anti
314e6c6388
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
103 lines
3.8 KiB
Python
103 lines
3.8 KiB
Python
import json
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import asyncio
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from typing import AsyncGenerator, Optional
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from fastapi import APIRouter, Depends, Query, Request
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from fastapi.responses import StreamingResponse
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from decnet.env import DECNET_DEVELOPER
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from decnet.logging import get_logger
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from decnet.web.dependencies import require_stream_viewer, repo
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log = get_logger("api")
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router = APIRouter()
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@router.get("/stream", tags=["Observability"],
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responses={
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200: {
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"content": {"text/event-stream": {}},
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"description": "Real-time Server-Sent Events (SSE) stream"
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},
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401: {"description": "Could not validate credentials"},
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422: {"description": "Validation error"}
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},
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)
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async def stream_events(
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request: Request,
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last_event_id: int = Query(0, alias="lastEventId"),
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search: Optional[str] = None,
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start_time: Optional[str] = None,
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end_time: Optional[str] = None,
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max_output: Optional[int] = Query(None, alias="maxOutput"),
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user: dict = Depends(require_stream_viewer)
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) -> StreamingResponse:
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async def event_generator() -> AsyncGenerator[str, None]:
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last_id = last_event_id
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stats_interval_sec = 10
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loops_since_stats = 0
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emitted_chunks = 0
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try:
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yield ": keepalive\n\n" # flush headers immediately; helps diagnose pre-yield hangs
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if last_id == 0:
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last_id = await repo.get_max_log_id()
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# Emit initial snapshot immediately so the client never needs to poll /stats
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stats = await repo.get_stats_summary()
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yield f"event: message\ndata: {json.dumps({'type': 'stats', 'data': stats})}\n\n"
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histogram = await repo.get_log_histogram(
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search=search, start_time=start_time,
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end_time=end_time, interval_minutes=15,
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)
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yield f"event: message\ndata: {json.dumps({'type': 'histogram', 'data': histogram})}\n\n"
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while True:
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if DECNET_DEVELOPER and max_output is not None:
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emitted_chunks += 1
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if emitted_chunks > max_output:
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log.debug("Developer mode: max_output reached (%d), closing stream", max_output)
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break
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if await request.is_disconnected():
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break
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new_logs = await repo.get_logs_after_id(
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last_id, limit=50, search=search,
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start_time=start_time, end_time=end_time,
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)
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if new_logs:
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last_id = max(entry["id"] for entry in new_logs)
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yield f"event: message\ndata: {json.dumps({'type': 'logs', 'data': new_logs})}\n\n"
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loops_since_stats = stats_interval_sec
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if loops_since_stats >= stats_interval_sec:
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stats = await repo.get_stats_summary()
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yield f"event: message\ndata: {json.dumps({'type': 'stats', 'data': stats})}\n\n"
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histogram = await repo.get_log_histogram(
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search=search, start_time=start_time,
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end_time=end_time, interval_minutes=15,
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)
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yield f"event: message\ndata: {json.dumps({'type': 'histogram', 'data': histogram})}\n\n"
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loops_since_stats = 0
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loops_since_stats += 1
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await asyncio.sleep(1)
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except asyncio.CancelledError:
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pass
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except Exception:
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log.exception("SSE stream error for user %s", last_event_id)
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yield f"event: error\ndata: {json.dumps({'type': 'error', 'message': 'Stream interrupted'})}\n\n"
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return StreamingResponse(
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event_generator(),
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media_type="text/event-stream",
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headers={
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"Cache-Control": "no-cache",
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"X-Accel-Buffering": "no",
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},
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)
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