feat(signal_v2): pull_worker + FastAPI app + 2 integration tests

poll_loop: asyncio.gather parallel fetch of 3 endpoints (portfolio,
news_sentiment, screener_preview) + state update. main.py: FastAPI
lifespan creates StockClient/SignalDedup/shutdown.Event then spawns
poll_loop as background task. GET /health reports status, last poll
times, cache size.

Signal V2 test suite: 19/19 PASS.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

signal_v2/main.py

@@ -0,0 +1,70 @@
+"""FastAPI app — Signal V2 Pull Worker."""
+from __future__ import annotations
+import asyncio
+import logging
+from contextlib import asynccontextmanager
+
+from fastapi import FastAPI
+
+from signal_v2 import state as state_mod
+from signal_v2.config import get_settings
+from signal_v2.pull_worker import poll_loop
+from signal_v2.rate_limit import SignalDedup
+from signal_v2.stock_client import StockClient
+
+logger = logging.getLogger(__name__)
+
+
+class AppContext:
+    client: StockClient | None = None
+    dedup: SignalDedup | None = None
+    shutdown: asyncio.Event | None = None
+    poll_task: asyncio.Task | None = None
+
+
+_ctx = AppContext()
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    settings = get_settings()
+    if not settings.webai_api_key:
+        logger.warning(
+            "WEBAI_API_KEY not configured — stock API calls will fail with 401"
+        )
+
+    _ctx.client = StockClient(settings.stock_api_url, settings.webai_api_key)
+    _ctx.dedup = SignalDedup(settings.db_path)
+    _ctx.shutdown = asyncio.Event()
+    _ctx.poll_task = asyncio.create_task(
+        poll_loop(_ctx.client, state_mod.state, _ctx.shutdown)
+    )
+
+    yield
+
+    # Shutdown
+    if _ctx.shutdown is not None:
+        _ctx.shutdown.set()
+    if _ctx.poll_task is not None:
+        try:
+            await asyncio.wait_for(_ctx.poll_task, timeout=5.0)
+        except asyncio.TimeoutError:
+            _ctx.poll_task.cancel()
+    if _ctx.client is not None:
+        await _ctx.client.close()
+
+
+app = FastAPI(
+    title="Signal V2 Pull Worker", version="0.1.0", lifespan=lifespan
+)
+
+
+@app.get("/health")
+async def health():
+    settings = get_settings()
+    return {
+        "status": "online",
+        "stock_api_url": settings.stock_api_url,
+        "last_poll": state_mod.state.last_updated,
+        "cache_size": len(_ctx.client._cache) if _ctx.client is not None else 0,
+    }

signal_v2/pull_worker.py

@@ -0,0 +1,58 @@
+"""Polling loop — async cron + state update."""
+from __future__ import annotations
+import asyncio
+import logging
+from datetime import datetime
+
+from signal_v2.scheduler import (
+    KST, _is_market_day, _is_polling_window, _next_interval,
+)
+from signal_v2.state import PollState
+from signal_v2.stock_client import StockClient
+
+logger = logging.getLogger(__name__)
+
+
+async def poll_loop(
+    client: StockClient, state: PollState, shutdown: asyncio.Event
+) -> None:
+    """FastAPI lifespan 에서 asyncio.create_task 로 시작."""
+    logger.info("poll_loop started")
+    while not shutdown.is_set():
+        now = datetime.now(KST)
+        if _is_market_day(now) and _is_polling_window(now):
+            try:
+                await _run_polling_cycle(client, state)
+            except Exception:
+                logger.exception("poll cycle failed")
+        interval = _next_interval(now)
+        try:
+            await asyncio.wait_for(shutdown.wait(), timeout=interval)
+            break
+        except asyncio.TimeoutError:
+            continue
+    logger.info("poll_loop ended")
+
+
+async def _run_polling_cycle(client: StockClient, state: PollState) -> None:
+    """3 endpoint 병렬 fetch + state 갱신."""
+    portfolio, sentiment, screener = await asyncio.gather(
+        client.get_portfolio(),
+        client.get_news_sentiment(),
+        client.run_screener_preview(),
+        return_exceptions=True,
+    )
+    now_iso = datetime.now(KST).isoformat()
+
+    for name, result in (
+        ("portfolio", portfolio),
+        ("news_sentiment", sentiment),
+        ("screener_preview", screener),
+    ):
+        if isinstance(result, dict):
+            setattr(state, name, result)
+            state.last_updated[name] = now_iso
+            state.fetch_errors[name] = 0
+        else:
+            state.fetch_errors[name] = state.fetch_errors.get(name, 0) + 1
+            logger.warning("fetch %s failed: %r", name, result)

signal_v2/tests/test_main.py

@@ -0,0 +1,36 @@
+"""Tests for FastAPI main app."""
+import logging
+
+import pytest
+from fastapi.testclient import TestClient
+
+
+def test_health_endpoint_returns_status_online(monkeypatch):
+    monkeypatch.setenv("STOCK_API_URL", "https://test.stock.local")
+    monkeypatch.setenv("WEBAI_API_KEY", "test-secret")
+    # Reload modules so they pick up the new env
+    import importlib
+    from signal_v2 import config as cfg
+    importlib.reload(cfg)
+    from signal_v2 import main as main_mod
+    importlib.reload(main_mod)
+    with TestClient(main_mod.app) as client:
+        r = client.get("/health")
+        assert r.status_code == 200
+        body = r.json()
+        assert body["status"] == "online"
+        assert body["stock_api_url"] == "https://test.stock.local"
+
+
+def test_startup_warns_if_webai_api_key_missing(monkeypatch, caplog):
+    monkeypatch.delenv("WEBAI_API_KEY", raising=False)
+    monkeypatch.setenv("STOCK_API_URL", "https://test.stock.local")
+    import importlib
+    from signal_v2 import config as cfg
+    importlib.reload(cfg)
+    from signal_v2 import main as main_mod
+    importlib.reload(main_mod)
+    with caplog.at_level(logging.WARNING, logger="signal_v2.main"):
+        with TestClient(main_mod.app) as client:
+            client.get("/health")
+        assert any("WEBAI_API_KEY" in rec.message for rec in caplog.records)