perf: shared httpx client, gzip, overlay cache-control

Reuse one TLS pool for overlay upstreams (8s/3s timeouts). Gzip JSON
over 1 KB. Aircraft/vessels Cache-Control max-age=5, alerts/perimeters 30.
Lifespan replaces deprecated on_event startup.

app/live_layers.py

@@ -49,7 +49,8 @@ CONUS = (-125.0, 24.0, -66.0, 50.0)
 MAX_RADIUS_NM = 150
 DEFAULT_LIMIT = 2000
 
-_HTTP_TIMEOUT = 25.0
+_HTTP_TIMEOUT = httpx.Timeout(8.0, connect=3.0)
+_http: httpx.AsyncClient | None = None
 _COMPASS = {
     "N": 0, "NE": 45, "E": 90, "SE": 135,
     "S": 180, "SW": 225, "W": 270, "NW": 315,
@@ -529,12 +530,36 @@ async def _ttl_get(key: str, ttl: float, factory: Callable[[], Awaitable[Any]])
         return value
 
 
+async def init_http() -> None:
+    """Shared outbound client — one TLS pool for all overlay upstreams."""
+    global _http
+    if _http is None:
+        _http = httpx.AsyncClient(
+            timeout=_HTTP_TIMEOUT,
+            follow_redirects=True,
+            headers=_headers(),
+            limits=httpx.Limits(max_connections=20, max_keepalive_connections=10),
+        )
+
+
+async def close_http() -> None:
+    global _http
+    if _http is not None:
+        await _http.aclose()
+        _http = None
+
+
 async def _get_json(url: str, params: dict | None = None) -> Any:
-    async with httpx.AsyncClient(timeout=_HTTP_TIMEOUT, follow_redirects=True,
+    if _http is None:
-                                 headers=_headers()) as client:
+        async with httpx.AsyncClient(
-        resp = await client.get(url, params=params)
+            timeout=_HTTP_TIMEOUT, follow_redirects=True, headers=_headers(),
-        resp.raise_for_status()
+        ) as client:
-        return resp.json()
+            resp = await client.get(url, params=params)
+            resp.raise_for_status()
+            return resp.json()
+    resp = await _http.get(url, params=params)
+    resp.raise_for_status()
+    return resp.json()
 
 
 async def fetch_aircraft(bbox: str, limit: int = DEFAULT_LIMIT) -> list[dict]:

app/main.py

@@ -14,6 +14,7 @@ from __future__ import annotations
 import asyncio
 import json
 import logging
+from contextlib import asynccontextmanager
 from datetime import datetime, timedelta, timezone
 from decimal import Decimal
 from pathlib import Path
@@ -21,7 +22,8 @@ from uuid import UUID
 
 import structlog
 from fastapi import FastAPI, HTTPException, Query
-from fastapi.responses import FileResponse, HTMLResponse
+from fastapi.middleware.gzip import GZipMiddleware
+from fastapi.responses import FileResponse, HTMLResponse, JSONResponse
 from fastapi.staticfiles import StaticFiles
 from sqlalchemy import and_, func, or_, select, text
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -53,11 +55,30 @@ from live_layers import (
 logging.basicConfig(level=logging.INFO)
 logger = structlog.get_logger("osint.dashboard")
 
+
+@asynccontextmanager
+async def _lifespan(app: FastAPI):
+    await init_extensions()
+    from live_layers import close_http, init_http
+    await init_http()
+    from config import AISSTREAM_IN_APP
+    ais_task = None
+    if AISSTREAM_IN_APP:
+        from ais_stream import run_ais_worker
+        ais_task = asyncio.create_task(run_ais_worker())
+    yield
+    if ais_task is not None:
+        ais_task.cancel()
+    await close_http()
+
+
 app = FastAPI(
     title="OSINT Dashboard",
     description="Real-time geospatial OSINT intelligence dashboard",
     version="0.1.0",
+    lifespan=_lifespan,
 )
+app.add_middleware(GZipMiddleware, minimum_size=1024)
 
 STATIC_DIR = Path(__file__).parent / "static"
 
@@ -131,20 +152,11 @@ async def health():
     return {"status": "ok", "db_time": db_time.isoformat() if db_time else None}
 
