Accept TradingView webhooks immediately and deliver in background.

Chart and Telegram work no longer block the HTTP response, avoiding TV webhook timeouts.

Co-authored-by: Cursor <cursoragent@cursor.com>

README.md

@@ -143,12 +143,12 @@ For seq >1, profit % is signed vs entry; RR is `|price−entry| / |entry−SL|`
 
 ## Behavior
 
-1. Validate payload
-2. Fetch ~90 klines from Binance USDT-M Futures (public, no API key)
+1. Validate secret + payload, then immediately respond `200` (`{"ok": true, "accepted": true}`) so TradingView does not time out
+2. In the background: fetch ~90 klines from Binance USDT-M Futures (public, no API key)
 3. Render PNG: candles + Entry / SL / TP1–3 from the payload, starting at the `signal_time` candle (seq `>1` reuses frozen seq-1 levels/time and also marks live `Price`)
 4. `sendPhoto` to `TELEGRAM_CHAT_ID` topic from URL path or env `TELEGRAM_MESSAGE_THREAD_ID`
-5. If chart/klines fail → text-only `sendMessage` fallback (still `200`)
-6. If Telegram fails → `502`
+5. If chart/klines fail → text-only `sendMessage` fallback
+6. If Telegram fails → logged only (HTTP already returned `200`)
 
 ## Endpoints
 

app/main.py

@@ -1,17 +1,18 @@
 from __future__ import annotations
 
+import asyncio
 import json
 import logging
 import secrets
 from typing import Any
 
-from fastapi import FastAPI, HTTPException, Request
+from fastapi import BackgroundTasks, FastAPI, HTTPException, Request
 from fastapi.responses import JSONResponse
 from pydantic import ValidationError
 
 from app.binance import fetch_klines, to_binance_interval, to_binance_symbol
 from app.chart import render_setup_chart
-from app.config import get_settings
+from app.config import Settings, get_settings
 from app.formatter import format_caption
 from app.models import SignalPayload
 from app.telegram import TelegramError, send_message, send_photo
@@ -52,35 +53,13 @@ def _parse_signal_body(raw: bytes) -> SignalPayload:
         raise HTTPException(status_code=422, detail=json.loads(exc.json())) from exc
 
 
-@app.api_route("/health", methods=["GET", "HEAD"])
-async def health() -> dict[str, str]:
-    return {"status": "ok"}
-
-
-async def _handle_webhook(
-    token: str,
-    request: Request,
-    thread_id: int | None,
-) -> JSONResponse:
-    settings = get_settings()
-    if not secrets.compare_digest(token, settings.webhook_secret):
-        raise HTTPException(status_code=404, detail="Not Found")
-
-    message_thread_id = (
-        thread_id if thread_id is not None else settings.telegram_message_thread_id
-    )
-
-    signal = _parse_signal_body(await request.body())
+async def _deliver_signal(
+    settings: Settings,
+    signal: SignalPayload,
+    message_thread_id: int,
+) -> None:
+    """Fetch chart + post to Telegram after the webhook HTTP response is sent."""
     caption = format_caption(signal)
-    logger.info(
-        "Signal received: %s %s seq=%s tf=%s thread=%s",
-        signal.ticker,
-        signal.action.value,
-        signal.signal_sequence,
-        signal.visual_timeframe,
-        message_thread_id,
-    )
-
     photo: bytes | None = None
     chart_error: str | None = None
 
@@ -88,10 +67,11 @@ async def _handle_webhook(
         symbol = to_binance_symbol(signal.ticker)
         interval = to_binance_interval(signal.visual_timeframe)
         df = await fetch_klines(symbol, interval)
-        photo = render_setup_chart(
+        photo = await asyncio.to_thread(
+            render_setup_chart,
             df,
             ticker=signal.ticker,
-            action=signal.action.value,  # type: ignore[arg-type]
+            action=signal.action.value,
             entry=signal.entry_price,
             stop_loss=signal.stop_loss_price,
             tp1=signal.take_profit_1_price,
@@ -115,35 +95,81 @@ async def _handle_webhook(
                 caption=caption,
                 message_thread_id=message_thread_id,
             )
-            return JSONResponse(
-                {"ok": True, "delivered": "photo", "chart_error": None},
-                status_code=200,
+            logger.info(
+                "Delivered photo: %s %s seq=%s thread=%s",
+                signal.ticker,
+                signal.action.value,
+                signal.signal_sequence,
+                message_thread_id,
             )
+            return
 
         await send_message(
             settings,
             text=caption,
             message_thread_id=message_thread_id,
         )
-        return JSONResponse(
-            {
-                "ok": True,
-                "delivered": "text",
-                "chart_error": chart_error,
-            },
-            status_code=200,
+        logger.info(
+            "Delivered text: %s %s seq=%s thread=%s chart_error=%s",
+            signal.ticker,
+            signal.action.value,
+            signal.signal_sequence,
+            message_thread_id,
+            chart_error,
         )
     except TelegramError as exc:
         logger.exception("Telegram delivery failed: %s", exc)
-        raise HTTPException(status_code=502, detail=str(exc)) from exc
     except Exception as exc:  # noqa: BLE001
         logger.exception("Unexpected delivery error: %s", exc)
-        raise HTTPException(status_code=500, detail=str(exc)) from exc
+
+
+@app.api_route("/health", methods=["GET", "HEAD"])
+async def health() -> dict[str, str]:
+    return {"status": "ok"}
+
+
+async def _handle_webhook(
+    token: str,
+    request: Request,
+    thread_id: int | None,
+    background_tasks: BackgroundTasks,
+) -> JSONResponse:
+    settings = get_settings()
+    if not secrets.compare_digest(token, settings.webhook_secret):
+        raise HTTPException(status_code=404, detail="Not Found")
+
+    message_thread_id = (
+        thread_id if thread_id is not None else settings.telegram_message_thread_id
+    )
+
+    signal = _parse_signal_body(await request.body())
+    logger.info(
+        "Signal accepted: %s %s seq=%s tf=%s thread=%s",
+        signal.ticker,
+        signal.action.value,
+        signal.signal_sequence,
+        signal.visual_timeframe,
+        message_thread_id,
+    )
+
+    background_tasks.add_task(
+        _deliver_signal,
+        settings,
+        signal,
+        message_thread_id,
+    )
+    return JSONResponse({"ok": True, "accepted": True}, status_code=200)
 
 
 @app.post("/h/{token}")
-async def webhook(token: str, request: Request) -> JSONResponse:
-    return await _handle_webhook(token, request, thread_id=None)
+async def webhook(
+    token: str,
+    request: Request,
+    background_tasks: BackgroundTasks,
+) -> JSONResponse:
+    return await _handle_webhook(
+        token, request, thread_id=None, background_tasks=background_tasks
+    )
 
 
 @app.post("/h/{token}/{thread_id}")
@@ -151,7 +177,10 @@ async def webhook_with_thread(
     token: str,
     thread_id: int,
     request: Request,
+    background_tasks: BackgroundTasks,
 ) -> JSONResponse:
     if thread_id < 1:
         raise HTTPException(status_code=422, detail="thread_id must be >= 1")
-    return await _handle_webhook(token, request, thread_id=thread_id)
+    return await _handle_webhook(
+        token, request, thread_id=thread_id, background_tasks=background_tasks
+    )