 0
         emitted_chunks = 0
         try:
+            yield ": keepalive\n\n"  # flush headers immediately; helps diagnose pre-yield hangs
+
             if last_id == 0:
                 last_id = await repo.get_max_log_id()
 
@@ -90,4 +92,11 @@ async def stream_events(
             log.exception("SSE stream error for user %s", last_event_id)
             yield f"event: error\ndata: {json.dumps({'type': 'error', 'message': 'Stream interrupted'})}\n\n"
 
-    return StreamingResponse(event_generator(), media_type="text/event-stream")
+    return StreamingResponse(
+        event_generator(),
+        media_type="text/event-stream",
+        headers={
+            "Cache-Control": "no-cache",
+            "X-Accel-Buffering": "no",
+        },
+    )