 
-# ── Startup ───────────────────────────────────────────────────────────────
+def overlay_json(data, max_age: int) -> JSONResponse:
-
+    """JSON overlay payload with a short browser/proxy TTL."""
-@app.on_event("startup")
+    resp = JSONResponse(content=data)
-async def startup():
+    resp.headers["Cache-Control"] = f"public, max-age={max_age}"
-    """Initialize PostGIS/TimescaleDB extensions on first connection.
+    return resp
-
-    Schema migrations are applied by the container entrypoint (alembic upgrade
-    head) before uvicorn starts, so they don't run nested inside the event loop.
-    """
-    await init_extensions()
-    from config import AISSTREAM_IN_APP
-    if AISSTREAM_IN_APP:
-        from ais_stream import run_ais_worker
-        asyncio.create_task(run_ais_worker())
 
 
 # ── Feed Sources ──────────────────────────────────────────────────────────
@@ -1114,7 +1126,7 @@ def _upstream_or_502(exc: Exception, name: str):
 async def map_radar():
     """RainViewer frame list + IEM NEXRAD tile template. Browser fetches tiles."""
     try:
-        return await fetch_radar_meta()
+        return overlay_json(await fetch_radar_meta(), 60)
     except Exception as exc:
         _upstream_or_502(exc, "radar")
 
@@ -1127,7 +1139,7 @@ async def list_aircraft(
     """Viewport ADS-B last-known (ADSB.lol). Requires bbox; radius clamped ≤ 150 nm."""
     _parse_bbox_query(bbox)
     try:
-        return await fetch_aircraft(bbox, limit)
+        return overlay_json(await fetch_aircraft(bbox, limit), 5)
     except ValueError as exc:
         raise HTTPException(422, str(exc)) from exc
     except Exception as exc:
@@ -1143,7 +1155,7 @@ async def list_trains(
     if bbox:
         _parse_bbox_query(bbox)
     try:
-        return await fetch_trains(bbox, limit)
+        return overlay_json(await fetch_trains(bbox, limit), 20)
     except ValueError as exc:
         raise HTTPException(422, str(exc)) from exc
     except Exception as exc:
@@ -1159,7 +1171,7 @@ async def list_vessels(
     if bbox:
         _parse_bbox_query(bbox)
     try:
-        return await fetch_vessels(bbox, limit)
+        return overlay_json(await fetch_vessels(bbox, limit), 5)
     except ValueError as exc:
         raise HTTPException(422, str(exc)) from exc
 
@@ -1173,7 +1185,7 @@ async def list_fire_incidents(
     if bbox:
         _parse_bbox_query(bbox)
     try:
-        return await fetch_fire_incidents(bbox, limit)
+        return overlay_json(await fetch_fire_incidents(bbox, limit), 30)
     except Exception as exc:
         _upstream_or_502(exc, "fire-incidents")
 
@@ -1184,7 +1196,7 @@ async def list_fire_perimeters(bbox: str | None = Query(None)):
     if bbox:
         _parse_bbox_query(bbox)
     try:
-        return await fetch_fire_perimeters(bbox)
+        return overlay_json(await fetch_fire_perimeters(bbox), 30)
     except Exception as exc:
         _upstream_or_502(exc, "fire-perimeters")
 
@@ -1202,7 +1214,7 @@ async def list_weather_alerts(
     if bbox:
         _parse_bbox_query(bbox)
     try:
-        return await fetch_weather_alerts(area, bbox)
+        return overlay_json(await fetch_weather_alerts(area, bbox), 30)
     except Exception as exc:
         _upstream_or_502(exc, "weather-alerts")
 
@@ -1211,7 +1223,7 @@ async def list_weather_alerts(
 async def list_storms():
     """NHC active tropical cyclones."""
     try:
-        return await fetch_storms()
+        return overlay_json(await fetch_storms(), 20)
     except Exception as exc:
         _upstream_or_502(exc, "storms")
 

tests/test_api_live_layers.py

@@ -36,3 +36,4 @@ def test_vessels_empty_without_ais_key():
     resp = asyncio.run(_get("/api/vessels"))
     assert resp.status_code == 200
     assert resp.json() == []
+    assert "max-age" in (resp.headers.get("cache-control") or "").lower()